Exploring cotton SFR2's conundrum in response to cold stress.

Cotton is an important agricultural crop to many regions across the globe but is sensitive to low-temperature exposure. The activity of the enzyme SENSITIVE TO FREEZING 2 (SFR2) improves cold tolerance of plants and produces trigalactosylsyldiacylglycerol (TGDG), but its role in cold sensitive plants, such as cotton remains unknown. Recently, it was reported that cotton SFR2 produced very little TGDG under normal and cold conditions. Here, we investigate cotton SFR2 activation and TGDG production. Using multiple approaches in the native system and transformation into Arabidopsis thaliana, as well as heterologous yeast expression, we provide evidence that cotton SFR2 activates differently than previously found among other plant species. We conclude with the hypothesis that SFR2 in cotton is not activated in a similar manner regarding acidification or freezing like Arabidopsis and that other regions of SFR2 protein are critical for activation of the enzyme than previously reported.

Genomic insights into CKX genes: key players in cotton fibre development and abiotic stress responses.

Cytokinin oxidase/dehydrogenase (CKX), responsible for irreversible cytokinin degradation, also controls plant growth and development and response to abiotic stress. While the CKX gene has been studied in other plants extensively, its function in cotton is still unknown. Therefore, a genome-wide study to identify the CKX gene family in the four cotton species was conducted using transcriptomics, quantitative real-time PCR (qRT-PCR) and bioinformatics. As a result, in G. hirsutum and G. barbadense (the tetraploid cotton species), 87 and 96 CKX genes respectively and 62 genes each in G. arboreum and G. raimondii, were identified. Based on the evolutionary studies, the cotton CKX gene family has been divided into five distinct subfamilies. It was observed that CKX genes in cotton have conserved sequence logos and gene family expansion was due to segmental duplication or whole genome duplication (WGD). Collinearity and multiple synteny studies showed an expansion of gene families during evolution and purifying selection pressure has been exerted. G. hirsutum CKX genes displayed multiple exons/introns, uneven chromosomal distribution, conserved protein motifs, and cis-elements related to growth and stress in their promoter regions. Cis-elements related to resistance, physiological metabolism and hormonal regulation were identified within the promoter regions of the CKX genes. Expression analysis under different stress conditions (cold, heat, drought and salt) revealed different expression patterns in the different tissues. Through virus-induced gene silencing (VIGS), the GhCKX34A gene was found to improve cold resistance by modulating antioxidant-related activity. Since GhCKX29A is highly expressed during fibre development, we hypothesize that the increased expression of GhCKX29A in fibres has significant effects on fibre elongation. Consequently, these results contribute to our understanding of the involvement of GhCKXs in both fibre development and response to abiotic stress.

Positive roles of the Ca2+ sensors GbCML45 and GbCML50 in improving cotton Verticillium wilt resistance.

As a universal second messenger, cytosolic calcium (Ca2+) functions in multifaceted intracellular processes, including growth, development and responses to biotic/abiotic stresses in plant. The plant-specific Ca2+ sensors, calmodulin and calmodulin-like (CML) proteins, function as members of the second-messenger system to transfer Ca2+ signal into downstream responses. However, the functions of CMLs in the responses of cotton (Gossypium spp.) after Verticillium dahliae infection, which causes the serious vascular disease Verticillium wilt, remain elusive. Here, we discovered that the expression level of GbCML45 was promoted after V. dahliae infection in roots of cotton, suggesting its potential role in Verticillium wilt resistance. We found that knockdown of GbCML45 in cotton plants decreased resistance while overexpression of GbCML45 in Arabidopsis thaliana plants enhanced resistance to V. dahliae infection. Furthermore, there was physiological interaction between GbCML45 and its close homologue GbCML50 by using yeast two-hybrid and bimolecular fluorescence assays, and both proteins enhanced cotton resistance to V. dahliae infection in a Ca2+-dependent way in a knockdown study. Detailed investigations indicated that several defence-related pathways, including salicylic acid, ethylene, reactive oxygen species and nitric oxide signalling pathways, as well as accumulations of lignin and callose, are responsible for GbCML45- and GbCML50-modulated V. dahliae resistance in cotton. These results collectively indicated that GbCML45 and GbCML50 act as positive regulators to improve cotton Verticillium wilt resistance, providing potential targets for exploitation of improved Verticillium wilt-tolerant cotton cultivars by genetic engineering and molecular breeding.

