Leveraging Multiomics Insights and Exploiting Wild Relatives' Potential for Drought and Heat Tolerance in Maize.

Climate change, particularly drought and heat stress, may slash agricultural productivity by 25.7% by 2080, with maize being the hardest hit. Therefore, unraveling the molecular nature of plant responses to these stressors is vital for the development of climate-smart maize. This manuscript's primary objective was to examine how maize plants respond to these stresses, both individually and in combination. Additionally, the paper delved into harnessing the potential of maize wild relatives as a valuable genetic resource and leveraging AI-based technologies to boost maize resilience. The role of multiomics approaches particularly genomics and transcriptomics in dissecting the genetic basis of stress tolerance was also highlighted. The way forward was proposed to utilize a bunch of information obtained through omics technologies by an interdisciplinary state-of-the-art forward-looking big-data, cyberagriculture system, and AI-based approach to orchestrate the development of climate resilient maize genotypes.

Duration of Zearalenone Exposure Has Implications on Health Parameters of Lactating Cows.

There is a limited research focus on evaluating the detrimental effects of prolonged zearalenone (ZEN) intake on dairy cows' health under controlled conditions. This experiment was conducted to evaluate whether the length of exposure to a ZEN-contaminated total mixed ration (TMR) at a level of 9.45 mg per day can negatively influence animal health parameters, such as milk composition, rumen and fecal fermentation, and the chewing activity of lactating dairy cows. For this experiment, we used 18 lactating Simmental cows that were fed a diet of 60% forage and 40% concentrate (on dry matter basis) for 26 consecutive days. The first 4 days were for adaptation prior to the first sampling day (day 0). The sampling events took place on day 0 (baseline) without ZEN, followed by day 1, day 7, day 14, and day 21 (with toxin). Dry matter intake (DMI) and ruminating chews per minute increased on the third week of ZEN inclusion; meanwhile, ruminating, eating, and drinking times were not affected. Most milk composition variables were also unaffected. Rumen fluid osmolality increased on day 21 and total short-chain fatty acids (SCFA) of ruminal fluid decreased on day 7. Fecal SCFA increased on day 21 and the acetate-to-propionate ratio increased from day 1 onwards, showing the influence of toxin intake. Animal health parameters, like heart rate, respiratory rate, and body temperature, were negatively influenced by ZEN intake, all increasing consistently on days 4 and 6, 9 and 12, and 16 and 18, respectively. The liver enzyme glutamate dehydrogenase decreased in response to ZEN intake on day 7. A total daily ZEN intake at the level of 9.45 mg did not show detrimental effects on DMI. Nevertheless, certain health parameters were negatively affected, including body temperature, respiratory rate, and heart rate, starting from the 7th day of ZEN intake, with additional signs of possible loss of water balance on the last sampling day.

In Silico Comparison of WRKY Transcription Factors in Wild and Cultivated Soybean and Their Co-expression Network Arbitrating Disease Resistance.

WRKY Transcription factors (TFs) play critical roles in plant defence mechanisms that are activated in response to biotic and abiotic stresses. However, information on the Glycine soja WRKYs (GsoWRKYs) is scarce. Owing to its importance in soybean breeding, here we identified putative WRKY TFs in wild soybean, and compared the results with Glycine max WRKYs (GmaWRKYs) by phylogenetic, conserved motif, and duplication analyses. Moreover, we explored the expression trends of WRKYs in G. max (oomycete, fungi, virus, bacteria, and soybean cyst nematode) and G. soja (soybean cyst nematode), and identified commonly expressed WRKYs and their co-expressed genes. We identified, 181 and 180 putative WRKYs in G. max and G. soja, respectively. Though the number of WRKYs in both studied species is almost the same, they differ in many ways, i.e., the number of WRKYs on corresponding chromosomes, conserved domain structures, WRKYGQK motif variants, and zinc-finger motifs. WRKYs in both species grouped in three major clads, i.e., I-III, where group-II had sub-clads IIa-IIe. We found that GsoWRKYs expanded mostly through segmental duplication. A large number of WRKYs were expressed in response to biotic stresses, i.e., Phakospora pachyrhizi, Phytoplasma, Heterodera glycines, Macrophomina phaseolina, and Soybean mosaic virus; 56 GmaWRKYs were commonly expressed in soybean plants infected with these diseases. Finally, 30 and 63 GmaWRKYs and GsoWRKYs co-expressed with 205 and 123 non-WRKY genes, respectively, indicating that WRKYs play essential roles in biotic stress tolerance in Glycine species.

