Publications by authors named "Jianchang Yang"

77 Publications

Jasmonates Alleviate the Harm of High-Temperature Stress During Anthesis to Stigma Vitality of Photothermosensitive Genetic Male Sterile Rice Lines.

Front Plant Sci 2021 29;12:634959. Epub 2021 Mar 29.

Jiangsu Key Laboratory of Crop Genetics and Physiology, Co-innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, China.

Using photothermosensitive genic male sterile (PTSGMS) rice ( L.) lines to produce hybrids can obtain great heterosis. However, PTSGMS rice lines exhibit low stigma vitality when high-temperature (HT) stress happens during anthesis. Jasmonates (JAs) are novel phytohormones and play vital roles in mediating biotic and abiotic stresses. Little is known, however, if and how JAs could alleviate the harm of HT stress during anthesis to the stigma vitality of PTSGMS lines. This study investigated the question. Two PTSGMS lines and one restorer line of rice were pot-grown and subjected to normal temperature and HT stress during anthesis. The stigma exertion rate, sigma fresh weight, stigma area, contents of JAs, hydrogen peroxide (HO), and ascorbic acid (AsA), activity of catalase in stigmas, and the number of pollens germinated on the stigma of PTSGMS lines were determined. The results showed that a rice line with higher JAs content in the stigma under HT stress showed lower HO content, higher AsA content and catalase activity in stigmas, larger stigma area, heavier stigma fresh weight, more pollens germinated on the stigma, and higher fertilization and seed-setting and rates. Applying methyl JAs during anthesis to rice panicles decreased the accumulation of reactive oxygen species and enhanced stigma vitality, thereby increasing fertilization and seed-setting rates of the hybrids of PTSGMS rice lines under HT stress. The results demonstrate that JAs attenuate the injury of HT stress to the stigma vitality of PTSGMS rice lines through enhancing antioxidant ability.
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http://dx.doi.org/10.3389/fpls.2021.634959DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8039518PMC
March 2021

Field experiments and model simulation based evaluation of rice yield response to projected climate change in Southeastern China.

Sci Total Environ 2021 Mar 28;761:143206. Epub 2020 Oct 28.

State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China. Electronic address:

Evaluating the impact of climate change factors, especially temperature and carbon dioxide (CO), on rice yield is essential to ensure future food security. Because of the wide biogeographical distribution of rice, such evaluations are conducted exclusively through modeling efforts. However, geographical forecasts could, potentially, be improved by the inclusion of field-based data on projected increases in temperature and CO concentration from a given rice-growing region. In this study, the latest version of the ORYZA (v3) crop model was evaluated with additional yield data obtained from a temperature-controlled free-air CO enrichment system (T-FACE) in Southeastern China. ORYZA (v3) results were then evaluated in the context of phase five of the Coupled Model Intercomparison Project (CMIP5) for representative concentration pathways (RCP) 4.5 and RCP 8.5 using five global change models (GCMs). Our findings indicate that climate change, i.e., inclusion of CO and temperature effects, decreased mean rice yield by 3.5%, and 9.4% for RCP 4.5; and by 10.5 and 47.9% for RCP 8.5 for the scenarios in the 2050s and 2080s, respectively. The CO fertilizer effect partially compensated but did not offset the negative impacts of rising temperature on rice yields. Warmer temperatures were the primary factor that influenced yield by adversely affecting the spikelet fertility factor and spikelet number. Overall, climate change would have positive effects on rice yields until the middle-century in Southeastern China but negative effects were noted by the end of the century. These results may be of interest for informing policy makers and developing appropriate strategies to improve future rice productivity for this region of China.
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http://dx.doi.org/10.1016/j.scitotenv.2020.143206DOI Listing
March 2021

Analysis of Global Methylome and Gene Expression during Carbon Reserve Mobilization in Stems under Soil Drying.

Plant Physiol 2020 08 8;183(4):1809-1824. Epub 2020 Jun 8.

School of Life Sciences and State Key Laboratory of Agrobiotechnology, Chinese University of Hong Kong, Shatin 99077, Hong Kong

In rice (), a specific temporary source organ, the stem, is important for grain filling, and moderate soil drying (MD) enhanced carbon reserve flow from stems to increase grain yield. The dynamics and biological relevance of DNA methylation in carbon reserve remobilization during grain filling are unknown. Here, we generated whole-genome single-base resolution maps of the DNA methylome in the stem. During grain filling under MD, we observed an increase in DNA methylation of total cytosines, with more hypomethylated than hypermethylated regions. Genes responsible for DNA methylation and demethylation were up-regulated, suggesting that DNA methylation changes in the stem were regulated by antagonism between DNA methylation and demethylation activity. In addition, methylation in the CG and CHG contexts was negatively associated with gene expression, while that in the CHH context was positively associated with gene expression. A hypermethylated/up-regulated transcription factor of inhibited expression and possibly enhanced expression, promoting subsequent starch degradation in rice stems under MD treatment. In addition, a hypermethylated/down-regulated transcription factor of was predicted to interact with, and thereby decrease the expression of, abscisic acid 8'-hydroxylase1, thus increasing abscisic acid concentration under MD treatment. Our findings provide insight into the DNA methylation dynamics in carbon reserve remobilization of rice stems, demonstrate that MD increased this remobilization, and suggest a link between DNA methylation and gene expression in rice stems during grain filling.
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http://dx.doi.org/10.1104/pp.20.00141DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7401115PMC
August 2020

Enhanced Generation of Induced Cardiomyocytes Using a Small-Molecule Cocktail to Overcome Barriers to Cardiac Cellular Reprogramming.

J Am Heart Assoc 2020 06 5;9(12):e015686. Epub 2020 Jun 5.

Michael E. DeBakey Department of Surgery Baylor College of Medicine Houston TX.

