Cotton Genome Research Articles

Convergence and divergence of diploid and tetraploid cotton genomes.

Polyploidy is an important driving force in speciation and evolution; however, the genomic basis for parallel selection of a particular trait between polyploids and ancestral diploids remains unexplored. Here we construct graph-based pan-genomes for diploid (A2) and allotetraploid (AD1) cotton species, enabled by an assembly of 50 genomes of genetically diverse accessions. We delineate a mosaic genome map of tetraploid cultivars that illustrates genomic contributions from semi-wild forms into modern cultivars. Pan-genome comparisons identify syntenic and hyper-divergent regions of continued variation between diploid and tetraploid cottons, and suggest an ongoing process of sequence evolution potentially linked to the contrasting genome size change in two subgenomes. We highlight 43% of genetic regulatory relationships for gene expression in diploid encompassing sequence divergence after polyploidy, and specifically characterize six underexplored convergent genetic loci contributing to parallel selection of fiber quality. This study offers a framework for pan-genomic dissection of genetic regulatory components underlying parallel selection of desirable traits in organisms.

Characterization and expression analysis of the MADS-box gene AGL8 in cotton: insights into gene function differentiation in plant growth and stress resistance.

AGAMOUS-LIKE 8 (AGL8) belongs to the MADS-box family, which plays important roles in transcriptional regulation, sequence-specific DNA binding and other biological processes and molecular functions. The genome of cotton, a representative polyploid plant, contains multiple AGL8 genes. However, their functional differentiation is still unclear. In this study, a comprehensive genomic analysis of AGL8 genes was conducted. Cotton AGL8s were subdivided into four subgroups (Groups 1, 2, 3, and 4) based on phylogenetic analysis, and different subgroups of AGL8s presented different characteristics, including different structures and conserved motifs. With respect to the promoter regions of the GhAGL8 genes, we successfully predicted cis-elements that respond to phytohormone signal transduction and the stress response of plants. Transcriptome data and real-time quantitative PCR validation indicated that three genes, namely, GH_D07G0744, GH_A03G0856 and GH_A07G0749, were highly induced by methyl jasmonate (MeJA), salicylic acid (SA), and abscisic acid (ABA), which indicated that they function in plant resistance to abiotic and biotic stresses. The information from the gene structure, number and types of conserved domains, tissue-specific expression levels, and expression patterns under different treatments highlights the differences in sequence and function of the cotton AGL8 genes. Different AGL8s play roles in vegetative growth, reproductive development, and plant stress resistance. These results lay a foundation for further study of GhAGL8s in cotton.

Integrative analyses of long and short-read RNA sequencing reveal the spliced isoform regulatory network of seedling growth dynamics in upland cotton.

The polyploid genome of cotton has significantly increased the transcript complexity. Recent advances in full-length transcript sequencing are now widely used to characterize the complete landscape of transcriptional events. Such studies in cotton can help us to explore the genetic mechanisms of the cotton seedling growth. Through long-read single-molecule RNA sequencing, this study compared the transcriptomes of three yield contrasting genotypes of upland cotton. Our analysis identified different numbers of spliced isoforms from 31,166, 28,716, and 28,713 genes in SJ48, Z98, and DT8 cotton genotypes, respectively, most of which were novel compared to previous cotton reference transcriptomes, and showed significant differences in the number of exon structures and coding sequence length due to intron retention. Quantification of isoform expression revealed significant differences in expression in the root and leaf of each genotype. An array of key isoform target genes showed protein kinase or phosphorylation functions, and their protein interaction network contained most of the circadian oscillator proteins. Spliced isoforms from the GIGANTEA (GI) protien were differentially regulated in each genotype and might be expected to regulate translational activities, including the sequence and function of target proteins. In addition, these spliced isoforms generate diurnal expression profiles in cotton leaves, which may alter the transcriptional regulatory network of seedling growth. Silencing of the novel spliced GI isoform Gh_A02G0645_N17 significantly affected biomass traits, contributed to variable growth, and increased transcription of the early flowering pathway gene ELF in cotton. Our high-throughput hybrid sequencing results will be useful to dissect functional differences among spliced isoforms in the polyploid cotton genome.

