Publications by authors named "Zhujun Zhu"

31 Publications

Effects of on Plant Development, Glucosinolate Metabolism, and Resistance in Transgenic .

Front Plant Sci 2021 3;12:707054. Epub 2021 Sep 3.

Collaborative Innovation Center for Efficient and Green Production of Agriculture in Mountainous Areas of Zhejiang Province, College of Horticulture Science, Zhejiang A&F University, Hangzhou, China.

MYC2/3/4, known as a basic helix-loop-helix (bHLH) transcription factor, directly activate the genes involved in diverse plant development and secondary metabolites biosynthesis. In this study, we identified and cloned five paralogs (////) from Chinese cabbage ( ssp. ). analyses for the physicochemical properties suggested that BrMYC2/3-1/3-2/4-2/4-3 are unstable hydrophobic and acidic proteins, while BrMYC4-1 is an unstable hydrophobic and basic protein. BrMYC2/3/4 belong to the bHLH superfamily and are closely related to AthMYC2/3/4 orthologs that mediate the regulation of various secondary metabolites. It was demonstrated that BrMYC2/3/4-GFP fusion protein localized in the nucleus and expression levels of five homologous genes all elevated relative to control (Ctrl). When expressed in under the control of 35S promoter, each of the transgenes differentially influenced root and shoot elongation, vegetative phase change, flowering time, plant height and tiller number after flowering, and seed production. Despite the variation of phenotypes between the transgenic lines, all the lines except for exhibited shorter seed length, less seed weight, higher accumulation of glucosinolates (GSs), and resistance to than Ctrl. Notably, overexpression (OE) line significantly reduced the lengths of root and hypocotyl, seed length, and weight, along with faster bolting time and strikingly higher accumulation of total GSs. Accumulation of GSs at the highest levels in the line conferred the highest resistance to . Unlike and , stimulated the growth of plant height after fluorescence. The results of this study point to the overexpression that may provide a beneficial effect on plant growth and development plant resistance to the fungal pathogen.
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http://dx.doi.org/10.3389/fpls.2021.707054DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8446384PMC
September 2021

Complete chloroplast genome and phylogenetic analysis of (L.) Cass. ex Spach (Asteraceae).

Mitochondrial DNA B Resour 2021 18;6(9):2693-2694. Epub 2021 Aug 18.

Collaborative Innovation Center for Efficient and Green Production of Agriculture in Mountainous Areas of Zhejiang Province, College of Horticulture Science, Zhejiang A&F University, Hangzhou, Zhejiang, China.

(Asteraceae) is widely distributed in China, and it regulates the stomach, strengthens the spleen, reduces blood pressure, and reinforces the brain. In this study, the complete chloroplast genome sequence of was reported. The total chloroplast genome cycle was 149,750 bp, and it formed a large single-copy (LSC, 82,290 bp), a small single-copy (SSC, 18,414 bp), and two inverted repeats (IR, 24,523 bp) regions. The GC content of this genome was 36.35%. The whole-genome contained 128 genes, including 84 protein-coding genes, 36 tRNA genes, and eight rRNA genes. Phylogenetic analysis indicated that appeared within a clade comprised of species.
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http://dx.doi.org/10.1080/23802359.2021.1966331DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8381952PMC
August 2021

Astrocyte-derived CCL7 promotes microglia-mediated inflammation following traumatic brain injury.

Int Immunopharmacol 2021 Oct 19;99:107975. Epub 2021 Jul 19.

Neurology Department, Jintan Hospital affiliated to Jiangsu University, Changzhou 213200, China. Electronic address:

Microglia are immune cells of the central nervous system that mediate neuroinflammation. It is widely known that microglia-mediated inflammation in the brain contribute to the widespread tissue damage and neurological deficits in traumatic brain injury (TBI). However, the mechanisms responsible for this inflammatory response remain elusive. Here, we investigated the role of astrocyte-derived chemokine (C-C motif) ligand 7 (CCL7) in microglial-controlled inflammation following TBI. Our results demonstrated that astrocyte-derived CCL7 induced microglial activation and the release of proinflammatory mediators in the cortex and serum of rats that underwent experimental TBI. Furthermore, CCL7 knockout improved microglia-controlled inflammation, brain morphology and neurological dysfunction following TBI. In vitro, CCL7-siRNA attenuated the LPS-induced expression of pro-inflammatory markers in the co-culture of microglia and astrocytes. Collectively, our findings uncover an important role for astrocyte-derived CCL7 in promoting microglia-mediated inflammation after TBI and suggests CCL7 could serve as a potential therapeutic strategy for attenuating TBI by inhibiting microglial activation.
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http://dx.doi.org/10.1016/j.intimp.2021.107975DOI Listing
October 2021

Mitochondrial dysfunction and apoptosis are attenuated through activation of AMPK/GSK-3β/PP2A pathway in Parkinson's disease.

Eur J Pharmacol 2021 Sep 26;907:174202. Epub 2021 May 26.

Department of Rehabilitation Medicine, Jintan Hospital Affiliated to Jiangsu University, No. 16, Nanmen Street, Jintan District, Changzhou, 213200, Jiangsu, China. Electronic address:

Parkinson's disease (PD) is a common neurological disorder worldwide, characterized by loss of dopaminergic neurons and decrease of dopamine content. Mitochondria plays an important role in the development of PD. Adenosine 5'-monophosphate-activated protein kinase (AMPK), glycogen synthase kinase 3 (GSK-3β) and protein phosphatase 2A (PP2A) are all key proteins that regulate mitochondrial metabolism and apoptosis, and they are involved in a variety of neurodegenerative diseases. Here, we aimed to explore the involvement of mitochondrial dysfunction and apoptosis in 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine hydrochloride (MPTP)-induced PD mice and MPP iodide-induced PC12 cells. MPTP-induced mice were subjected to behavioral testing to assess PD-like behaviors. Various molecular biological techniques including ELISA, Western blot, TUNEL assay, flow cytometry, and the important instruments Seahorse XF24 Extracellular and high performance liquid chromatography (HPLC), were used to identify the underlying molecular events of mitochondria. Treatment with the AMPK activator GSK621 dramatically ameliorated PD by increasing the levels of dopamine and rescuing the loss of dopaminergic neurons, which is dependent on the mitochondrial pathway. Moreover, regulation of AMPK/GSK-3β/PP2A pathway-related proteins by GSK621 was partially inhibited the development of PD, suggesting a negative feedback loop exists between AMPK action and mitochondrial dysfunction-mediated apoptosis. Our data preliminarily indicated that mitochondrial dysfunction and apoptosis in the pathogenesis of PD might be mediated by AMPK/GSK-3β/PP2A pathway action, which might be a promising new option for future therapy of PD.
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http://dx.doi.org/10.1016/j.ejphar.2021.174202DOI Listing
September 2021

Melatonin elevated Sclerotinia sclerotiorum resistance via modulation of ATP and glucosinolate biosynthesis in Brassica rapa ssp. pekinensis.

