查看更多>>摘要：Cotton fiber quality is a persistent concern that determines planting benefits and the quality of finished textile products.However,the limitations of measurement instruments have hindered the accurate evaluation of some important fiber characteristics such as fiber maturity,fineness,and neps,which in turn has impeded the genetic improvement and industrial utilization of cotton fiber.Here,12 single fiber quality traits were measured using Advanced Fiber Information System (AFIS) equipment among 383 accessions of upland cotton (Gossypium hirsutum L.).In addition,eight conventional fiber quality traits were assessed by the High Volume Instrument (HVI) System.Genome-wide association study (GWAS),linkage disequilibrium (LD) block genotyping and functional identification were conducted sequentially to uncover the associated elite loci and candidate genes of fiber quality traits.As a result,the previously reported pleiotropic locus FL_D11 regulating fiber length-related traits was identified in this study.More importantly,three novel pleiotropic loci (FM_A03,FF_A05,and FN_A07) regulating fiber maturity,fineness and neps,respectively,were detected based on AFIS traits.Numerous highly promising candidate genes were screened out by integrating RNA-seq and qRT-PCR analyses,including the reported GhKRP6 for fiber length,the newly identified GhMAP8 for maturity and GhDFR for fineness.The origin and evolutionary analysis of pleiotropic loci indicated that the selection pressure on FL_D11,FM_A03 and FF_A05 increased as the breeding period approached the present and the origins of FM_A03 and FF_A05 were traced back to cotton landraces.These findings reveal the genetic basis underlying fiber quality and provide insight into the genetic improvement and textile utilization of fiber in G.hirsutum.
查看更多>>摘要：Pectin is a major constituent of the plant cell wall.Pectate lyase (PEL,EC 4.2.2.2) uses anti-β-elimination chemistry to cleave the α-1,4 glycosidic linkage in the homogalacturonan region of pectin.However,limited information is available on the comprehensive and evolutionary analysis of PELs in the Malvaceae.In this study,we identified 597 PEL genes from 10 Malvaceae species.Phylogenetic and motif analyses revealed that these PELs are classified into six subfamilies:Clades I,Ⅱ,Ⅲ,IV,Va,and Vb.The two largest subfamilies,Clades I and Ⅱ,contained 237 and 222 PEL members,respectively.The members of Clades Va and Vb only contained four or five motifs,far fewer than the other subfamilies.Gene duplication analysis showed that segmental duplication played a crucial role in the expansion of the PEL gene family in Gossypium species.The PELs from Clades I,IV,Va,and Vb were expressed during the fiber elongation stage,but nearly all PEL genes from Clades Ⅱ and Ⅲ showed no expression in any of the investigated fiber developmental stages.We further performed single-gene haplotype association analysis in 2,001 G.hirsutum accessions and 229 G.barbadense accessions.Interestingly,14 PELs were significantly associated with fiber length and strength traits in G.barbadense with superior fiber quality,while only eight GhPEL genes were found to be significantly associated with fiber quality traits in G.hirsutum.Our findings provide important information for further evolutionary and functional research on the PEL gene family members and their potential use for fiber quality improvement in cotton.
查看更多>>摘要：Cotton is an important natural fiber crop worldwide which plays a vital role in our daily life.High yield is a constant goal of cotton breeding,and lint percentage (LP) is one of the important components of cotton fiber yield.A stable QTL controlling LP,qLPA01.1,was identified on chromosome A01 from Gossypium hirsutum introgressed lines with G.tomentosum chromosome segments in a previous study.To fine-map qLPA01.1,an F2 population with 986 individuals was established by crossing G.hirsutum cultivar CCRI35 with the chromosome segment substitution line HT_390.A high-resolution genetic map including 47 loci and spanning 56.98 cM was constructed in the QTL region,and qLPA01.1 was ultimately mapped into an interval corresponding to an～80 kb genome region of chromosome A01 in the reference genome,which contained six annotated genes.Transcriptome data and sequence analysis revealed that S-acyltransferase protein 24 (GoPAT24) might be the target gene of qLPA01.1.This result provides the basis for cotton fiber yield improvement via marker-assisted selection (MAS) and further studies on the mechanism of cotton fiber development.