Phylogenomic curation of Ovate Family Proteins (OFPs) in the U's Triangle of Brassica L. indicates stress-induced growth modulation.

The Ovate Family Proteins (OFPs) gene family houses a class of proteins that are involved in regulating plant growth and development. To date, there is no report of the simultaneous functional characterization of this gene family in all members of U's Triangle of Brassica. Here, we retrieved a combined total of 256 OFP protein sequences and analyzed their chromosomal localization, gene structure, conserved protein motif domains, and the pattern of cis-acting regulatory elements. The abundance of light-responsive elements like G-box, MRE, and GT1 motif suggests that OFPs are sensitive to the stimuli of light. The protein-protein interaction network analysis revealed that OFP05 and its orthologous genes were involved in regulating the process of transcriptional repression through their interaction with homeodomain transcription factors like KNAT and BLH. The presence of domains like DNA binding 2 and its superfamily speculated the involvement of OFPs in regulating gene expression. The biotic and abiotic stress, and the tissue-specific expression analysis of the RNA-seq datasets revealed that some of the genes such as BjuOFP30, and BnaOFP27, BolOFP11, and BolOFP10 were highly upregulated in seed coat at the mature stage and roots under various chemical stress conditions respectively which suggests their crucial role in plant growth and development processes. Experimental validation of prominent BnaOFPs such as BnaOFP27 confirmed their involvement in regulating gene expression under salinity, heavy metal, drought, heat, and cold stress. The GO and KEGG pathway enrichment analysis also sheds light on the involvement of OFPs in regulating plant growth and development. These findings have the potential to serve as a forerunner for future studies in terms of functionally diverse analysis of the OFP gene family in Brassica and other plant species.

De novo transcriptome assembly of Dalbergia sissoo Roxb. (Fabaceae) under Botryodiplodia theobromae-induced dieback disease.

Dalbergia sissoo Roxb. (Shisham) is a timber-producing species of economic, cultural, and medicinal importance in the Indian subcontinent. In the past few decades, Shisham's dieback disease caused by the fungus Botryodiplodia theobromae has become an evolving issue in the subcontinent endangering its survival. To gain insights into this issue, a standard transcriptome assembly was deployed to assess the response of D. sissoo at the transcriptomic level under the stress of B. theobromae infection. For RNA isolation, the control and infected leaf tissue samples were taken from 1-year-old greenhouse-grown D. sissoo plants after 20 days of stem-base spore inoculation. cDNA synthesis was performed from these freshly isolated RNA samples that were then sent for sequencing. About 18.14 Gb (Giga base) of data was generated using the BGISEQ-500 sequencing platform. In terms of Unigenes, 513,821 were identified after a combined assembly of all samples and then filtering the abundance. The total length of Unigenes, their average length, N50, and GC-content were 310,523,693 bp, 604 bp, 1,101 bp, and 39.95% respectively. The Unigenes were annotated using 7 functional databases i.e., 200,355 (NR: 38.99%), 164,973 (NT: 32.11%), 123,733 (Swissprot: 24.08%), 142,580 (KOG: 27.75%), 139,588 (KEGG: 27.17%), 99,752 (GO: 19.41%), and 137,281 (InterPro: 26.72%). Furthermore, the Transdecoder detected 115,762 CDS. In terms of SSR (Simple Sequence Repeat) markers, 62,863 of them were distributed on 51,508 Unigenes and on the predicted 4673 TF (Transcription Factor) coding Unigenes. A total of 16,018 up- and 19,530 down-regulated Differentially Expressed Genes (DEGs) were also identified. Moreover, the Plant Resistance Genes (PRGs) had a count of 9230. We are hopeful that in the future, these identified Unigenes, SSR markers, DEGs and PRGs will provide the prerequisites for managing Shisham dieback disease, its breeding, and in tree improvement programs.

Targeted genome editing in polyploids: lessons from Brassica.