J Proteomics 2021 07 14;243:104264. Epub 2021 May 14.

Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, College of Agricultural and Food Science, Zhejiang A&F University, Wusu Street 666, Lin'an, Hangzhou 311300, China. Electronic address:

Sclerotinia stem rot is a common disease found in Brassica rapa that is caused by the necrotic plant pathogen Sclerotinia sclerotiorum. Melatonin (MT) has known biological activity and effectively relieved this type of Sclerotinia stem rot in B. rapa. To better understand the mechanisms behind MT-induced S. sclerotiorum resistance in B. rapa, we performed both proteomic and metabolomic analysis. Our results showed that during S. sclerotiorum infection, thiamine synthesis was activated and defended against it. In infected leaves, ribosomal synthesis-related proteins responded positively to MT treatment. Integrated proteomic and metabolomic analysis showed that amino acid metabolism was activated by MT treatment. After MT treatment, adenosine-triphosphate (ATP) content and the activity of antioxidant enzymes were both increased in B. rapa infected leaves. Cysteine synthase, sulfur transfer-related proteins, and glucosinolate (GS) were all increased after MT treatment in infected B. rapa leaves. Taken together, these results indicated that B. rapa leaves promoted thiamine formation to defend against S. sclerotiorum infection. Moreover, MT helped further induce antioxidant activation in B. rapa in an ATP-dependent manner and stimulating GS biosynthesis to well inhibit the S. sclerotiorum infection. SIGNIFICANCE: Melatonin (MT) has biological activity and effectively relieved the Sclerotinia stem rot of Brassica rapa caused by the necrotic plant pathogen Sclerotinia sclerotiorum. In order to reveal the molecular mechanisms of MT-induced S. sclerotiorum resistance in B. rapa, comprehensive proteomic and metabolomic analyses were conducted. The integration analysis of omic-data illustrated that the modulation of ATP and glucosinolate biosynthesis induced by MT administration helped to defend the infection of S. sclerotiorum in B. rapa. Our results will provide insights into MT-induced anti-fungal mechanism and therapeutic strategies to mitigate Sclerotinia stem rot of B. rapa, thereby increasing plant yield and decreasing economic losses.
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http://dx.doi.org/10.1016/j.jprot.2021.104264DOI Listing
July 2021

CircUBQLN1 Promotes Proliferation but Inhibits Apoptosis and Oxidative Stress of Hippocampal Neurons in Epilepsy via the miR-155-Mediated SOX7 Upregulation.

J Mol Neurosci 2021 Sep 9;71(9):1933-1943. Epub 2021 Apr 9.

Department of Neurology, Changzhou Third People's Hospital, Changzhou, 213000, Jiangsu, China.

Circular RNAs (circRNAs) have key roles in a variety of neurological diseases, including epilepsy. This objective of this study was to perform the functional exploration and mechanism investigation of circRNA Ubiquilin1 (circUBQLN1) in epilepsy. Epilepsy cell model was established by the treatment of Mg-free in human neurons-hippocampal (HN-h) cells. The quantitative real-time polymerase chain reaction (qRT-PCR) was used for the expression analysis of circUBQLN1, linear-UBQLN1, microRNA-155 (miR-155), and sex-determining region Y-box 7 (SOX7). Proliferation detection was completed using Cell Counting Kit-8 (CCK-8) assay. Apoptosis analysis was conducted by flow cytometry and caspase-3 assay. Oxidative stress was assessed through determining the levels of superoxide dismutase (SOD) and malondialdehyde (MDA). Target analysis was performed by dual-luciferase reporter and RNA pull-down assays. SOX7 protein level was examined by Western blot. CircUBQLN1 was downregulated in epilepsy samples and Mg-free-induced cell model. Functional analysis in vitro suggested that circUBQLN1 overexpression facilitated proliferation but reduced apoptosis and oxidative stress in Mg-free-treated HN-h cells. Target analysis showed that circUBQLN1 acted as a miR-155 sponge and miR-155-targeted SOX7. Moreover, circUBQLN1 could combine with miR-155 to regulate the SOX7 expression. Reverted assays indicated that circUBQLN1 overexpression alleviated the Mg-free-induced nerve injury by sponging miR-155, and knockdown of SOX7 abrogated the protective function of in-miR-155 or circUBQLN1 in the Mg-free-treated HN-h cells. Our data revealed that circUBQLN1 prevented nerve injury in Mg-free-treated HN-h cells by regulating the miR-155/SOX7 axis, showing that circUBQLN1 might be used as a biomolecular target for the treatment of epilepsy.
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http://dx.doi.org/10.1007/s12031-021-01838-2DOI Listing
September 2021

Thermodynamic and Economic Analysis of Oxy-Fuel-Integrated Coal Partial Gasification Combined Cycle.

ACS Omega 2021 Feb 2;6(6):4262-4272. Epub 2021 Feb 2.

State Key Laboratory of Clean Energy Utilization, Zhejiang University, Zhejiang, Hangzhou 310027, China.

A novel partial gasification combined cycle (PGCC) system integrating coal partial gasification, oxy-fuel combustion, combined cycle, and CO separation is proposed. The coal-CO partial gasification technology is introduced in the coal gasification unit, and the oxy-fuel combustion technology is employed in the char combustion unit and gas turbine (GT) unit. The thermodynamic and economic analysis of the proposed system is carried out, showing that both energy and exergy efficiency have an increasing/decreasing tendency when the recycled flue gas (RFG) ratio of char combustion and GT increase. When the RFG ratios of char combustion and GT are 0.43 and 0.34, energy and exergy efficiencies reach maximum values of 48.18 and 45.11%, respectively. The energy efficiency of the PGCC-Oxy system is higher than that of the integrated gasification combined cycle (IGCC)-Oxy system by approximately 3%. It can be concluded from the economic analysis that the total investment on the PGCC-Oxy system is 3272.71 million RMB, and the internal rate of return (IRR) and payback time is 8.07% and 12.38 years, respectively.
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http://dx.doi.org/10.1021/acsomega.0c05277DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7893634PMC
February 2021

Integrating Sugar Metabolism With Transport: Elevation of Endogenous Cell Wall Invertase Activity Up-Regulates and Expression for Early Fruit Development in Tomato.