GhiPLATZ17 and GhiPLATZ22, zinc-dependent DNA-binding transcription factors, promote salt tolerance in upland cotton.

KEY MESSAGE: The utilization of transcriptome analysis, functional validation, VIGS, and DAB techniques have provided evidence that GhiPLATZ17 and GhiPLATZ22 play a pivotal role in improving the salt tolerance of upland cotton. PLATZ (Plant AT-rich sequences and zinc-binding proteins) are known to be key regulators in plant growth, development, and response to salt stress. In this study, we comprehensively analyzed the PLATZ family in ten cotton species in response to salinity stress. Gossypium herbaceum boasts 25 distinct PLATZ genes, paralleled by 24 in G. raimondii, 25 in G. arboreum, 46 in G. hirsutum, 48 in G. barbadense, 43 in G. tomentosum, 67 in G. mustelinum, 60 in G. darwinii, 46 in G. ekmanianum, and a total of 53 PLATZ genes attributed to G. stephensii. The PLATZ gene family shed light on the hybridization and allopolyploidy events that occurred during the evolutionary history of allotetraploid cotton. Ka/Ks analysis suggested that the PLATZ gene family underwent intense purifying selection during cotton evolution. Analysis of synteny and gene collinearity revealed a complex pattern of segmental and dispersed duplication events to expand PLATZ genes in cotton. Cis-acting elements and gene expressions revealed that GhiPLATZ exhibited salt stress resistance. Transcriptome analysis, functional validation, virus-induced gene silencing (VIGS), and diaminobenzidine staining (DAB) demonstrated that GhiPLATZ17 and GhiPLATZ22 enhance salt tolerance in upland cotton. The study can potentially advance our understanding of identifying salt-resistant genes in cotton.

Exploring agro-morphological and fiber traits diversity in cotton (G. barbadense L.).

Cotton (Gossypium barbadense L.) is a leading fiber and oilseed crop globally, but genetic diversity among breeding materials is often limited. This study analyzed genetic variability in 14 cotton genotypes from Egypt and other countries, including both cultivated varieties and wild types, using agro-morphological traits and genomic SSR markers. Field experiments were conducted over two seasons to evaluate 12 key traits related to plant growth, yield components, and fiber quality. Molecular diversity analysis utilized 10 SSR primers to generate DNA profiles. The Molecular diversity analysis utilized 10 SSR primers to generate DNA profiles. Data showed wide variation for the morphological traits, with Egyptian genotypes generally exhibiting higher means for vegetative growth and yield parameters. The top-performing genotypes for yield were Giza 96, Giza 94, and Big Black Boll genotypes, while Giza 96, Giza 92, and Giza 70 ranked highest for fiber length, strength, and fineness. In contrast, molecular profiles were highly polymorphic across all genotypes, including 82.5% polymorphic bands out of 212. Polymorphism information content was high for the SSR markers, ranging from 0.76 to 0.86. Genetic similarity coefficients based on the SSR data varied extensively from 0.58 to 0.91, and cluster analysis separated genotypes into two major groups according to geographical origin. The cotton genotypes displayed high diversity in morphology and genetics, indicating sufficient variability in the germplasm. The combined use of physical traits and molecular markers gave a thorough understanding of the genetic diversity and relationships between Egyptian and global cotton varieties. The SSR markers effectively profiled the genotypes and can help select ideal parents for enhancing cotton through hybridization and marker-assisted breeding.

Drought response revealed by chromatin organization variation and transcriptional regulation in cotton.