Background Given known inefficiencies in reprogramming of fibroblasts into mature induced cardiomyocytes (iCMs), we sought to identify small molecules that would overcome these barriers to cardiac cell transdifferentiation. Methods and Results We screened alternative combinations of compounds known to impact cell reprogramming using morphologic and functional cell differentiation assays in vitro. After screening 6 putative reprogramming factors, we found that a combination of the histone deacetylase inhibitor sodium butyrate, the WNT inhibitor ICG-001, and the cardiac growth regulator retinoic acid (RA) maximally enhanced iCM generation from primary rat cardiac fibroblasts when combined with administration of the cardiodifferentiating transcription factors Gata4, Mef2C, and Tbx5 (GMT) compared with GMT administration alone (23±1.5% versus 3.3±0.2%; <0.0001). Expression of the cardiac markers cardiac troponin T, Myh6, and Nkx2.5 was upregulated as early as 10 days after GMT-sodium butyrate, ICG-001, and RA treatment. Human iCM generation was likewise enhanced when administration of the human cardiac reprogramming factors GMT, Hand2, and Myocardin plus miR-590 was combined with sodium butyrate, ICG-001, and RA compared with GMT, Hand2, and Myocardin plus miR-590 treatment alone (25±1.3% versus 5.7±0.4%; <0.0001). Rat and human iCMs also more frequently demonstrated spontaneous beating in coculture with neonatal cardiomyocytes with the addition of sodium butyrate, ICG-001, and RA to transcription factor cocktails compared with transcription factor treatment alone. Conclusions The combined administration of histone deacetylase and WNT inhibitors with RA enhances rat and human iCM generation induced by transcription factor administration alone. These findings suggest opportunities for improved translational approaches for cardiac regeneration.
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http://dx.doi.org/10.1161/JAHA.119.015686DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7429035PMC
June 2020

Spermidine Enhanced Free Polyamine Levels and Expression of Polyamine Biosynthesis Enzyme Gene in Rice Spikelets under Heat Tolerance before Heading.

Sci Rep 2020 06 2;10(1):8976. Epub 2020 Jun 2.

College of Life Sciences, Nantong University, Nantong, Jiangsu, China.

High temperatures (HT) before heading strongly inhibit the development of spikelets in rice. Spermidine (Spd) can improve rice's resistance to HT stress; however, the mechanism underlying this effect has not been elucidated. This study investigated several parameters, including yield, superoxide anion (O), protective enzyme activities, and polyamine content, in a heat-sensitive genotype, Shuanggui 1. The yield and yield components decreased dramatically when subjected to HT stress, while this reduction could be partially recovered by exogenous Spd. Spd also slowed the generation rate of O and increased protective enzyme, superoxide dismutase (SOD) and catalase (CAT) activities both under normal and high temperatures, which suggested that Spd may participate in the antioxidant system. Furthermore, genes involved in polyamine synthesis were analyzed. The results show that HT before heading significantly increased the expression of arginine decarboxylase OsADC1, Spd synthase OsSPDS1 and OsSPDS3 and had little effect on the expression of the S-adenosylmethionine decarboxylase OsSAMDC2 and ornithine decarboxylase OsODC1. In addition, exogenous Spd considerably reduced the expression of OsSAMDC2, OsSPDS1 and OsSPDS3 under HT but not the expression of OsADC1. The above mentioned results indicate that the exogenous Spd could help young rice spikelets to resist HT stress by reducing the expression of OsSAMDC2, OsSPDS1 and OsSPDS3, resulting in higher levels of endogenous Spd and Spm, which were also positively correlated with yield. In conclusion, the adverse effect of HT stress on young spikelets seems to be alleviated by increasing the amounts of Spd and Spm, which provides guidance for adaptation to heat stress during rice production.
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http://dx.doi.org/10.1038/s41598-020-64978-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7265301PMC
June 2020

Effects of nitrogen fertilizer on structure and physicochemical properties of 'super' rice starch.

Carbohydr Polym 2020 Jul 8;239:116237. Epub 2020 Apr 8.

Jiangsu Key Laboratory of Crop Genetics and Physiology/ Jiangsu Key Laboratory of Crop Cultivation and Physiology, Agricultural College of Yangzhou University, Yangzhou 225009, China; Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou 225009, China; Key Laboratory of Plant Functional Genomics of the Ministry of Education/ Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, College of Agriculture, Yangzhou University, Yangzhou 225009, China. Electronic address:

Nitrogen fertilizer is an essential nutrient for rice (Oryza sativa L.), especially, for newly bred 'super' rice cultivars with great yield potential. The effects of nitrogen fertilizer (0, 100, 200, 300, 400 kg N ha) on the physicochemical properties of two high yielding 'super' rice Yongyou 2640 and Lianjing 7 were investigated in this study. The application of nitrogen fertilizer affects the structure of rice starch, thus changing its functional properties, which ultimately leads to a change in the quality of both rice cultivars. There were dose effects of nitrogen fertilizer on grain quality. Grain quality was improved under moderate nitrogen inputs (100 & 200 kg N ha), but deteriorated at excessive nitrogen levels (300 & 400 kg N ha). With moderate N application, starch granule size increased and the surface of starch granule became smoother; there were higher proportion of short branch-chain of amylopectin and lower proportion of long branch-chain of amylopectin with low relative crystallinity, lower degree of order of structure and higher content of amorphous structure at the outer region of the starch granules; peak viscosity, hot viscosity, breakdown value were increased while setback and pasting temperature were decreased; gelatinization temperature, gelatinization enthalpy, retrogradation enthalpy, retrogradation percentage, hardness were decreased while viscosity were increased. At excessive nitrogen inputs, the grain quality was deteriorated and the opposite results of structure and physicochemical properties of rice starch were observed. These results indicate that nitrogen fertilizer significantly affected the structure and physicochemical properties of rice starch, and appropriate fertilization would improve rice grain quality.
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http://dx.doi.org/10.1016/j.carbpol.2020.116237DOI Listing
July 2020

Physiological mechanism underlying the effect of high temperature during anthesis on spikelet-opening of photo-thermo-sensitive genic male sterile rice lines.

Sci Rep 2020 02 10;10(1):2210. Epub 2020 Feb 10.

Jiangsu Key Laboratory of Crop Genetics and Physiology/Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, Jiangsu, China.

Decrease in the grain yield resulted from a low percentage of opened spikelets under high temperature (HT) during anthesis is a serious problem in the seed production of photo-thermo-sensitive genic male sterile (PTGMS) rice (Oryza sativa L.) lines, and the mechanism is little understood. Elucidating the physiological mechanism underlying the effect of HT during anthesis on spikelet-opening of PTGMS lines would have great significance in exploring the effective way to mitigate the adverse effect of HT. In this study, two PTGMS lines and one restorer line of rice were used and were subjected to normal temperature (NT) and HT treatments. The results showed that, compared with NT, HT significantly decreased the percentage of opened spikelets, fertilization percentage and seed-setting by significantly increasing the percentage of wrapped spikelets and reducing the spikelet-opening angle, length of spikelet-opening time. The HT significantly decreased the contents of soluble sugars, jasmonic acid (JA) and methyl jasmonate (MeJA) in the lodicules before and at glume-opening, which were significantly correlated with and accounts for the low percentage of opened spikelets under HT for rice, especially for the PTGMS lines.
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http://dx.doi.org/10.1038/s41598-020-59183-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7010791PMC
February 2020

Regulation of gene expression involved in the remobilization of rice straw carbon reserves results from moderate soil drying during grain filling.

Plant J 2020 02 15;101(3):604-618. Epub 2019 Nov 15.