Unveiling the genetic landscape: Exploring the SSR-based genetic architecture and amino acid dissection of Gossypium barbadense and G. darwinii genomes

Genetic maps highlight the genome organization and structure but also provide the chance of tagging superior traits for crop improvement through marker-assisted selection. Amino acids are building blocks of proteins and perform crucial function in regulating the signaling of molecules involved in the development and growth of plants. Plant architecture also have an impact on crop productivity. In order to select elite cultivars for breeding and identification of favorable alleles and their functional properties, a deep understanding of genetic architecture and development of genetic map is essential. In present investigation, an interspecific cross of Gossypium barbadense XH-18 × G. darwinii 5-7 was made to develop a genetic map utilizing single sequence repeat markers for the dissection of amino acids involved in genetic architecture of G. barbadense and G. darwinii. We measured chromosomal distribution of 20 amino acids across the whole genome of both species. The map consists of 613 markers spread across all 26 chromosomes, covering 2371.4 cM of cotton genome with an average inter-marker distance of 9.35 cM. The marker number anchored on the chromosomes varied from 5 to 76 with an average of 23.57 on each chromosome. The Dt sub-genome had more markers (83.03%) than the At sub-genome (15.66%). Moreover, the longest chromosome was 143.387 cM, the shortest was 58.430 cM, and the average length was 91.207 cM. The Dt subgenome spans a greater genomic distance than the At subgenome. A sum of 21,035 genes were discovered, covering the complete genome of G. barbadense; G. darwinii and have been found to be involved in tRNA 3'-trailer cleavage, macromolecule modification, peptide deformylase activity, response to biotic stimulus and defense response. The minimum Glutamic acid (Glu), Histidine (His), and Lysine (Lys) were found on Chr.13 (0.00-17.74), Chr.02 (0.00-8.01), and Chr.06 (0.00-17.97), respectively found through chromosomal amino acid dissection. The genome-wide SSR interspecific genetic map of G. barbadense and G. darwinii is first of its kind, and studying chromosomal distribution of amino acids will set a landmark step to dissect the genome structure of G. darwinii.

A novel role of the cotton calcium sensor CBL3 was involved in Verticillium wilt resistance in cotton.

Verticillium wilt, causes mainly by the soilborne pathogen Verticillium dahliae, is a devastated vascular disease resulting in huge financial losses in cotton, so research on improving V. dahliae stress tolerance in cotton is the utmost importance. Calcium as the second messenger acts as a crucial role in plant innate immunity. Cytosolic Ca2+during the pathogen infection is a significant increase in plant immune responses. Calcineurin B-like (CBL) proteins are widely known calcium sensors that regulate abiotic stress responses. However, the role of cotton CBLs in response to V. dahliae stress remains unclear. To discover and utilize the gene to Verticillium wilt resistance and defense response mechanism of cotton. Through screening the gene to Verticillium wilt resistance in cotton, four GhCBL3 copies were obtained from the current common cotton genome sequences. The protein domain and phylogenetic analyses of GhCBL3 were performed using NCBI Blast, DNAMAN, and MotifScan programs. Real-time RT-PCR was used to detect the expression of GhCBL3 gene in cotton seedlings under various stress treatments. The expression construct including GhCBL3 cDNA was transduced into Agrobacterium tumefaciens (GV3101) by heat shock method and transformed into cotton plants by Virus-Induced Gene Silencing (VIGS) method. The results of silencing of GhCBl3 on ROS accumulation and plant disease resistance in cotton plants were assessed. A member of calcineurin B-like proteins (defined as GhCBL3) in cotton was obtained. The expression of GhCBL3 was significantly induced and raised by various stressors, including dahliae, jasmonic acid (JA) and H2O2 stresses. Knockdown GhCBL3 in cotton by Virus-Induced Gene Silencing analysis enhanced Verticillium wilt tolerance and changed the occurrence of reactive oxygen species. Some disease-resistant genes were increased in GhCBL3-silencing cotton lines. GhCBL3 may function on regulating the Verticillium dahliae stress response of plants.

