Down regulation of cotton GbTRP1 leads to accumulation of anthranilates and confers resistance to Verticillium dahliae

Journal of Cotton Research

[Background] Verticillium wilt, caused by Verticillium dahliae, is called a “cancer” disease of cotton. The discovery and identification of defense-related genes is essential for the breeding of Verticillium wilt-resistant varieties. In previous research we identified some possible broad-spectrum resistance genes. Here, we report a tryptophan synthesis-related gene GbTRP1 and its functional analysis in relation to the resistance of cotton to V. dahliae.

[Results] Expression analysis shows that GbTRP1 is suppressed at 1 h and 6 h post V. dahliae infection, but activated at 12 h and 24 h, and the expression of GbTRP1 is highly induced by treatment with salicylic acid and jasmonic acid. Sub-cellular localization studies show that GbTRP1 is localized in the chloroplast. Suppression of GbTRP1 expression leads to lesion-mimic phenotypes and activates the immune response in cotton by showing enhanced resistance to V. dahliae and B. cinerea. Metabolomic analysis shows that anthranilic compounds significantly accumulated in GbTRP1-silenced plants, and these metabolites can inhibit the growth of V. dahliae and B. cinerea in vitro.

[Conclusions] Our results show that suppression of GbTRP1 expression dramatically activates the immune response and increases resistance of cotton to V. dahliae and B. cinerea, possibly due to the accumulation of anthranilate compounds. This study not only provides genetic resources for disease resistance breeding, but also may provide a basis for new chemical control methods for combatting of fungal disease in cotton.

[Title] Down regulation of cotton GbTRP1 leads to accumulation of anthranilates and confers resistance to Verticillium dahliae

[Authors] MIAO Yuhuan, ZHU Longfu and ZHANG Xianlong

Journal of Cotton Research. 2019; 2:19

https://doi.org/10.1186/s42397-019-0034-1

https://jcottonres.biomedcentral.com/articles/10.1186/s42397-019-0034-1

Identification and Functional Analysis of Betv1 in Three D Genome-containing Wild Cotton Varieties

Abstract:

[Objective] By analyzing the major birch pollen allergen Betv1 gene family in D genomes of cotton and comparing the expression patterns of three diploid D-genome cotton varieties with different Verticillium wilt resistance levels, we aimed to provide a theoretical basis for further studies on the role of Betv1 genes in cotton resistant to Verticillium wilt. [Method] The Betv1 genes were identified, and a bioinformatics analysis of the physicochemical properties of their encoded sequences in Gossypium raimondii (D5) was performed. The transcriptome sequencing and quantitative real time-PCR of G. raimondii (D5), Gossypium trilobum (D8) and Gossypium thurberi (D1) were used to verify the expression patterns of Bet v 1 genes under Verticillium dahlia infection stress. Betv1 genes were silenced by virus-induced gene silencing in G. hirsutum to identify their functions. [Result] The D genome of cotton contains 59 members, 58 of which have introns and are distributed on eight chromosomes, and most encode hydrophilic proteins that localize to the cytoplasm. The expression levels of Betv1 genes in three wild cotton species having D genomes after being inoculated with V. dahliae were consistent with their disease resistance levels. The genes were separated into three groups based on their expression levels. Genes of Group 3 responded to V. dahliae infection and were highly expressed in disease-resistant cotton species G. thurberi. This indicated that Group 3 genes may be involved in the immune response of Verticillium wilt. A gene with a high expression level was screened out of Group 3. A corresponding homologous gene was silenced in G. hirsutum by virus-induced gene silencing, and gene-silenced plants were more susceptible to V. dahliae, indicating that the gene plays a positive regulatory role in the progress of Verticillium wilt resistance in cotton. [Conclusion] The Betv1 genes act in response to V. dahliae infection and are critical in cotton resistance to Verticillium wilt. The information obtained provides a basis for further studies of the cotton Bet v 1 family genes and their functions.