CRISPR-mediated genome editing has emerged as a powerful tool for creating targeted mutations in the genome for various applications, including studying gene functions, engineering resilience against biotic and abiotic stresses, and increasing yield and quality. However, its utilization is limited to model crops for which well-annotated genome sequences are available. Many crops of dietary and economic importance, such as wheat, cotton, rapeseed-mustard, and potato, are polyploids with complex genomes. Therefore, progress in these crops has been hampered due to genome complexity. Excellent work has been conducted on some species of Brassica for its improvement through genome editing. Although excellent work has been conducted on some species of Brassica for genome improvement through editing, work on polyploid crops, including U's triangle species, holds numerous implications for improving other polyploid crops. In this review, we summarize key examples from genome editing work done on Brassica and discuss important considerations for deploying CRISPR-mediated genome editing more efficiently in other polyploid crops for improvement.

Comparative transcriptomic and evolutionary analysis of FAD-like genes of Brassica species revealed their role in fatty acid biosynthesis and stress tolerance.

BACKGROUND: Fatty acid desaturases (FADs) are involved in regulating plant fatty acid composition by adding double bonds to growing hydrocarbon chain. Apart from regulating fatty acid composition FADs are of great importance, and are involved in stress responsiveness, plant development, and defense mechanisms. FADs have been extensively studied in crop plants, and are broadly classed into soluble and non-soluble fatty acids. However, FADs have not yet been characterized in Brassica carinata and its progenitors. RESULTS: Here we have performed comparative genome-wide identification of FADs and have identified 131 soluble and 28 non-soluble FADs in allotetraploid B. carinata and its diploid parents. Most soluble FAD proteins are predicted to be resided in endomembrane system, whereas FAB proteins were found to be localized in chloroplast. Phylogenetic analysis classed the soluble and non-soluble FAD proteins into seven and four clusters, respectively. Positive type of selection seemed to be dominant in both FADs suggesting the impact of evolution on these gene families. Upstream regions of both FADs were enriched in stress related cis-regulatory elements and among them ABRE type of elements were in abundance. Comparative transcriptomic data analysis output highlighted that FADs expression reduced gradually in mature seed and embryonic tissues. Moreover, under heat stress during seed and embryo development seven genes remained up-regulated regardless of external stress. Three FADs were only induced under elevated temperature whereas five genes were upregulated under Xanthomonas campestris stress suggesting their involvement in abiotic and biotic stress response. CONCLUSIONS: The current study provides insights into the evolution of FADs and their role in B. carinata under stress conditions. Moreover, the functional characterization of stress-related genes would exploit their utilization in future breeding programs of B. carinata and its progenitors.

Genomic diversity of aquaporins across genus Oryza provides a rich genetic resource for development of climate resilient rice cultivars.

BACKGROUND: Plant aquaporins are critical genetic players performing multiple biological functions, especially climate resilience and water-use efficiency. Their genomic diversity across genus Oryza is yet to be explored. RESULTS: This study identified 369 aquaporin-encoding genes from 11 cultivated and wild rice species and further categorized these into four major subfamilies, among which small basic intrinsic proteins are speculated to be ancestral to all land plant aquaporins. Evolutionarily conserved motifs in peptides of aquaporins participate in transmembrane transport of materials and their relatively complex gene structures provide an evolutionary playground for regulation of genome structure and transcription. Duplication and evolution analyses revealed higher genetic conservation among Oryza aquaporins and strong purifying selections are assisting in conserving the climate resilience associated functions. Promoter analysis highlighted enrichment of gene upstream regions with cis-acting regulatory elements involved in diverse biological processes, whereas miRNA target site prediction analysis unveiled substantial involvement of osa-miR2102-3p, osa-miR2927 and osa-miR5075 in post-transcriptional regulation of gene expression patterns. Moreover, expression patterns of japonica aquaporins were significantly perturbed in response to different treatment levels of six phytohormones and four abiotic stresses, suggesting their multifarious roles in plants survival under stressed environments. Furthermore, superior haplotypes of seven conserved orthologous aquaporins for higher thousand-grain weight are reported from a gold mine of 3,010 sequenced rice pangenomes. CONCLUSIONS: This study unveils the complete genomic atlas of aquaporins across genus Oryza and provides a comprehensive genetic resource for genomics-assisted development of climate-resilient rice cultivars.