Actively Expressed Intergenic Genes Generated by Transposable Element Insertions in Gossypium hirsutum Cotton.

The genomes and annotated genes of allotetraploid cotton Gossypium hirsutum have been extensively studied in recent years. However, the expression, regulation, and evolution of intergenic genes (ITGs) have not been completely deciphered. In this study, we identified a novel set of actively expressed ITGs in G. hirsutum cotton, through transcriptome profiling based on deep sequencing data, as well as chromatin immunoprecipitation, followed by sequencing (ChIP-seq) of histone modifications and how the ITGs evolved. Totals of 17,567 and 8249 ITGs were identified in G. hirsutum and Gossypium arboreum, respectively. The expression of ITGs in G. hirsutum was significantly higher than that in G. arboreum. Moreover, longer exons were observed in G. hirsutum ITGs. Notably, 42.3% of the ITGs from G. hirsutum were generated by the long terminal repeat (LTR) insertions, while their proportion in genic genes was 19.9%. The H3K27ac and H3K4me3 modification proportions and intensities of ITGs were equivalent to genic genes. The H3K4me1 modifications were lower in ITGs. Additionally, evolution analyses revealed that the ITGs from G. hirsutum were mainly produced around 6.6 and 1.6 million years ago (Mya), later than the pegged time for genic genes, which is 7.0 Mya. The characterization of ITGs helps to elucidate the evolution of cotton genomes and shed more light on their biological functions in the transcriptional regulation of eukaryotic genes, along with the roles of histone modifications in speciation and diversification.

Characterization of Caulimovirid-like Sequences from Upland Cotton (Gossypium hirsutum L.) Exhibiting Terminal Abortion in Georgia, USA.

In this study, we investigated the potential involvement of endogenous viral elements (EVEs) in the development of apical tissue necrosis, resulting in the terminal abortion of upland cotton (Gossypium hirsutum L.) in Georgia. The high-throughput sequence analysis of symptomatic and asymptomatic plant tissue samples revealed near-complete EVE-Georgia (EVE-GA) sequences closely related to caulimoviruses. The analysis of EVE-GA's putative open reading frames (ORFs) compared to cotton virus A and endogenous cotton pararetroviral elements (eCPRVE) revealed their similarity in putative ORFs 1-4. However, in the ORF 5 and ORF 6 encoding putative coat protein and reverse transcriptase, respectively, the sequences from EVE-GA have stop codons similar to eCPRVE sequences from Mississippi. In silico mining of the cotton genome database using EVE-GA as a query uncovered near-complete viral sequence insertions in the genomes of G. hirsutum species (~7 kb) but partial in G. tomentosum (~5.3 kb) and G. mustelinum (~5.1 kb) species. Furthermore, cotton EVEs' episomal forms and messenger RNA (mRNA) transcripts were detected in both symptomatic and asymptomatic plants collected from cotton fields. No significant yield difference was observed between symptomatic and asymptomatic plants of the two varieties evaluated in the experimental plot. Additionally, EVEs were also detected in cotton seeds and seedlings. This study emphasizes the need for future research on EVE sequences, their coding capacity, and any potential role in host immunity or pathogenicity.

Advances in genome sequencing and artificially induced mutation provides new avenues for cotton breeding.

