Tolerance Genes Research Articles

Whole-genome sequencing of allotetraploid bermudagrass reveals the origin of Cynodon and candidate genes for salt tolerance.

Bermudagrass (Cynodon dactylon) is a globally distributed, extensively used warm-season turf and forage grass with high tolerance to salinity and drought stress in alkaline environments. However, the origin of the species and genetic mechanisms for salinity tolerance in the species are basically unknown. Accordingly, we set out to study evolution divergence events in the Cynodon genome and to identify genes for salinity tolerance. We developed a 604.0 Mb chromosome-level polyploid genome sequence for bermudagrass 'A12359' (n = 18). The C. dactylon genome comprises 2 complete sets of homoeologous chromosomes, each with approximately 30 000 genes, and most genes are conserved as syntenic pairs. Phylogenetic study showed that the initial Cynodon species diverged from Oropetium thomaeum approximately 19.7-25.4 million years ago (Mya), the A and B subgenomes of C. dactylon diverged approximately 6.3-9.1 Mya, and the bermudagrass polyploidization event occurred 1.5 Mya on the African continent. Moreover, we identified 82 candidate genes associated with seven agronomic traits using a genome-wide association study, and three single-nucleotide polymorphisms were strongly associated with three salt resistance genes: RAP2-2, CNG channels, and F14D7.1. These genes may be associated with enhanced bermudagrass salt tolerance. These bermudagrass genomic resources, when integrated, may provide fundamental insights into evolution of diploid and tetraploid genomes and enhance the efficacy of comparative genomics in studying salt tolerance in Cynodon.

Genome-wide identification analysis of the 4-Coumarate: CoA ligase (4CL) gene family expression profiles in Juglans regia and its wild relatives J. Mandshurica resistance and salt stress

Persian walnut (Juglans regia) and Manchurian walnut (Juglans mandshurica) belong to Juglandaceae, which are vulnerable, temperate deciduous perennial trees with high economical, ecological, and industrial values. 4-Coumarate: CoA ligase (4CL) plays an essential function in plant development, growth, and stress. Walnut production is challenged by diverse stresses, such as salinity, drought, and diseases. However, the characteristics and expression levels of 4CL gene family in Juglans species resistance and under salt stress are unknown. Here, we identified 36 Jr4CL genes and 31 Jm4CL genes, respectively. Based on phylogenetic relationship analysis, all 4CL genes were divided into three branches. WGD was the major duplication mode for 4CLs in two Juglans species. The phylogenic and collinearity analyses showed that the 4CLs were relatively conserved during evolution, but the gene structures varied widely. 4CLs promoter region contained multiply cis-acting elements related to phytohormones and stress responses. We found that Jr4CLs may be participated in the regulation of resistance to anthracnose. The expression level and some physiological of 4CLs were changed significantly after salt treatment. According to qRT-PCR results, positive regulation was found to be the main mode of regulation of 4CL genes after salt stress. Overall, J. mandshurica outperformed J. regia. Therefore, J. mandshurica can be used as a walnut rootstock to improve salt tolerance. Our results provide new understanding the potential functions of 4CL genes in stress tolerance, offer the theoretical genetic basis of walnut varieties adapted to salt stress, and provide an important reference for breeding cultivated walnuts for stress tolerance.

Mining Heat-Resistant Key Genes of Peony Based on Weighted Gene Co-Expression Network Analysis.

The RNA-Seq and gene expression data of mature leaves under high temperature stress of Paeonia suffruticosa 'Hu Hong' were used to explore the key genes of heat tolerance of peony. The weighted gene co-expression network analysis (WGCNA) method was used to construct the network, and the main modules and core genes of co-expression were screened according to the results of gene expression and module function enrichment analysis. According to the correlation of gene expression, the network was divided into 19 modules. By analyzing the expression patterns of each module gene, Blue, Salmon and Yellow were identified as the key modules of peony heat response related functions. GO and KEGG functional enrichment analysis was performed on the genes in the three modules and a network diagram was constructed. Based on this, two key genes PsWRKY53 (TRINITY_DN60998_c1_g2, TRINITY_DN71537_c0_g1) and PsHsfB2b (TRINITY_DN56794_c0_g1) were excavated, which may play a key role in the heat shock response of peony. The three co-expression modules and two key genes were helpful to further elucidate the heat resistance mechanism of P. suffruticosa 'Hu Hong'.