Comparative phylogenomic insights of KCS and ELO gene families in Brassica species indicate their role in seed development and stress responsiveness.

Very long-chain fatty acids (VLCFAs) possess more than twenty carbon atoms and are the major components of seed storage oil, wax, and lipids. FAE (Fatty Acid Elongation) like genes take part in the biosynthesis of VLCFAs, growth regulation, and stress responses, and are further comprised of KCS (Ketoacyl-CoA synthase) and ELO (Elongation Defective Elongase) sub-gene families. The comparative genome-wide analysis and mode of evolution of KCS and ELO gene families have not been investigated in tetraploid Brassica carinata and its diploid progenitors. In this study, 53 KCS genes were identified in B. carinata compared to 32 and 33 KCS genes in B. nigra and B. oleracea respectively, which suggests that polyploidization might has impacted the fatty acid elongation process during Brassica evolution. Polyploidization has also increased the number of ELO genes in B. carinata (17) over its progenitors B. nigra (7) and B. oleracea (6). Based on comparative phylogenetics, KCS, and ELO proteins can be classified into eight and four major groups, respectively. The approximate date of divergence for duplicated KCS and ELO genes varied from 0.03 to 3.20 million years ago (MYA). Gene structure analysis indicated that the maximum number of genes were intron-less and remained conserved during evolution. The neutral type of selection seemed to be predominant in both KCS and ELO genes evolution. String-based protein-protein interaction analysis suggested that bZIP53, a transcription factor might be involved in the activation of transcription of ELO/KCS genes. The presence of biotic and abiotic stress-related cis-regulatory elements in the promoter region suggests that both KCS and ELO genes might also play their role in stress tolerance. The expression analysis of both gene family members reflect their preferential seed-specific expression, especially during the mature embryo development stage. Furthermore, some KCS and ELO genes were found to be specifically expressed under heat stress, phosphorus starvation, and Xanthomonas campestris infection. The current study provides a basis to understand the evolution of both KCS and ELO genes in fatty acid elongation and their role in stress tolerance.

Using Exogenous Melatonin, Glutathione, Proline, and Glycine Betaine Treatments to Combat Abiotic Stresses in Crops.

Abiotic stresses, such as drought, salinity, heat, cold, and heavy metals, are associated with global climate change and hamper plant growth and development, affecting crop yields and quality. However, the negative effects of abiotic stresses can be mitigated through exogenous treatments using small biomolecules. For example, the foliar application of melatonin provides the following: it protects the photosynthetic apparatus; it increases the antioxidant defenses, osmoprotectant, and soluble sugar levels; it prevents tissue damage and reduces electrolyte leakage; it improves reactive oxygen species (ROS) scavenging; and it increases biomass, maintains the redox and ion homeostasis, and improves gaseous exchange. Glutathione spray upregulates the glyoxalase system, reduces methylglyoxal (MG) toxicity and oxidative stress, decreases hydrogen peroxide and malondialdehyde accumulation, improves the defense mechanisms, tissue repairs, and nitrogen fixation, and upregulates the phytochelatins. The exogenous application of proline enhances growth and other physiological characteristics, upregulates osmoprotection, protects the integrity of the plasma lemma, reduces lipid peroxidation, increases photosynthetic pigments, phenolic acids, flavonoids, and amino acids, and enhances stress tolerance, carbon fixation, and leaf nitrogen content. The foliar application of glycine betaine improves growth, upregulates osmoprotection and osmoregulation, increases relative water content, net photosynthetic rate, and catalase activity, decreases photorespiration, ion leakage, and lipid peroxidation, protects the oxygen-evolving complex, and prevents chlorosis. Chemical priming has various important advantages over transgenic technology as it is typically more affordable for farmers and safe for plants, people, and animals, while being considered environmentally acceptable. Chemical priming helps to improve the quality and quantity of the yield. This review summarizes and discusses how exogenous melatonin, glutathione, proline, and glycine betaine can help crops combat abiotic stresses.

Exploration of the genomic atlas of Dof transcription factor family across genus Oryza provides novel insights on rice breeding in changing climate.