Cotton production faces challenges in fluctuating environmental conditions due to limited genetic variation in cultivated cotton species. To enhance the genetic diversity crucial for this primary fiber crop, it is essential to augment current germplasm resources. High-throughput sequencing has significantly impacted cotton functional genomics, enabling the creation of diverse mutant libraries and the identification of mutant functional genes and new germplasm resources. Artificial mutation, established through physical or chemical methods, stands as a highly efficient strategy to enrich cotton germplasm resources, yielding stable and high-quality raw materials. In this paper, we discuss the good foundation laid by high-throughput sequencing of cotton genome for mutant identification and functional genome, and focus on the construction methods of mutant libraries and diverse sequencing strategies based on mutants. In addition, the important functional genes identified by the cotton mutant library have greatly enriched the germplasm resources and promoted the development of functional genomes. Finally, an innovative strategy for constructing a cotton CRISPR mutant library was proposed, and the possibility of high-throughput screening of cotton mutants based on a UAV phenotyping platform was discussed. The aim of this review was to expand cotton germplasm resources, mine functional genes, and develop adaptable materials in a variety of complex environments.

Robust CRISPR/Mb2Cas12a genome editing tools in cotton plants.

The efficiency and accuracy of the CRISPR/Mb2Cas12a system were demonstrated in cotton, achieving an efficiency of over 90% at target sites. Notably, Mb2Cas12a exhibited significant tolerance under different temperatures ranging from 22°C to 32°C. Additionally, the Mb2Cas12a system revealed effective editing at more relaxed VTTV PAM sites in the cotton genome, which expanded the genome editing range by approximately 2.6-fold than the wide-type LbCas12a. Finally, a multiplex genome editing system was also developed based on Mb2Cas12a, enabling simultaneous editing of eight target sites using a single crRNA cassette.

GhWRKY75 positively regulates GhPR6-5b via binding to a W-box TTGAC (C/T) to orchestrate cotton resistance to Verticillium dahliae

Verticillium dahliae is an important fungal pathogen affecting cotton yield and quality. Therefore, the mining of V. dahlia-resistance genes is urgently needed. Proteases and protease inhibitors play crucial roles in plant defense responses. However, the functions and regulatory mechanisms of the protease inhibitor PR6 gene family remain largely unknown. This study provides a comprehensive analysis of the PR6 gene family in the cotton genome. We performed genome-wide identification and functional characterization of the cotton GhPR6 gene family, which belongs to the potato protease inhibitor I family of inhibitors. Thirty-nine PR6s were identified in Gossypium arboreum, G. raimondii, G. barbadense, and G. hirsutum, and they were clustered into four groups. Based on the analysis of pathogen-induced and Ghlmm transcriptome data, GhPR6-5b was identified as the key gene for V. dahliae resistance. Virus-induced gene silencing experiments revealed that cotton was more sensitive to V. dahliae V991 after PR6-5b silencing. The present study established that GhWRKY75 plays an important role in resistance to Verticillium wilt in cotton by positively regulating GhPR6-5b expression by directly binding to the W-box TTGAC(T/C). Our findings established that GhWRKY75 is a potential candidate for improving cotton resistance to V. dahliae, and provide primary information for further investigations and the development of specific strategies to bolster the defense mechanisms of cotton against V. dahliae.

Cotton transposon-related variome reveals roles of transposon-related variations in modern cotton cultivation