Front Genet 2020 19;11:592596. Epub 2020 Oct 19.

School of Environmental and Life Sciences, Australia-China Research Centre for Crop Improvement, The University of Newcastle, Callaghan, NSW, Australia.

Early fruit development is critical for determining crop yield. Cell wall invertase (CWIN) and sugar transporters both play important roles in carbon allocation and plant development. However, there is little information about the relationship between CWIN and those functionally related sugar transporters during fruit development. By using transgenic tomato with an elevated CWIN activity, we investigated how an increase in CWIN activity may regulate the expression of sugar transporter genes during fruit development. Our analyses indicate that CWIN activity may be under tight regulation by multiple regulators, including two invertase inhibitors (INVINHs) and one defective CWIN (deCWIN) in tomato ovaries prior to anthesis. Among the sugar transporters, expression of for sucrose efflux and for hexose uptake was enhanced by the elevated CWIN activity at 10 and 15 days after anthesis of tomato fruit development, respectively. The findings show that some specific sugars will eventually be exported transporters (SWEETs) and hexose transporters (HTs) respond to elevate CWIN activity probably to promote rapid fruit expansion when sucrose efflux from phloem and hexose uptake by parenchyma cell are in high demand. The analyses provide new leads for improving crop yield by manipulating CWIN-responsive sugar transporters, together with CWIN itself, to enhance fruit development and sugar accumulation.
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http://dx.doi.org/10.3389/fgene.2020.592596DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7604364PMC
October 2020

Putative trehalose biosynthesis proteins function as differential floridoside-6-phosphate synthases to participate in the abiotic stress response in the red alga Pyropia haitanensis.

BMC Plant Biol 2019 Jul 19;19(1):325. Epub 2019 Jul 19.

Key Laboratory of Marine Biotechnology of Zhejiang Province, Ningbo University, Post Box 71, Ningbo, 315211, Zhejiang Province, China.

Background: The heteroside floridoside is a primary photosynthetic product that is known to contribute to osmotic acclimation in almost all orders of Rhodophyta. However, the encoding genes and enzymes responsible for the synthesis of floridoside and its isomeric form, L- or D-isofloridoside, are poorly studied.

Results: Here, four putative trehalose-6-phosphate synthase (TPS) genes, designated as PhTPS1, PhTPS2, PhTPS3, and PhTPS4, were cloned and characterized from the red alga Pyropia haitanensis (Bangiophyceae). The deduced amino acid sequence is similar to the annotated TPS proteins of other organisms, especially the UDP-galactose substrate binding sites of PhTPS1, 2, which are highly conserved. Of these, PhTPS1, 4 are involved in the biosynthesis of floridoside and isofloridoside, with isofloridoside being the main product. PhTPS3 is an isofloridoside phosphate synthase, while PhTPS2 exhibits no activity. When challenged by desiccation, high temperature, and salt stress, PhTPS members were expressed to different degrees, but the responses to thermal stress and desiccation were stronger.

Conclusions: Thus, in P. haitanensis, PhTPSs encode the enzymatical activity of floridoside and isofloridoside phosphate synthase and are crucial for the abiotic stress defense response.
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http://dx.doi.org/10.1186/s12870-019-1928-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6642608PMC
July 2019

Genome-Wide Identification and Analysis of Polygalacturonase Genes in .

Int J Mol Sci 2018 Aug 4;19(8). Epub 2018 Aug 4.

Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, College of Agricultural and Food Science, Zhejiang A&F University, Wusu Street 666, Lin'an, Hangzhou 311300, China.

Polygalacturonase (PG), a large hydrolase family in plants, is involved in pectin disassembly of the cell wall in plants. The present study aims to characterize PG genes and investigate their expression patterns in . We identified 54 PG genes in the tomato genome and compared their amino acid sequences with their Arabidopsis counterpart. Subsequently, we renamed these PG genes according to their Arabidopsis homologs. Phylogenetic and evolutionary analysis revealed that these tomato PG genes could be classified into seven clades, and within each clade the exon/intron structures were conserved. Expression profiles analysis through quantitive real-time polymerase chain reaction (qRT-PCR) revealed that most had specific or high expression patterns in at least one organ, and particularly five PG genes (, , , , and ) associated with fruit development. Promoter analysis showed that more than three -elements associated with plant hormone response, environmental stress response or specific organ/tissue development exhibited in each SlPG promoter regions. In conclusion, our results may provide new insights for the further study of PG gene function during plant development.
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http://dx.doi.org/10.3390/ijms19082290DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6121401PMC
August 2018

Repression of miR156 by miR159 Regulates the Timing of the Juvenile-to-Adult Transition in Arabidopsis.

Plant Cell 2017 Jun 23;29(6):1293-1304. Epub 2017 May 23.

State Key Laboratory of Subtropical Silviculture, Laboratory of Plant Molecular and Developmental Biology, Zhejiang Agriculture and Forestry University, Hangzhou 311300, China

Temporally regulated microRNAs have been identified as master regulators of developmental timing in both animals and plants. In plants, vegetative development is regulated by a temporal decrease in miR156 level, but how this decreased expression is initiated and then maintained during shoot development remains elusive. Here, we show that miR159 is required for the correct timing of vegetative development in Loss of miR159 increases miR156 level throughout shoot development and delays vegetative development, whereas overexpression of miR159 slightly accelerated vegetative development. The repression of miR156 by miR159 is predominantly mediated by MYB33, an R2R3 MYB domain transcription factor targeted by miR159. Loss of led to subtle precocious vegetative phase change phenotypes in spite of the significant downregulation of miR156. MYB33 simultaneously promotes the transcription of and , as well as their target, , by directly binding to the promoters of these three genes. Rather than acting as major players in vegetative phase change in Arabidopsis, our results suggest that miR159 and MYB33 function as modifiers of vegetative phase change; i.e., miR159 facilitates vegetative phase change by repressing MYB33 expression, thus preventing MYB33 from hyperactivating miR156 expression throughout shoot development to ensure correct timing of the juvenile-to-adult transition in Arabidopsis.
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http://dx.doi.org/10.1105/tpc.16.00975DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5502449PMC
June 2017

Regulation of Vegetative Phase Change by SWI2/SNF2 Chromatin Remodeling ATPase BRAHMA.