Genetic diversity and candidate genes for transient waterlogging tolerance in mungbean at the germination and seedling stages.

Mungbean [Vigna radiata var. radiata (L.) Wilczek] production in Asia is detrimentally affected by transient soil waterlogging caused by unseasonal and increasingly frequent extreme precipitation events. While mungbean exhibits sensitivity to waterlogging, there has been insufficient exploration of germplasm for waterlogging tolerance, as well as limited investigation into the genetic basis for tolerance to identify valuable loci. This research investigated the diversity of transient waterlogging tolerance in a mini-core germplasm collection of mungbean and identified candidate genes for adaptive traits of interest using genome-wide association studies (GWAS) at two critical stages of growth: germination and seedling stage (i.e., once the first trifoliate leaf had fully-expanded). In a temperature-controlled glasshouse, 292 genotypes were screened for tolerance after (i) 4 days of waterlogging followed by 7 days of recovery at the germination stage and (ii) 8 days of waterlogging followed by 7 days of recovery at the seedling stage. Tolerance was measured against drained controls. GWAS was conducted using 3,522 high-quality DArTseq-derived SNPs, revealing five significant associations with five phenotypic traits indicating improved tolerance. Waterlogging tolerance was positively correlated with the formation of adventitious roots and higher dry masses. FGGY carbohydrate kinase domain-containing protein was identified as a candidate gene for adventitious rooting and mRNA-uncharacterized LOC111241851, Caffeoyl-CoA O-methyltransferase At4g26220 and MORC family CW-type zinc finger protein 3 and zinc finger protein 2B genes for shoot, root, and total dry matter production. Moderate to high broad-sense heritability was exhibited for all phenotypic traits, including seed emergence (81%), adventitious rooting (56%), shoot dry mass (81%), root dry mass (79%) and SPAD chlorophyll content (70%). The heritability estimates, marker-trait associations, and identification of sources of waterlogging tolerant germplasm from this study demonstrate high potential for marker-assisted selection of tolerance traits to accelerate breeding of climate-resilient mungbean varieties.

Unlocking the genetic diversity and population structure of the newly introduced two-row spring European HerItage Barley collecTion (ExHIBiT).

In the last century, breeding programs have traditionally favoured yield-related traits, grown under high-input conditions, resulting in a loss of genetic diversity and an increased susceptibility to stresses in crops. Thus, exploiting understudied genetic resources, that potentially harbour tolerance genes, is vital for sustainable agriculture. Northern European barley germplasm has been relatively understudied despite its key role within the malting industry. The European Heritage Barley collection (ExHIBiT) was assembled to explore the genetic diversity in European barley focusing on Northern European accessions and further address environmental pressures. ExHIBiT consists of 363 spring-barley accessions, focusing on two-row type. The collection consists of landraces (~14%), old cultivars (~18%), elite cultivars (~67%) and accessions with unknown breeding history (~1%), with 70% of the collection from Northern Europe. The population structure of the ExHIBiT collection was subdivided into three main clusters primarily based on the accession's year of release using 26,585 informative SNPs based on 50k iSelect single nucleotide polymorphism (SNP) array data. Power analysis established a representative core collection of 230 genotypically and phenotypically diverse accessions. The effectiveness of this core collection for conducting statistical and association analysis was explored by undertaking genome-wide association studies (GWAS) using 24,876 SNPs for nine phenotypic traits, four of which were associated with SNPs. Genomic regions overlapping with previously characterised flowering genes (HvZTLb) were identified, demonstrating the utility of the ExHIBiT core collection for locating genetic regions that determine important traits. Overall, the ExHIBiT core collection represents the high level of untapped diversity within Northern European barley, providing a powerful resource for researchers and breeders to address future climate scenarios.