Southern Regional Collaborative Innovation Center for Grain and Oil Crops in China, College of Agriculture, Hunan Agricultural University, Changsha, 410128, China.

Carbon reserves in rice straw before flowering contribute greatly to grain filling. Moderate soil drying imposed at the post-anthesis stage significantly promotes carbon reserve remobilization in straws of rice, but the regulation of this process at the proteomic and transcriptomic level remains poorly understood. In this study, we applied moderate soil drying (MD) to rice at the post-anthesis stage, which was followed by dynamic proteomic and transcriptomic studies using SWATH-MS and RNA-seq analysis. MD treatment upregulated the proteins alpha-glucosidase, beta-glucosidase and starch phosphorylase, which are responsible for starch degradation. Furthermore, MD treatment enhanced the expression of proteins involved in the sucrose synthesis pathway, including SPS8 and SPP1. In addition, various monosaccharide transporters (MSTs) and sucrose transporter 2 (SUT2), which are pivotal in carbon reserve remobilization, were also upregulated in straw by MD treatment. Differentially expressed transcription factors, including GRAS, TCP, trihelix, TALE, C3H, and NF-YC, were predicted to interact with other proteins to mediate carbon reserve remobilization in response to MD treatment. Further correlation analysis revealed that the abundances of most of the differentially expressed proteins were not correlated with the corresponding transcript levels, indicating that the carbon reserve remobilization process was probably regulated by posttranscriptional modification. Our results provide insights into the molecular mechanisms underlying the regulation of carbon reserve remobilization from straw to grain in rice under MD conditions.
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http://dx.doi.org/10.1111/tpj.14565DOI Listing
February 2020

Role of brassinosteroids in rice spikelet differentiation and degeneration under soil-drying during panicle development.

BMC Plant Biol 2019 Sep 18;19(1):409. Epub 2019 Sep 18.

Department of Biology, Hong Kong Baptist University, Hong Kong, China.

Background: Brassinosteroids (BRs) are a new group of plant hormones and play important roles in plant growth and development. However, little information is available if BRs could regulate spikelet development in rice (Oryza sativa L.) especially under soil-drying conditions. This study investigated whether and how BRs mediate the effect of soil-drying on spikelet differentiation and degeneration in rice. A rice cultivar was field-grown and exposed to three soil moisture treatments during panicle development, that is, well-watered (WW), moderate soil-drying (MD) and severe soil-drying (SD).

Results: Compared with the WW treatment, the MD treatment enhanced BRs biosynthesis in young panicles, increased spikelet differentiation and reduced spikelet degeneration. The SD treatment had the opposite effects. Changes in expression levels of key rice inflorescence development genes (OsAPO2 and OsTAW1), ascorbic acid (AsA) content, and activities of enzymes involved AsA synthesis and recycle, and amount of nonstructural carbohydrates (NSC) in young panicles were consistent with those in BRs levels, whereas hydrogen peroxide (HO) content showed opposite trend. Knockdown of the BRs synthesis gene OsD11 or application of a BRs biosynthesis inhibitor to young panicles markedly decreased OsAPO2 and OsTAW1 expression levels, BRs and AsA contents, activities of enzymes involved AsA synthesis and recycle, NSC amount in rice panicles and spikelet differentiation but increased the HO content and spikelet degeneration compared to the control (the wide type or application of water). The opposite effects were observed when exogenous BRs were applied.

Conclusions: The results suggest that BRs mediate the effect of soil-drying on spikelet differentiation and degeneration, and elevated BRs levels in rice panicles promote spikelet development under MD by enhancing inflorescence meristem activity, AsA recycle and NSC partitioning to the growing panicles.
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http://dx.doi.org/10.1186/s12870-019-2025-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6749693PMC
September 2019

Brassinosteroids function in spikelet differentiation and degeneration in rice.

J Integr Plant Biol 2019 Aug 1;61(8):943-963. Epub 2019 Jan 1.

Department of Biology, Hong Kong Baptist University, Hong Kong, China.

Brassinosteroids (BRs) play crucial roles in many aspects of plant development. However, their function in spikelet differentiation and degeneration in rice (Oryza sativa L.) remains unclear. Here, we investigated the roles of these phytohormones in spikelet development in field-grown rice subjected to five different nitrogen (N) fertilization treatments during panicle differentiation. BR levels and expression of genes involved in BR biosynthesis and signal transduction were measured in spikelets. Pollen fertility and the number of differentiated spikelets were closely associated with 24-epicastasterone (24-epiCS) and 28-homobrassinolide (28-homoBL) levels in spikelets. Enhanced BR biosynthesis and signal transduction, in response to N treatment, enhanced spikelet differentiation, reduced spikelet degeneration, and increased grain yield. Increases in proton-pumping ATPase activity, ATP concentration, energy charge, and antioxidant system (AOS) levels were consistent with 24-epiCS and 28-homoBL concentrations. Exogenous application of 24-epiCS or 28-homoBL on young panicles induced a marked increase in endogenous 24-epiCS or 28-homoBL levels, energy charge, AOS levels, spikelet differentiation, and panicle weight. The opposite effects were observed following treatment with a BR biosynthesis inhibitor. Our findings indicate that, in rice, BRs mediate the effects of N fertilization on spikelet development and play a role in promoting spikelet development through increasing AOS levels and energy charge during panicle development.
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http://dx.doi.org/10.1111/jipb.12722DOI Listing
August 2019

Roles of nitrogen and cytokinin signals in root and shoot communications in maximizing of plant productivity and their agronomic applications.

Plant Sci 2018 Sep 19;274:320-331. Epub 2018 Jun 19.

Jiangsu Key Laboratory of Crop Genetics and Physiology / Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou 225009, China. Electronic address:

Nitrogen is an essential, often limiting, factor in plant growth and development. To regulate growth under limited nitrogen supply, plants sense the internal and external nitrogen status, and coordinate various metabolic processes and developmental programs accordingly. This coordination requires the transmission of various signaling molecules that move across the entire plant. Cytokinins, phytohormones derived from adenine and synthesized in various parts of the plant, are considered major local and long-distance messengers. Cytokinin metabolism and signaling are closely associated with nitrogen availability. They are systemically transported via the vasculature from plant roots to shoots, and vice versa, thereby coordinating shoot and root development. Tight linkage exists between the nitrogen signaling network and cytokinins during diverse developmental and physiological processes. However, the cytokinin-nitrogen interactions and the communication systems involved in sensing rhizospheric nitrogen status and in regulating canopy development remain obscure. We review current knowledge on cytokinin biosynthesis, transport and signaling, nitrogen acquisition, metabolism and signaling, and their interactive roles in regulating root-shoot morphological and physiological characteristics. We also discuss the role of spatio-temporal regulation of cytokinins in enhancing beneficial crop traits of yield and nitrogen use efficiency.
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http://dx.doi.org/10.1016/j.plantsci.2018.06.010DOI Listing
September 2018

p63 Silencing induces reprogramming of cardiac fibroblasts into cardiomyocyte-like cells.

