Publications by authors named "Xinquan Zhang"

97 Publications

Alterations of Endogenous Hormones, Antioxidant Metabolism, and Aquaporin Gene Expression in Relation to γ-Aminobutyric Acid-Regulated Thermotolerance in White Clover.

Antioxidants (Basel) 2021 Jul 8;10(7). Epub 2021 Jul 8.

College of Grassland Science and Technology, Sichuan Agricultural University, Chengdu 611130, China.

Persistent high temperature decreases the yield and quality of crops, including many important herbs. White clover () is a perennial herb with high feeding and medicinal value, but is sensitive to temperatures above 30 °C. The present study was conducted to elucidate the impact of changes in endogenous γ-aminobutyric acid (GABA) level by exogenous GABA pretreatment on heat tolerance of white clover, associated with alterations in endogenous hormones, antioxidant metabolism, and aquaporin-related gene expression in root and leaf of white clover plants under high-temperature stress. Our results reveal that improvement in endogenous GABA level in leaf and root by GABA pretreatment could significantly alleviate the damage to white clover during high-temperature stress, as demonstrated by enhancements in cell membrane stability, photosynthetic capacity, and osmotic adjustment ability, as well as lower oxidative damage and chlorophyll loss. The GABA significantly enhanced gene expression and enzyme activities involved in antioxidant defense, including superoxide dismutase, catalase, peroxidase, and key enzymes of the ascorbic acid-glutathione cycle, thus reducing the accumulation of reactive oxygen species and the oxidative injury to membrane lipids and proteins. The GABA also increased endogenous indole-3-acetic acid content in roots and leaves and cytokinin content in leaves, associated with growth maintenance and reduced leaf senescence under heat stress. The GABA significantly upregulated the expression of and in leaves and the expression in leaves and roots under high temperature, and also alleviated the heat-induced inhibition of , , , and expression in roots, which could help to improve the water transportation and homeostasis from roots to leaves. In addition, the GABA-induced aquaporins expression and decline in endogenous abscisic acid level could improve the heat dissipation capacity through maintaining higher stomatal opening and transpiration in white clovers under high-temperature stress.
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http://dx.doi.org/10.3390/antiox10071099DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8301151PMC
July 2021

Research on the drought tolerance mechanism of Pennisetum glaucum (L.) in the root during the seedling stage.

BMC Genomics 2021 Jul 23;22(1):568. Epub 2021 Jul 23.

College of Grassland Science and Technology, Sichuan Agricultural University, Chengdu, 611130, China.

Background: Drought is one of the major environmental stresses resulting in a huge reduction in crop growth and biomass production. Pearl millet (Pennisetum glaucum L.) has excellent drought tolerance, and it could be used as a model plant to study drought resistance. The root is a very crucial part of plant that plays important roles in plant growth and development, which makes it a focus of research.

Results: In this study, we explored the mechanism of drought tolerance of pearl millet by comparing physiological and transcriptomic data under normal condition and drought treatment at three time points (1 h, 3 h and 7 h) in the root during the seedling stage. The relative electrical conductivity went up from 1 h to 7 h in both control and drought treatment groups while the content of malondialdehyde decreased. A total of 2004, 1538 and 605 differentially expressed genes were found at 1 h, 3 h and 7 h respectively and 12 genes showed up-regulation at all time points. Some of these differentially expressed genes were significantly enriched into 'metabolic processes', 'MAPK signaling pathway' and 'plant hormone signal transduction' such as the ABA signal transduction pathway in GO and KEGG enrichment analysis.

Conclusions: Pearl millet was found to have a quick drought response, which may occur before 1 h that contributes to its tolerance against drought stress. These results can provide a theoretical basis to enhance the drought resistance in other plant species.
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http://dx.doi.org/10.1186/s12864-021-07888-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8305952PMC
July 2021

Effects of silicon on heavy metal uptake at the soil-plant interphase: A review.

Ecotoxicol Environ Saf 2021 Oct 14;222:112510. Epub 2021 Jul 14.

College of Grassland Science and Technology, Sichuan Agricultural University, Chengdu 611130, China. Electronic address:

Silicon (Si) is the second richest element in the soil and surface of earth crust with a variety of positive roles in soils and plants. Different soil factors influence the Si bioavailability in soil-plant system. The Si involves in the mitigation of various biotic (insect pests and pathogenic diseases) and abiotic stresses (salt, drought, heat, and heavy metals etc.) in plants by improving plant tolerance mechanism at various levels. However, Si-mediated restrictions in heavy metals uptake and translocation from soil to plants and within plants require deep understandings. Recently, Si-based improvements in plant defense system, cell damage repair, cell homeostasis, and regulation of metabolism under heavy metal stress are getting more attention. However, limited knowledge is available on the molecular mechanisms by which Si can reduce the toxicity of heavy metals, their uptake and transfer from soil to plant roots. Thus, this review is focused the following facets in greater detail to provide better understandings about the role of Si at molecular level; (i) how Si improves tolerance in plants to variable environmental conditions, (ii) how biological factors affect Si pools in the soil (iii) how soil properties impact the release and capability of Si to decrease the bioavailability of heavy metals in soil and their accumulation in plant roots; (iv) how Si influences the plant root system with respect to heavy metals uptake or sequestration, root Fe/Mn plaque, root cell wall and compartment; (v) how Si makes complexes with heavy metals and restricts their translocation/transfer in root cell and influences the plant hormonal regulation; (vi) the competition of uptake between Si and heavy metals such as arsenic, aluminum, and cadmium due to similar membrane transporters, and (vii) how Si-mediated regulation of gene expression involves in the uptake, transportation and accumulation of heavy metals by plants and their possible detoxification mechanisms. Furthermore, future research work with respect to mitigation of heavy metal toxicity in plants is also discussed.
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http://dx.doi.org/10.1016/j.ecoenv.2021.112510DOI Listing
October 2021

MicroRNA-Mediated Responses to Chromium Stress Provide Insight Into Tolerance Characteristics of .

Front Plant Sci 2021 23;12:666117. Epub 2021 Jun 23.

Department of Forage Science, College of Grassland Science and Technology, Sichuan Agricultural University, Chengdu, China.