BACKGROUND: Cotton is a major world cash crop and an important source of natural fiber, oil, and protein. Drought stress is becoming a restrictive factor affecting cotton production. To facilitate the development of drought-tolerant cotton varieties, it is necessary to study the molecular mechanism of drought stress response by exploring key drought-resistant genes and related regulatory factors. RESULTS: In this study, two cotton varieties, ZY007 (drought-sensitive) and ZY168 (drought-tolerant), showing obvious phenotypic differences under drought stress, were selected. A total of 25,898 drought-induced genes were identified, exhibiting significant enrichment in pathways related to plant stress responses. Under drought induction, At subgenome expression bias was observed at the whole-genome level, which may be due to stronger inhibition of Dt subgenome expression. A gene co-expression module that was significantly associated with drought resistance was identified. About 90% of topologically associating domain (TAD) boundaries were stable, and 6613 TAD variation events were identified between the two varieties under drought. We identified 92 genes in ZY007 and 98 in ZY168 related to chromatin 3D structural variation and induced by drought stress. These genes are closely linked to the cotton response to drought stress through canonical hormone-responsive pathways, modulation of kinase and phosphatase activities, facilitation of calcium ion transport, and other related molecular mechanisms. CONCLUSIONS: These results lay a foundation for elucidating the molecular mechanism of the cotton drought response and provide important regulatory locus and gene resources for the future molecular breeding of drought-resistant cotton varieties.

Genome-wide identification and expression-pattern analysis of sulfate transporter (SULTR) gene family in cotton under multiple abiotic stresses and fiber development.

Sulfate transporter (SULTR) proteins are in charge of the transport and absorption on sulfate substances, and have been reported to play vital roles in the biological processes of plant growth and stress response. However, there were few reports of genome-wide identification and expression-pattern analysis of SULTRs in Hibiscus mutabilis. Gossypium genus is a ideal model for studying the allopolyploidy, therefore two diploid species (G. raimondii and G. arboreum) and two tetraploid species (G. hirsutum and G. barbadense) were chosen in this study to perform bioinformatic analyses, identifying 18, 18, 35, and 35 SULTR members, respectively. All the 106 cotton SULTR genes were utilized to construct the phylogenetic tree together with 11 Arabidopsis thaliana, 13 Oryza sativa, and 8 Zea mays ones, which was divided into Group1-Group4. The clustering analyses of gene structures and 10 conserved motifs among the cotton SULTR genes showed the consistent evolutionary relationship with the phylogenetic tree, and the results of gene-duplication identification among the four representative Gossypium species indicated that genome-wide or segment duplication might make main contributions to the expansion of SULTR gene family in cotton. Having conducted the cis-regulatory element analysis in promoter region, we noticed that the existing salicylic acid (SA), jasmonic acid (JA), and abscisic acid (ABA) elements could have influences with expression levels of cotton SULTR genes. The expression patterns of GhSULTR genes were also investigated on the 7 different tissues or organs and the developing ovules and fibers, most of which were highly expressed in root, stem, sepal, receptacel, ovule at 10 DPA, and fiber at 20 and 25 DPA. In addition, more active regulatory were observed in GhSULTR genes responding to multiple abiotic stresses, and 12 highly expressed genes showed the similar expression patterns in the quantitative Real-time PCR experiments under cold, heat, salt, and drought treatments. These findings broaden our insight into the evolutionary relationships and expression patterns of the SULTR gene family in cotton, and provide the valuable information for further screening the vital candidate genes on trait improvement.

GhTKPR1_8 functions to inhibit anther dehiscence and reduce pollen viability in cotton.