J Thorac Cardiovasc Surg 2018 08 13;156(2):556-565.e1. Epub 2018 Apr 13.

Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, Tex. Electronic address:

Objective: Reprogramming of fibroblasts into induced cardiomyocytes represents a potential new therapy for heart failure. We hypothesized that inactivation of p63, a p53 gene family member, may help overcome human cell resistance to reprogramming.

Methods: p63 Knockout () and knockdown murine embryonic fibroblasts (MEFs), p63 adult murine cardiac fibroblasts, and human cardiac fibroblasts were assessed for cardiomyocyte-specific feature changes, with or without treatment by the cardiac transcription factors Hand2-Myocardin (HM).

Results: Flow cytometry revealed that a significantly greater number of p63 MEFs expressed the cardiac-specific marker cardiac troponin T (cTnT) in culture compared with wild-type (WT) cells (38% ± 11% vs 0.9% ± 0.9%, P < .05). HM treatment of p63 MEFs increased cTnT expression to 74% ± 3% of cells but did not induce cTnT expression in wild-type murine embryonic fibroblasts. shRNA-mediated p63 knockdown likewise yielded a 20-fold increase in cTnT microRNA expression compared with untreated MEFs. Adult murine cardiac fibroblasts demonstrated a 200-fold increase in cTnT gene expression after inducible p63 knockout and expressed sarcomeric α-actinin as well as cTnT. These p63 adult cardiac fibroblasts exhibited calcium transients and electrically stimulated contractions when co-cultured with neonatal rat cardiomyocytes and treated with HM. Increased expression of cTnT and other marker genes was also observed in p63 knockdown human cardiac fibroblasts procured from patients undergoing procedures for heart failure.

Conclusions: Downregulation of p63 facilitates direct cardiac cellular reprogramming and may help overcome the resistance of human cells to reprogramming.
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http://dx.doi.org/10.1016/j.jtcvs.2018.03.162DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6050095PMC
August 2018

Pursuing sustainable productivity with millions of smallholder farmers.

Nature 2018 03 7;555(7696):363-366. Epub 2018 Mar 7.

Institute of Agricultural Resources and Environment, Hebei Academy of Agriculture and Forestry Sciences, Shijiazhuang 050051, China.

Sustainably feeding a growing population is a grand challenge, and one that is particularly difficult in regions that are dominated by smallholder farming. Despite local successes, mobilizing vast smallholder communities with science- and evidence-based management practices to simultaneously address production and pollution problems has been infeasible. Here we report the outcome of concerted efforts in engaging millions of Chinese smallholder farmers to adopt enhanced management practices for greater yield and environmental performance. First, we conducted field trials across China's major agroecological zones to develop locally applicable recommendations using a comprehensive decision-support program. Engaging farmers to adopt those recommendations involved the collaboration of a core network of 1,152 researchers with numerous extension agents and agribusiness personnel. From 2005 to 2015, about 20.9 million farmers in 452 counties adopted enhanced management practices in fields with a total of 37.7 million cumulative hectares over the years. Average yields (maize, rice and wheat) increased by 10.8-11.5%, generating a net grain output of 33 million tonnes (Mt). At the same time, application of nitrogen decreased by 14.7-18.1%, saving 1.2 Mt of nitrogen fertilizers. The increased grain output and decreased nitrogen fertilizer use were equivalent to US$12.2 billion. Estimated reactive nitrogen losses averaged 4.5-4.7 kg nitrogen per Megagram (Mg) with the intervention compared to 6.0-6.4 kg nitrogen per Mg without. Greenhouse gas emissions were 328 kg, 812 kg and 434 kg CO equivalent per Mg of maize, rice and wheat produced, respectively, compared to 422 kg, 941 kg and 549 kg CO equivalent per Mg without the intervention. On the basis of a large-scale survey (8.6 million farmer participants) and scenario analyses, we further demonstrate the potential impacts of implementing the enhanced management practices on China's food security and sustainability outlook.
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http://dx.doi.org/10.1038/nature25785DOI Listing
March 2018

Natural variation in the promoter of rice calcineurin B-like protein10 (OsCBL10) affects flooding tolerance during seed germination among rice subspecies.

Plant J 2018 05 1;94(4):612-625. Epub 2018 Apr 1.

State Key Laboratory of Crop Biology, College of Life Science, Shandong Agricultural University, Taian, Shandong, China.

Rice (Oryza sativa L.) has two ecotypes, upland and lowland rice, that have been observed to show different tolerance levels under flooding stress. In this study, two rice cultivars, upland (Up221, flooding-intolerant) and lowland (Low88, flooding-tolerant), were initially used to study their molecular mechanisms in response to flooding germination. We observed that variations in the OsCBL10 promoter sequences in these two cultivars might contribute to this divergence in flooding tolerance. Further analysis using another eight rice cultivars revealed that the OsCBL10 promoter could be classified as either a flooding-tolerant type (T-type) or a flooding-intolerant type (I-type). The OsCBL10 T-type promoter only existed in japonica lowland cultivars, whereas the OsCBL10 I-type promoter existed in japonica upland, indica upland and indica lowland cultivars. Flooding-tolerant rice cultivars containing the OsCBL10 T-type promoter have shown lower Ca flow and higher α-amylase activities in comparison to those in flooding-intolerant cultivars. Furthermore, the OsCBL10 overexpression lines were sensitive to both flooding and hypoxic treatments during rice germination with enhanced Ca flow in comparison to wild-type. Subsequent findings also indicate that OsCBL10 may affect OsCIPK15 protein abundance and its downstream pathways. In summary, our results suggest that the adaptation to flooding stress during rice germination is associated with two different OsCBL10 promoters, which in turn affect OsCBL10 expression in different cultivars and negatively affect OsCIPK15 protein accumulation and its downstream cascade.
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http://dx.doi.org/10.1111/tpj.13881DOI Listing
May 2018

SALL4 as a transcriptional and epigenetic regulator in normal and leukemic hematopoiesis.

Authors:
Jianchang Yang

Biomark Res 2018 3;6. Epub 2018 Jan 3.

Department of Surgery and Medicine, Baylor College of Medicine, Houston, TX 77030 USA.