Chromium (Cr) is a heavy metal in nature, which poses a potential risk to toxicity to both animals and plants when releasing into the environment. However, the regulation of microRNA (miRNA)-mediated response to heavy metal Cr has not been studied in . In this study, based on high-throughput miRNA sequencing, a total of 104 conserved miRNAs and 158 nonconserved miRNAs were identified. Among them, there were 45 differentially expressed miRNAs in roots and 13 differentially expressed miRNAs in leaves. The hierarchical clustering analysis showed that these miRNAs were preferentially expressed in a certain tissue. There were 833 differentially expressed target genes of 45 miRNAs in roots and 280 differentially expressed target genes of 13 miRNA in leaves. After expression trend analysis, five significantly enriched modules were obtained in roots, and three significantly enriched trend blocks in leaves. Based on the candidate gene annotation and gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) function analysis, miR167a, novel_miR15, and novel_miR22 and their targets were potentially involved in Cr transportation and chelation. Besides, miR156a, miR164, miR396d, and novel_miR155 were identified as participating in the physiological and biochemical metabolisms and the detoxification of Cr of plants. The results demonstrated the critical role of miRNA-mediated responses to Cr treatment in , which involves ion uptake, transport, accumulation, and tolerance characteristics.
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http://dx.doi.org/10.3389/fpls.2021.666117DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8261058PMC
June 2021

Transcriptome characterization of candidate genes related to chromium uptake, transport and accumulation in Miscanthus sinensis.

Ecotoxicol Environ Saf 2021 Sep 26;221:112445. Epub 2021 Jun 26.

Department of Grassland Science, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu 611130, China. Electronic address:

Miscanthus sinensis is a C4 perennial grass species that is widely used as forage, ornamental grass and bioenergy crop due to its broad adaption and great biological traits. Recent studies indicated that M. sinensis could also grow in marginal lands which were contaminated with heavy metals, and exhibited important ecological restoration potential. In this study, transcriptome characterization of candidate genes related to chromium (Cr) uptake, transport and accumulation in M. sinensis were employed to investigate the molecular mechanism of plant tolerance to heavy metal stress. The result showed that following treatment of 200 mg/L of Cr, plant roots could accumulate most Cr and localize mainly in cell walls and soluble fractions, whereas Cr in stems and leaves was primarily in soluble fractions. A total of 83,645 differentially expressed genes (DEGs) were obtained after the treatment. Many genes involved in heavy metal transport, metal ion chelation and photosynthesis were found to be Cr-induced DEGs. Co-expression and weighted correlation network analysis revealed that Glutathion metabolism and ABC transporters pathways play an important role in Cr tolerance of M. sinensis. A hypothesis schematic diagram for the Cr uptake, transport and accumulation of M. sinensis cells were suggested, which could provide a molecular and genetic basis for future candidate genes validation and breeding of such crops.
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http://dx.doi.org/10.1016/j.ecoenv.2021.112445DOI Listing
September 2021

Arsenic behavior in soil-plant system and its detoxification mechanisms in plants: A review.

Environ Pollut 2021 Oct 21;286:117389. Epub 2021 May 21.

College of Grassland Science and Technology, Sichuan Agricultural University, Chengdu, 611130, China. Electronic address:

Arsenic (As) is one of the most toxic and cancer-causing metals which is generally entered the food chain via intake of As contaminated water or food and harmed the life of living things especially human beings. Therefore, the reduction of As content in the food could be of great importance for healthy life. To reduce As contamination in the soil and food, the evaluation of plant-based As uptake and transportation mechanisms is critically needed. Different soil factors such as physical and chemical properties of soil, soil pH, As speciation, microbial abundance, soil phosphates, mineral nutrients, iron plaques and roots exudates effectively regulate the uptake and accumulation of As in different parts of plants. The detoxification mechanisms of As in plants depend upon aquaporins, membrane channels and different transporters that actively control the influx and efflux of As inside and outside of plant cells, respectively. The xylem loading is responsible for long-distance translocation of As and phloem loading involves in the partitioning of As into the grains. However, As detoxification mechanism based on the clear understandings of how As uptake, accumulations and translocation occur inside the plants and which factors participate to regulate these processes. Thus, in this review we emphasized the different soil factors and plant cell transporters that are critically responsible for As uptake, accumulation, translocation to different organs of plants to clearly understand the toxicity reasons in plants. This study could be helpful for further research to develop such strategies that may restrict As entry into plant cells and lead to high crop yield and safe food production.
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http://dx.doi.org/10.1016/j.envpol.2021.117389DOI Listing
October 2021

Genome-wide identification, phylogenetic analysis, and expression analysis of the SPL gene family in orchardgrass (Dactylis glomerata L.).

Genomics 2021 Jul 28;113(4):2413-2425. Epub 2021 May 28.

College of Grassland Science and Technology, Sichuan Agricultural University, Chengdu 611130, China. Electronic address:

SPL (SQUAMOSA promoter binding protein-like) is a plant-specific transcription factor family that contains the conserved SBP domain, which plays a vital role in the vegetative-to-reproductive phase transition, flowering development and regulation, tillering/branching, and stress responses. Although the SPL family has been identified and characterized in various plant species, limited information about it has been obtained in orchardgrass, which is a critical forage crop worldwide. In this study, 17 putative DgSPL genes were identified among seven chromosomes, and seven groups that share similar gene structures and conserved motifs were determined by phylogenetic analysis. Of these, eight genes have potential target sites for miR156. cis-Element and gene ontology annotation analysis indicated DgSPLs may be involved in regulating development and abiotic stress responses. The expression patterns of eight DgSPL genes at five developmental stages, in five tissues, and under three stress conditions were determined by RNA-seq and qRT-PCR. These assays indicated DgSPLs are involved in vegetative-to-reproductive phase transition, floral development, and stress responses. The transient expression analysis in tobacco and heterologous expression assays in yeast indicated that miR156-targeted DG1G01828.1 and DG0G01071.1 are nucleus-localized proteins, that may respond to drought, salt, and heat stress. Our study represents the first systematic analysis of the SPL family in orchardgrass. This research provides a comprehensive assessment of the DgSPL family, which lays the foundation for further examination of the role of miR156/DgSPL in regulating development and stress responses in forages grasses.
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http://dx.doi.org/10.1016/j.ygeno.2021.05.032DOI Listing
July 2021

Exogenous Methyl Jasmonate Improves Heat Tolerance of Perennial Ryegrass Through Alteration of Osmotic Adjustment, Antioxidant Defense, and Expression of Jasmonic Acid-Responsive Genes.

Front Plant Sci 2021 7;12:664519. Epub 2021 May 7.

Department of Forage Science, College of Grassland Science and Technology, Sichuan Agricultural University, Chengdu, China.