Plant Physiol 2016 12 1;172(4):2416-2428. Epub 2016 Nov 1.

Zhejiang Provincial Key Laboratory of Bioremediation of Soil Contamination, Laboratory of Plant Molecular and Developmental Biology, Zhejiang Agriculture and Forestry University, Hangzhou 311300, China (Y.X., C.G., B. Zhou., H.W., B. Zheng, H.D., Z.Z., G.W.);

Plants progress from a juvenile vegetative phase of development to an adult vegetative phase of development before they enter the reproductive phase. miR156 has been shown to be the master regulator of the juvenile-to-adult transition in plants. However, the mechanism of how miR156 is transcriptionally regulated still remains elusive. In a forward genetic screen, we identified that a mutation in the SWI2/SNF2 chromatin remodeling ATPase BRAHMA (BRM) exhibited an accelerated vegetative phase change phenotype by reducing the expression of miR156, which in turn caused a corresponding increase in the levels of SQUAMOSA PROMOTER BINDING PROTEIN LIKE genes. BRM regulates miR156 expression by directly binding to the MIR156A promoter. Mutations in BRM not only increased occupancy of the -2 and +1 nucleosomes proximal to the transcription start site at the MIR156A locus but also the levels of trimethylated histone H3 at Lys 27. The precocious phenotype of brm mutant was partially suppressed by a second mutation in SWINGER (SWN), but not by a mutation in CURLEY LEAF, both of which are key components of the Polycomb Group Repressive Complex 2 in plants. Our results indicate that BRM and SWN act antagonistically at the nucleosome level to fine-tune the temporal expression of miR156 to regulate vegetative phase change in Arabidopsis.
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http://dx.doi.org/10.1104/pp.16.01588DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5129735PMC
December 2016

Modulation of miR156 to identify traits associated with vegetative phase change in tobacco (Nicotiana tabacum).

J Exp Bot 2016 Mar 13;67(5):1493-504. Epub 2016 Jan 13.

Zhejiang Provincial Key Laboratory of Bioremediation of Soil Contamination, Laboratory of Plant Molecular and Developmental Biology, Zhejiang Agriculture & Forestry University, Hangzhou 311300, China

After germination, plants progress through juvenile and adult phases of vegetative development before entering the reproductive phase. The character and timing of these phases vary significantly between different plant species, which makes it difficult to know whether temporal variations in various vegetative traits represent the same, or different, developmental processes. miR156 has been shown to be the master regulator of vegetative development in plants. Overexpression of miR156 prolongs the juvenile phase of development, whereas knocking-down the level of miR156 promotes the adult phase of development. Therefore, artificial modulation of miR156 expression is expected to cause corresponding changes in vegetative-specific traits in different plant species, particularly in those showing no substantial difference in morphology during vegetative development. To identify specific traits associated with the juvenile-to-adult transition in tobacco, we examined the phenotype of transgenic tobacco plants with elevated or reduced levels of miR156. We found that leaf shape, the density of abaxial trichomes, the number of leaf veins, the number of stomata, the size and density of epidermal cells, patterns of epidermal cell staining, the content of chlorophyll and the rate of photosynthesis, are all affected by miR156. These newly identified miR156-regulated traits therefore can be used to distinguish between juvenile and adult phases of development in tobacco, and provide a starting point for future studies of vegetative phase change in the family Solanaceae.
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http://dx.doi.org/10.1093/jxb/erv551DOI Listing
March 2016

Gene Expression Analysis of Pak Choi in Response to Vernalization.

PLoS One 2015 30;10(10):e0141446. Epub 2015 Oct 30.

College of Horticulture, Shanxi Agricultural University, Taigu, Shanxi, China.

Pak choi is a seed vernalization-type plant whose vernalization mechanism is currently unclear. Therefore, it is critical to discover genes related to vernalization and research its functions during vernalization in pak choi. Here, the gene expression profiles in the shoot apex were analyzed after low temperature treatment using high-throughput RNA sequencing technology. The results showed that there are 1,664 and 1,192 differentially expressed genes (DEGs) in pak choi in cold treatment ending and before flower bud differentiation, respectively, including 42 genes that exhibited similar expression trend at both stages. Detailed annotation revealed that the proteins encoded by the DEGs are located in the extracellular region, cell junction and extracellular matrix. These proteins exhibit activity such as antioxidant activity and binding protein/transcription factor activity, and they are involved in signal transduction and the immune system/biological processes. Among the DEGs, Bra014527 was up-regulated in low temperature treatment ending, Bra024097 was up-regulated before flower bud differentiation and Bra035940 was down-regulated at both stages in low temperature-treated shoot apices. Homologues of these genes in A. thaliana, AT3G59790, AT4G30200 and AT5G61150, are involved in flowering and vernalization, suggesting that they take part in the vernalization process in pak choi. Further pathway enrichment analysis revealed that most genes were enriched in the tryptophan metabolism and glucosinolate biosynthesis pathways. However, the functions of tryptophan and glucosinolate in vernalization are not yet clear and require further analysis.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0141446PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4627790PMC
June 2016

Glucosinolate Accumulation and Related Gene Expression in Pak Choi (Brassica rapa L. ssp. chinensis var. communis [N. Tsen & S.H. Lee] Hanelt) in Response to Insecticide Application.

J Agric Food Chem 2015 Nov 27;63(44):9683-9. Epub 2015 Oct 27.

The Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, College of Agricultural and Food Science, Zhejiang A&F University , Hangzhou 311300, China.