In recent years, there has been substantial progress in our knowledge of the molecular pathways by which stem cell factor SALL4 regulates the embryonic stem cell (ESC) properties, developmental events, and human cancers. This review summarizes recent advances in the biology of SALL4 with a focus on its regulatory functions in normal and leukemic hematopoiesis. In the normal hematopoietic system, expression of SALL4 is mainly enriched in the bone marrow hematopoietic stem/progenitor cells (HSCs/HPCs), but is rapidly silenced following lineage differentiation. In hematopoietic malignancies, however, SALL4 expression is abnormally re-activated and linked with deteriorated disease status in patients. Further, SALL4 activation participates in the pathogenesis of tumor initiation and disease progression. Thus, a better understanding of SALL4's biologic functions and mechanisms will facilitate development of advanced targeted anti-leukemia approaches in future.
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http://dx.doi.org/10.1186/s40364-017-0115-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5751604PMC
January 2018

Stomatal conductance, mesophyll conductance, and transpiration efficiency in relation to leaf anatomy in rice and wheat genotypes under drought.

J Exp Bot 2017 Nov;68(18):5191-5205

College of Agriculture, Yangzhou University, 48 Wenhui East Road, Yangzhou, Jiangsu 225009, China.

Increasing leaf transpiration efficiency (TE) may provide leads for growing rice like dryland cereals such as wheat (Triticum aestivum). To explore avenues for improving TE in rice, variations in stomatal conductance (gs) and mesophyll conductance (gm) and their anatomical determinants were evaluated in two cultivars from each of lowland, aerobic, and upland groups of Oryza sativa, one cultivar of O. glaberrima, and two cultivars of T. aestivum, under three water regimes. The TE of upland rice, O. glaberrima, and wheat was more responsive to the gm/gs ratio than that of lowland and aerobic rice. Overall, the explanatory power of the particular anatomical trait varied among species. Low stomatal density mostly explained the low gs in drought-tolerant rice, whereas rice genotypes with smaller stomata generally responded more strongly to drought. Compared with rice, wheat had a higher gm, which was associated with thicker mesophyll tissue, mesophyll and chloroplasts more exposed to intercellular spaces, and thinner cell walls. Upland rice, O. glaberrima, and wheat cultivars minimized the decrease in gm under drought by maintaining high ratios of chloroplasts to exposed mesophyll cell walls. Rice TE could be improved by increasing the gm/gs ratio via modifying anatomical traits.
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http://dx.doi.org/10.1093/jxb/erx314DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5853379PMC
November 2017

The stem cell factor SALL4 is an essential transcriptional regulator in mixed lineage leukemia-rearranged leukemogenesis.

J Hematol Oncol 2017 10 3;10(1):159. Epub 2017 Oct 3.

Department of Surgery and Medicine, Baylor College of Medicine (BCM), Houston, TX, 77030, USA.

Background: The stem cell factor spalt-like transcription factor 4 (SALL4) plays important roles in normal hematopoiesis and also in leukemogenesis. We previously reported that SALL4 exerts its effect by recruiting important epigenetic factors such as DNA methyltransferases DNMT1 and lysine-specific demethylase 1 (LSD1/KDM1A). Both of these proteins are critically involved in mixed lineage leukemia (MLL)-rearranged (MLL-r) leukemia, which has a very poor clinical prognosis. Recently, SALL4 has been further linked to the functions of MLL and its target gene homeobox A9 (HOXA9). However, it remains unclear whether SALL4 is indeed a key player in MLL-r leukemia pathogenesis.

Methods: Using a mouse bone marrow retroviral transduction/ transplantation approach combined with tamoxifen-inducible, CreER-mediated Sall4 gene deletion, we studied SALL4 functions in leukemic transformation that was induced by MLL-AF9-one of the most common MLL-r oncoproteins found in patients. In addition, the underlying transcriptional and epigenetic mechanisms were explored using chromatin immunoprecipitation (ChIP) sequencing (ChIP-Seq), mRNA microarray, qRT-PCR, histone modification, co-immunoprecipitation (co-IP), cell cycle, and apoptosis assays. The effects of SALL4 loss on normal hematopoiesis in mice were also investigated.

Results: In vitro and in vivo studies revealed that SALL4 expression is critically required for MLL-AF9-induced leukemic transformation and disease progression in mice. Loss of SALL4 in MLL-AF9-transformed cells induced apoptosis and cell cycle arrest at G1. ChIP-Seq assay identified that Sall4 binds to key MLL-AF9 target genes and important MLL-r or non-MLL-r leukemia-related genes. ChIP-PCR assays indicated that SALL4 affects the levels of the histone modification markers H3K79me2/3 and H3K4me3 at MLL-AF9 target gene promoters by physically interacting with DOT1-like histone H3K79 methyltransferase (DOT1l) and LSD1/KDM1A, and thereby regulates transcript expression. Surprisingly, normal Sall4 /CreER mice treated with tamoxifen or vav-Cre-mediated (hematopoietic-specific) Sall4 mice were healthy and displayed no significant hematopoietic defects.

Conclusions: Our findings indicate that SALL4 critically contributes to MLL-AF9-induced leukemia, unraveling the underlying transcriptional and epigenetic mechanisms in this disease and suggesting that selectively targeting the SALL4 pathway may be a promising approach for managing human MLL-r leukemia.
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http://dx.doi.org/10.1186/s13045-017-0531-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5627455PMC
October 2017

Comparison of Structural and Functional Properties of Wheat Starch Under Different Soil Drought Conditions.

Sci Rep 2017 09 26;7(1):12312. Epub 2017 Sep 26.

School of Life Sciences and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China.

Drought influences cereal crop yield and quality. However, little is known about changes in the structural and functional properties of wheat starch under soil drought conditions. In this study, two wheat cultivars were subjected to well-watered (WW), moderate soil-drought (MD), and severe soil-drought (SD) from 7 tillers in the main stem to maturity. The structural and functional properties of the resultant endosperm starch were investigated. In comparison with WW soil, the MD increased starch accumulation in grains, the proportion of large starch granules, amylose and amylopectin long branch chain contents, and average amylopectin branch chain length, which were accompanied by the increase in activities of granule bound starch synthase and soluble starch synthase. MD treated-starch had a lower gelatinization enthalpy, and swelling power, but a higher gelatinization temperature, retrogradation enthalpy, and retrogradation percentage when compared to WW conditions. The MD also increased starch resistance to acid hydrolysis, amylase hydrolysis, and in vitro digestion. The SD had the opposite effects to the MD in all cases. The results suggest that soil drought more severely affects amylose synthesis than amylopectin synthesis in wheat grains, and moderate soil-drought improves molecular structure and functional properties of the starch.
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http://dx.doi.org/10.1038/s41598-017-10802-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5615046PMC
September 2017

Cardiac reprogramming factor Gata4 reduces postinfarct cardiac fibrosis through direct repression of the profibrotic mediator snail.