Key words: wild cotton; Verticillium wilt; Betv1 gene; transcriptome; quantitative real time-PCR (qRT-PCR); virus-induced gene silencing (VIGS)

Cotton Science. 2019, 31(5):361-380.

https://doi.org/10.11963/1002-7807.dqmzy.20190723

Comparative transcriptional analysis provides insights of possible molecular mechanisms of wing polyphenism induced by postnatal crowding in Aphis gossypii

Background
Aphis gossypii is a worldwide sap-sucking pest with a variety of hosts and a  vector of more than 50 plant viruses. The strategy of wing polyphenism, mostly resulting from population density increasing, contributes to the evolutionary success of this pest. However, the related molecular basis remains unclear. Here, we identified the effects of postnatal crowding on wing morph determination in cotton aphid, and examined the transcriptomic differences between wingless and wing morphs.

Results
Effect of postnatal crowding on wing determination in A. gossypii was evaluated firstly. Under the density of 5 nymphs·cm− 2, no wing aphids appeared. Proportion of wing morphs rised with the increase of density in a certain extent, and peaked to 56.1% at the density of 20 nymphs·cm− 2, and reduced afterwards. Then, transcriptomes of wingless and wing morphs were assembled and annotated separately to identify potentially exclusively or differentially expressed transcripts between these two morphs, in which 3 126 and 3 392 unigenes annotated in Nr (Non-redundant protein sequence) database were found in wingless or wing morphs exclusively. Moreover, 3 187 up- and 1 880 down-regulated genes were identified in wing versus wingless aphid. Pathways analysis suggested the involvement of differentially expressed genes in multiple cellular signaling pathways involved in wing morphs determination, including lipid catabolic and metabolism, insulin, ecdysone and juvenile hormone biosynthesis. The expression levels of related genes were validated by the reverse transcription quantitative real time polymerase chain reaction (RT-qPCR) soon afterwards.

Conclusions
The present study identified the effects of postnatal crowding on wing morphs induction and demonstrated that the critical population density for wing morphs formation in A. gossypii was 20 nymphs·cm− 2. Comparative transcriptome analysis provides transcripts potentially expressed exclusively in wingless or wing morph, respectively. Differentially expressed genes between wingless and wing morphs were identified and several signaling pathways potentially involved in cotton aphid wing differentiation were obtained.

Authors:

JI Jichao, ZHANG Shuai, LUO Junyu, WANG Li, ZHU Xiangzhen, ZHANG Kaixin, ZHANG Lijuan & CUI Jinjie

Journal of Cotton Research. 2019,2:17

https://doi.org/10.1186/s42397-019-0036-z

Genome-wide identification and expression analysis of DNA demethylase family in cotton

Journal of Cotton Research

[Background] DNA methylation is an important epigenetic factor that maintains and regulates gene expression. The mode and level of DNA methylation depend on the roles of DNA methyltransferase and demethylase, while DNA demethylase plays a key role in the process of DNA demethylation. The results showed that the plant’s DNA demethylase all contained conserved DNA glycosidase domain. This study identified the cotton DNA demethylase gene family and analyzed it using bioinformatics methods to lay the foundation for further study of cotton demethylase gene function.

[Results] This study used genomic information from diploid Gossypium raimondii JGI (D), Gossypium arboreum L. CRI (A), Gossypium hirsutum L. JGI (AD1) and Gossypium barbadebse L. NAU (AD2) to Arabidopsis thaliana. Using DNA demethylase genes sequence of Arabidopsis as reference, 25 DNA demethylase genes were identified in cotton by BLAST analysis. There are 4 genes in the genome D, 5 genes in the genome A, 10 genes in the genome AD1, and 6 genes in the genome AD2. The gene structure and evolution were analyzed by bioinformatics, and the expression patterns of DNA demethylase gene family in Gossypium hirsutum L. were analyzed. From the phylogenetic tree analysis, the DNA demethylase gene family of cotton can be divided into four subfamilies: REPRESSOR of SILENCING 1 (ROS1), DEMETER (DME), DEMETER-LIKE 2 (DML2), and DEMETER-LIKE3 (DML3). The sequence similarity of DNA demethylase genes in the same species was higher, and the genetic relationship was also relatively close. Analysis of the gene structure revealed that the DNA demethylase gene family members of the four subfamilies varied greatly. Among them, the number of introns of ROS1 and DME subfamily was larger, and the gene structure was more complex. For the analysis of the conserved domain, it was known that the DNA demethylase family gene member has an endonuclease III (ENDO3c) domain.