Sporopollenin, as the main component of the pollen exine, is a highly resistant polymer that provides structural integrity under unfavourable environmental conditions. Tetraketone α-pyrone reductase 1 (TKPR1) is essential for sporopollenin formation, catalyzing the reduction of tetraketone carbonyl to hydroxylated α-pyrone. The functional role of TKPR1 in male sterility has been reported in flowering plants such as maize, rice, and Arabidopsis. However, the molecular cloning and functional characterization of TKPR1 in cotton remain unaddressed. In this study, we identified 68 TKPR1s from four cotton species, categorized into three clades. Transcriptomics and RT-qPCR demonstrated that GhTKPR1_8 exhibited typical expression patterns in the tetrad stage of the anther. GhTKPR1_8 was localized to the endoplasmic reticulum. Moreover, ABORTED MICROSPORES (GhAMS) transcriptionally activated GhTKPR1_8 as indicated by luciferase complementation tests. GhTKPR1_8-knockdown inhibited anther dehiscence and reduced pollen viability in cotton. Additionally, overexpression of GhTKPR1_8 in the attkpr1 mutant restored its male sterile phenotype. This study offers novel insights into the investigation of TKPR1 in cotton while providing genetic resources for studying male sterility.

Decoding drought resilience: a comprehensive exploration of the cotton Eceriferum (CER) gene family and its role in stress adaptation.

BACKGROUND: The cuticular wax serves as a primary barrier that protects plants from environmental stresses. The Eceriferum (CER) gene family is associated with wax production and stress resistance. RESULTS: In a genome-wide identification study, a total of 52 members of the CER family were discovered in four Gossypium species: G. arboreum, G. barbadense, G. raimondii, and G. hirsutum. There were variations in the physicochemical characteristics of the Gossypium CER (GCER) proteins. Evolutionary analysis classified the identified GCERs into five groups, with purifying selection emerging as the primary evolutionary force. Gene structure analysis revealed that the number of conserved motifs ranged from 1 to 15, and the number of exons varied from 3 to 13. Closely related GCERs exhibited similar conserved motifs and gene structures. Analyses of chromosomal positions, selection pressure, and collinearity revealed numerous fragment duplications in the GCER genes. Additionally, nine putative ghr-miRNAs targeting seven G. hirsutum CER (GhCER) genes were identified. Among them, three miRNAs, including ghr-miR394, ghr-miR414d, and ghr-miR414f, targeted GhCER09A, representing the most targeted gene. The prediction of transcription factors (TFs) and the visualization of the regulatory TF network revealed interactions with GhCER genes involving ERF, MYB, Dof, bHLH, and bZIP. Analysis of cis-regulatory elements suggests potential associations between the CER gene family of cotton and responses to abiotic stress, light, and other biological processes. Enrichment analysis demonstrated a robust correlation between GhCER genes and pathways associated with cutin biosynthesis, fatty acid biosynthesis, wax production, and stress response. Localization analysis showed that most GCER proteins are localized in the plasma membrane. Transcriptome and quantitative reverse transcription-polymerase chain reaction (qRT-PCR) expression assessments demonstrated that several GhCER genes, including GhCER15D, GhCER04A, GhCER06A, and GhCER12D, exhibited elevated expression levels in response to water deficiency stress compared to control conditions. The functional identification through virus-induced gene silencing (VIGS) highlighted the pivotal role of the GhCER04A gene in enhancing drought resistance by promoting increased tissue water retention. CONCLUSIONS: This investigation not only provides valuable evidence but also offers novel insights that contribute to a deeper understanding of the roles of GhCER genes in cotton, their role in adaptation to drought and other abiotic stress and their potential applications for cotton improvement.

GhMYB52 Like: A Key Factor That Enhances Lint Yield by Negatively Regulating the Lignin Biosynthesis Pathway in Fibers of Upland Cotton (Gossypium hirsutum L.).