J Thorac Cardiovasc Surg 2017 11 21;154(5):1601-1610.e3. Epub 2017 Jun 21.

Division of Cardiothoracic Surgery, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, Tex; Department of Cardiovascular Surgery, Texas Heart Institute, Houston, Tex. Electronic address:

Objective: The administration of a variety of reprogramming factor cocktails has now been shown to reprogram cardiac fibroblasts into induced cardiomyocyte-like cells. However, reductions in ventricular fibrosis observed after reprogramming factor administration seem to far exceed the extent of induced cardiomyocyte-like cell generation in vivo. We investigated whether reprogramming factor administration might primarily play a role in activating antifibrotic molecular pathways.

Methods: Adult rat cardiac fibroblasts were infected with lentivirus encoding the transcription factors Gata4, Mef2c, or Tbx5, all 3 vectors, or a green fluorescent protein control vector. Gene and protein expression assays were performed to identify relevant antifibrotic targets of these factors. The antifibrotic effects of these factors were then investigated in a rat coronary ligation model.

Results: Gata4, Mef2c, or Tbx5 administration to rat cardiac fibroblasts in vitro significantly downregulated expression of Snail and the profibrotic factors connective tissue growth factor, collagen1a1, and fibronectin. Of these factors, Gata4 was shown to be the one responsible for the downregulation of the profibrotic factors and Snail (mRNA expression fold change relative to green fluorescent protein for Snail, Gata4: 0.5 ± 0.3, Mef2c: 1.3 ± 1.0, Tbx5: 0.9 ± 0.5, Gata4, Mef2c, or Tbx5: 0.6 ± 0.2, P < .05). Chromatin immunoprecipitation quantitative polymerase chain reaction identified Gata4 binding sites in the Snail promoter. In a rat coronary ligation model, only Gata4 administration alone improved postinfarct ventricular function and reduced the extent of postinfarct fibrosis.

Conclusions: Gata4 administration reduces postinfarct ventricular fibrosis and improves ventricular function in a rat coronary ligation model, potentially as a result of Gata4-mediated downregulation of the profibrotic mediator Snail.
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http://dx.doi.org/10.1016/j.jtcvs.2017.06.035DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5647235PMC
November 2017

Photosynthetic Properties and Potentials for Improvement of Photosynthesis in Pale Green Leaf Rice under High Light Conditions.

Front Plant Sci 2017 20;8:1082. Epub 2017 Jun 20.

Jiangsu Key Laboratory of Crop Genetics and Physiology/Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou UniversityYangzhou, China.

Light is the driving force of plant growth, providing the energy required for photosynthesis. However, photosynthesis is also vulnerable to light-induced damage caused by the production of reactive oxygen species (ROS). Plants have therefore evolved various protective mechanisms such as non-photochemical quenching () to dissipate excessively absorbed solar energy as heat; however, photoinhibition and represent a significant loss in solar energy and photosynthetic efficiency, which lowers the yield potential in crops. To estimate light capture and light energy conversion in rice, a genotype with pale green leaves () and a normally pigmented control (Z802) were subjected to high (HL) and low light (LL). Chlorophyll content, light absorption, chloroplast micrographs, abundance of light-harvesting complex (LHC) binding proteins, electron transport rates (ETR), photochemical and non-photochemical quenching, and generation of ROS were subsequently examined. had a smaller size of light-harvesting chlorophyll antenna and absorbed less photons than Z802. and the generation of ROS were also low, while photosystem II efficiency and ETR were high, resulting in improved photosynthesis and less photoinhibition in than Z802. Chlorophyll synthesis and solar conversion efficiency were higher in under HL compared to LL treatment, while Z802 showed an opposite trend due to the high level of photoinhibition under HL. In Z802, excessive absorption of solar energy not only increased the generation of ROS and , but also exacerbated the effects of increases in temperature, causing midday depression in photosynthesis. These results suggest that photosynthesis and yield potential in rice could be enhanced by truncated light-harvesting chlorophyll antenna size.
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http://dx.doi.org/10.3389/fpls.2017.01082DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5476740PMC
June 2017

Changes in mineral elements and starch quality of grains during the improvement of japonica rice cultivars.

J Sci Food Agric 2018 Jan 6;98(1):122-133. Epub 2017 Jul 6.

Jiangsu Key Laboratory of Crop Genetics and Physiology, Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, China.

Background: The improvement of rice cultivars plays an important role in yield increase. However, little is known about the changes in starch quality and mineral elements during the improvement of rice cultivars. This study was conducted to investigate the changes in starch quality and mineral elements in japonica rice cultivars.

Results: Twelve typical rice cultivars, applied in the production in Jiangsu province during the last 60 years, were grown in the paddy fields. These cultivars were classified into six types according to their application times, plant types and genotypes. The nitrogen (N), phosphorus (P) and, and potassium (K) were mainly distributed in endosperm, bran and bran, respectively. Secondary and micromineral nutrients were distributed throughout grains. With the improvement of cultivars, total N contents gradually decreased, while total P, K and magnesium contents increased in grains. Total copper and zinc contents in type 80'S in grains were highest. The improvement of cultivars enhanced palatability (better gelatinisation enthalpy and amylose content), taste (better protein content) and protein quality (better protein components and essential amino acids). Correlation analysis indicated the close relationship between mineral elements and starch quality.

Conclusion: The mineral elements and starch quality of grains during the improvement of japonica rice cultivars are improved. © 2017 Society of Chemical Industry.
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http://dx.doi.org/10.1002/jsfa.8446DOI Listing
January 2018

MiR-590 Promotes Transdifferentiation of Porcine and Human Fibroblasts Toward a Cardiomyocyte-Like Fate by Directly Repressing Specificity Protein 1.

J Am Heart Assoc 2016 11 10;5(11). Epub 2016 Nov 10.

Department of Surgery, Baylor College of Medicine, Houston, TX

Background: Reprogramming of cardiac fibroblasts into induced cardiomyocyte-like cells represents a promising potential new therapy for treating heart disease, inducing significant improvements in postinfarct ventricular function in rodent models. Because reprogramming factors effective in transdifferentiating rodent cells are not sufficient to reprogram human cells, we sought to identify reprogramming factors potentially applicable to human studies.