查看更多>>摘要：Improving plant resistance to Verticillium wilt (VW),which causes massive losses in Gossypium hirsutum,is a global challenge.Crop plants need to efficiently allocate their limited energy resources to maintain a balance between growth and defense.However,few transcriptional regulators specifically respond to Verticillium dahliae and the underlying mechanism has not been identified in cotton.In this study,we found that the that expression of most R2R3-MYB members in cotton is significantly changed by V.dahliae infection relative to the other MYB types.One novel R2R3-MYB transcription factor (TF) that specifically responds to V.dahliae,GhMYB3D5,was identified.GhMYB3D5 was not expressed in 15 cotton tissues under normal conditions,but it was dramatically induced by V.dahliae stress.We functionally characterized its positive role and underlying mechanism in VW resistance.Upon V.dahliae infection,the up-regulated GhMYB3D5 bound to the GhADH1 promoter and activated GhADH1 expression.In addition,GhMYB3D5 physically interacted with GhADH1 and further enhanced the transcriptional activation of GhADH1.Consequently,the transcriptional regulatory module GhMYB3D5-GhADH1 then promoted lignin accumulation by improving the transcriptional levels of genes related to lignin biosynthesis (GhPAL,GhC4H,Gh4CL,and GhPOD/GhLAC) in cotton,thereby enhancing cotton VW resistance.Our results demonstrated that the GhMYB3D5 promotes defense-induced lignin accumulation,which can be regarded as an effective way to orchestrate plant immunity and growth.
查看更多>>摘要：Abiotic and biotic stressors adversely affect plant survival,biomass generation,and crop yields.As the global availability of arable land declines and the impacts of global warming intensify,such stressors may have increasingly pronounced effects on agricultural productivity.Currently,researchers face the overarching challenge of comprehensively enhancing plant resilience to abiotic and biotic stressors.The secondary cell wall plays a crucial role in bolstering the stress resistance of plants.To increase plant resistance to stress through genetic manipulation of the secondary cell wall,we cloned a cell wall protein designated glycine-rich protein-like (GhGRPL) from cotton fibers,and found that it is specifically expressed during the period of secondary cell wall biosynthesis.Notably,this protein differs from its Arabidopsis homolog,AtGRP,since its glycine-rich domain is deficient in glycine residues.GhGRPL is involved in secondary cell wall deposition.Upregulation of GhGRPL enhances lignin accumulation and,consequently,the thickness of the secondary cell walls,thereby increasing the plant's resistance to abiotic stressors,such as drought and salinity,and biotic threats,including Verticillium dahliae infection.Conversely,interference with GhGRPL expression in cotton reduces lignin accumulation and compromises that resistance.Taken together,our findings elucidate the role of GhGRPL in regulating secondary cell wall development through its influence on lignin deposition,which,in turn,reinforces cell wall robustness and impermeability.These findings highlight the promising near-future prospect of adopting GhGRPL as a viable,effective approach for enhancing plant resilience to abiotic and biotic stress factors.
查看更多>>摘要：Verticillium dahliae causes significant losses in cotton production.To reveal the mechanism of the defense response to V.dahliae in cotton,transcriptomic analyses were performed using cotton cultivars M138 (V.dahliae-resistant) and P2 (V.dahliae-susceptible).The results revealed 11,076 and 6,640 differentially expressed genes (DEGs) in response to V.dahliae,respectively.The weighted gene co-expression network analysis of 4,633 transcription factors (TFs) indicated a "MEblue" module containing 654 TFs that strongly correlate with resistance to V.dahliae.Among these TFs,the ethylene response factor Ghi_A05G10166 (GhERF91) was identified as a putative hub gene with a defense response against V.dahliae.A virus-induced gene silencing assay and exogenous application of ethephon showed that GhERF91 is activated by ethylene and positively regulates the response to V.dahliae exposure in cotton.This study provides fundamental transcriptome data and a putative causal gene (GhERF91) associated with resistance to V.dahliae,as well as genetic resources for breeding V.dahliae-resistant cotton.