In the context of sustainable agriculture and biomaterial development, understanding and enhancing plant secondary cell wall formation are crucial for improving crop fiber quality and biomass conversion efficiency. This is especially critical for economically important crops like upland cotton (Gossypium hirsutum L.), for which fiber quality and its processing properties are essential. Through comprehensive genome-wide screening and analysis of expression patterns, we identified a particularly high expression of an R2R3 MYB transcription factor, GhMYB52 Like, in the development of the secondary cell wall in cotton fiber cells. Utilizing gene-editing technology to generate a loss-of-function mutant to clarify the role of GhMYB52 Like, we revealed that GhMYB52 Like does not directly contribute to cellulose synthesis in cotton fibers but instead represses a subset of lignin biosynthesis genes, establishing it as a lignin biosynthesis inhibitor. Concurrently, a substantial decrease in the lint index, a critical measure of cotton yield, was noted in parallel with an elevation in lignin levels. This study not only deepens our understanding of the molecular mechanisms underlying cotton fiber development but also offers new perspectives for the molecular improvement of other economically important crops and the enhancement of biomass energy utilization.

Genome-wide expression analysis of LACS gene family implies GhLACS25 functional responding to salt stress in cotton.

BACKGROUND: Long-chain acyl-coenzyme A synthetase (LACS) is a type of acylating enzyme with AMP-binding, playing an important role in the growth, development, and stress response processes of plants. RESULTS: The research team identified different numbers of LACS in four cotton species (Gossypium hirsutum, Gossypium barbadense, Gossypium raimondii, and Gossypium arboreum). By analyzing the structure and evolutionary characteristics of the LACS, the GhLACS were divided into six subgroups, and a chromosome distribution map of the family members was drawn, providing a basis for further research classification and positioning. Promoter cis-acting element analysis showed that most GhLACS contain plant hormones (GA, MeJA) or non-biological stress-related cis-elements. The expression patterns of GhLACS under salt stress treatment were analyzed, and the results showed that GhLACS may significantly participate in salt stress response through different mechanisms. The research team selected 12 GhLACSs responsive to salt stress for tissue expression analysis and found that these genes are expressed in different tissues. CONCLUSIONS: There is a certain diversity of LACS among different cotton species. Analysis of promoter cis-acting elements suggests that GhLACS may be involved in regulating plant growth, development and stress response processes. GhLACS25 was selected for in-depth study, which confirmed its significant role in salt stress response through virus-induced gene silencing (VIGS) and induced expression in yeast cells.

Transcriptome dynamics of Gossypium purpurascens in response to abiotic stresses by Iso-seq and RNA-seq data.

Gossypium purpurascens is a member of the Malvaceae family, holds immense economic significance as a fiber crop worldwide. Abiotic stresses harm cotton crops, reduce yields, and cause economic losses. Generating high-quality reference genomes and large-scale transcriptomic datasets across diverse conditions can offer valuable insights into identifying preferred agronomic traits for crop breeding. The present research used leaf tissues to conduct PacBio Iso-seq and RNA-seq analysis. We carried out an in-depth analysis of DEGs using both correlations with cluster analysis and principal component analysis. Additionally, the study also involved the identification of both lncRNAs and CDS. We have prepared RNA-seq libraries from 75 RNA samples to study the effects of drought, salinity, alkali, and saline-alkali stress, as well as control conditions. A total of 454.06 Gigabytes of transcriptome data were effectively validated through the identification of differentially expressed genes and KEGG and GO analysis. Overwhelmingly, gene expression profiles and full-length transcripts from cotton tissues will aid in understanding the genetic mechanism of abiotic stress tolerance in G. purpurascens.

Co-localization and analysis of miR477b with fiber length quantitative trait loci in cotton.

Cotton is an important cash crop for the textile industry. However, the understanding of natural genetic variation of fiber elongation in relation to miRNA is lacking. A miRNA gene (miR477b) was found to co-localize with a previously mapped fiber length (FL) quantitative trait locus (QTL). The miR477b was differentially expressed during fiber elongation between two backcross inbred lines (BILs) differing in FL and its precursor sequences. Bioinformatics and qRT-PCR analysis were further used to analyse the miRNA genes, which could produce mature miR477b. Cotton plants with virus-induced gene silencing (VIGS) constructs to over-express the allele of miR477b from the BIL with longer fibers had significantly longer fibers as compared with negative control plants, while the VIGS plants with suppressed miRNA expression had significantly shorter fibers. The expression level of the target gene (DELLA) and related genes (RDL1 and EXPA1 for DELLA through HOX3 protein) in the two BILs and/or the VIGS plants were generally congruent, as expected. This report represents one of the first comprehensive studies to integrate QTL linkage mapping and physical mapping of small RNAs with both small and mRNA transcriptome analysis, followed by VIGS, to identify candidate small RNA genes affecting the natural variation of fiber elongation in cotton.