Methods And Results: Lentivirus vectors expressing Gata4, Mef2c, and Tbx5 (GMT); Hand2 (H), Myocardin (My), or microRNA (miR)-590 were administered to rat, porcine, and human cardiac fibroblasts in vitro. induced cardiomyocyte-like cell production was then evaluated by assessing expression of the cardiomyocyte marker, cardiac troponin T (cTnT), whereas signaling pathway studies were performed to identify reprogramming factor targets. GMT administration induced cTnT expression in ≈6% of rat fibroblasts, but failed to induce cTnT expression in porcine or human cardiac fibroblasts. Addition of H/My and/or miR-590 to GMT administration resulted in cTNT expression in ≈5% of porcine and human fibroblasts and also upregulated the expression of the cardiac genes, MYH6 and TNNT2. When cocultured with murine cardiomyocytes, cTnT-expressing porcine cardiac fibroblasts exhibited spontaneous contractions. Administration of GMT plus either H/My or miR-590 alone also downregulated fibroblast genes COL1A1 and COL3A1. miR-590 was shown to directly suppress the zinc finger protein, specificity protein 1 (Sp1), which was able to substitute for miR-590 in inducing cellular reprogramming.

Conclusions: These data support porcine studies as a surrogate for testing human cardiac reprogramming, and suggest that miR-590-mediated repression of Sp1 represents an alternative pathway for enhancing human cardiac cellular reprogramming.
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http://dx.doi.org/10.1161/JAHA.116.003922DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5210349PMC
November 2016

Science and technology backyard improves farmers' productivity.

Authors:
Jianchang Yang

Sci China Life Sci 2016 Dec 31;59(12):1348-1349. Epub 2016 Oct 31.

College of Agriculture, Yangzhou University, Yangzhou, 225009, China.

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http://dx.doi.org/10.1007/s11427-016-0301-xDOI Listing
December 2016

Grain Filling Characteristics and Their Relations with Endogenous Hormones in Large- and Small-Grain Mutants of Rice.

PLoS One 2016 25;11(10):e0165321. Epub 2016 Oct 25.

Jiangsu Key Laboratory of Crop Genetics and Physiology, Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, China.

This study determined if the variation in grain filling parameters between two different spikelet types of rice (Oryza sativa L.) is regulated by the hormonal levels in the grains. Two rice mutants, namely, a large-grain mutant (AZU-M) and a small-grain mutant (ZF802-M), and their respective wild types (AZU-WT and ZF802-WT) were grown in the field. The endosperm cell division rate, filling rate, and hormonal levels: zeatin + zeatin riboside (Z+ZR), indo-3-acetic acid (IAA), polyamines (PAs), and abscisic acid (ABA) were determined. The results showed that there was no significant difference between the filling and endosperm cell division rates. These rates were synchronous between the superior and inferior spikelets for both mutants. However, the abovementioned parameters were significantly different between the two spikelet types for the two wild types. The superior spikelets filled faster and their filling rate was higher compared to the inferior ones. Changes in the concentrations of plant hormones were consistent with the observed endosperm cell division rate and the filling rate for both types of spikelets of mutant and wild type plants. Regression analysis showed a significant positive correlation between cell division and filling rates with the concentrations of the investigated hormones. Exogenous chemical application verified the role of ABA, IAA, and PAs in grain filling. The results indicate that poor filling of inferior spikelets in rice occurs primarily due to the reduced hormone concentrations therein, leading to lower division rate of endosperm cells, fewer endosperm cells, slower filling rate, and smaller grain weight.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0165321PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5079568PMC
June 2017

In situ reprogramming to transdifferentiate fibroblasts into cardiomyocytes using adenoviral vectors: Implications for clinical myocardial regeneration.

J Thorac Cardiovasc Surg 2017 02 23;153(2):329-339.e3. Epub 2016 Sep 23.

Division of Cardiothoracic Surgery, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, Tex; Department of Cardiovascular Surgery, Texas Heart Institute, Houston, Tex. Electronic address:

Objective: The reprogramming of cardiac fibroblasts into induced cardiomyocyte-like cells improves ventricular function in myocardial infarction models. Only integrating persistent expression vectors have thus far been used to induce reprogramming, potentially limiting its clinical applicability. We therefore tested the reprogramming potential of nonintegrating, acute expression adenoviral (Ad) vectors.

Methods: Ad or lentivirus vectors encoding Gata4 (G), Mef2c (M), and Tbx5 (T) were validated in vitro. Sprague-Dawley rats then underwent coronary ligation and Ad-mediated administration of vascular endothelial growth factor to generate infarct prevascularization. Three weeks later, animals received Ad or lentivirus encoding G, M, or T (AdGMT or LentiGMT) or an equivalent dose of a null vector (n = 11, 10, and 10, respectively). Outcomes were analyzed by echocardiography, magnetic resonance imaging, and histology.

Results: Ad and lentivirus vectors provided equivalent G, M, and T expression in vitro. AdGMT and LentiGMT both likewise induced expression of the cardiomyocyte marker cardiac troponin T in approximately 6% of cardiac fibroblasts versus <1% cardiac troponin T expression in AdNull (adenoviral vector that does not encode a transgene)-treated cells. Infarcted myocardium that had been treated with AdGMT likewise demonstrated greater density of cells expressing the cardiomyocyte marker beta myosin heavy chain 7 compared with AdNull-treated animals. Echocardiography demonstrated that AdGMT and LentiGMT both increased ejection fraction compared with AdNull (AdGMT: 21% ± 3%, LentiGMT: 14% ± 5%, AdNull: -0.4% ± 2%; P < .05).

Conclusions: Ad vectors are at least as effective as lentiviral vectors in inducing cardiac fibroblast transdifferentiation into induced cardiomyocyte-like cells and improving cardiac function in postinfarct rat hearts. Short-term expression Ad vectors may represent an important means to induce cardiac cellular reprogramming in humans.
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http://dx.doi.org/10.1016/j.jtcvs.2016.09.041DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5297447PMC
February 2017

Direct Cardiac Cellular Reprogramming for Cardiac Regeneration.

Curr Treat Options Cardiovasc Med 2016 Sep;18(9):58

Michael E. DeBakey Department of Surgery, Baylor College of Medicine, 6501 Fannin Street, Suite NC114, Houston, TX, 77030, USA.

Opinion Statement: Direct cardiac cellular reprogramming of endogenous cardiac fibroblasts directly into induced cardiomyocytes is a highly feasible, promising therapeutic option for patients with advanced heart failure. The most successful cardiac reprogramming strategy will likely be a multimodal approach involving an optimal combination of cardio-differentiating factors, suppression of fibroblast gene expression, and induction of angiogenic factors.
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http://dx.doi.org/10.1007/s11936-016-0480-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5278776PMC
September 2016

Synergistic enhancement of bone regeneration by LMP-1 and HIF-1α delivered by adipose derived stem cells.

Biotechnol Lett 2016 Mar 12;38(3):377-84. Epub 2015 Nov 12.

Department of Human Movement Studies, Xi'an Physical Education University, Xi'an City, Shaanxi Province, 710068, People's Republic of China.

Objectives: To investigate the effect of the combination of LMP-1 and HIF-1α delivered by adipose-derived stem cells (ADSCs) on osteogenesis in vitro and in vivo.