Glucosinolates and their breakdown products are well-known for their cancer-chemoprotective functions and biocidal activities against pathogens and generalist herbivores. Insecticides are commonly used in the production of pak choi (Brassica rapa L. ssp. chinensis var. communis [N. Tsen & S.H. Lee] Hanelt). We studied the effects of four commonly used insecticides, namely, β-cypermethrin, acephate, pymetrozine, and imidacloprid, on glucosinolate metabolism in pak choi. All insecticides significantly increased both the transcription of glucosinolate biosynthetic genes and the aliphatic and total glucosinolate accumulations in pak choi. β-Cypermethrin and acephate caused gradual and continuous up-regulation of gene expression from 0.5 to 24 h after treatment, whereas pymetrozine and imidacloprid did so more rapidly, reaching a peak at 1 h and returning to normal at 3 h. Our findings indicate that the four insecticides affect glucosinolate metabolism in pak choi plants to various degrees and suggest that glucosinolates may be involved in plant insecticide metabolism.
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http://dx.doi.org/10.1021/acs.jafc.5b03894DOI Listing
November 2015

A lipoxygenase from red alga Pyropia haitanensis, a unique enzyme catalyzing the free radical reactions of polyunsaturated fatty acids with triple ethylenic bonds.

PLoS One 2015 6;10(2):e0117351. Epub 2015 Feb 6.

School of Marine Science, Ningbo University, Ningbo, Zhejiang, 315211, China.

Lipoxygenases (LOXs) are key enzymes to regulate the production of hormones and defensive metabolites in plants, animals and algae. In this research, a full length LOX gene has been cloned and expressed from the red alga Pyropia haitanensis (Bangiales, Rhodophyta) gametophyte (PhLOX2). Subsequent phylogenetic analysis showed that such LOX enzymes are separated at the early stage of evolution, establishing an independent branch. The LOX activity was investigated at the optimal pH of 8.0. It appears that PhLOX2 is a multifunctional enzyme featuring both lipoxygenase and hydroperoxidase activities. Additionally, PhLOX2 exhibits remarkable substrate and position flexibility, and it can catalyze an array of chemical reactions involving various polyunsaturated fatty acids, ranging from C18 to C22. As a matter of fact, mono-hydroperoxy, di-hydroperoxy and hydroxyl products have been obtained from such transformations, and eicosapentaenoic acid seem to be the most preferred substrate. It was found that at least triple ethylenic bonds are required for PhLOX2 to function as a LOX, and the resulting hydroxy products should be originated from the PhLOX2 mediated reduction of mono-hydroperoxides, in which the hydrogen abstraction occurs on the carbon atom between the second and third double bond. Most of the di-hydroperoxides observed seem to be missing their mono-position precursors. The substrate and position flexibility, as well as the function versatility of PhLOXs represent the ancient enzymatic pathway for organisms to control intracellular oxylipins.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0117351PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4319731PMC
February 2016

Different responses to heat shock stress revealed heteromorphic adaptation strategy of Pyropia haitanensis (Bangiales, Rhodophyta).

PLoS One 2014 7;9(4):e94354. Epub 2014 Apr 7.

School of Marine Science, Ningbo University, Ningbo, Zhejiang, China.

Pyropia has a unique heteromorphic life cycle with alternation stages between thallus and conchocelis, which lives at different water temperatures in different seasons. To better understand the different adaptation strategies for temperature stress, we tried to observe comparative biochemical changes of Pyropia haitanensis based on a short term heat shock model. The results showed that: (1) At normal temperature, free-living conchocelis contains significantly higher levels of H2O2, fatty acid-derived volatiles, the copy number of Phrboh and Phhsp70 genes,the activities of NADPH oxidase and floridoside than those in thallus. The released H2O2 and NADPH oxidase activity of conchocelis were more than 7 times higher than those of thallus. The copy number of Phrboh in conchocelis was 32 times that in thallus. (2) After experiencing heat shock at 35°C for 30 min, the H2O2 contents, the mRNA levels of Phrboh and Phhsp70, NADPH oxidase activity and the floridoside content in thallus were all significantly increased. The mRNA levels of Phrboh increased 5.78 times in 5 min, NADPH oxidase activity increased 8.45 times in 20 min. (3) Whereas, in conchocelis, the changes in fatty acids and their down-stream volatiles predominated, significantly increasing levels of saturated fatty acids and decreasing levels of polyunsaturated fatty acids occurred, and the 8-carbon volatiles were accumulated. However, the changes in H2O2 content and expression of oxidant-related genes and enzymatic activity were not obvious. Overall, these results indicate that conchocelis maintains a high level of active protective apparatus to endure its survival at high temperature, while thallus exhibit typical stress responses to heat shock. It is concluded that Pyropia haitanensis has evolved a delicate strategy for temperature adaptation for its heteromorphic life cycle.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0094354PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3978056PMC
December 2014

Isolation and expression of glucosinolate synthesis genes CYP83A1 and CYP83B1 in Pak Choi (Brassica rapa L. ssp. chinensis var. communis (N. Tsen & S.H. Lee) Hanelt).

Int J Mol Sci 2012 15;13(5):5832-43. Epub 2012 May 15.

Department of Horticulture, Zhejiang University, Zijingang Campus, Yuhangtang Road 866, Hangzhou 310058, China; E-Mails: (B.Z.); (Z.W.).

CYP83A1 and CYP83B1 are two key synthesis genes in the glucosinolate biosynthesis pathway. CYP83A1 mainly metabolizes the aliphatic oximes to form aliphatic glucosinolate and CYP83B1 mostly catalyzes aromatic oximes to synthesis corresponding substrates for aromatic and indolic glucosinolates. In this study, two CYP83A1 genes named BcCYP83A1-1 (JQ289997), BcCYP83A1-2 (JQ289996) respectively and one CYP83B1 (BcCYP83B1, HM347235) gene were cloned from the leaves of pak choi (Brassica rapa L. ssp. chinensis var. communis (N. Tsen & S.H. Lee) Hanelt) "Hangzhou You Dong Er" cultivar. Their ORFs were 1506, 1509 and 1500 bp in length, encoding 501, 502 and 499 amino acids, respectively. The predicted amino acid sequences of CYP83A1-1, CYP83A1-2 and CYP83B1 shared high sequence identity of 87.65, 86.48 and 95.59% to the corresponding ones in Arabidopsis, and 98.80, 98.61 and 98.80% to the corresponding ones in Brassica pekinensis (Chinese cabbage), respectively. Quantitative real-time PCR analysis indicated that both CYP83A1 and CYP83B1 expressed in roots, leaves and petioles of pak choi, while the transcript abundances of CYP83A1 were higher in leaves than in petioles and roots, whereas CYP83B1 showed higher abundances in roots. The expression levels of glucosinolate biosynthetic genes were consistent with the glucosinolate profile accumulation in shoots of seven cultivars and three organs. The isolation and characterization of the glucosinolate synthesis genes in pak choi would promote the way for further development of agronomic traits via genetic engineering.
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http://dx.doi.org/10.3390/ijms13055832DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3382748PMC
August 2015

Functional divergence of the NIP III subgroup proteins involved altered selective constraints and positive selection.