Evolutionary Dynamics of Chromatin Structure and Duplicate Gene Expression in Diploid and Allopolyploid Cotton.

Polyploidy is a prominent mechanism of plant speciation and adaptation, yet the mechanistic understandings of duplicated gene regulation remain elusive. Chromatin structure dynamics are suggested to govern gene regulatory control. Here, we characterized genome-wide nucleosome organization and chromatin accessibility in allotetraploid cotton, Gossypium hirsutum (AADD, 2n = 4X = 52), relative to its two diploid parents (AA or DD genome) and their synthetic diploid hybrid (AD), using DNS-seq. The larger A-genome exhibited wider average nucleosome spacing in diploids, and this intergenomic difference diminished in the allopolyploid but not hybrid. Allopolyploidization also exhibited increased accessibility at promoters genome-wide and synchronized cis-regulatory motifs between subgenomes. A prominent cis-acting control was inferred for chromatin dynamics and demonstrated by transposable element removal from promoters. Linking accessibility to gene expression patterns, we found distinct regulatory effects for hybridization and later allopolyploid stages, including nuanced establishment of homoeolog expression bias and expression level dominance. Histone gene expression and nucleosome organization are coordinated through chromatin accessibility. Our study demonstrates the capability to track high-resolution chromatin structure dynamics and reveals their role in the evolution of cis-regulatory landscapes and duplicate gene expression in polyploids, illuminating regulatory ties to subgenomic asymmetry and dominance.

GhVIM28, a negative regulator identified from VIM family genes, positively responds to salt stress in cotton.

The VIM (belonged to E3 ubiquitin ligase) gene family is crucial for plant growth, development, and stress responses, yet their role in salt stress remains unclear. We analyzed phylogenetic relationships, chromosomal localization, conserved motifs, gene structure, cis-acting elements, and gene expression patterns of the VIM gene family in four cotton varieties. Our findings reveal 29, 29, 17, and 14 members in Gossypium hirsutum (G.hirsutum), Gossypium barbadense (G.barbadense), Gossypium arboreum (G.arboreum), and Gossypium raimondii (G. raimondii), respectively, indicating the maturity and evolution of this gene family. motifs among GhVIMs genes were observed, along with the presence of stress-responsive, hormone-responsive, and growth-related elements in their promoter regions. Gene expression analysis showed varying patterns and tissue specificity of GhVIMs genes under abiotic stress. Silencing GhVIM28 via virus-induced gene silencing revealed its role as a salt-tolerant negative regulator. This work reveals a mechanism by which the VIM gene family in response to salt stress in cotton, identifying a potential negative regulator, GhVIM28, which could be targeted for enhancing salt tolerance in cotton. The objective of this study was to explore the evolutionary relationship of the VIM gene family and its potential function in salt stress tolerance, and provide important genetic resources for salt tolerance breeding of cotton.

Quantitative genomics-enabled selection for simultaneous improvement of lint yield and seed traits in cotton (Gossypium hirsutum L.).