In vitro induction and investigation of salinity tolerance in the callus of Vigna spp. (L)

Cowpeas can be employed for rotational grazing or generating high-quality food when paired with crops such as maize. Cowpea seeds provide a substantial amount of protein and other essential elements. The purpose of this work was to use a mutagen and a high salt concentration to extract a salt tolerance gene from the callus. The callus was induced by adding 2,4-Dichlorophenoxyacetic acid 2,4- D at mg/l and was then subjected to various concentrations of a combination of salts consisting of sodium chloride NaCl and Calcium Chloride.CaCl2, in addition to Magnesium chloride MgCl2, with a rate of 2:2:1 and potion 0, 50, 100, 150, 200, and 250 mM of the salt mixture added to the culture medium. Various levels of di ethyl sulfate (DES) mutagenic solution at a concentration of 0.1 mM were used to soak the callus for 30 minutes. The results showed that when using quantitative polymerase chain reaction q-PCR, they showed two genes of vigna, the first gene in this research. Aldehyde dehydrogenase family 3 (ADF3) demonstrated the explanation of the genes at doses of DES+200, 200, and 250 mM; however, the most elevated level of gene expression at DES+200mM is CT 30.47, with an upregulation of 2.479. The second gene, Protein S2, demonstrated that the gene is highly expressed at DES+200mM, cycle threshold (CT) 31.68, and DES+250mM concentrations and is upregulated at DES+150mM was 128.

A major gene for chilling tolerance variation in Indica rice codes for a kinase OsCTK1 that phosphorylates multiple substrates under cold.

Rice is susceptible to chilling stress. Identifying chilling tolerance genes and their mechanisms are key to improve rice performance. Here, we performed a genome-wide association study to identify regulatory genes for chilling tolerance in rice. One major gene for chilling tolerance variation in Indica rice was identified as a casein kinase gene OsCTK1. Its function and natural variation are investigated at the physiological and molecular level by its mutants and transgenic plants. Potential substrates of OsCTK1 were identified by phosphoproteomic analysis, protein-protein interaction assay, in vitro kinase assay, and mutant characterization. OsCTK1 positively regulates rice chilling tolerance. Three of its putative substrates, acidic ribosomal protein OsP3B, cyclic nucleotide-gated ion channel OsCNGC9, and dual-specific mitogen-activated protein kinase phosphatase OsMKP1, are each involved in chilling tolerance. In addition, a natural OsCTK1 chilling-tolerant (CT) variant exhibited a higher kinase activity and conferred greater chilling tolerance compared with a chilling-sensitive (CS) variant. The CT variant is more prevalent in CT accessions and is distributed more frequently in higher latitude compared with the CS variant. This study thus enables a better understanding of chilling tolerance mechanisms and provides gene variants for genetic improvement of chilling tolerance in rice.

Genome-wide analysis of acid tolerance genes of Enterococcus faecalis with RNA-seq and Tn-seq

Enterococcus faecalis, a formidable nosocomial and community-acquired opportunistic pathogen, can persist a wide range of extreme environments, including low pH and nutrient deficiency. Clarifying the survival mechanism of E. faecalis in low-pH conditions is the key to combating the infectious diseases caused by E. faecalis. In this study, we combined transcriptome profiling (RNA-seq) and transposon insertion sequencing (TIS) to comprehensively understand the genes that confer these features on E. faecalis. The metadata showed that genes whose products are involved in cation transportation and amino acid biosynthesis were predominantly differentially expressed under acid conditions. The products of genes such as opp1C and copY reduced the hydrion concentration in the cell, whereas those of gldA2, gnd2, ubiD, and ubiD2 mainly participated in amino metabolism, increasing matters to neutralize excess acid. These, together with the folE and hexB genes, which are involved in mismatch repair, form a network of E. faecalis genes necessary for its survival under acid conditions.

Full-length transcriptome sequencing provides insights into alternative splicing under cold stress in peanut.