Perennial ryegrass ( L.) is an important cool-season grass species that is widely cultivated in temperate regions worldwide but usually sensitive to heat stress. Jasmonates (JAs) may have a positive effect on plant tolerance under heat stress. In this study, results showed that exogenous methyl jasmonic acid (MeJA) could significantly improve heat tolerance of perennial ryegrass through alteration of osmotic adjustment, antioxidant defense, and the expression of JA-responsive genes. MeJA-induced heat tolerance was involved in the maintenance of better relative water content (RWC), the decline of chlorophyll (Chl) loss for photosynthetic maintenance, as well as maintained lower electrolyte leakage (EL) and malondialdehyde (MDA) content under heat condition, so as to avoid further damage to plants. Besides, results also indicated that exogenous MeJA treatment could increase the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX), thus enhancing the scavenging ability of reactive oxygen species, alleviating the oxidative damage caused by heat stress. Heat stress and exogenous MeJA upregulated transcript levels of related genes (, , , and ) in JA biosynthetic pathway, which also could enhance the accumulation of JA and MeJA content. Furthermore, some NAC transcription factors and heat shock proteins may play a positive role in enhancing resistance of perennial ryegrass with heat stress.
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http://dx.doi.org/10.3389/fpls.2021.664519DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8137847PMC
May 2021

Genetic diversity and population structure analysis in a large collection of white clover ( L.) germplasm worldwide.

PeerJ 2021 3;9:e11325. Epub 2021 May 3.

Department of Grassland Science, Animal Science and Technology College, Sichuan Agricultural University, Chengdu, Sichuan, China.

White clover is an important temperate legume forage with high nutrition. In the present study, 448 worldwide accessions were evaluated for the genetic variation and polymorphisms using 22 simple sequence repeat (SSR) markers. All the markers were highly informative, a total of 341 scored bands were amplified, out of which 337 (98.83%) were polymorphic. The PIC values ranged from 0.89 to 0.97 with an average of 0.95. For the AMOVA analysis, 98% of the variance was due to differences within the population and the remaining 2% was due to differences among populations. The white clover accessions were divided into different groups or subgroups based on PCoA, UPGMA, and STRUCTURE analyses. The existence of genetic differentiation between the originally natural and introduced areas according to the PCoA analysis of the global white clover accessions. There was a weak correlation between genetic relationships and geographic distribution according to UPGMA and STRUCTURE analyses. The results of the present study will provide the foundation for future breeding programs, genetic improvement, core germplasm collection establishment for white clover.
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http://dx.doi.org/10.7717/peerj.11325DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8101478PMC
May 2021

Transcriptome analysis revealed the regulation of gibberellin and the establishment of photosynthetic system promote rapid seed germination and early growth of seedling in pearl millet.

Biotechnol Biofuels 2021 Apr 11;14(1):94. Epub 2021 Apr 11.

College of Grassland Science and Technology, Sichuan Agricultural University, Chengdu, 6111130, China.

Background: Seed germination is the most important stage for the formation of a new plant. This process starts when the dry seed begins to absorb water and ends when the radicle protrudes. The germination rate of seed from different species varies. The rapid germination of seed from species that grow on marginal land allows seedlings to compete with surrounding species, which is also the guarantee of normal plant development and high yield. Pearl millet is an important cereal crop that is used worldwide, and it can also be used to extract bioethanol. Previous germination experiments have shown that pearl millet has a fast seed germination rate, but the molecular mechanisms behind pearl millet are unclear. Therefore, this study explored the expression patterns of genes involved in pearl millet growth from the germination of dry seed to the early growth stages.

Results: Through the germination test and the measurement of the seedling radicle length, we found that pearl millet seed germinated after 24 h of swelling of the dry seed. Using transcriptome sequencing, we characterized the gene expression patterns of dry seed, water imbibed seed, germ and radicle, and found more differentially expressed genes (DEGs) in radicle than germ. Further analysis showed that different genome clusters function specifically at different tissues and time periods. Weighted gene co-expression network analysis (WGCNA) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis showed that many genes that positively regulate plant growth and development are highly enriched and expressed, especially the gibberellin signaling pathway, which can promote seed germination. We speculated that the activation of these key genes promotes the germination of pearl millet seed and the growth of seedlings. To verify this, we measured the content of gibberellin and found that the gibberellin content after seed imbibition rose sharply and remained at a high level.

Conclusions: In this study, we identified the key genes that participated in the regulation of seed germination and seedling growth. The activation of key genes in these pathways may contribute to the rapid germination and growth of seed and seedlings in pearl millet. These results provided new insight into accelerating the germination rate and seedling growth of species with slow germination.
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http://dx.doi.org/10.1186/s13068-021-01946-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8040237PMC
April 2021

Resource islands of Salix cupularis facilitating seedling emergence of the companion herbs in the restoration process of desertified alpine meadow, the Tibetan Plateau.

J Environ Manage 2021 Jul 31;289:112434. Epub 2021 Mar 31.

College of Grassland Science and Technology, Sichuan Agricultural University, Chengdu, 611130, Sichuan, PR China. Electronic address:

Salix cupularis is a common shrub for ecological restoration of the desertified alpine meadow on the Tibetan Plateau. However, the effect of S. cupularis on spatial heterogeneity of soil resources (i.e., resource islands effect) has not been systematically evaluated, and the influence of shrub patches on the rehabilitation of understory herbs has also been unknown. In this study, we randomly selected S. cupularis individuals in the early restoration stage of desertified alpine meadow, where the three native forages (Elymus nutans, Elymus sibiricus and Festuca sinensis) were sown at different microsites around S. cupularis to explore the effects of S. cupularis on soil resources and emergence rates of the native forages. The results showed that S. cupularis significantly increased SWC (soil water content), C (carbon) and N (nitrogen) nutrients (p < 0.01) and enzyme activities (p < 0.05) under canopy compared with the bare land, and the improvement performed better in the topsoil (0-5 cm) than in the subtop-soil (5-15 cm). Moreover, the soil properties were affected significantly by microsites around S. cupularis, resulting in regular changes of SWC, nutrients and enzyme activities in different microsites (Shrub center > Middle of canopy radius > Bare land). In addition, there are significant regression relationships between emergence rates and enriching soil water, C and N nutrients, so the emergence rates of native forages under canopy may be improved significantly with the enriched soil resources, especially for E. nutans. As a result, S. cupularis is a suitable pioneer shrub for the vegetation restoration of desertified alpine meadow on the Tibetan Plateau, because it could not only shape the enrichment of soil resources under canopy, but also facilitate emergence of companion forages in the process of vegetation restoration.
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http://dx.doi.org/10.1016/j.jenvman.2021.112434DOI Listing
July 2021

Genome-wide identification, characterization, and expression analysis of the NAC transcription factor family in orchardgrass (Dactylis glomerata L.).

BMC Genomics 2021 Mar 12;22(1):178. Epub 2021 Mar 12.

College of Grassland Science and Technology, Sichuan Agricultural University, Chengdu, 611130, Sichuan Province, China.

