Comparative effects of crop residue incorporation and inorganic potassium fertilization on soil C and N characteristics and microbial activities in cotton field

[Background] Crop residue incorporation into the soil is an effective method to augment soil potassium (K) content, and effects of crop residue and K fertilizer on soil K balance have been compared. However, their influences on other soil characteristics such as carbon (C) and nitrogen (N) characteristics and microbial activities have not been quantified. To address this, field experiments were conducted in 2011 at Dafeng (sandy loam) and Nanjing (clay loam) in China with treatments including blank control without crop residue incorporation and K fertilizer application, 0.9 t·ha− 1 wheat straw incorporation (W1C0), 0.7 t·ha− 1 cotton residue incorporation (W0C1), 0.9 t·ha− 1 wheat straw + 0.7 t·ha− 1 cotton residue incorporation (W1C1) and two K fertilizer rates (150 and 300 kg·ha− 1 (K2O)) during the cotton season.

[Results] Compared with control, K fertilizer treatments did not alter soil water-soluble organic carbon/soil organic carbon (WSOC/SOC) ratio, microbial biomass carbon (MBC)/SOC ratio, MBC/microbial biomass nitrogen (MBN) ratio, water inorganic nitrogen/total nitrogen ratio (WIN/TN), the number of cellulose-decomposing bacteria, or related enzymes activities, however, W0C1, W1C0 and W1C1 treatments significantly increased WSOC/SOC ratio, MBC/SOC ratio and MBC/ MBN ratio, and decreased WIN/TN ratio at both sites. W0C1, W1C0 and W1C1 treatments also increased the number of soil cellulose-decomposing bacteria and activities of cellulase, β-glucosidase and arylamidase. Regarding different crop residue treatments, W1C0 and W1C1 treatments had more significant influences on above mentioned parameters than W0C1 treatment. Moreover, MBC/MBN ratio was the most important factor to result in the differences in the number of cellulose-decomposing bacteria and soil enzymes activities among different treatments.

[Conclusions] This study provided a detailed phenotypic diversity description of a population representing a wide range of upland cotton germplasm. Our findings provide useful information about possible elite fibre quality parents for cotton breeding programs.

[Title] Evaluation of the genetic diversity of fibre quality traits in upland cotton (Gossypium hirsutum L.) inferred from phenotypic variations

[Authors] HU Wei, SUI Ning , YU Chaoran, YANG Changqin, LIU Ruixian and ZHOU Zhiguo

Journal of Cotton Research2019; 2:24

https://doi.org/10.1186/s42397-019-0040-3

https://jcottonres.biomedcentral.com/articles/10.1186/s42397-019-0040-3

Bt insecticidal efficacy variation and agronomic regulation in Bt cotton

Abstract: The bollworm can be controlled effectively with Bacillus thuringiensistransgenic cotton (Bt cotton) which is being applied worldwide. However, the insecticidal efficacy is not stable. Here we give a summary of research progress for the mechanism of the altered insecticidal efficacy, factors affecting the expression of insect resistance, agronomic practices on regulation of insecticidal efficacy in Bt cotton. To realize the transgenic potential of Bt cotton cultivars, future research may be conducted by increasing synthesis and reducing degradation of Bt protein to maintain high insecticidal ability in the transgenic cotton by agronomic management.

[Title] Bt insecticidal efficacy variation and agronomic regulation in Bt cotton

[Authors] LIU Zhenyu, ELTAYIB H M. A. Abidallha, WU Huimin, ZHOU Mingyuan, ZHANG Xiang, CHEN Yuan and CHEN Dehua

Journal of Cotton Research2019; 2:23

https://doi.org/10.1186/s42397-019-0042-1

https://jcottonres.biomedcentral.com/articles/10.1186/s42397-019-0042-1

Evaluation of the genetic diversity of fibre quality traits in upland cotton (Gossypium hirsutum L.) inferred from phenotypic variations

[Background] Evaluating phenotypic traits is very important for the selection of elite lines in Gossypium hirsutum L. Cotton breeders are interested in using diverse genotypes in hybridization that can segregate for traits of interested with the possibility of selection and genetic gain. Information on phenotypic and molecular diversity helps the breeders for parental selection.

[Methods] In this study, 719 global collections of G. hirsutum L. were evaluated for five fibre-related traits during two consecutive years in eight different environments. A series of phenotypic data for fibre quality traits were obtained and the elite accessions were further screened using principal component analysis and phylogenetic tree construction based on single nucleotide polymorphism markers.