Peanut (Arachis hypogaea L.), also called groundnut is an important oil and cash crop grown widely in the world. The annual global production of groundnuts has increased to approximately 50 million tons, which provides a rich source of vegetable oils and proteins for humans. Low temperature (non-freezing) is one of the major factors restricting peanut growth, yield, and geographic distribution. Since the complexity of cold-resistance trait, the molecular mechanism of cold tolerance and related gene networks were largely unknown in peanut. In this study, comparative transcriptomic analysis of two peanut cultivars (SLH vs. ZH12) with differential cold tolerance under low temperature (10°C) was performed using Oxford Nanopore Technology (ONT) platform. As a result, we identified 8,949 novel gene loci and 95,291 new/novel isoforms compared with the reference database. More differentially expressed genes (DEGs) were discovered in cold-sensitive cultivar (ZH12) than cold-tolerant cultivar (SLH), while more alternative splicing events were found in SLH compared to ZH12. Gene Ontology (GO) analyses of the common DEGs showed that the "response to stress", "chloroplast part", and "transcription factor activity" were the most enriched GO terms, indicating that photosynthesis process and transcription factors play crucial roles in cold stress response in peanut. We also detected a total of 708 differential alternative splicing genes (DASGs) under cold stress compared to normal condition. Intron retention (IR) and exon skipping (ES) were the most prevalent alternative splicing (AS) events. In total, 4,993 transcription factors and 292 splicing factors were detected, many of them had differential expression levels and/or underwent AS events in response to cold stress. Overexpression of two candidate genes (encoding trehalose-6-phosphatephosphatases, AhTPPs) in yeast improves cold tolerance. This study not only provides valuable resources for the study of cold resistance in peanut but also lay a foundation for genetic modification of cold regulators to enhance stress tolerance in crops.

Natural variation of STKc_GSK3 kinase TaSG-D1 contributes to heat stress tolerance in Indian dwarf wheat

Heat stress threatens global wheat (Triticum aestivum) production, causing dramatic yield losses worldwide. Identifying heat tolerance genes and comprehending molecular mechanisms are essential. Here, we identify a heat tolerance gene, TaSG-D1E286K, in Indian dwarf wheat (Triticum sphaerococcum), which encodes an STKc_GSK3 kinase. TaSG-D1E286K improves heat tolerance compared to TaSG-D1 by enhancing phosphorylation and stability of downstream target TaPIF4 under heat stress condition. Additionally, we reveal evolutionary footprints of TaPIF4 during wheat selective breeding in China, that is, InDels predominantly occur in the TaPIF4 promoter of Chinese modern wheat cultivars and result in decreased expression level of TaPIF4 in response to heat stress. These sequence variations with negative effect on heat tolerance are mainly introduced from European germplasm. Our study provides insight into heat stress response mechanisms and proposes a potential strategy to improve wheat heat tolerance in future.

Screening for cold tolerance genes in C. elegans, whose expressions are affected by anticancer drugs camptothecin and leptomycin B

Temperature is a vital environmental factor affecting organisms’ survival as they determine the mechanisms to tolerate rapid temperature changes. We demonstrate an experimental system for screening chemicals that affect cold tolerance in Caenorhabditis elegans. The anticancer drugs leptomycin B and camptothecin were among the 4000 chemicals that were screened as those affecting cold tolerance. Genes whose expression was affected by leptomycin B or camptothecin under cold stimuli were investigated by transcriptome analysis. Abnormal cold tolerance was detected in several mutants possessing genes that were rendered defective and whose expression altered after exposure to either leptomycin B or camptothecin. The genetic epistasis analysis revealed that leptomycin B or camptothecin may increase cold tolerance by affecting a pathway upstream of the insulin receptor DAF-2 that regulates cold tolerance in the intestine. Our experimental system combining drug and cold tolerance could be used for a comprehensive screening of genes that control cold tolerance at a low cost and in a short time period.

Back to the future for drought tolerance.

Global agriculture faces increasing pressure to produce more food with fewer resources. Drought, exacerbated by climate change, is a major agricultural constraint costing the industry an estimated US$80 billion per year in lost production. Wild relatives of domesticated crops, including wheat (Triticum spp.) and barley (Hordeum vulgare L.), are an underutilized source of drought tolerance genes. However, managing their undesirable characteristics, assessing drought responses, and selecting lines with heritable traits remains a significant challenge. Here, we propose a novel strategy of using multi-trait selection criteria based on high-throughput spectral images to facilitate the assessment and selection challenge. The importance of measuring plant capacity for sustained carbon fixation under drought stress is explored, and an image-based transpiration efficiency (iTE) index obtained via a combination of hyperspectral and thermal imaging, is proposed. Incorporating iTEalong with other drought-related variables in selection criteria will allow the identification of accessions with diverse tolerance mechanisms. A comprehensive approach that merges high-throughput phenotyping and de novo domestication is proposed for developing drought-tolerant prebreeding material and providing breeders with access to gene pools containing unexplored drought tolerance mechanisms.