Background: Orchardgrass (Dactylis glomerata L.) is one of the most important cool-season perennial forage grasses that is widely cultivated in the world and is highly tolerant to stressful conditions. However, little is known about the mechanisms underlying this tolerance. The NAC (NAM, ATAF1/2, and CUC2) transcription factor family is a large plant-specific gene family that actively participates in plant growth, development, and response to abiotic stress. At present, owing to the absence of genomic information, NAC genes have not been systematically studied in orchardgrass. The recent release of the complete genome sequence of orchardgrass provided a basic platform for the investigation of DgNAC proteins.

Results: Using the recently released orchardgrass genome database, a total of 108 NAC (DgNAC) genes were identified in the orchardgrass genome database and named based on their chromosomal location. Phylogenetic analysis showed that the DgNAC proteins were distributed in 14 subgroups based on homology with NAC proteins in Arabidopsis, including the orchardgrass-specific subgroup Dg_NAC. Gene structure analysis suggested that the number of exons varied from 1 to 15, and multitudinous DgNAC genes contained three exons. Chromosomal mapping analysis found that the DgNAC genes were unevenly distributed on seven orchardgrass chromosomes. For the gene expression analysis, the expression levels of DgNAC genes in different tissues and floral bud developmental stages were quite different. Quantitative real-time PCR analysis showed distinct expression patterns of 12 DgNAC genes in response to different abiotic stresses. The results from the RNA-seq data revealed that orchardgrass-specific NAC exhibited expression preference or specificity in diverse abiotic stress responses, and the results indicated that these genes may play an important role in the adaptation of orchardgrass under different environments.

Conclusions: In the current study, a comprehensive and systematic genome-wide analysis of the NAC gene family in orchardgrass was first performed. A total of 108 NAC genes were identified in orchardgrass, and the expression of NAC genes during plant growth and floral bud development and response to various abiotic stresses were investigated. These results will be helpful for further functional characteristic descriptions of DgNAC genes and the improvement of orchardgrass in breeding programs.
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http://dx.doi.org/10.1186/s12864-021-07485-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7953825PMC
March 2021

RNF167 activates mTORC1 and promotes tumorigenesis by targeting CASTOR1 for ubiquitination and degradation.

Nat Commun 2021 02 16;12(1):1055. Epub 2021 Feb 16.

UPMC Hillman Cancer Center, Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA, USA.

mTORC1, a central controller of cell proliferation in response to growth factors and nutrients, is dysregulated in cancer. Whereas arginine activates mTORC1, it is overridden by high expression of cytosolic arginine sensor for mTORC1 subunit 1 (CASTOR1). Because cancer cells often encounter low levels of nutrients, an alternative mechanism might exist to regulate CASTOR1 expression. Here we show K29-linked polyubiquitination and degradation of CASTOR1 by E3 ubiquitin ligase RNF167. Furthermore, AKT phosphorylates CASTOR1 at S14, significantly increasing its binding to RNF167, and hence its ubiquitination and degradation, while simultaneously decreasing its affinity to MIOS, leading to mTORC1 activation. Therefore, AKT activates mTORC1 through both TSC2- and CASTOR1-dependent pathways. Several cell types with high CASTOR1 expression are insensitive to arginine regulation. Significantly, AKT and RNF167-mediated CASTOR1 degradation activates mTORC1 independent of arginine and promotes breast cancer progression. These results illustrate a mTORC1 regulating mechanism and identify RNF167 as a therapeutic target for mTORC1-dysregulated diseases.
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http://dx.doi.org/10.1038/s41467-021-21206-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7887217PMC
February 2021

Exogenous abscisic acid and jasmonic acid restrain polyethylene glycol-induced drought by improving the growth and antioxidative enzyme activities in pearl millet.

Physiol Plant 2021 Jun 10;172(2):809-819. Epub 2020 Nov 10.

Department of Grassland Science, Animal Science and Technology College, Sichuan Agricultural University, Chengdu, China.

Drought stress is one of the most immense and permanent constraints in agriculture, which leads to a massive loss of crop productivity. However, little is known about the mitigation role of exogenously applied abscisic acid (ABA) and jasmonic acid (JA) in pearl millet (Pennisetum glaucum L.) under PEG-induced drought stress. Therefore, the current study investigated the putative role of exogenous ABA and JA in improving drought stress tolerance in pearl millet. Thirteen-day-old seedlings were exposed to six different treatments as follow; control (ck), PEG-600 (20%), JA (100 μM), ABA (100 μM), PEG+JA, and PEG+ABA, and data were collected at 7 and 14 days after treatment (DAT). Results showed that PEG decreased plant growth while the oxidative damage increased due to over production of H O and MDA content as a result of decreased activities of the antioxidative enzymes including APX, CAT, and SOD in the leaves. However, exogenous ABA and JA positively enhanced the growth profile of seedlings by improving chlorophyll and relative water content under PEG treatment. A significant improvement was observed in the plant defense system resulting from increased activities of antioxidative enzymes due to exogenous ABA and JA under PEG. Overall, the performance of JA was found better than ABA under PEG-induced drought stress, and future investigations are needed to explore the potential effects of these phytohormones on the long-term crop management and productivity under drought stress.
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http://dx.doi.org/10.1111/ppl.13247DOI Listing
June 2021

Comparative transcriptome study of switchgrass ( L.) homologous autopolyploid and its parental amphidiploid responding to consistent drought stress.

Biotechnol Biofuels 2020 15;13:170. Epub 2020 Oct 15.

Department of Grassland Science, Animal Science and Technology College, Sichuan Agricultural University, Chengdu, 611130 China.

Background: Newly formed polyploids may experience short-term adaptative changes in their genome that may enhance the resistance of plants to stress. Considering the increasingly serious effects of drought on biofuel plants, whole genome duplication (WGD) may be an efficient way to proceed with drought resistant breeding. However, the molecular mechanism of drought response before/after WGD remains largely unclear.

Result: We found that autoploid switchgrass ( L.) 8X Alamo had higher drought tolerance than its parent amphidiploid 4X Alamo using physiological tests. RNA and microRNA sequencing at different time points during drought were then conducted on 8X Alamo and 4X Alamo switchgrass. The specific differentially expressed transcripts (DETs) that related to drought stress (DS) in 8X Alamo were enriched in ribonucleoside and ribonucleotide binding, while the drought-related DETs in 4X Alamo were enriched in structural molecule activity. Ploidy-related DETs were primarily associated with signal transduction mechanisms. Weighted gene co-expression network analysis (WGCNA) detected three significant DS-related modules, and their DETs were primarily enriched in biosynthesis process and photosynthesis. A total of 26 differentially expressed microRNAs (DEmiRs) were detected, and among them, sbi-microRNA 399b was only expressed in 8X Alamo. The targets of microRNAs that were responded to polyploidization and drought stress all contained cytochrome P450 and superoxide dismutase genes.