IntroductionTransposon plays a vital role in cotton genome evolution, contributing to the expansion and divergence of genomes within the Gossypium genus. However, knowledge of transposon activity in modern cotton cultivation is limited. ObjectivesIn this study, we aimed to construct transposon-related variome within Gossypium genus and reveal role of transposon-related variations during cotton cultivation. In addition, we try to identify valuable transposon-related variations for cotton breeding. MethodsWe utilized graphical genome construction to build up the graphical transposon-related variome. Based on the graphical variome, we integrated t-test, eQTL analysis and Mendelian Randomization (MR) to identify valuable transposon activities and elite genes. In addition, a convolutional neural network (CNN) model was constructed to evaluate epigenomic effects of transposon-related variations. ResultsWe identified 35,980 transposon activities among 10 cotton genomes, and the diversity of genomic and epigenomic features was observed among 21 transposon categories. The graphical cotton transposon-related variome was constructed, and 9,614 transposon-related variations with plasticity in the modern cotton cohort were used for eQTL, phenotypic t-test and Mendelian Randomization. 128 genes were identified as gene resources improving fiber length and strength simultaneously. 4 genes were selected from 128 genes to construct the elite gene panel whose utility has been validated in a natural cotton cohort and 2 accessions with phenotypic divergence. Based on the eQTL analysis results, we identified transposon-related variations involved in cotton’s environmental adaption and human domestication, providing evidence of their role in cotton’s adaption-domestication cooperation. ConclusionsThe cotton transposon-related variome revealed the role of transposon-related variations in modern cotton cultivation, providing genomic resources for cotton molecular breeding.

Genome-wide characterization of DNA methyltransferase family genes implies GhDMT6 improving tolerance of salt and drought on cotton

BackgroundDNA methylation is an important epigenetic mode of genomic DNA modification and plays a vital role in maintaining epigenetic content and regulating gene expression. Cytosine-5 DNA methyltransferase (C5-MTase) are the key enzymes in the process of DNA methylation. However, there is no systematic analysis of the C5-MTase in cotton so far, and the function of DNMT2 genes has not been studied.MethodsIn this study, the whole genome of cotton C5-MTase coding genes was identified and analyzed using a bioinformatics method based on information from the cotton genome, and the function of GhDMT6 was further validated by VIGS experiments and subcellular localization analysis.Results33 C5-MTases were identified from three cotton genomes, and were divided into four subfamilies by systematic evolutionary analysis. After the protein domain alignment of C5-MTases in cotton, 6 highly conserved motifs were found in the C-terminus of 33 proteins involved in methylation modification, which indicated that C5-MTases had a basic catalytic methylation function. These proteins were divided into four classes based on the N-terminal difference, of which DNMT2 lacks the N-terminal regulatory domain. The expression of C5-MTases in different parts of cotton was different under different stress treatments, which indicated the functional diversity of cotton C5-MTase gene family. Among the C5-MTases, the GhDMT6 had a obvious up-regulated expression. After silencing GhDMT6 with VIGS, the phenotype of cotton seedlings under different stress treatments showed a significant difference. Compared with cotton seedlings that did not silence GhDMT6, cotton seedlings silencing GhDMT6 showed significant stress resistance.ConclusionThe results show that C5-MTases plays an important role in cotton stress response, which is beneficial to further explore the function of DNMT2 subfamily genes.

Pangenome analysis reveals transposon-driven genome evolution in cotton

BackgroundTransposable elements (TEs) have a profound influence on the trajectory of plant evolution, driving genome expansion and catalyzing phenotypic diversification. The pangenome, a comprehensive genetic pool encompassing all variations within a species, serves as an invaluable tool, unaffected by the confounding factors of intraspecific diversity. This allows for a more nuanced exploration of plant TE evolution.ResultsHere, we constructed a pangenome for diploid A-genome cotton using 344 accessions from representative geographical regions, including 223 from China as the main component. We found 511 Mb of non-reference sequences (NRSs) and revealed the presence of 5479 previously undiscovered protein-coding genes. Our comprehensive approach enabled us to decipher the genetic underpinnings of the distinct geographic distributions of cotton. Notably, we identified 3301 presence-absence variations (PAVs) that are closely tied to gene expression patterns within the pangenome, among which 2342 novel expression quantitative trait loci (eQTLs) were found residing in NRSs. Our investigation also unveiled contrasting patterns of transposon proliferation between diploid and tetraploid cotton, with long terminal repeat (LTR) retrotransposons exhibiting a synchronized surge in polyploids. Furthermore, the invasion of LTR retrotransposons from the A subgenome to the D subgenome triggered a substantial expansion of the latter following polyploidization. In addition, we found that TE insertions were responsible for the loss of 36.2% of species-specific genes, as well as the generation of entirely new species-specific genes.ConclusionsOur pangenome analyses provide new insights into cotton genomics and subgenome dynamics after polyploidization and demonstrate the power of pangenome approaches for elucidating transposon impacts and genome evolution.