BMC Plant Biol 2010 Nov 20;10:256. Epub 2010 Nov 20.

College of Agriculture and Food Science, Zhejiang A & F University, Lin'an, Hangzhou 311300, China.

Background: Nod26-like intrinsic proteins (NIPs) that belong to the aquaporin superfamily are unique to plants. According to homology modeling and phylogenetic analysis, the NIP subfamily can be further divided into three subgroups with distinct biological functions (NIP I, NIP II, and NIP III). In some grasses, the NIP III subgroup proteins (NIP2s) were demonstrated to be permeable to solutes with larger diameter, such as silicic acid and arsenous acids. However, to date there is no data-mining or direct experimental evidences for the permeability of such larger solutes for dicot NIP2s, although they exhibit similar three-dimensional structures as those in grasses. It is therefore intriguing to investigate the molecular mechanisms that drive the evolution of plant NIP2s.

Results: The NIP III subgroup is more ancient with a divergence time that predates the monocot-dicot split. The proliferation of NIP2 genes in modern grass species is primarily attributed to whole genome and segmental chromosomal duplication events. The structure of NIP2 genes is relatively conserved, possessing five exons and four introns. All NIP2s possess an ar/R filter consisting of G, S, G, and R, except for the cucumber CsNIP2;2, where a small G in the H2 is substituted with the bulkier C residue. Our maximum likelihood analysis revealed that NIP2s, especially the loop A (LA) region, have undergone strong selective pressure for adaptive evolution. The analysis at the amino acid level provided strong statistical evidences for the functional divergence between monocot and dicot NIP III subgroup proteins. In addition, several SDPs (Specificity Determining Positions) responsible for functional specificity were predicted.

Conclusions: The present study provides the first evidences of functional divergence between dicot and monocot NIP2s, and suggests that positive selection, as well as a radical shift of evolutionary rate at some critical amino acid sites is the primary driver. These findings will expand our understanding to evolutionary mechanisms driving the functional diversification of monocot and dicot NIP III subgroup proteins.
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http://dx.doi.org/10.1186/1471-2229-10-256DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3095335PMC
November 2010

The investigation of noise attenuation by plants and the corresponding noise-reducing spectrum.

J Environ Health 2010 Apr;72(8):8-15

School of Landscape Architecture, Zhejiang Forestry University, Hangzhou, China.

As noise pollution is becoming more and more serious, many researchers are studying the noise attenuation effect provided by plants. This article examines six kinds of evergreens as research subjects so as to compare the different arrangements and densities of plants and their effect on noise attenuation. The authors studied the relationship between each of the plant's characteristics (the characteristics include leaf area, leaf fresh weight, leaf tactility, and leaf shape) and their average relative noise attenuation (deltaLAep). The authors then generated the noise-reducing spectrum of the six plants. The results show that there is a notable difference in noise-reducing effects for low frequency and high frequency (p < .05) when the plants are arranged differently. Also, every plant demonstrates a specific noise-reducing spectrum. By quantifying noise attenuation characteristics and abilities of plants, the authors combine noise attenuation species to achieve the mutual benefits of plant varieties and establish an ecotypic sound barrier model with effective density and arrangement.
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April 2010

Divergence in function and expression of the NOD26-like intrinsic proteins in plants.

BMC Genomics 2009 Jul 15;10:313. Epub 2009 Jul 15.

School of Agriculture and Food Science, Zhejiang Forestry University, Lin'an, Hangzhou, PR China.

Background: NOD26-like intrinsic proteins (NIPs) that belong to the aquaporin superfamily are plant-specific and exhibit a similar three-dimensional structure. Experimental evidences however revealed that functional divergence should have extensively occurred among NIP genes. It is therefore intriguing to further investigate the evolutionary mechanisms being responsible for the functional diversification of the NIP genes. To better understand this process, a comprehensive analysis including the phylogenetic, positive selection, functional divergence, and transcriptional analysis was carried out.

Results: The origination of NIPs could be dated back to the primitive land plants, and their diversification would be no younger than the emergence time of the moss P. patens. The rapid proliferation of NIPs in plants may be primarily attributed to the segmental chromosome duplication produced by polyploidy and tandem duplications. The maximum likelihood analysis revealed that NIPs should have experienced strong selective pressure for adaptive evolution after gene duplication and/or speciation, prompting the formation of distinct NIP groups. Functional divergence analysis at the amino acid level has provided strong statistical evidence for shifted evolutionary rate and/or radical change of the physiochemical properties of amino acids after gene duplication, and DIVERGE2 has identified the critical amino acid sites that are thought to be responsible for the divergence for further investigation. The expression of plant NIPs displays a distinct tissue-, cell-type-, and developmental specific pattern, and their responses to various stress treatments are quite different also. The differences in organization of cis-acting regulatory elements in the promoter regions may partially explain their distinction in expression.

Conclusion: A number of analyses both at the DNA and amino acid sequence levels have provided strong evidences that plant NIPs have suffered a high divergence in function and expression during evolution, which is primarily attributed to the strong positive selection or a rapid change of evolutionary rate and/or physiochemical properties of some critical amino acid sites.
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http://dx.doi.org/10.1186/1471-2164-10-313DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2726226PMC
July 2009

Dicer-like (DCL) proteins in plants.

Funct Integr Genomics 2009 Aug 17;9(3):277-86. Epub 2009 Feb 17.

School of Agriculture and Food Science, Zhejiang Forestry University, Lin'an, Hangzhou, People's Republic of China.