[Results] We found that fibre quality traits showed a wide range of variation among the G. hirsutum accessions over 2 years. In general, accessions from outside China tended to have higher fibre length (FL) and fibre strength (FS) than did Chinese accessions. Among different regional accessions in China, North/Northwest accessions tended to have the highest FL, FS and best fibre macronaire. By assessing five fibre quality traits over 2 years with genotypic data, 31 elite germplasms reaching double-thirty quality values (FL ≥ 30 mm and FS ≥ 30 cN·tex− 1) were selected.

[Conclusions] This study provided a detailed phenotypic diversity description of a population representing a wide range of upland cotton germplasm. Our findings provide useful information about possible elite fibre quality parents for cotton breeding programs.
[Title] Evaluation of the genetic diversity of fibre quality traits in upland cotton (Gossypium hirsutum L.) inferred from phenotypic variations

[Authors] SUN Zhengwen, WANG Xingfen, LIU Zhengwen, GU Qishen, ZHANG Yan, LI Zhikun, KE Huifeng, YANG Jun, WU Jinhua, WU Liqiang, ZHANG Guiyin and MA Zhiying
Journal of Cotton Research2019; 2:22

https://doi.org/10.1186/s42397-019-0041-2

https://jcottonres.biomedcentral.com/articles/10.1186/s42397-019-0041-2

Towards improving drought resistance and lodging resistance in cotton

Abstract: Cotton is one of the most important fiber and oil crop in the world and the fiber yield as well as quality traits are negatively affected by drought and lodging. Improving root gravitropism is a very effective way to enhance the crop resistance to drought and lodging stresses. Recent advance in origin and formation of root gravitropism may provide new insights to increase drought and lodging resistance in cotton.

[Title] Towards improving drought resistance and lodging resistance in cotton

[Authors] LI Fuguang

Journal of Cotton Research2019; 2:21
https://doi.org/10.1186/s42397-019-0037-y
https://jcottonres.biomedcentral.com/articles/10.1186/s42397-019-0037-y

Large-scale inversions majorly drive upland cotton population differentiation

Journal of Cotton Research

Abstract: Recently, Li and his team hosted a project on roles of inversion in upland cotton population differentiation. Strikingly, genomic comparison identified, and subsequent RIL population and germplasm panel haplotype analyses confirmed, that large-scale inversions on chromosome At08 are widely distributed and have over time mediated the reduction of meiotic recombination that has ultimately driven genetically isolated haplotypes of G. hirsutum. This work is likely to become the new benchmark for cotton functional genomics research, and the scientific insights from the comparative analyses contributed substantially to our basic understanding of how genomic inversions influence meiotic recombination and thus lower genetic diversity in plant populations.

[Title] Large-scale inversions majorly drive upland cotton population differentiation

[Authors] TIAN Shilin &MA  Zhiying

Journal of Cotton Research2019; 2:20
https://doi.org/10.1186/s42397-019-0037-y
https://jcottonres.biomedcentral.com/articles/10.1186/s42397-019-0037-y

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

High-throughput phenotyping in cotton: a review

Abstract

Recent technological advances in cotton (Gossypium hirsutum L.) phenotyping have offered tools to improve the efficiency of data collection and analysis. High-throughput phenotyping (HTP) is a non-destructive and rapid approach of monitoring and measuring multiple phenotypic traits related to the growth, yield, and adaptation to biotic or abiotic stress. Researchers have conducted extensive experiments on HTP and developed techniques including spectral, fluorescence, thermal, and three-dimensional imaging to measure the morphological, physiological, and pathological resistance traits of cotton. In addition, ground-based and aerial-based platforms were also developed to aid in the implementation of these HTP systems. This review paper highlights the techniques and recent developments for HTP in cotton, reviews the potential applications according to morphological and physiological traits of cotton, and compares the advantages and limitations of these HTP systems when used in cotton cropping systems. Overall, the use of HTP has generated many opportunities to accurately and efficiently measure and analyze diverse traits of cotton. However, because of its relative novelty, HTP has some limitations that constrains the ability to take full advantage of what it can offer. These challenges need to be addressed to increase the accuracy and utility of HTP, which can be done by integrating analytical techniques for big data and continuous advances in imaging.

Authors:

PABUAYON Irish Lorraine B., SUN Yazhou, GUO Wenxuan & RITCHIE  Glen L.

 

Journal of Cotton Research2019; 2:18

https://doi.org/10.1186/s42397-019-0035-0

https://jcottonres.biomedcentral.com/articles/10.1186/s42397-019-0035-0

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