Fingerprint Finder: Identifying Genomic Fingerprint Sites in Cotton Cohorts for Genetic Analysis and Breeding Advancement.

Genomic data in Gossypium provide numerous data resources for the cotton genomics community. However, to fill the gap between genomic analysis and breeding field work, detecting the featured genomic items of a subset cohort is essential for geneticists. We developed FPFinder v1.0 software to identify a subset of the cohort's fingerprint genomic sites. The FPFinder was developed based on the term frequency-inverse document frequency algorithm. With the short-read sequencing of an elite cotton pedigree, we identified 453 pedigree fingerprint genomic sites and found that these pedigree-featured sites had a role in cotton development. In addition, we applied FPFinder to evaluate the geographical bias of fiber-length-related genomic sites from a modern cotton cohort consisting of 410 accessions. Enriching elite sites in cultivars from the Yangtze River region resulted in the longer fiber length of Yangze River-sourced accessions. Apart from characterizing functional sites, we also identified 12,536 region-specific genomic sites. Combining the transcriptome data of multiple tissues and samples under various abiotic stresses, we found that several region-specific sites contributed to environmental adaptation. In this research, FPFinder revealed the role of the cotton pedigree fingerprint and region-specific sites in cotton development and environmental adaptation, respectively. The FPFinder can be applied broadly in other crops and contribute to genetic breeding in the future.

A comprehensive review on Gossypium hirsutum resistance against cotton leaf curl virus.

Cotton (Gossypium hirsutum L.) is a significant fiber crop. Being a major contributor to the textile industry requires continuous care and attention. Cotton is subjected to various biotic and abiotic constraints. Among these, biotic factors including cotton leaf curl virus (CLCuV) are dominant. CLCuV is a notorious disease of cotton and is acquired, carried, and transmitted by the whitefly (Bemisia tabaci). A cotton plant affected with CLCuV may show a wide range of symptoms such as yellowing of leaves, thickening of veins, upward or downward curling, formation of enations, and stunted growth. Though there are many efforts to protect the crop from CLCuV, long-term results are not yet obtained as CLCuV strains are capable of mutating and overcoming plant resistance. However, systemic-induced resistance using a gene-based approach remained effective until new virulent strains of CLCuV (like Cotton Leaf Curl Burewala Virus and others) came into existence. Disease control by biological means and the development of CLCuV-resistant cotton varieties are in progress. In this review, we first discussed in detail the evolution of cotton and CLCuV strains, the transmission mechanism of CLCuV, the genetic architecture of CLCuV vectors, and the use of pathogen and nonpathogen-based approaches to control CLCuD. Next, we delineate the uses of cutting-edge technologies like genome editing (with a special focus on CRISPR-Cas), next-generation technologies, and their application in cotton genomics and speed breeding to develop CLCuD resistant cotton germplasm in a short time. Finally, we delve into the current obstacles related to cotton genome editing and explore forthcoming pathways for enhancing precision in genome editing through the utilization of advanced genome editing technologies. These endeavors aim to enhance cotton's resilience against CLCuD.

In Silico Identification and Characterization of Rare Cold Inducible 2 (RCI2) Gene Family in Cotton.