Conclusions: This study explored the drought response of 8X and 4X Alamo switchgrass on both physiological and transcriptional levels, and provided experimental and sequencing data basis for a short-term adaptability study and drought-resistant biofuel plant breeding.
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http://dx.doi.org/10.1186/s13068-020-01810-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7559793PMC
October 2020

Fingerprint identification of white clover cultivars based on SSR molecular markers.

Mol Biol Rep 2020 Nov 10;47(11):8513-8521. Epub 2020 Oct 10.

Department of Grassland Science, Animal Science and Technology College, Sichuan Agricultural University, Chengdu, 611130, Sichuan, China.

White clover (Trifolium repens L.) is an important perennial legume forage with high productivity and quality. To strengthen the basic research on the genetic characteristics, fingerprint identification and adaptability of white clover germplasm resources, Simple sequence repeat (SSR) molecular markers were applied to 10 white clover cultivars to assess the genetic diversity and related lines of white clover at the molecular level in order to lay a theoretical foundation for the selection of high-quality seeds and cultivars of white clover. A total of 120 different bands were amplified by 29 pairs of SSR primers with good polymorphism, of which 103 (89.5%) were polymorphic. Meanwhile, the PIC of each primer was 0.181-0.588, with an average of 0.329. Analysis of molecular variance revealed that 57% of the genetic variation occurred within cultivars and 43% occurred among cultivars. The results of cluster analysis and the principal coordinate analysis revealed that the parental relationships of the 10 cultivars, with the 'Purple' cultivar very distantly related to the other 9 cultivars and the closest parental relationship between 'Ladino' and 'Sulky'. The fingerprints constructed by three representative primers (gtrs679, gtrs319, and gtrs678) have a strong identification ability. In summary, the SSR markers had good polymorphism and could be used for DNA fingerprint analysis of white clover cultivars.
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http://dx.doi.org/10.1007/s11033-020-05893-7DOI Listing
November 2020

Amelioration of salt induced toxicity in pearl millet by seed priming with silver nanoparticles (AgNPs): The oxidative damage, antioxidant enzymes and ions uptake are major determinants of salt tolerant capacity.

Plant Physiol Biochem 2020 Nov 17;156:221-232. Epub 2020 Sep 17.

Department of Grassland Science, Animal Science and Technology College, Sichuan Agricultural University, Chengdu, 611130, China. Electronic address:

Abiotic stresses in plants reduce crop growth and productivity. Nanoparticles (NPs) are effectively involved in the physiochemical processes of crop plants, especially under the abiotic stresses; whereas, less information is available regarding the role of AgNPs in salt-stressed plants. Therefore, in the current study, we investigated the effects of seed priming with commercially available silver nanoparticles (AgNPs) (size range between 50 and 100 nm) on plant morphology, physiology, and antioxidant defence system of pearl millet (Pennisetum glaucum L.) under different concentrations of salt stress (0, 120 and 150 mM NaCl). The seed priming with AgNPs at different levels (0, 10, 20 and 30 mM) mitigated the adverse impacts of salt stress and improved plant growth and defence system. The results demonstrated that salt-stressed plants had restricted growth and a noticeable decline in fresh and dry weight. Salt stress enhanced the oxidative damage by excessive production of hydrogen peroxide (HO), malondialdehyde (MDA) contents in pearl millet leaves. However, seed priming with AgNPs significantly improved the plant height growth related attributes, relative water content, proline contents and ultimately fresh and dry weight at 20 mM AgNPs alone or with salt stress. The AgNPs reduced the oxidative damage by improving antioxidant enzyme activities in the pearl millet leaves under salt stress. Furthermore, sodium (Na) and Na/K ratio was decreased and potassium (K) increased by NPs, and the interactive effects between salt and AgNPs significantly impacted the total phenolic and flavonoid content in pearl millet. It was concluded that seed priming with AgNPs could enhance salinity tolerance in crop plants by enhancing physiological and biochemical responses. This might boost global crop production in salt-degraded lands.
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http://dx.doi.org/10.1016/j.plaphy.2020.09.018DOI Listing
November 2020

γ-Aminobutyric Acid Enhances Heat Tolerance Associated with the Change of Proteomic Profiling in Creeping Bentgrass.

Molecules 2020 Sep 18;25(18). Epub 2020 Sep 18.

Department of Grassland Science, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu 611130, China.

γ-Aminobutyric acid (GABA) participates in the regulation of adaptability to abiotic stress in plants. The objectives of this study were to investigate the effects of GABA priming on improving thermotolerance in creeping bentgrass () based on analyses of physiology and proteome using iTRAQ technology. GABA-treated plants maintained significantly higher endogenous GABA content, photochemical efficiency, performance index on absorption basis, membrane stability, and osmotic adjustment (OA) than untreated plants during a prolonged period of heat stress (18 days), which indicated beneficial effects of GABA on alleviating heat damage. Protein profiles showed that plants were able to regulate some common metabolic processes including porphyrin and chlorophyll metabolism, glutathione metabolism, pyruvate metabolism, carbon fixation, and amino acid metabolism for heat acclimation. It is noteworthy that the GABA application particularly regulated arachidonic acid metabolism and phenylpropanoid biosynthesis related to better thermotolerance. In response to heat stress, the GABA priming significantly increased the abundances of Cu/ZnSOD and APX4 that were consistent with superoxide dismutase (SOD) and ascorbate peroxidase (APX) activities. The GABA-upregulated proteins in relation to antioxidant defense (Cu/ZnSOD and APX4) for the reactive oxygen species scavenging, heat shock response (HSP90, HSP70, and HSP16.9) for preventing denatured proteins aggregation, stabilizing abnormal proteins, promoting protein maturation and assembly, sugars, and amino acids metabolism (PFK5, ATP-dependent 6-phosphofructokinase 5; FK2, fructokinase 2; BFRUCT, β-fructofuranosidase; RFS2, galactinol-sucrose galactosyltransferase 2; ASN2, asparagine synthetase 2) for OA and energy metabolism, and transcription factor (C2H2 ZNF, C2H2 zinc-finger protein) for the activation of stress-defensive genes could play vital roles in establishing thermotolerance. Current findings provide an illuminating insight into the new function of GABA on enhancing adaptability to heat stress in plants.
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http://dx.doi.org/10.3390/molecules25184270DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7571209PMC
September 2020

Dual-template strategy for electrocatalyst of cobalt nanoparticles encapsulated in nitrogen-doped carbon nanotubes for oxygen reduction reaction.

J Colloid Interface Sci 2021 Jan 10;581(Pt B):523-532. Epub 2020 Jul 10.