Dicer and Dicer-like (DCL) proteins are key components in small RNA biogenesis. DCLs form a small protein family in plants whose diversification time dates to the emergence of mosses (Physcomitrella patens). DCLs are ubiquitously but not evenly expressed in tissues, at different developmental stages, and in response to environmental stresses. In Arabidopsis, AtDCL1, AtDCL2, and AtDCL4 exhibit similar expression pattern during the leaf or stem development, which is distinguished from AtDCL3. However, distinct expression profiles for all DCLs are found during the development of reproductive organs flower and seed. The grape VvDCL1 and VvDCL3 may act sequentially to face the fungi challenge. Overall, the responses of DCLs to drought, cold, and salt are quite different, indicating that plants might have specialized regulatory mechanism in response to different abiotic stresses. Further analysis of the promoter regions reveals a few of cis-elements that are hormone- and stress-responsive and developmental-related. However, gain and loss of cis-elements are frequent during evolution, and not only paralogous but also orthologous DCLs have dissimilar cis-element organization. In addition to cis-elements, AtDCL1 is probably regulated by both ath-miR162 and ath-miR414. Posterior analysis has identified some critical amino acid sites that are responsible for functional divergence between DCL family members. These findings provide new insights into understanding DCL protein functions.
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http://dx.doi.org/10.1007/s10142-009-0111-5DOI Listing
August 2009

Free and bound phenolic compounds in leaves of pak choi (Brassica campestris L. ssp. chinensis var. communis) and Chinese leaf mustard (Brassica juncea Coss).

Food Chem 2008 Oct 29;110(4):838-46. Epub 2008 Feb 29.

Department of Food Technology, Institute of Human Nutrition and Food Science, University of Kiel, Heinrich-Hecht-Platz 10, 24118 Kiel, Germany.

Eleven pak choi cultivars and two leaf mustard cultivars grown under field conditions in China were investigated for the free polyphenol content in their outer and inner leaves, as well as in their leaf blades and leaf stalks. In most cases, there were no significant differences between the hydroxycinnamic acid derivative and flavonoid derivative contents in the outer and inner leaves for the 13 cultivars. However, the contents of blades and stalks differed: hydroxycinnamic acids and flavonoids were present in greater amounts in the leaf blade than in the leaf stalk. Trace or small amounts of flavonoids were detected in the pak choi and leaf mustard stalks. Additionally, the bound phenolic contents of two pak choi cultivars and two leaf mustard cultivars were investigated. The concentrations of cell wall-bound phenolic compounds were higher in the leaf blade than in the leaf stalk under field conditions in China. These compounds represent only a minor portion of the total phenolic contents (flavonoids and hydroxycinnamic acids) in leaf stalks (0.81-1.18%) and leaf blades (0.05-0.08%) from fresh plant material. The storage of plant samples from four Chinese cabbage cultivars resulted, in most cases, in an increase of phenolic content, within six days, at 4°C and 20°C. The increase might have been triggered by post-harvest plant stresses, which stimulate the biosynthesis of polyphenols.
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http://dx.doi.org/10.1016/j.foodchem.2008.02.069DOI Listing
October 2008

Identification of two AFLP markers linked to bacterial wilt resistance in tomato and conversion to SCAR markers.

Mol Biol Rep 2009 Mar 23;36(3):479-86. Epub 2007 Dec 23.

Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China.

Tomato bacterial wilt (BW) incited by Ralstonia solanacearum is a constraint on tomato production in tropical, subtropical and humid regions of the world. In this paper, we present the results of a research aimed at the identification of PCR-based markers amplified fragment length polymorphism (AFLP) linked to the genes that confer resistance to tomato BW. To this purpose, bulked segregant analysis was applied to an F(2) population segregating for the BW resistant gene and derived from the pair-cross between a BW resistant cultivar T51A and the susceptible cultivar T9230. Genetic analysis indicated that tomato BW was conferred by two incomplete dominant genes. A CTAB method for total DNA extraction, developed by Murray and Thompson with some modifications was used to isolation the infected tomato leaves. Thirteen differential fragments were detected using 256 primer combinations, and two AFLP markers were linked to the BW resistance. Subsequently, the AFLP markers were converted to co-dominant SCAR markers, named TSCAR(AAT/CGA) and TSCAR(AAG/CAT). Linkage analysis showed that the two markers are on the contralateral side of TRSR-1. Genetic distance between TSCAR(AAT/CGA) and TRS-1 was estimated to 4.6 cM, while 8.4 cM between TSCAR(AAG/CAT) and TRS-1.
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http://dx.doi.org/10.1007/s11033-007-9204-1DOI Listing
March 2009

Impact of fermentation on phenolic compounds in leaves of pak choi (Brassica campestris L. ssp. chinensis var. communis) and Chinese leaf mustard (Brassica juncea coss).

J Agric Food Chem 2008 Jan 14;56(1):148-57. Epub 2007 Dec 14.

Department of Food Technology, Institute of Human Nutrition and Food Science, University of Kiel, Heinrich-Hecht-Platz 10, 24118, Kiel, Germany.

Four different cultivars of Chinese Brassica vegetables (two pak choi cultivars and two Chinese leaf mustard cultivars) were fermented according to a traditional Chinese method called pickling. The plant material was investigated before and after the fermentation procedure to determine the qualitative and quantitative changes in its polyphenols. A detailed description of the identified phenolic compounds of leaf mustard by HPLC-ESI-MS(n) is presented here for the first time, including hydroxycinnamic acid mono- and diglycosides (gentiobioses) and flavonoid tetraglycosides. Flavonoid derivatives with a lower molecular mass (di- and triglycosides) and aglycones of flavonoids and hydroxycinnamic acids were detected in fermented cabbages compared to the main compounds detected in nonfermented cabbages (tri- and tetraglycosides of flavonoids and hydroxycinnamic acid derivatives of malic acid, glycoside, and quinic acid). During the fermentation process, contents of flavonoid derivatives and some hydroxycinnamic acid derivatives were found to decrease. Some marginal losses of polyphenols were observed even in the kneading step of the plant material prior to the fermentation procedure. The antioxidative potential of fermented cabbages was much higher compared to that of nonfermented cabbages in the TEAC assay, but not observable in the DPPH assay. The increase of the antioxidative potential detected in the TEAC assay was attributed to the qualitative changes of polyphenols as well as other reductones potentially present.
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http://dx.doi.org/10.1021/jf072428oDOI Listing
January 2008

Identification of flavonoids and hydroxycinnamic acids in pak choi varieties (Brassica campestris L. ssp. chinensis var. communis) by HPLC-ESI-MSn and NMR and their quantification by HPLC-DAD.

J Agric Food Chem 2007 Oct 12;55(20):8251-60. Epub 2007 Sep 12.