DNA-binding with one finger (Dof) transcription factors have been demonstrated to regulate various stresses and developmental processes in plants. Their identification and comparative evolutionary analyses in cultivated and wild species of genus oryza were yet to be explored. In this context, we report a comprehensive genomics atlas of DNA-binding with one finger (Dof) family genes in 13 diverse rice genomes (five cultivated and eight rice wild-relatives) through a genome-wide scanning approach. A galore of 238 Dof genes, identified across the genus Oryza, are categorized into seven distinct subgroups by comparative phylogenetic analysis with the model plant Arabidopsis. Conserved motifs and gene structure analyses unveiled the prevalence of species- and subgroups-specific structural and functional diversity that is expediating with the evolutionary period. Our results indicate that Dof genes might have undergone strong purifying selections and segmental duplications to expand their gene family members in corresponding Oryza genomes. We speculate that miR2927 potentially targets the Dof domain to regulate gene expression under different climatic conditions, which are supported by in-silico and wet-lab experiments-based expression profiles. In a nutshell, we report several superior haplotypes significantly associated with early flowering in a treasure trove of 3,010 sequenced rice accessions and have validated these haplotypes with two years of field evaluation-based flowering data of a representative subpanel. Finally, we have provided some insights on the resolution of Oryza species phylogeny discordance and divergence highlighting the mosaic evolutionary history of the genus Oryza. Overall, this study reports a complete genomic landscape of the Dof family in cultivated and wild Oryza species that could greatly facilitate in fast-track development of early maturing and climate-resilient rice cultivars through modern haplotype-led breeding.

Unveiling the genetic architecture for lodging resistance in rice (Oryza sativa. L) by genome-wide association analyses.

Lodging is one of the major abiotic stresses, affecting the total crop yield and quality. The improved lodging resistance and its component traits potentially reduce the yield losses. The section modulus (SM), bending moment at breaking (M), pushing resistance (PR), and coefficient of lodging resistance (cLr) are the key elements to estimate the lodging resistance. Understanding the genetic architecture of lodging resistance-related traits will help to improve the culm strength and overall yield potential. In this study, a natural population of 795 globally diverse genotypes was further divided into two (indica and japonica) subpopulations and was used to evaluate the lodging resistance and culm strength-related traits. Significant diversity was observed among the studied traits. We carried out the genome-wide association evaluation of four lodging resistance traits with 3.3 million deep resolution single-nucleotide polymorphic (SNP) markers. The general linear model (GLM) and compressed mixed linear model (MLM) were used for the whole population and two subpopulation genome-wide association studies (GWAS), and a 1000-time permutation test was performed to remove the false positives. A total of 375 nonredundant QTLs were observed for four culm strength traits on 12 chromosomes of the rice genome. Then, 33 pleiotropic loci governing more than one trait were mined. A total of 4031 annotated genes were detected within the candidate genomic region of 33 pleiotropic loci. The functional annotations and metabolic pathway enrichment analysis showed cellular localization and transmembrane transport as the top gene ontological terms. The in silico and in vitro expression analyses were conducted to validate the three candidate genes in a pleiotropic QTL on chromosome 7. It validated OsFBA2 as a candidate gene to contribute to lodging resistance in rice. The haplotype analysis for the candidate gene revealed a significant functional variation in the promoter region. Validation and introgression of alleles that are beneficial to induce culm strength may be used in rice breeding for lodging resistance.

Genome Wide Analysis of Family-1 UDP Glycosyltransferases in Populus trichocarpa Specifies Abiotic Stress Responsive Glycosylation Mechanisms.