Institute for Sustainable Energy, College of Sciences, Shanghai University, Shanghai 200444, PR China.

Development of non-precious metal catalysts (NPMCs) with high performance and stability has important value for oxygen reduction reaction (ORR) of fuel cells. In this paper, a novel structure of nitrogen-doped carbon nanotubes-encapsulated cobalt nanoparticles ([email protected]) is synthesized by a simple dual-template strategy using silica colloid and tri-block copolymer (polyethylene oxide-polypropylene oxide-polyethylene oxide, PEO-PPO-PEO, F127) as hard and soft templates, respectively. The [email protected] synthesized at 800 °C shows an excellent ORR performance, which can be attributed to the desirable combination of their unique one-dimensional carbon nanotube structure, the adequate nitrogen doping level, the large surface area created by the dual-template strategy, and the synergistic effect between graphitic carbon layer and cobalt nanoparticles. The doped N atoms can provide coordination sites for cobalt nanoparticles and form NC moieties as dominant active sites, which provide positive effect on catalytic ORR activity. The graphitic carbon layers can protect cobalt nanoparticles against agglomeration and electrolyte corrosion, while cobalt nanoparticles can activate the bordering graphitic carbon layers and further increase ORR activities. This dual-template synthetic strategy provides an opportunity to promote the catalytic performance of NPMCs for application of polymer electrolyte membrane fuel cells.
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http://dx.doi.org/10.1016/j.jcis.2020.07.008DOI Listing
January 2021

Diffusion-layer-free air cathode based on ionic conductive hydrogel for microbial fuel cells.

Sci Total Environ 2020 Nov 11;743:140836. Epub 2020 Jul 11.

School of Resource and Environmental Sciences, Hubei International Scientific and Technological Cooperation Base of Sustainable Resource and Energy, Wuhan University, Wuhan 430079, PR China.

High hydraulic pressure in air-cathode microbial fuel cells (MFCs) can lead to severe cathodic water leakage and power reduction, thereby hindering the practical applications of MFCs. In this study, an alternative air cathode without a diffusion layer was developed using a cross-linked hydrogel, oxidized konjac glucomannan/2-hydroxypropytrimethyl ammonium chloride chitosan (OKH), for ion bridging. The cathode was placed horizontally to avoid hydraulic pressure on its surface. Ion transportation was sustained with a minimal OKH hydrogel loading of 10 mg/cm. A maximum power density of 1.0 ± 0.04 W/m was achieved, which was only slightly lower than the 1.28 ± 0.02 W/m of common air cathodes. Moreover, the cost of the OKH hydrogel is only $0.12/m, which can reduce ~85% of the cathode cost without using the advanced polyvinylidene fluoride diffusion layer. Therefore, the development of this new diffusion-layer-free air cathode using conductive ionic hydrogel provides a low-cost strategy for stable MFC operation, thereby demonstrating great potential for practical applications of MFC technology.
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http://dx.doi.org/10.1016/j.scitotenv.2020.140836DOI Listing
November 2020

Comparative transcriptome analyses reveal different mechanism of high- and low-tillering genotypes controlling tiller growth in orchardgrass (Dactylis glomerata L.).

BMC Plant Biol 2020 Aug 5;20(1):369. Epub 2020 Aug 5.

Department of Grassland Science, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China.

Background: Tillering is an important agronomic trait underlying the yields and reproduction of orchardgrass (Dactylis glomerata), an important perennial forage grass. Although some genes affecting tiller initiation have been identified, the tillering regulatory network is still largely unknown, especially in perennial forage grasses. Thus, unraveling the regulatory mechanisms of tillering in orchardgrass could be helpful in developing selective strategies for high-yield perennial grasses. In this study, we generated high-throughput RNA-sequencing data from multiple tissues of tillering stage plants to identify differentially expressed genes (DEGs) between high- and low-tillering orchardgrass genotypes. Gene Ontology and pathway enrichment analyses connecting the DEGs to tillering number diversity were conducted.

Results: In the present study, approximately 26,282 DEGs were identified between two orchardgrass genotypes, AKZ-NRGR667 (a high-tillering genotype) and D20170203 (a low-tillering genotype), which significantly differed in tiller number. Pathway enrichment analysis indicated that DEGs related to the biosynthesis of three classes of phytohormones, i.e., strigolactones (SLs), abscisic acid (ABA), and gibberellic acid (GA), as well as nitrogen metabolism dominated such differences between the high- and low-tillering genotypes. We also confirmed that under phosphorus deficiency, the expression level of the major SL biosynthesis genes encoding DWARF27 (D27), 9-cis-beta-carotene 9',10'-cleaving dioxygenase (CCD7), carlactone synthase (CCD8), and more axillary branching1 (MAX1) proteins in the high-tillering orchardgrass genotype increased more slowly relative to the low-tillering genotype.

Conclusions: Here, we used transcriptomic data to study the tillering mechanism of perennial forage grasses. We demonstrated that differential expression patterns of genes involved in SL, ABA, and GA biosynthesis may differentiate high- and low-tillering orchardgrass genotypes at the tillering stage. Furthermore, the core SL biosynthesis-associated genes in high-tillering orchardgrass were more insensitive than the low-tillering genotype to phosphorus deficiency which can lead to increases in SL biosynthesis, raising the possibility that there may be distinct SL biosynthesis way in tillering regulation in orchardgrass. Our research has revealed some candidate genes involved in the regulation of tillering in perennial grasses that is available for establishment of new breeding resources for high-yield perennial grasses and will serve as a new resource for future studies into molecular mechanism of tillering regulation in orchardgrass.
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http://dx.doi.org/10.1186/s12870-020-02582-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7409468PMC
August 2020

Transcriptome analysis of heat stress and drought stress in pearl millet based on Pacbio full-length transcriptome sequencing.

BMC Plant Biol 2020 Jul 8;20(1):323. Epub 2020 Jul 8.

Department of Grassland Science, Sichuan Agricultural University, Chengdu, 6111130, China.

Background: Heat and drought are serious threats for crop growth and development. As the sixth largest cereal crop in the world, pearl millet can not only be used for food and forage but also as a source of bioenergy. Pearl millet is highly tolerant to heat and drought. Given this, it is considered an ideal crop to study plant stress tolerance and can be used to identify heat-resistant genes.

Results: In this study, we used Pacbio sequencing data as a reference sequence to analyze the Illumina data of pearl millet that had been subjected to heat and drought stress for 48 h. By summarizing previous studies, we found 26,299 new genes and 63,090 new transcripts, and the number of gene annotations increased by 20.18%. We identified 2792 transcription factors and 1223 transcriptional regulators. There were 318 TFs and 149 TRs differentially expressed under heat stress, and 315 TFs and 128 TRs were differentially expressed under drought stress. We used RNA sequencing to identify 6920 genes and 6484 genes differentially expressed under heat stress and drought stress, respectively.