Department of Food Technology, Institute of Human Nutrition and Food Science, University of Kiel, Heinrich-Hecht-Platz 10, 24118 Kiel, Germany.

Twenty-eight polyphenols (11 flavonoid derivatives and 17 hydroxycinnamic acid derivatives) were detected in different cultivars of the Chinese cabbage pak choi ( Brassica campestris L. ssp. chinensis var. communis) by HPLC-DAD-ESI-MS(n). Kaempferol was found to be the major flavonoid in pak choi, glycosylated and acylated with different compounds. Smaller amounts of isorhamnetin were also detected. A structural determination was carried out by (1)H and (13)C NMR spectroscopy for the main compound, kaempferol-3-O-hydroxyferuloylsophoroside-7-O-glucoside, for the first time. Hydroxycinnamic acid derivatives were identified as different esters of quinic acid, glycosides, and malic acid. The latter ones are described for the first time in cabbages. The content of polyphenols was determined in 11 cultivars of pak choi, with higher concentrations present in the leaf blade than in the leaf stem. Hydroxycinnamic acid esters, particularly malic acid derivatives, are present in both the leaf blade and leaf stem, whereas flavonoid levels were determined only in the leaf blade.
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http://dx.doi.org/10.1021/jf071314+DOI Listing
October 2007

Assessing the willingness of the public to pay to conserve urban green space: the Hangzhou City, China, case.

J Environ Health 2006 Dec;69(5):26-30

Zhejiang University, Department of Horticulture, Hangzhou, Zhejiang, China.

The authors assessed the willingness of residents to pay for urban green-space conservation in Hangzhou, China, using the contingent-valuation method. The aim of the study was to provide policy makers with information that would be useful for making informed decisions in urban-development planning. The findings of the study are as follows: 1) The willingness of residents to pay for urban green-space conservation was positively correlated with their perceptions of the benefits of green spaces and negatively correlated with perceptions of the annoyances. 2) The willingness to pay a higher premium for green-space conservation is directly related to gender, income level, and residential-ownership status. Age and education level are not significantly correlated with willingness to pay. 3) A majority of respondents view the conservation of urban green spaces as a very important function of the city, and most of them are willing to pay additional taxes for this conservation. 4) The total value per year to the public of the conservation program in Hangzhou is about $15.4 million. These qualitative and quantitative findings can be used in the policy-making process for urban-development plans.
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December 2006

[Effects of excess Mn on photosynthesis characteristics in cucumber under different light intensity].

Ying Yong Sheng Tai Xue Bao 2005 Jun;16(6):1047-50

Key Laboratory of Horticultural Plant Development and Biotechnology of Agriculture Ministry, Department of Horticulture, Zhejiang University, Hangzhou 310029, China.

By a solution culture experiment, this paper studied the effects of excess Mn on the growth, chlorophyll content, chlorophyll fluorescence parameters and photosynthesis of cucumber under different light intensity. The results indicated that excess Mn inhibited plant growth, which was more obvious under high light intensity than under low light intensity. The primary maximum photochemical efficiency of PSII (v/Fm), quantum efficiency of non-cyclic electron transport of PSII (phiPSII), and photochemical quenching (qP) were significantly decreased in excess Mn treatment under high light intensity, while no significant effects on Fv/Fm and qP were observed under low light intensity. Excess Mn, particularly under high light intensity, decreased net photosynthetic rate (Pn) and stomatal conductance (Gs). Excess Mn increased intracellular CO2 (Ci) under high light intensity and decreased Ci under low light intensity, while stomatal limitation value (Ls) was just reverse to Ci. It could be concluded that the decrease of Pn in excess Mn treatment was not resulted from stomatal limitation under high light intensity, but was true under low light intensity.
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June 2005

Silicon-mediated alleviation of Mn toxicity in Cucumis sativus in relation to activities of superoxide dismutase and ascorbate peroxidase.

Phytochemistry 2005 Jul;66(13):1551-9

Department of Horticulture, Zhejiang University, Hangzhou 310029, PR China.

The effects of exogenous silicon (Si) on plant growth, activities of superoxide dismutase (SOD), guaiacol peroxidase (GPX), ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR), glutathione reductase (GR) and catalase, and concentrations of ascorbate and glutathione were investigated in cucumber (Cucumis sativus L.) plants treated with excess manganese (Mn) (600 microM). Compared with the treatment of normal Mn (10 microM), excess Mn significantly increased H2O2 concentration and lipid peroxidation indicated by accumulation of thiobarbituric acid reactive substances. The leaves showed apparent symptoms of Mn toxicity and the plant growth was significantly inhibited by excess Mn. The addition of Si significantly decreased lipid peroxidation caused by excess Mn, inhibited the appearance of Mn toxicity symptoms, and improved plant growth. This alleviation of Mn toxicity by Si was related to a significant increase in the activities of SOD, APX, DHAR and GR and the concentrations of ascorbate and glutathione.
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http://dx.doi.org/10.1016/j.phytochem.2005.05.006DOI Listing
July 2005

[Effects of silicon supply and Sphaerotheca fuliginea inoculation on resistance of cucumber seedlings against powdery mildew].

Ying Yong Sheng Tai Xue Bao 2004 Nov;15(11):2147-51

State Agriculture Ministry Laboratory of Horticultural Plant Growth Development and Biotechnology, Department of Horticulture, Zhejiang University, Hangzhou 310029, China.

By the method of hydroponic culture, this paper studied the effects of soluble silicon (Si) supply and Sphaerotheca fuliginea inoculation on the active oxygen metabolism, SiO2 content and disease resistance of a susceptible cultivar. The results showed that the O2*- producing rate and H2O2 and MDA contents of cucumber leaf were increased by Sphaerotheca fuliginea inoculation, but reduced by the inoculation plus Si supply. The inoculation enhanced the catalase (CAT) and peroxidase (POD) activities in plant leaves but decreased their superoxide dismutase (SOD) activity, while inoculation plus Si supply increased the activities of these enzymes. Inoculation increased the scorbate (AsA) and glutathione (GSH) contents in plant leaves. The AsA content in Si-supplied plant leaves was lower than that of Si-deprived ones, whereas the GSH content was in reverse. Whether inoculated or not, the SiO2 content in Si-supplied plant leaves was significantly higher than that of Si-deprived ones. The disease index was significantly decreased by Si-supply.
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November 2004
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