[Conclusions] The genes of the DNA demethylase family are distributed differently in different cotton species, and the gene structure is very different. High expression of ROS1 genes in cotton were under abiotic stress. The expression levels of ROS1 genes were higher during the formation of cotton ovule. The transcription levels of ROS1 family genes were higher during cotton fiber development.

[Title]Genome-wide identification and expression analysis of DNA demethylase family in cotton

[Authors] YANG Xiaomin, LU Xuke, CHEN Xiugui, WANG Delong, WANG Junjuan, WANG Shuai, GUO Lixue, CHEN Chao, WANG Xiaoge, WANG Xinlei & YE Wuwei *

Journal of Cotton Research. 2019, 2: 16

https://doi.org/10.1186/s42397-019-0033-2

https://jcottonres.biomedcentral.com/articles/10.1186/s42397-019-0033-2

An isopentyl transferase gene driven by the senescence-inducible SAG12 promoter improves salinity stress tolerance in cotton

Journal of Cotton Research

[Background] Soil salinity seriously affects cotton growth, leading to the reduction of yield and fiber quality. Recently, genetic engineering has become an efficient tool to increase abiotic stress tolerance in crops.

[Results] In this study, isopentyl transferase (IPT), a key enzyme involved in cytokinin (CTK) biosynthesis from Agrobacterium tumefaciens, was selected to generate transgenic cotton via Agrobacterium-mediated transformation. A senescence-inducible SAG12promoter from Arabidopsis was fused with the IPT gene. Ectopic-expression of SAG12::IPT significantly promoted seed germination or seedling tolerance to salt stress. Two IPTtransgenic lines, OE3 as a tolerant line during seed germination, and OE8 as a tolerant line at seedling stage, were selected for further physiological analysis. The data showed that ectopic-expression of SAG12::IPT induced the accumulation of CTKs not only in leaves and roots, but also in germinating seeds. Moreover, ectopic-expressing IPT increased the activity of antioxidant enzymes, which was associated with the less reactive oxygen species (ROS) accumulation compared with control plants. Also, ectopic-expression of IPT produced higher K+/Na+ ratio in cotton shoot and root.

[Conclusions] The senescence-induced CTK accumulation in cotton seeds and seedlings positively regulates salt stress partially by elevating ROS scavenging capability.

[TitleAn isopentyl transferase gene driven by the senescence-inducible SAG12 promoter improves salinity stress tolerance in cotton

[Authors] SHAN Yi, ZHAO Peng, LIU Zhao, LI Fangjun* & TIAN Xiaoli

Journal of Cotton Research. 2019, 2: 15

https://doi.org/10.1186/s42397-019-0032-3

https://jcottonres.biomedcentral.com/articles/10.1186/s42397-019-0032-3

Genetic analysis of yield and fiber quality traits in upland cotton (Gossypium hirsutum L.) cultivated in different ecological regions of China

Journal of Cotton Research

[Background] Cotton is an important fiber crop worldwide. The yield potential of current genotypes of cotton can be exploited through hybridization. However, to develop superior hybrids with high yield and fiber quality traits, information of genetic control of traits is prerequisite. Therefore, genetic analysis plays pivotal role in plant breeding.

[Results] In present study, North Carolina II mating design was used to cross 5 female parents with 6 male parents to produce 30 intraspecific F1 cotton hybrids. All plant materials were tested in three different ecological regions of China during the year of 2016–2017. Additive-dominance-environment (ADE) genetic model was used to estimate the genetic effects and genotypic and phenotypic correlation of yield and fiber quality traits. Results showed that yield traits except lint percentage were mainly controlled by genetic and environment interaction effects, whereas lint percentage and fiber quality traits were determined by main genetic effects. Moreover, dominant and additive-environment interaction effects had more influence on yield traits, whereas additive and dominance-environment interaction effects were found to be predominant for fiber traits. Broad-sense and its interaction heritability were significant for all yield and most of fiber quality traits. Narrow-sense and its interaction heritability were non-significant for boll number and seed cotton yield. Correlation analysis indicated that seed cotton yield had significant positive correlation with other yield attributes and non-significant with fiber quality traits. All fiber quality traits had significant positive correlation with each other except micronaire.