Prediction of drought regulating gene (s) in barley (Hordeum vulgare L.) using express sequence tags (ESTs) through in silico approaches

Climate change is a major current issue in the world, affecting the availability and stability of food. It leads to the most damaging abiotic stress for the ecosystem and the one that results in the greatest output loss is drought. Barley was once thought to be an abiotic stress-tolerant plant but the production of barley dropped significantly due to drought-stress. In this study, a computational method was used to predict the genes in barley that are associated with drought stress. The expressed sequence tags (ESTs) were investigated to identify the gene expression profiling in barley during drought stress. Various software, tools, and servers were used to predict the genes using ESTs, which were responsive to drought stress. The TFcat and blast2GO tools were used to predict transcription factors and enzymes respectively. Phytozome and plantCARE databases were used to validate newly predicted novel candidate genes using promoter studies. By using the Ensemble plant genome database, new genes related to drought stress were discovered. There were only 37 locations in the barley genome that had candidate genes. According to the promoter analysis, twenty nine genes had more than ten cis acting controlling elements that was related to drought stress in various plants. The promoter study showed that 29 out of 37 genes contained more than 10 cis-acting regulatory elements involved in drought stress in different plants. These findings will be helpful to identify the novel drought stress tolerant gene in barley that may play an important role in developing new varieties in near future.

Biosafety and toxicity assessment of transgenic cotton-harboring insecticide and herbicide tolerant genes on albino mice.

Genetic engineering has revolutionized agriculture by transforming biotic and abiotic stress-resistance genes in plants. The biosafety of GM crops is a major concern for consumers and regulatory authorities. A 14-week biosafety and toxicity analysis of transgenic cotton, containing 5 transgenes ((Cry1Ac, Cry2A, CP4 EPSPS, VIP3Aa, and ASAL)), was conducted on albino mice. Thirty mice were divided into three groups (Conventional, Non-transgenic, without Bt, and transgenic, containing targeted crop) according to the feed given, with 10 mice in each group, with 5 male and 5 female mice in each group. During the study, no biologically significant changes were observed in the non-transgenic and transgenic groups compared to the control group in any of the study's parameters i.e. increase in weight of mice, physiological, pathological, and molecular analysis, irrespective of the gender of the mice. However, a statistically significant change was observed in the hematological parameters of the male mice, while no such change was observed in the female study group mice. The expression analysis, however, of the TNF gene increases many folds in the transgenic group as compared to the non-transgenic and conventional groups. Overall, no physiological, pathological, or molecular toxicity was observed in the mice fed with transgenic feed. Therefore, it can be speculated that the targeted transgenic crop is biologically safe. However, more study is required to confirm the biosafety of the product on the animal by expression profiling.

Transcriptomic analysis of salt-tolerant and sensitive high-yield japonica rice (Oryza sativa L.) reveals complicated salt-tolerant mechanisms.

Developing and cultivating rice varieties is a potent strategy for reclaiming salinity-affected soils for rice production. Nevertheless, the molecular mechanisms conferring salt tolerance, especially in conventional high-yield japonica rice varieties, remain obscure. In this study, Zhendao 23309 (ZD23309) exhibited significantly less grain yield reduction under a salt stress gradient than the control variety Wuyunjing 30 (WYJ30). High positive correlations between grain yield and dry matter accumulation at the jointing, heading and maturity stages indicated that early salt tolerance performance is a crucial hallmark for yield formation. After a mild salt stress (85 mM NaCl) of young seedlings, RNA sequencing (RNA-seq) of shoot and root separately identified a total of 1952 and 3647 differentially expressed genes (DEGs) in ZD23309, and 2114 and 2711 DEGs in WYJ30, respectively. Gene ontology (GO) analysis revealed numerous DEGs in ZD23309 that play pivotal roles in strengthening salt tolerance, encompassing the response to stimulus (GO:0050896) in shoots and nucleoside binding (GO:0001882) in roots. Additionally, distinct expression patterns were observed in a fraction of genes in the two rice varieties under salt stress, corroborating the efficacy of previously reported salt tolerance genes. Our research not only offers fresh insights into the differences in salt stress tolerance among conventional high-yield rice varieties but also unveils the intricate nature of salt tolerance mechanisms. These findings lay a solid groundwork for deciphering the mechanisms underlying salt tolerance.