Populus trichocarpa (Black cottonwood) is a dominant timber-yielding tree that has become a notable model plant for genome-level insights in forest trees. The efficient transport and solubility of various glycoside-associated compounds is linked to Family-1 UDP-glycosyltransferase (EC 2.4.1.x; UGTs) enzymes. These glycosyltransferase enzymes play a vital role in diverse plant functions, such as regulation of hormonal homeostasis, growth and development (seed, flower, fiber, root, etc.), xenobiotic detoxification, stress response (salt, drought, and oxidative), and biosynthesis of secondary metabolites. Here, we report a genome-wide analysis of the P. trichocarpa genome that identified 191 putative UGTs distributed across all chromosomes (with the exception of chromosome 20) based on 44 conserved plant secondary product glycosyltransferase (PSPG) motif amino acid sequences. Phylogenetic analysis of the 191 Populus UGTs together with 22 referenced UGTs from Arabidopsis and maize clustered the putative UGTs into 16 major groups (A-P). Whole-genome duplication events were the dominant pattern of duplication among UGTs in Populus. A well-conserved intron insertion was detected in most intron-containing UGTs across eight examined eudicots, including Populus. Most of the UGT genes were found preferentially expressed in leaf and root tissues in general. The regulation of putative UGT expression in response to drought, salt and heat stress was observed based on microarray and available RNA sequencing datasets. Up- and down-regulated UGT expression models were designed, based on transcripts per kilobase million values, confirmed their maximally varied expression under drought, salt and heat stresses. Co-expression networking of putative UGTs indicated their maximum co-expression with cytochrome P450 genes involved in triterpenoid biosynthesis. Our results provide an important resource for the identification of functional UGT genes to manipulate abiotic stress responsive glycosylation in Populus.

Characterization of SOD and GPX Gene Families in the Soybeans in Response to Drought and Salinity Stresses.

Plant stresses causing accumulation of reactive oxidative species (ROS) are scavenged by effective antioxidant defense systems. Therefore, the present study performed genome-wide identification of superoxide dismutase (SOD) and glutathione peroxidase (GPX) gene families in cultivated and wild soybeans, and 11 other legume species. We identified a total of 101 and 95 genes of SOD and GPX, respectively, across thirteen legume species. The highest numbers of SODs and GPXs were identified in cultivated (Glycine max) and wild (Glycine soja). A comparative phylogenetic study revealed highest homology among the SODs and GPXs of cultivated and wild soybeans relative to other legumes. The exon/intron structure, motif and synteny blocks were conserved in both soybean species. According to Ka/Ks, purifying the selection played the major evolutionary role in these gene families, and segmental duplication are major driving force for SODs and GPXs expansion. In addition, the qRT-PCR analysis of the G. max and G. soja SOD and GPX genes revealed significant differential expression of these genes in response to oxidative, drought and salinity stresses in root tissue. In conclusion, our study provides new insights for the evolution of SOD and GPX gene families in legumes, and provides resources for further functional characterization of these genes for multiple stresses.

Genome-wide characterization and functional analysis of class III peroxidase gene family in soybean reveal regulatory roles of GsPOD40 in drought tolerance.

Class III peroxidases (PODs) are plant-specific glycoproteins, that play essential roles in various plant physiological processes and defence responses. To date, scarce information is available about the POD gene family in soybean. Hence, the present study is the first comprehensive report about the genome-wide characterization of GmPOD gene family in soybean (Glycine max L.). Here, we identified a total of 124 GmPOD genes in soybean, that are unevenly distributed across the genome. Phylogenetic analysis classified them into six distinct sub-groups (A-F), with one soybean specific subgroup. Exon-intron and motif analysis suggested the existence of structural and functional diversity among the sub-groups. Duplication analysis identified 58 paralogous gene pairs; segmental duplication and positive/Darwinian selection were observed as the major factors involved in the evolution of GmPODs. Furthermore, RNA-seq analysis revealed that 23 out of a total 124 GmPODs showed differential expression between drought-tolerant and drought-sensitive genotypes under stress conditions; however, two of them (GmPOD40 and GmPOD42) revealed the maximum deregulation in all contrasting genotypes. Overexpression (OE) lines of GsPOD40 showed considerably higher drought tolerance compared to wild type (WT) plants under stress treatment. Moreover, the OE lines showed enhanced photosynthesis and enzymatic antioxidant activities under drought stress, resulting in alleviation of ROS induced oxidative damage. Hence, the GsPOD40 enhanced drought tolerance in soybean by regulating the key physiological and biochemical pathways involved in the defence response. Lastly, the results of our study will greatly assist in further functional characterization of GsPODs in plant growth and stress tolerance in soybean.

Foliar Application of Salicylic Acid Improves Water Stress Tolerance in Conocarpus erectus L. and Populus deltoides L. Saplings: Evidence from Morphological, Physiological, and Biochemical Changes.