KEY MESSAGE: A Bayesian linkage disequilibrium-based multiple-locus mixed model identified QTLs for fibre, seed and oil traits and predicted breeding worthiness of test lines, enabling their simultaneous improvement in cotton. Improving cotton seed and oil yields has become increasingly important while continuing to breed for higher lint yield. In this study, a novel Bayesian linkage disequilibrium-based multiple-locus mixed model was developed for QTL identification and genomic prediction (GP). A multi-parent population consisting of 256 recombinant inbred lines, derived from four elite cultivars with distinct combinations of traits, was used in the analysis of QTLs for lint percentage, seed index, lint index and seed oil content and their interrelations. All four traits were moderately heritable and correlated but with no large influence of genotype × environment interactions across multiple seasons. Seven to ten major QTLs were identified for each trait with many being adjacent or overlapping for different trait pairs. A fivefold cross-validation of the model indicated prediction accuracies of 0.46-0.62. GP results based on any two-season phenotypes were strongly correlated with phenotypic means of a pooled analysis of three-season experiments (r = 0.83-0.92). When used for selection of improvement in lint, seed and oil yields, GP captured 40-100% of individuals with comparable lint yields of those selected based on the three-season phenotypic results. Thus, this quantitative genomics-enabled approach can not only decipher the genomic variation underlying lint, seed and seed oil traits and their interrelations, but can provide predictions for their simultaneous improvement. We discuss future breeding strategies in cotton that will enhance the entire value of the crop, not just its fibre.

Transcriptome analysis of Gossypium hirsutum cultivar Zhongzhimian No.2 uncovers the gene regulatory networks involved in defense against Verticillium dahliae.

BACKGROUND: Cotton is globally important crop. Verticillium wilt (VW), caused by Verticillium dahliae, is the most destructive disease in cotton, reducing yield and fiber quality by over 50% of cotton acreage. Breeding resistant cotton cultivars has proven to be an efficient strategy for improving the resistance of cotton to V. dahliae. However, the lack of understanding of the genetic basis of VW resistance may hinder the progress in deploying elite cultivars with proven resistance. RESULTS: We planted the VW-resistant Gossypium hirsutum cultivar Zhongzhimian No.2 (ZZM2) in an artificial greenhouse and disease nursery. ZZM2 cotton was subsequently subjected to transcriptome sequencing after Vd991 inoculation (6, 12, 24, 48, and 72 h post-inoculation). Several differentially expressed genes (DEGs) were identified in response to V. dahliae infection, mainly involved in resistance processes, such as flavonoid and terpenoid quinone biosynthesis, plant hormone signaling, MAPK signaling, phenylpropanoid biosynthesis, and pyruvate metabolism. Compared to the susceptible cultivar Junmian No.1 (J1), oxidoreductase activity and reactive oxygen species (ROS) production were significantly increased in ZZM2. Furthermore, gene silencing of cytochrome c oxidase subunit 1 (COX1), which is involved in the oxidation-reduction process in ZZM2, compromised its resistance to V. dahliae, suggesting that COX1 contributes to VW resistance in ZZM2. CONCLUSIONS: Our data demonstrate that the G. hirsutum cultivar ZZM2 responds to V. dahliae inoculation through resistance-related processes, especially the oxidation-reduction process. This enhances our understanding of the mechanisms regulating the ZZM2 defense against VW.

Investigation of salt tolerance in cotton germplasm by analyzing agro-physiological traits and ERF genes expression.

The development of genotypes that can tolerate high levels of salt is crucial for the efficient use of salt-affected land and for enhancing crop productivity worldwide. Therefore, incorporating salinity tolerance is a critical trait that crops must possess. Salt resistance is a complex character, controlled by multiple genes both physiologically and genetically. To examine the genetic foundation of salt tolerance, we assessed 16 F1 hybrids and their eight parental lines under normal and salt stress (15 dS/m) conditions. Under salt stress conditions significant reduction was observed for plant height (PH), bolls/plant (NBP), boll weight (BW), seed cotton yield (SCY), lint% (LP), fiber length (FL), fiber strength (FS), potassium to sodium ratio (K+/Na+), potassium contents (K+), total soluble proteins (TSP), carotenoids (Car) and chlorophyll contents. Furthermore, the mean values for hydrogen peroxide (H2O2), sodium contents (Na+), catalase (CAT), superoxide dismutase (SOD), peroxidase (POD), and fiber fineness (FF) were increased under salt stress. Moderate to high heritability and genetic advancement was observed for NBP, BW, LP, SCY, K+/Na+, SOD, CAT, POD, Car, TSP, FL, and FS. Mean performance and multivariate analysis of 24 cotton genotypes based on various agro-physiological and biochemical parameters suggested that the genotypes FBS-Falcon, Barani-333, JSQ-White Hold, Ghauri, along with crosses FBS-FALCON × JSQ-White Hold, FBG-222 × FBG-333, FBG-222 × Barani-222, and Barani-333 × FBG-333 achieved the maximum values for K+/Na+, K+, TSP, POD, Chlb, CAT, Car, LP, FS, FL, PH, NBP, BW, and SCY under salt stress and declared as salt resistant genotypes. The above-mentioned genotypes also showed relatively higher expression levels of Ghi-ERF-2D.6 and Ghi-ERF-7A.6 at 15 dS/m and proved the role of these ERF genes in salt tolerance in cotton. These findings suggest that these genotypes have the potential for the development of salt-tolerant cotton varieties with desirable fiber quality traits.