A wild rice CSSL population facilitated identification of salt tolerance genes and rice germplasm innovation.

Salt stress is one of the major factors that limits rice production. Therefore, identification of salt-tolerant alleles from wild rice is important for rice breeding. In this study, we constructed a set of chromosome segment substitution lines (CSSLs) using wild rice as the donor parent and cultivated rice Nipponbare (Nip) as the recurrent parent. Salt tolerance germinability (STG) was evaluated, and its association with genotypes was determined using this CSSL population. We identified 17 QTLs related to STG. By integrating the transcriptome and genome data, four candidate genes were identified, including the previously reported AGO2 and WRKY53. Compared with Nip, wild rice AGO2 has a structure variation in its promoter region and the expression levels were upregulated under salt treatments; wild rice WRKY53 also has natural variation in its promoter region, and the expression levels were downregulated under salt treatments. Wild rice AGO2 and WRKY53 alleles have combined effects for improving salt tolerance at the germination stage. One CSSL line, CSSL118 that harbors these two alleles was selected. Compared with the background parent Nip, CSSL118 showed comprehensive salt tolerance and higher yield, with improved transcript levels of reactive oxygen species scavenging genes. Our results provided promising genes and germplasm resources for future rice salt tolerance breeding.

Shared and more specific genetic determinants and pathways underlying yeast tolerance to acetic, butyric, and octanoic acids

BackgroundThe improvement of yeast tolerance to acetic, butyric, and octanoic acids is an important step for the implementation of economically and technologically sustainable bioprocesses for the bioconversion of renewable biomass resources and wastes. To guide genome engineering of promising yeast cell factories toward highly robust superior strains, it is instrumental to identify molecular targets and understand the mechanisms underlying tolerance to those monocarboxylic fatty acids. A chemogenomic analysis was performed, complemented with physiological studies, to unveil genetic tolerance determinants in the model yeast and cell factory Saccharomyces cerevisiae exposed to equivalent moderate inhibitory concentrations of acetic, butyric, or octanoic acids.ResultsResults indicate the existence of multiple shared genetic determinants and pathways underlying tolerance to these short- and medium-chain fatty acids, such as vacuolar acidification, intracellular trafficking, autophagy, and protein synthesis. The number of tolerance genes identified increased with the linear chain length and the datasets for butyric and octanoic acids include the highest number of genes in common suggesting the existence of more similar toxicity and tolerance mechanisms. Results of this analysis, at the systems level, point to a more marked deleterious effect of an equivalent inhibitory concentration of the more lipophilic octanoic acid, followed by butyric acid, on the cell envelope and on cellular membranes function and lipid remodeling. The importance of mitochondrial genome maintenance and functional mitochondria to obtain ATP for energy-dependent detoxification processes also emerged from this chemogenomic analysis, especially for octanoic acid.ConclusionsThis study provides new biological knowledge of interest to gain further mechanistic insights into toxicity and tolerance to linear-chain monocarboxylic acids of increasing liposolubility and reports the first lists of tolerance genes, at the genome scale, for butyric and octanoic acids. These genes and biological functions are potential targets for synthetic biology approaches applied to promising yeast cell factories, toward more robust superior strains, a highly desirable phenotype to increase the economic viability of bioprocesses based on mixtures of volatiles/medium-chain fatty acids derived from low-cost biodegradable substrates or lignocellulose hydrolysates.

GmGLU1 and GmRR4 contribute to iron deficiency tolerance in soybean.