Conclusions: Through Pacbio sequencing, we have identified more new genes and new transcripts. On the other hand, comparing the differentially expressed genes under heat tolerance with the DEGs under drought stress, we found that even in the same pathway, pearl millet responds with a different protein.
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http://dx.doi.org/10.1186/s12870-020-02530-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7346438PMC
July 2020

Genome-wide investigation of the NAC transcript factor family in perennial ryegrass (Lolium perenne L.) and expression analysis under various abiotic stressor.

Genomics 2020 11 5;112(6):4224-4231. Epub 2020 Jul 5.

Department of Grassland Science, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu 611130, China. Electronic address:

NAC is one of the largest family of plant-specific transcription factors, and it plays important roles in plant development and stress responses. The study identified 72 LpNACs genes from the perennial ryegrass genome database. Gene length, MW and pI of NAC family transcription factors varied, but the gene structure and motifs were relatively conserved in bioinformatics analysis. Phylogenetic analyses of perennial ryegrass, rice and Arabidopsis were performed to study the evolutionary and functional relationships in various species. The expression of LpNAC genes that respond to various abiotic stresses including high salinity, ABA, high temperature, polyethylene glycol (PEG) and heavy metal was comprehensively analyzed. The present study provides a basic understanding of the NAC gene family in perennial ryegrass for further abiotic stress studies and improvements in breeding.
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http://dx.doi.org/10.1016/j.ygeno.2020.06.033DOI Listing
November 2020

Genome-wide AP2/ERF gene family analysis reveals the classification, structure, expression profiles and potential function in orchardgrass (Dactylis glomerata).

Mol Biol Rep 2020 Jul 23;47(7):5225-5241. Epub 2020 Jun 23.

College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, 611130, China.

The AP2/ERF transcription factor (TF) family is of great importance in developmental regulation and responses to stress and pathogenic stimuli. Orchardgrass (Dactylis glomerata), a perennial cold-season forage of high quality in the world's temperate zones, contributes to grazing land through mixed sowing with alfalfa (Medicago sativa) and white clover (Trifolium repens). However, little is known about AP2/ERF TFs in orchardgrass. In this study, 193 AP2/ERF genes were classified into five subfamilies and 13 subgroups through phylogenetic analysis. Chromosome structure analysis showed that AP2/ERF family genes in orchardgrass were distributed on seven chromosomes and specific conservative sequences were found in each subgroup. Exon-intron structure and motifs in the same subgroup were almost identical, and the unique motifs contributed to the classification and functional annotation of DgERFs. Expression analysis showed tissue-specific expression of DgERFs in roots and flowers, with most DgERFs widely expressed in roots. The expression levels of each subgroup (subgroups Vc, VIIa, VIIIb, IXa, and XIa) were high at the before-heading and heading stages (BH_DON and H_DON). In addition, 12 DgERFs in various tissues and five DgERFs associated with abiotic stresses were selected for qRT-PCR analysis showed that four dehydration-responsive element binding (DREB) genes and one ERF subfamily gene in orchardgrass were regulated with PEG, heat and salt stresses. DgERF056 belonged to ERF subfamily was involved in the processes of flowering and development stage. This study systematic explored the DgERFs at the genome level for the first time, which lays a foundation for a better understanding of AP2/ERF gene function in Dactylis glomerata and other types of forage.
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http://dx.doi.org/10.1007/s11033-020-05598-xDOI Listing
July 2020

Dynamic microbial diversity and fermentation quality of the mixed silage of corn and soybean grown in strip intercropping system.

Bioresour Technol 2020 Oct 9;313:123655. Epub 2020 Jun 9.

Animal Science and Technology College, Sichuan Agricultural University, Chengdu 610000, China. Electronic address:

This study assessed the fermentation quality and microbial community of corn (Zea mays L.) and soybean (Glycine max Merr.) (CS) mixed silage in strip intercropping system. CS mixed silage increased lactic acid content and decreased ammonia-N content compared to 100% soybean (S) silage, while it decreased ammonia-N content compared to 100% corn (C) silage. The largest number of epiphytic lactic acid bacteria was detected in CS fresh materials. During ensiling, Weissella and Lactobacillus dominated silage, the relative abundance of Lactobacillus in mixed silage was higher than that in S silage with the same S variety. After aerobic exposure (AE), synergistic effect existed in low relative abundance bacteria correlating with ammonia-N content and pH at ensiling 60 days and AE 7 days. In conclusion, CS mixed silage modified microbial community and improved fermentation quality.
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http://dx.doi.org/10.1016/j.biortech.2020.123655DOI Listing
October 2020

Microbial Community and FermentationDynamics of Corn Silage Prepared withHeat-Resistant Lactic Acid Bacteria in a HotEnvironment.

Microorganisms 2020 May 12;8(5). Epub 2020 May 12.

College of Animal Science and Technology, Sichuan Agricultural University,Chengdu 6111130, China.

To develop a silage fermentation technique to adapt to global climate changes, the microbiome and fermentation dynamics of corn silage inoculated with heat-resistant lactic acid bacteria (LAB) under high-temperature conditions were studied. Corn was ensiled in laboratory silo, with and without two selected strains, LS358 and LR753, two type strains ATCC 11741and ATCC 7469. The ensiling temperatures were designed at 30 °C and 45 °C, and the sampling took place after 0, 3, 7, 14, and 60 days of fermentation. The higher pH and dry matter losses were observed in the silages stored at 45 °C compared to those stored at 30 °C. Silages inoculated with strains LS358 and LR753 at 30 °C had a lower ratio of lactic acid/acetic acid. The dominant bacterial genera gradually changed from and to in silages during ensiling at 30 °C, while the bacterial community became more complex and fragmented after 7 d of ensiling at 45 °C. The high temperatures significantly led to a transformation of the LAB population from homo-fermentation to hetero-fermentation. This study is the first to describe microbial population dynamics response to high temperature during corn ensiling, and the results indicate that 753 shows potential ability to improve silage fermentation in tropics and subtropics. bacteria community; fermentation dynamics; high temperature; lactic acidbacteria; corn silage.
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http://dx.doi.org/10.3390/microorganisms8050719DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7285033PMC
May 2020

The Complete Chloroplast Genome of Two Important Annual Clover Species, and : Genome Structure, Comparative Analyses and Phylogenetic Relationships with Relatives in Leguminosae.

Plants (Basel) 2020 Apr 9;9(4). Epub 2020 Apr 9.