Reforestation efforts are being challenged as water stress is hampering the sapling growth and survival in arid to semiarid regions. A controlled experiment was conducted to evaluate the effect of foliar application of salicylic acid (SA) on water stress tolerance of Conocarpus erectus and Populus deltoides. Saplings were watered at 90%, 60%, and 30% of field capacity (FC), and half of the saplings under 60% and 30% FC were sprayed with 1.0 mM SA. Results indicated that dry weight production decreased significantly in Populus deltoides under both water deficit conditions, and leaf gas exchange parameters decreased significantly in both the species under both soil water deficit conditions. Foliar application of SA resulted in a significant increase in leaf gas exchange parameters, and compatible solutes, thereby increasing the dry weight production in both of the species under soil water deficit. Oxidative stress (hydrogen peroxide and superoxide anions) increased under soil water deficit and decreased after the foliar application of SA and was parallel to the increased antioxidant enzymes activity (superoxide dismutase, catalase, peroxidase, and ascorbate peroxidase). Therefore, it can be concluded that foliar application of 1.0 mM SA can significantly improve the water stress tolerance in both species, however, positive impacts of SA application were higher in Conocarpus erectus due to improved photosynthetic capacity and increased antioxidant enzyme activity.

Genome wide identification, classification and functional characterization of heat shock transcription factors in cultivated and ancestral cottons (Gossypium spp.).

Heat shock transcription factors (HSF) have been demonstrated to play a significant transcriptional regulatory role in plants and considered as an integral part of signal transduction pathways against environmental stresses especially heat stress. Despite of their importance, HSFs have not yet been identified and characterized in all cotton species. In this study, we report the identification of 42, 39, 67, and 79 non-redundant HSF genes from diploid cottons G. arboreum (A2) and G. raimondii (D5), and tetraploid cottons G. barbadense (AD2) and G. hirsutum (AD1) respectively. The chromosome localization of identified HSFs revealed their random distribution on all the 13 chromosomes of A and D genomes of cotton with few regions containing HSFs in clusters. The genes structure and conserved domain analysis revealed the family-specific conservation of intron/exon organization and conserved domains in HSFs. Various abiotic stress-related cis-regulatory elements were identified from the putative promoter regions of cotton HSFs suggesting their possible role in mediating abiotic stress tolerance. The combined phylogenetic analysis of all the cotton HSFs grouped them into three subfamilies; with 145 HSFs belong to class A, 85 to class B, and 17 to class C subfamily. Moreover, a detailed analysis of HSF gene family in four species of cotton elucidated the role of allopolyploid and hybridization during evolutionary cascade of allotetraploid cotton. Comparatively, existence of more orthologous genes in cotton species than Arabidopsis, advocated that polyploidization produced new cotton specific orthologous gene clusters. Phylogenetic, collinearity and multiple synteny analyses exhibited dispersed, segmental, proximal, and tandem gene duplication events in HSF gene family. Duplication of gene events suggests that HSF gene family of cotton evolution was under strong purifying selection. Expression analysis revealed that GarHSF04 were found to be actively involved in PEG and salinity tolerance in G. arboreum. GhiHSF14 upregulated in heat and downregulated in salinity whilst almost illustrated similar behavior under cold and PEG treatments and GhiHSF21 exhibited down regulation almost across all the stresses in G. hirsutum. Overwhelmingly, present study paves the way to better understand the evolution of cotton HSF TFs and lays a foundation for future investigation of HSFs in improving abiotic stress tolerance in cotton.

Genome-Wide Diversity of MADS-Box Genes in Bread Wheat is Associated with its Rapid Global Adaptability.