Results: Cells expressing both LMP-1 and HIF-1α genes had elevated mRNA expression of BMP-2, RunX2, alkaline phosphatase, osteocalcin, collagen I and alkaline phosphatase activity compared to cells from other groups. Furthermore, mineralization at day 14 in the cells expressing both LMP-1 and HIF-1α was significantly higher than in all the other groups. In vivo, H&E staining and immunohistochemical analysis of the cell-scaffolds also showed more ectopic bone formation at 4 weeks compared to other groups. More new vessel formation was apparent in the pLVX-rHIF-1α and pLVX-rLMP-1-rHIF-1α groups.

Conclusion: LMP-1 and HIF-1α gene delivery synergistically enhanced the osteo-differentiation of ADSCs in vitro and promoted osteogenesis in vivo compared with LMP-1 alone or HIF-1α alone.
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http://dx.doi.org/10.1007/s10529-015-1988-9DOI Listing
March 2016

Exploiting Co-Benefits of Increased Rice Production and Reduced Greenhouse Gas Emission through Optimized Crop and Soil Management.

PLoS One 2015 9;10(10):e0140023. Epub 2015 Oct 9.

Rothamsted Research, Harpenden, Herts, United Kingdom.

Meeting the future food security challenge without further sacrificing environmental integrity requires transformative changes in managing the key biophysical determinants of increasing agronomic productivity and reducing the environmental footprint. Here, we focus on Chinese rice production and quantitatively address this concern by conducting 403 on-farm trials across diverse rice farming systems. Inherent soil productivity, management practices and rice farming type resulted in confounded and interactive effects on yield, yield gaps and greenhouse gas (GHG) emissions (N2O, CH4 and CO2-equivalent) with both trade-offs and compensating effects. Advances in nitrogen, water and crop management (Best Management Practices-BMPs) helped closing existing yield gaps and resulted in a substantial reduction in CO2-equivalent emission of rice farming despite a tradeoff of increase N2O emission. However, inherent soil properties limited rice yields to a larger extent than previously known. Cultivating inherently better soil also led to lower GHG intensity (GHG emissions per unit yield). Neither adopting BMPs only nor improving soils with low or moderate productivity alone can adequately address the challenge of substantially increasing rice production while reducing the environmental footprint. A combination of both represents the most efficient strategy to harness the combined-benefits of enhanced production and mitigating climate change. Extrapolating from our farm data, this strategy could increase rice production in China by 18%, which would meet the demand for direct human consumption of rice by 2030. It would also reduce fertilizer nitrogen consumption by 22% and decrease CO2-equivalent emissions during the rice growing period by 7% compared with current farming practice continues. Benefits vary by rice-based cropping systems. Single rice systems have the largest food provision benefits due to its wider yield gap and total cultivated area, whereas double-rice system (especially late rice) contributes primarily to reducing GHG emissions. The study therefore provides farm-based evidence for feasible, practical approaches towards achieving realistic food security and environmental quality targets at a national scale.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0140023PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4599856PMC
July 2016

Expression of proteins in superior and inferior spikelets of rice during grain filling under different irrigation regimes.

Proteomics 2016 Jan 30;16(1):102-21. Epub 2015 Nov 30.

School of Life Sciences and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, P. R. China.

Poor grain filling of later-flowering inferior spikelets is a serious problem in modern rice cultivars, but the reason and regulation remain unclear. This study investigated post-anthesis protein expression in relation with grain filling and the possibility to use irrigation methods to enhance grain filling through regulating protein expression. One japonica rice cultivar was field-grown under three irrigation treatments imposed during the grain filling period: alternate wetting and moderate soil-drying (WMD), alternate wetting and severe soil-drying (WSD), and conventional irrigation. High resolution 2DE, combined with MALDI/TOF, was used to compare differential protein expression between superior and inferior spikelets. Results showed that the expression of proteins that function in photosynthesis, carbohydrate and energy metabolism, amino acids metabolism and defense responses were largely down-regulated in inferior spikelets compared to those in superior spikelets. The WMD treatment enhanced grain filling rate and the expression of these proteins, whereas the WSD treatment decreased them. Similar results were observed for transcript levels of the genes encoding these proteins. These results suggest that down-regulated expression of the proteins associated with grain filling contribute to the poor grain filling of inferior spikelets, and post-anthesis WMD could improve grain filling through regulating protein expression in the spikelets.
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http://dx.doi.org/10.1002/pmic.201500070DOI Listing
January 2016

Map-Based Cloning of Seed Dormancy1-2 Identified a Gibberellin Synthesis Gene Regulating the Development of Endosperm-Imposed Dormancy in Rice.

Plant Physiol 2015 Nov 15;169(3):2152-65. Epub 2015 Sep 15.

Plant Science Department, South Dakota State University, Brookings, South Dakota 57007 (H.Y., J.F., L.Z., J.Z., M.S.M., X.-Y.G.);Agricultural College, Yangzhou University, Yangzhou 225009, China (Z.C., J.Y.); andDepartment of Agriculture, Southeast Missouri State University, Malden, Missouri 63863 (D.H.B.)

Natural variation in seed dormancy is controlled by multiple genes mapped as quantitative trait loci in major crop or model plants. This research aimed to clone and characterize the Seed Dormancy1-2 (qSD1-2) locus associated with endosperm-imposed dormancy and plant height in rice (Oryza sativa). qSD1-2 was delimited to a 20-kb region, which contains OsGA20ox2 and had an additive effect on germination. Naturally occurring or induced loss-of-function mutations of the gibberellin (GA) synthesis gene enhanced seed dormancy and also reduced plant height. Expression of this gene in seeds (including endospermic cells) during early development increased GA accumulation to promote tissue morphogenesis and maturation programs. The mutant allele prevalent in semidwarf cultivars reduced the seed GA content by up to 2-fold at the early stage, which decelerated tissue morphogenesis including endosperm cell differentiation, delayed abscisic acid accumulation by a shift in the temporal distribution pattern, and postponed dehydration, physiological maturity, and germinability development. As the endosperm of developing seeds dominates the moisture equilibrium and desiccation status of the embryo in cereal crops, qSD1-2 is proposed to control primary dormancy by a GA-regulated dehydration mechanism. Allelic distribution of OsGA20ox2, the rice Green Revolution gene, was associated with the indica and japonica subspeciation. However, this research provided no evidence that the primitive indica- and common japonica-specific alleles at the presumably domestication-related locus functionally differentiate in plant height and seed dormancy. Thus, the evolutionary mechanism of this agriculturally important gene remains open for discussion.
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http://dx.doi.org/10.1104/pp.15.01202DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4634095PMC
November 2015
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