RCI2/PMP3s are involved in biotic and abiotic stresses and have an influence on the regulation of many genes. RCI2/PMP3 genes, which particularly encode small membrane proteins of the PMP3 family, are involved in abiotic stress responses in plants. In this work, in silico studies were used to investigate RCI2's potential function in stress tolerance and organogenesis. We conducted an extensive study of the RCI2 gene family and revealed 36 RCI2 genes from cotton species that were distributed over 36 chromosomes of the cotton genome. Functional and phylogenetic examination of the RCI2/PMP3 gene family has been studied in Arabidopsis, but in cotton, the RCI2/PMP3 genes have not yet been studied. Phylogenetic and sequencing studies revealed that cotton RCI2s are conserved, with most of them categorized into six distinct clades. A chromosome distribution and localization study indicated that cotton RCI2 genes were distributed unevenly on 36 chromosomes with segmental duplications, suggesting that the cotton RCI2 family is evolutionarily conserved. Many cis-elements related to stress responsiveness, development, and hormone responsiveness were detected in the promoter regions of the cotton RCI2. Moreover, the 36 cotton RCI2s revealed tissue-specific expression patterns in the development of cotton performed by transcriptome analysis. Gene structure analysis indicated that nearly all RCI2 genes have two exons and one intron. All of the cotton RCI2 genes were highly sensitive to drought, abscisic acid, salt, and cold treatments, demonstrating that they may be employed as genetic objects to produce stress-resistant plants.

The 4Fs of cotton: genome editing of cotton for fiber, food, feed, and fuel to achieve zero hunger.

Cotton is globally known for its high-priority cellulose-rich natural fiber. In addition to providing fiber for the textile industry, it is an important source material for edible oil, livestock feed, and fuel products. Global warming and the growing population are the major challenges to the world's agriculture and the potential risks to food security. In this context, improving output traits in cotton is necessary to achieve sustainable cotton production. During the last few years, high throughput omics techniques have aided in identifying crucial genes associated with traits of cotton fiber, seed, and plant architecture which could be targeted with more precision and efficiency through the CIRPSR/Cas-mediated genome editing technique. The various CRISPR/Cas systems such as CRISPR/Cas9, CRISPR/nCas9, and CRISPR/Cas12a have been employed to edit cotton genes associated with a wide range of traits including fiber length, flowering, leaf colour, rooting, seed oil, plant architecture, gossypol content, somatic embryogenesis, and biotic and abiotic stresses tolerance, highlighting its effectiveness in editing the cotton genome. Thus, CRISPR/Cas-mediated genome editing has emerged as a technique of choice to tailor crop phenotypes for better yield potential and environmental resilience. The review covers a comprehensive analysis of cotton phenotypic traits and their improvement with the help of the latest genome editing tools to improve fiber, food, feed, and fuel-associated genes of cotton to ensure food security.

Crossing and Setting of Hybrid Seeds in the Creation of Chromosome-Substituted Cotton Lines g. Hirsutum l.

A comparative study of the indicators of crossability and setting of hybrid and backcross seeds F1, F1BC1, F1BC2, obtained from crossings of monosomic and monotelodisomic lines of cotton G.hirsutum L. with the donor line Pima 3-79 of the species G.barbadense L. and aneuploid backcross hybrids, was found to be a linear decrease of these indicators in some hybrids, as well as their increase, as well as the alternation of indicators of crossability and setting in different hybrid generations. The study of chromosome conjugation in hybrid monosomic F1 obtained from crossing monosomic lines with the donor line Pima 3-79 of the species G. barbadense L., as well as backcross monosomic F1BC1, F1BC2 with the replacement of specific chromosomes of the cotton genome, revealed normal chromosome conjugation with the formation of 25 bivalents and one univalent of different size in all studied PMCs in most hybrids.

Leveraging transcriptomics-based approaches to enhance genomic prediction: integrating SNPs and gene networks for cotton fibre quality improvement.