Gossypium hirsutum calmodulin-like protein (CML 11) interaction with geminivirus encoded protein using bioinformatics and molecular techniques.

Plant viruses are the most abundant destructive agents that exist in every ecosystem, causing severe diseases in multiple crops worldwide. Currently, a major gap is present in computational biology determining plant viruses interaction with its host. We lay out a strategy to extract virus-host protein interactions using various protein binding and interface methods for Geminiviridae, a second largest virus family. Using this approach, transcriptional activator protein (TrAP/C2) encoded by Cotton leaf curl Kokhran virus (CLCuKoV) and Cotton leaf curl Multan virus (CLCuMV) showed strong binding affinity with calmodulin-like (CML) protein of Gossypium hirsutum (Gh-CML11). Higher negative value for the change in Gibbs free energy between TrAP and Gh-CML11 indicated strong binding affinity. Consensus from gene ontology database and in-silico nuclear localization signal (NLS) tools identified subcellular localization of TrAP in the nucleus associated with Gh-CML11 for virus infection. Data based on interaction prediction and docking methods present evidences that full length and truncated C2 strongly binds with Gh-CML11. This computational data was further validated with molecular results collected from yeast two-hybrid, bimolecular fluorescence complementation system and pull down assay. In this work, we also show the outcomes of full length and truncated TrAP on plant machinery. This is a first extensive report to delineate a role of CML protein from cotton with begomoviruses encoded transcription activator protein.

Genome-wide identification and analysis of the cotton ALDH gene family.

BACKGROUND: Aldehyde dehydrogenases (ALDHs) are a family of enzymes that catalyze the oxidation of aldehyde molecules into the corresponding carboxylic acid, regulate the balance of aldehydes and protect plants from the poisoning caused by excessive accumulation of aldehydes; however, this gene family has rarely been studied in cotton. RESULTS: In the present study, genome-wide identification was performed, and a total of 114 ALDH family members were found in three cotton species, Gossypium hirsutum, Gossypium arboreum and Gossypium raimondii. The ALDH genes were divided into six subgroups by evolutionary analysis. ALDH genes in the same subgroup showed similar gene structures and conserved motifs, but some genes showed significant differences, which may result in functional differences. Chromosomal location analysis and selective pressure analysis revealed that the ALDH gene family had experienced many fragment duplication events. Cis-acting element analysis revealed that this gene family may be involved in the response to various biotic and abiotic stresses. The RT‒qPCR results showed that the expression levels of some members of this gene family were significantly increased under salt stress conditions. Gohir.A11G040800 and Gohir.D06G046200 were subjected to virus-induced gene silencing (VIGS) experiments, and the sensitivity of the silenced plants to salt stress was significantly greater than that of the negative control plants, suggesting that Gohir.A11G040800 and Gohir.D06G046200 may be involved in the response of cotton to salt stress. CONCLUSIONS: In total, 114 ALDH genes were identified in three Gossypium species by a series of bioinformatics analysis. Gene silencing of the ALDH genes of G. hirsutum revealed that ALDH plays an important role in the response of cotton to salt stress.