MADS-box gene family members play multifarious roles in regulating the growth and development of crop plants and hold enormous promise for bolstering grain yield potential under changing global environments. Bread wheat (Triticum aestivum L.) is a key stable food crop around the globe. Until now, the available information concerning MADS-box genes in the wheat genome has been insufficient. Here, a comprehensive genome-wide analysis identified 300 high confidence MADS-box genes from the publicly available reference genome of wheat. Comparative phylogenetic analyses with Arabidopsis and rice MADS-box genes classified the wheat genes into 16 distinct subfamilies. Gene duplications were mainly identified in subfamilies containing unbalanced homeologs, pointing towards a potential mechanism for gene family expansion. Moreover, a more rapid evolution was inferred for M-type genes, as compared with MIKC-type genes, indicating their significance in understanding the evolutionary history of the wheat genome. We speculate that subfamily-specific distal telomeric duplications in unbalanced homeologs facilitate the rapid adaptation of wheat to changing environments. Furthermore, our in-silico expression data strongly proposed MADS-box genes as active guardians of plants against pathogen insurgency and harsh environmental conditions. In conclusion, we provide an entire complement of MADS-box genes identified in the wheat genome that could accelerate functional genomics efforts and possibly facilitate bridging gaps between genotype-to-phenotype relationships through fine-tuning of agronomically important traits.

Genome-wide investigation and expression analysis of APETALA-2 transcription factor subfamily reveals its evolution, expansion and regulatory role in abiotic stress responses in Indica Rice (Oryza sativa L. ssp. indica).

Rice is an important cereal crop that serves as staple food for more than half of the world population. Abiotic stresses resulting from changing climatic conditions are continuously threating its yield and production. Genes in APETALA-2 (AP2) family encode transcriptional regulators implicated during regulation of developmental processes and abiotic stress responses but their identification and characterization in indica rice was still missing. In this context, twenty-six genes distributed among eleven chromosomes in Indica rice encoding AP2 transcription-factor subfamily were identified and their diverse haplotypes were studied. Phylogenetic analysis of OsAP2 TF family-members grouped them into three clades indicating conservation of clades among cereals. Segmental duplications were observed to be principal route of evolution, supporting the higher positive selection-pressure, which were estimated to be originated about 10.57 to 56.72 million years ago (MYA). Conserved domain analysis and intron-exon distribution pattern of identified OsAP2s revealed their exclusive distribution among the specific clades of the phylogenetic tree. Moreover, the members of osa-miR172 family were also identified potentially targeting four OsAP2 genes. The real-time quantitative expression profiling of OsAP2s under heat stress conditions in contrasting indica rice genotypes revealed the differential expression pattern of OsAP2s (6 genes up-regulated and 4 genes down-regulated) in stress- and genotype-dependent manner. These findings unveiled the evolutionary pathways of AP2-TF in rice, and can help the functional characterization under developmental and stress responses.

In-silico Exploration of Channel Type and Efflux Silicon Transporters and Silicification Proteins in 80 Sequenced Viridiplantae Genomes.

Silicon (Si) accumulation protects plants from biotic and abiotic stresses. It is transported and distributed within the plant body through a cooperative system of channel type (e.g., OsLsi1) and efflux (Lsi2s e.g., OsLsi2) Si transporters (SITs) that belong to Noduline-26 like intrinsic protein family of aquaporins and an uncharacterized anion transporter family, respectively. Si is deposited in plant tissues as phytoliths and the process is known as biosilicification but the knowledge about the proteins involved in this process is limited. In the present study, we explored channel type SITs and Lsi2s, and siliplant1 protein (Slp1) in 80 green plant species. We found 80 channel type SITs and 133 Lsi2s. The channel type SITs characterized by the presence of two NPA motifs, GSGR or STAR selectivity filter, and 108 amino acids between two NPA motifs were absent from Chlorophytes, while Streptophytes evolved two different types of channel type SITs with different selectivity filters. Both channel type SITs and Lsi2s evolved two types of gene structures each, however, Lsi2s are ancient and were also found in Chlorophyta. Homologs of Slp1 (225) were present in almost all Streptophytes regardless of their Si accumulation capacity. In Si accumulator plant species, the Slp1s were characterized by the presence of H, D-rich domain, P, K, E-rich domain, and P, T, Y-rich domain, while moderate Si accumulators lacked H, D-rich domain and P, T, Y-rich domains. The digital expression analysis and coexpression networks highlighted the role of channel type and Lsi2s, and how Slp1 homologs were ameliorating plants' ability to withstand different stresses by co-expressing with genes related to structural integrity and signaling. Together, the in-silico exploration made in this study increases our knowledge of the process of biosilicification in plants.