Cultivated cotton plants are the world's largest source of natural fibre, where yield and quality are key traits for this renewable and biodegradable commodity. The Gossypium hirsutum cotton genome contains ~80K protein-coding genes, making precision breeding of complex traits a challenge. This study tested approaches to improving the genomic prediction (GP) accuracy of valuable cotton fibre traits to help accelerate precision breeding. With a biology-informed basis, a novel approach was tested for improving GP for key cotton fibre traits with transcriptomics of key time points during fibre development, namely, fibre cells undergoing primary, transition, and secondary wall development. Three test approaches included weighting of SNPs in DE genes overall, in target DE gene lists informed by gene annotation, and in a novel approach of gene co-expression network (GCN) clusters created with partial correlation and information theory (PCIT) as the prior information in GP models. The GCN clusters were nucleated with known genes for fibre biomechanics, i.e., fasciclin-like arabinogalactan proteins, and cluster size effects were evaluated. The most promising improvements in GP accuracy were achieved by using GCN clusters for cotton fibre elongation by 4.6%, and strength by 4.7%, where cluster sizes of two and three neighbours proved most effective. Furthermore, the improvements in GP were due to only a small number of SNPs, in the order of 30 per trait using the GCN cluster approach. Non-trait-specific biological time points, and genes, were found to have neutral effects, or even reduced GP accuracy for certain traits. As the GCN clusters were generated based on known genes for fibre biomechanics, additional candidate genes were identified for fibre elongation and strength. These results demonstrate that GCN clusters make a specific and unique contribution in improving the GP of cotton fibre traits. The findings also indicate that there is room for incorporating biology-based GCNs into GP models of genomic selection pipelines for cotton breeding to help improve precision breeding of target traits. The PCIT-GCN cluster approach may also hold potential application in other crops and trees for enhancing breeding of complex traits.

From genes to fields: Environmental compatibility of herbicide tolerant transgenic cotton

IntroductionThere are several enticing reasons to use genetic engineering to develop transgenic cotton plants with economically relevant new traits. The use of transgenic cotton to protect crops from biotic stressors like weeds may prove to be a cost-effective solution. ObjectivesThe development of herbicide-resistant cotton variants is the primary motivation for gene transfer in this crop. In the current study, we conducted a battery of experiments on the herbicide-tolerant cotton variety MNH-786 to investigate its expression patterns and environmental adaptation. Material and methodsThe 35S promoter controls the expression of the codon-optimized Cp4-EPSPS gene that is present in this variety. Several different molecular approaches, such as polymerase chain reaction (PCR), Florescent In-Situ Hybridization analysis, and enzyme-linked immunosorbent assay (ELISA), are used to confirm the presence of transgenic cotton plants. The glyphosate spray assay was performed using molecular analysis, employing a dosage of 2000 ml per acre. The suitability of transgenic and non-transgenic cotton plants in four unique environments—the Multan, Vehari, Bahawalpur, and Faisalabad Districts of Punjab province, Pakistan was assessed using a comparative comparison. A gene x environment interaction (GEI) biplot was used to analyze the correlation between genes and their environments. ResultsTransgenic cotton plants screened using PCR to target 1.467 kb regions showed effective integration into cotton genomes. Results showed that Cp4-EPSPS proteins fluctuated and associated with environmental variables across all three generations (T0, T1, and T2). In the herbicide spray assay, all transgenic cotton plants survived, but non-transgenic cotton and all weeds died. According to the "which-won-where" polygon, transgenic cotton plant Events 3, 4, 5, 6, and 7 performed better in three settings, except Faisalabad. According to correlation and heat-map yield research, transgenic cotton variety MNH-786 Events 4, 5 and 6 have a higher consistency and influence in Vehari district's natural habitats. Multan and Bahawalpur also show encouraging results. In Faisalabad, no transgenic events perform well. ConclusionWe conclude that Events 4 and 5 show a substantial abundance of genetic potential that is robust over a wide range of environments thanks to our thorough study of the outcomes obtained under these conditions. SignificanceOur study emphasises the importance of transgenic cotton, its performance, and its exposure to appropriate agroecological zones. This knowledge can be advantageous for farmers in attaining optimal conditions to maximize productivity.