Iron deficiency chlorosis (IDC) is a form of abiotic stress that negatively impacts soybean yield. In a previous study, we demonstrated that the historical IDC quantitative trait locus (QTL) on soybean chromosome Gm03 was composed of four distinct linkage blocks, each containing candidate genes for IDC tolerance. Here, we take advantage of virus-induced gene silencing (VIGS) to validate the function of three high-priority candidate genes, each corresponding to a different linkage block in the Gm03 IDC QTL. We built three single-gene constructs to target GmGLU1 (GLUTAMATE SYNTHASE 1, Glyma.03G128300), GmRR4 (RESPONSE REGULATOR 4, Glyma.03G130000), and GmbHLH38 (beta Helix Loop Helix 38, Glyma.03G130400 and Glyma.03G130600). Given the polygenic nature of the iron stress tolerance trait, we also silenced the genes in combination. We built two constructs targeting GmRR4+GmGLU1 and GmbHLH38+GmGLU1. All constructs were tested on the iron-efficient soybean genotype Clark grown in iron-sufficient conditions. We observed significant decreases in soil plant analysis development (SPAD) measurements using the GmGLU1 construct and both double constructs, with potential additive effects in the GmRR4+GmGLU1 construct. Whole genome expression analyses (RNA-seq) revealed a wide range of affected processes including known iron stress responses, defense and hormone signaling, photosynthesis, and cell wall structure. These findings highlight the importance of GmGLU1 in soybean iron stress responses and provide evidence that IDC is truly a polygenic trait, with multiple genes within the QTL contributing to IDC tolerance. Finally, we conducted BLAST analyses to demonstrate that the Gm03 IDC QTL is syntenic across a broad range of plant species.

"Genome-wide identification of bZIP gene family in Pearl millet and transcriptional profiling under abiotic stress, phytohormonal treatments; and functional characterization of PgbZIP9".

Abiotic stresses are major constraints in crop production, and are accountable for more than half of the total crop loss. Plants overcome these environmental stresses using coordinated activities of transcription factors and phytohormones. Pearl millet an important C4 cereal plant having high nutritional value and climate resilient features is grown in marginal lands of Africa and South-East Asia including India. Among several transcription factors, the basic leucine zipper (bZIP) is an important TF family associated with diverse biological functions in plants. In this study, we have identified 98 bZIP family members (PgbZIP) in pearl millet. Phylogenetic analysis divided these PgbZIP genes into twelve groups (A-I, S, U and X). Motif analysis has shown that all the PgbZIP proteins possess conserved bZIP domains and the exon-intron organization revealed conserved structural features among the identified genes. Cis-element analysis, RNA-seq data analysis, and real-time expression analysis of PgbZIP genes suggested the potential role of selected PgbZIP genes in growth/development and abiotic stress responses in pearl millet. Expression profiling of selected PgbZIPs under various phytohormones (ABA, SA and MeJA) treatment showed differential expression patterns of PgbZIP genes. Further, PgbZIP9, a homolog of AtABI5 was found to localize in the nucleus and modulate gene expression in pearl millet under stresses. Our present findings provide a better understanding of bZIP genes in pearl millet and lay a good foundation for the further functional characterization of multi-stress tolerant PgbZIP genes, which could become efficient tools for crop improvement.

Heat-Resistant Inbred Lines Coordinate the Heat Response Gene Expression Remarkably in Maize (Zea mays L.).

High temperatures are increasingly becoming a prominent environmental factor accelerating the adverse influence on the growth and development of maize (Zea mays L.). Therefore, it is critical to identify the key genes and pathways related to heat stress (HS) tolerance in maize. Great challenges have been faced in dissecting genetic mechanisms and uncovering master genes for HS tolerance. Here, Z58D showed more thermotolerance than AF171 at the seedling stage with a lower wilted leaf rate and H2O2 accumulation under HS conditions. Transcriptomic analysis identified 3006 differentially expressed genes (DEGs) in AF171 and 4273 DEGs in Z58D under HS treatments, respectively. Subsequently, GO enrichment analysis showed that commonly upregulated genes in AF171 and Z58D were significantly enriched in the following biological processes, including protein folding, response to heat, response to temperature stimulus and response to hydrogen peroxide. Moreover, the comparison between the two inbred lines under HS showed that response to heat and response to temperature stimulus were significantly over-represented for the 1234 upregulated genes in Z58D. Furthermore, more commonly upregulated genes exhibited higher expression levels in Z58D than AF171. In addition, maize inbred CIMBL55 was verified to be more tolerant than B73, and more commonly upregulated genes also showed higher expression levels in CIMBL55 than B73 under HS. These consistent results indicate that heat-resistant inbred lines may coordinate the remarkable expression of genes in order to recover from HS. Additionally, 35 DEGs were conserved among five inbred lines via comparative transcriptomic analysis. Most of them were more pronounced in Z58D than AF171 at the expression levels. These candidate genes may confer thermotolerance in maize.