[Conclusions] Results of current study provide important information about genetic control of yield and fiber quality traits. Further, this study identified that parental lines, e.g., SJ48–1, ZB-1, 851–2, and DT-8 can be utilized to improve yield and fiber quality traits in cotton.

[Title] Genetic analysis of yield and fiber quality traits in upland cotton (Gossypium hirsutum L.) cultivated in different ecological regions of China

[Authors] SHAHZAD Kashif+, LI Xue+, QI Tingxiang, GUO Liping, TANG Huini, ZHANG Xuexian, WANG Hailin, ZHANG Meng, ZHANG Bingbing, QIAO Xiuqin, XING Chaozhu* & WU Jianyong*

Journal of Cotton Research. 2019, 2: 14

https://doi.org/10.1186/s42397-019-0031-4

https://jcottonres.biomedcentral.com/articles/10.1186/s42397-019-0031-4

JCR-QTL mapping for fiber quality and yield-related traits across multiple generations in segregating population of CCRI 70

Journal of Cotton Reseach

[Background] Cotton is a significant economic crop that plays an indispensable role in many domains. Gossypium hirsutum L. is the most important fiber crop worldwide and contributes to more than 95% of global cotton production. Identifying stable quantitative trait locus (QTLs) controlling fiber quality and yield related traits are necessary prerequisites for marker-assisted selection (MAS).

[Results] A genetic linkage map was constructed with 312 simple sequence repeat (SSR) loci and 35 linkage groups using JoinMap 4.0; the map spanned 1 929.9 cM, with an average interval between two markers of 6.19 cM, and covered approximately 43.37% of the cotton genome. A total of 74 QTLs controlling fiber quality and 41 QTLs controlling yield-related traits were identified in 4 segregating generations. These QTLs were distributed across 20 chromosomes and collectively explained 1.01%~27.80% of the observed phenotypic variations. In particular, 35 stable QTLs could be identified in multiple generations, 25 common QTLs were consistent with those in previous studies, and 15 QTL clusters were found in 11 chromosome segments.

[Conclusion] These studies provide a theoretical basis for improving cotton yield and fiber quality for molecular marker-assisted selection.

[Title] QTL mapping for fiber quality and yield-related traits across multiple generations in segregating population of CCRI 70

[Authors] DENG Xiaoying, GONG Juwu, LIU Aiying, SHI Yuzhen, GONG Wankui, GE Qun, LI Junwen, SHANG Haihong, WU Yuxiang & YUAN Youlu

Journal of Cotton Research. 2019, 2:13

https://doi.org/10.1186/s42397-019-0029-y

https://jcottonres.biomedcentral.com/articles/10.1186/s42397-019-0029-y

Genome-wide identification of OSCA gene family and their potential function in the regulation of dehydration and salt stress in Gossypium hirsutum

[Background] Cotton (Gossypium hirsutum) provides the largest natural fiber for the textile manufacturing industries, but its production is on the decline due to the effects of salinity. Soil salt-alkalization leads to damage in cotton growth and a decrease in yields. Hyperosmolality-gated calcium-permeable channels (OSCA) have been found to be involved in the detection of extracellular changes which trigger an increase in cytosolic free calcium concentration. Hyperosmolality-induced calcium ion increases have been widely speculated to be playing a role in osmosensing in plants. However, the molecular nature of the corresponding calcium ion channels remains unclearly. In this research work, we describe the OSCAgenes and their putative function in osmosensing in plants by carrying out genome-wide identification, characterization and functional analysis of the significantly up-regulated OSCA gene, GhOSCA1.1 through reverse genetics.

[Results] A total of 35, 21 and 22 OSCA genes were identified in G. hirsutum, G. arboreum, and G. raimondii genomes, respectively, and were classified into four different clades according to their gene structure and phylogenetic relationship. Gene and protein structure analysis indicated that 35 GhOSCA genes contained a conserved RSN1_7TM (PF02714) domain. Moreover, the cis-regulatory element analysis indicated that the OSCA genes were involved in response to abiotic stress. Furthermore, the knockdown of one of the highly up-regulated genes, Gh_OSCA1.1showed that the virus-induced gene silenced (VIGS) plants were highly sensitive to dehydration and salinity stresses compared with the none VIGS plants as evident with higher concentration levels of oxidant enzymes compared with the antioxidant enzymes on the leaves of the stressed plants.