查看更多>>摘要：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.
查看更多>>摘要：Verticillium wilt (VW),induced by the soil-borne fungus Verticillium dahliae (Vd),poses a substantial threat to a diverse array of plant species.Employing molecular breeding technology for the development of cotton varieties with heightened resistance to VW stands out as one of the most efficacious protective measures.In this study,we successfully generated two stable transgenic lines of cotton (Gossypium hirsutum L.),VdThit-RNAi-1 and VdThit-RNAi-2,using host-induced gene silencing (HIGS) technology to introduce double-stranded RNA (dsRNA) targeting the thiamine transporter protein gene (VdThit).Southern blot analysis confirmed the presence of a single-copy insertion in each line.Microscopic examination showed marked reductions in the colonization and spread of Vd-mCherry in the roots of VdThit-RNAi cotton compared to wild type (WT).The corresponding disease index and fungal biomass of VdThit-RNAi-1/2 also exhibited significant reductions.Real-time quantitative PCR (qRT-PCR) analysis demonstrated a substantial inhibition of VdThit expression following prolonged inoculation of VdThit-RNAi cotton.Small RNA sequencing (sRNA-Seq) analysis revealed the generation of a substantial number of VdThit-specific siRNAs in the VdThit-RNAi transgenic lines.Additionally,the silencing of VdThit by the siVdThit produced by VdThit-RNAi-1/2 resulted in the elevated expression of multiple genes involved in the thiamine biosynthesis pathway in Vd.Under field conditions,VdThit-RNAi transgenic cotton exhibited significantly enhanced disease resistance and yield compared with WT.In summary,our findings underscore the efficacy of HIGS targeting VdThit in restraining the infection and spread of Vd in cotton,thereby potentially enabling the development of cotton breeding as a promising strategy for managing VW.
查看更多>>摘要：Activity of bc1 complex kinase (ABC1K) is an atypical protein kinase (aPK) that plays a crucial role in plant mitochondrial and plastid stress responses,but little is known about the responses of ABC1Ks to stress in cotton (Gossypium spp.).Here,we identified 40 ABC1Ks in upland cotton (Gossypium hirsutum L.) and found that the GhABC1Ks were unevenly distributed across 17 chromosomes.The GhABC1K family members included 35 paralogous gene pairs and were expanded by segmental duplication.The GhABC1K promoter sequences contained diverse cis-acting regulatory elements relevant to hormone or stress responses.The qRT-PCR results revealed that most GhABC1Ks were upregulated by exposure to different stresses.GhABC1K2-A05 and GhABC1K12-A07 expression levels were upregulated by at least three stress treatments.These genes were further functionally characterized by virus-induced gene silencing (VIGS).Compared with the controls,the GhABC1K2-A05-and GhABC1K12-A07-silenced cotton lines exhibited higher malondialdehyde (MDA) contents,lower catalase (CAT),peroxidase (POD) and superoxide dismutase (SOD) activities and reduced chlorophyll and soluble sugar contents under NaCl and PEG stress.In addition,the expression levels of six stress marker genes (GhDREB2A,GhSOS1,GhCIPK6,GhSOS2,GhWRKY33,and GhRD29A) were significantly downregulated after stress in the GhABC1K2-A05-and GhABC1K12-A07-silenced lines.The results indicate that knockdown of GhABC1K2-A05 and GhABC1K12-A07 make cotton more sensitive to salt and PEG stress.These findings can provide valuable information for intensive studies of GhABC1Ks in the responses and resistance of cotton to abiotic stresses.
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