College of Animal science and Technology, Sichuan Agricultural University, Chengdu 611130, China.

L., which belongs to the IR lacking clade (IRLC), is one of the largest genera in the Leguminosae and contains several economically important fodder species. Here, we present whole chloroplast (cp) genome sequencing and annotation of two important annual grasses, (Egyptian clover) and (Persian clover). Abundant single nucleotide polymorphisms (SNPs) and insertions/deletions (In/Dels) were discovered between those two species. Global alignment of and to a further thirteen species revealed a large amount of rearrangement and repetitive events in these fifteen species. As hypothetical cp open reading frame (ORF) and RNA polymerase subunits, and in the cp genomes both contain vast repetitive sequences and observed high Pi values (0.7008, 0.3982) between and . Thus they could be considered as the candidate genes for phylogenetic analysis of species. In addition, the divergence time of those IR lacking species ranged from 84.8505 Mya to 4.7720 Mya. This study will provide insight into the evolution of species.
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http://dx.doi.org/10.3390/plants9040478DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7238141PMC
April 2020

Identification of candidate reference genes for quantitative RT-PCR in Miscanthus sinensis subjected to various abiotic stresses.

Mol Biol Rep 2020 Apr 28;47(4):2913-2927. Epub 2020 Mar 28.

Department of Grassland Science, Animal Science and Technology College, Sichuan Agricultural University, Chengdu, 611130, Sichuan, China.

Quantitative real-time PCR (qRT-PCR) has been widely used for studying gene expression at the transcript level. Its accuracy usually relies on the reference genes that are utilized for data normalization. Miscanthus sinensis, a perennial C4 grass with high biomass and strong resistance to adversities, is often utilized as a high value energy crop. However, no reliable reference genes have been investigated for normalizing gene expression for this species. In this study, 12 candidate reference genes were selected to identify their stability under five different abiotic stress treatments (drought, salt, cadmium, chromium and arsenic) by using geNorm, NormFinder, BestKeeper and RefFinder softwares. The results showed that 18S rRNA and Unigene33312 were the best reference genes under drought treatments. Unigene33312 and Unigene33024 were found to be the most stably expressed genes under salt stress and Cd stress. Moreover, Unigene33024 and PP2A were the most suitable reference genes under Cr stress and Unigene33024 and Sb09g019750 were deemed more suitable reference genes under As stress. In total, considering all the samples, Unigene33024 and PP2A were the most stable genes while ACTIN and Unigene26576 were the least stable reference genes for internal control. The expression patterns of two target genes (Cu/Zn SOD and CAT) were used to further verify those selected reference genes under different conditions. The results showed that the most and the least stable reference genes had clearly different expression patterns. This work comprehensively estimated the stability of reference genes in M. sinensis which may give insight to the reference genes selection in other tissues as well as other related varieties. These suggested reference genes would assist in further putative gene expression validation in M. sinensis.
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http://dx.doi.org/10.1007/s11033-020-05392-9DOI Listing
April 2020

Genome-wide identification, structural analysis and expression profiles of GRAS gene family in orchardgrass.

Mol Biol Rep 2020 Mar 5;47(3):1845-1857. Epub 2020 Feb 5.

Department of Grassland Science, Sichuan Agricultural University, Chengdu, Sichuan, China.

The GRAS gene family is a family of transcription factors that regulates plant growth and development. Despite being well-studied in many plant species, little is known about this gene family in orchardgrass (Dactylis glomerata L.), one of the top four economically important perennial forage grasses cultivated worldwide. We identified 46 GRAS genes in orchardgrass and analyzed their characteristics by phylogenetic, gene structural, motifs and expression patterns analysis. The phylogenetic analysis of eight species revealed that DgGRAS family had the evolutional conservation and closer homology relationship with the GRAS family of rice, barley and Brachypodium distachyon. Moreover, 46 DgGRAS proteins were divided into eight subfamilies based on the tree topology and rice or Arabidopsis classification, and LISCL subfamily was the largest one. Besides, we found that the motif 15 may be unique to the orchardgrass LISCL subfamily, and the motif 6 and motif 17 had indispensable functions in the orchardgrass LISCL subfamily. We further analyzed the expression profiles of DgGRAS genes at mature and seeding stage. And we found that DgGRAS17 played an important role in the growth and development no matter what stage it was at. DgGRAS5, DgGRAS28, DgGRAS31, DgGRAS42 and DgGRAS44 got involved in processes of the growth and development at seeding stage instead of mature stage. These results indicated that the major expression patterns and detailed functions of the DgGRAS genes varied with developmental stages. Taken together, this is the first systematic analysis of the GRAS gene family in the orchardgrass genome and the results provide insights into the potential functions of GRAS genes.
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http://dx.doi.org/10.1007/s11033-020-05279-9DOI Listing
March 2020

Proteomic and Metabolomic Profilings Reveal Crucial Functions of γ-Aminobutyric Acid in Regulating Ionic, Water, and Metabolic Homeostasis in Creeping Bentgrass under Salt Stress.

J Proteome Res 2020 02 16;19(2):769-780. Epub 2020 Jan 16.

Department of Grassland Science, College of Animal Science and Technology , Sichuan Agricultural University , Chengdu 611130 , China.

The global emergence of soil salinization poses a serious challenge to many countries and regions. γ-Aminobutyric acid (GABA) is involved in systemic regulation of plant adaptation to salt stress but the underlying molecular and metabolic mechanism still remains largely unknown. The elevated endogenous GABA level by the application of exogenous GABA improved salt tolerance associated with the enhancement of antioxidant capacity, photosynthetic characteristics, osmotic adjustment (OA), and water use efficiency in creeping bentgrass. GABA strongly upregulated transcript levels of , , , and in roots involved in enhanced capacity of Na compartmentalization and mitigation of Na toxicity in the cytosol. Significant downregulation of expression could be induced by GABA in leaves in relation to maintenance of the significantly lower Na content and higher K/Na ratio. GABA-depressed aquaporin expression and accumulation induced declines in stomatal conductance and transpiration, thereby reducing water loss in leaves during salt stress. For metabolic regulation, GABA primarily enhanced sugar and amino acid accumulation and metabolism, largely contributing to improved salt tolerance through maintaining OA and metabolic homeostasis. Other major pathways could be related to GABA-induced salt tolerance including increases in antioxidant defense, heat shock proteins, and myo-inositol accumulation in leaves. Integrative analyses of molecular, protein, metabolic, and physiological changes reveal systemic functions of GABA in regulating ionic, water, and metabolic homeostasis in nonhalophytic creeping bentgrass under salt stress.
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http://dx.doi.org/10.1021/acs.jproteome.9b00627DOI Listing
February 2020
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