[Conclusions] This study provides the first systematic analysis of the OSCA gene family and will be important for understanding the putative functions of the proteins encoded by the OSCA genes in cotton. These results provide a new insight of defense responses in general and lay the foundation for further investigation of the molecular role played by the OSCA genes, thereby providing suitable approaches to improve crop performance under salinity and drought stress conditions.

[Title] Genome-wide identification of OSCA gene family and their potential function in the regulation of dehydration and salt stress in Gossypium hirsutum 

[Authors] Xiu YANG, Yanchao XU, Fangfang YANG, Richard Odongo MAGWANGA, Xiaoyan CAI, Xingxing WANG, Yuhong WANG, Yuqing HOU, Kunbo WANG, Fang LIU & Zhongli ZHOU

Journal of Cotton Research. 2019; 2:11

https://doi.org/10.1186/s42397-019-0028-z

Amino acids application enhances flowers insecticidal protein content in Bt cotton

[Background] Low insecticidal protein expression at reproductive organs affect insect resistance in Bt transgenic cotton. In order to enhance flower insecticidal protein expression, the conventional cultivar Sikang1 (S1) and the hybrid cultivar Sikang3 (S3) were used as experimental materials; the applications of selected 5 types of amino acids and 21 types of amino acids were sprayed on the flowers in 2016 and 2017 cotton growing seasons.

[Results] The flower Bt protein contents increased significantly under the two amino acid treatments in both cultivars, the Bt protein concentration increased by 15.2 to 25.8% compared with the control. However, no significant differences were detected between the two treatments of amino acid application. Increased amino acid and soluble protein contents, enhanced GPT, GOT, protease,and peptidase activities were observed under the amino acid application at the flowering stage.

[Conclusions] These results suggest that exterior application of the amino acids treatments could bolster the flower insecticidal protein expression.

[Authors] TAMBEL Leila. I. M., ZHOU Mingyuan, CHEN Yuan, ZHANG Xiang, CHEN Yuan  and CHEN Dehua

Journal of Cotton Research. 2019; 2:7
https://doi.org/10.1186/s42397-019-0023-4

Use of Male Sterility in Cotton and Molecular markers for Fertility Restoration in CGMS of G.hirstum Cotton

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Authors

I.S. Katageri, *Rashmi Ranjan Toppo, and B.M. Khadi

 *Department of Biotechnology, College of Agriculture University of Agricultural Sciences, Dharwad – 580 005, India

*Email: katageriis@uasd.in

Abstract

Cotton is one among the few often cross-pollinated crops, where the achievement of commercial exploitation of heterosis is comparable to even that of cross-pollinated crops like  maize.  The main bottleneck in exploitation of hybrid vigour in cotton is the complicated technique of seed production, which involves hand emasculation and pollination that makes hybrid cotton seed more costly. To improve the remunerative value of hybrid seed production and commercial cultivation of hybrid it is necessary to develop productive male sterile based hybrids. Although Cytoplasmic Genetic Male Sterility is available, the identification of restorer for 100 percent fertility restoration was problematic. Molecular markers are coming handy in identifying such plants. The present study, therefore, comprised 413 individual plants comprising of 164 A-line and B-line, 124 IPS of R-line, 13 hybrids, 3 cultivars, 4 wild species, 24 G. hirsutum germplasm lines, 80 RILs and 1 GMS line were studied during 2012-13 and 2013-14 at ARS, Dharwad farm. Twenty four molecular markers known to be associated with fertility restoration (10 RAPD, 7 SSR, 6 STS, and 1 TRAP) were studied. Out of these, 3 STS markers (Y1107, UBC 147 and UBC 607) were able to amplify only in 44 plants out of 124 belong to DR-7 (known for fertility restoration). No amplification was observed in diverse genetic background of A-lines and their respective B-lines, wild species, G. barbadense var. SBYF 425, G. arboreum var. DLSa 17, G. herbaceum var. Jayadhar, G. hirsutum germplasm lines and Abadhita GMS line (sterile and its maintainer line). However amplification by these three markers was recorded in 6 out of 80 RILs of DCH-32 hybrids. Co-segregation for 98-100 percent fertility restoration and molecular markers associated was observed in F2 of cross between A line and fertility restorer carrying three molecular markers.

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