A genome-wide identification of the BLH gene family reveals BLH1 involved in cotton fiber development

[Background] Cotton is the world’s largest and most important source of renewable natural fiber. BEL1-like homeodomain (BLH) genes are ubiquitous in plants and have been reported to contribute to plant development. However, there is no comprehensive characterization of this gene family in cotton. In this study, 32, 16, and 18 BLH genes were identified from the G. hirsutumG. arboreum, and G. raimondii genome, respectively. In addition, we also studied the phylogenetic relationships, chromosomal location, gene structure, and gene expression patterns of the BLH genes.

[Result] The results indicated that these BLH proteins were divided into seven distinct groups by phylogenetic analysis. Among them, 25 members were assigned to 15 chromosomes. Furthermore, gene structure, chromosomal location, conserved motifs, and expression level of BLH genes were investigated in G. hirsutum. Expression profiles analysis showed that four genes (GhBLH1_3GhBLH1_4GhBLH1_5, and GhBLH1_6) from BLH1 subfamily were highly expressed during the fiber cell elongation period. The expression levels of these genes were significantly induced by gibberellic acid and brassinosteroid, but not auxin. Exogenous application of gibberellic acid significantly enhanced GhBLH1_3GhBLH1_4, and GhBLH1_5transcripts. Expression levels of GhBLH1_3 and GhBLH1_4 genes were significantly increased under brassinosteroid treatment.

[Conclusion] The BLH gene family plays a very important role in many biological processes during plant growth and development. This study deepens our understanding of the role of the GhBLH1gene involved in fiber development and will help us in breeding better cotton varieties in the future.

[Title] A genome-wide identification of the BLH gene family reveals BLH1 involved in cotton fiber development

[Authors] LIU Cuixia, LI Zhifang, DOU Lingling, Yi YUAN, ZOU Changsong, SHANG Haihong, CUI Langjun & XIAO  Guanghui

Journal of Cotton Research 2020, 326

https://doi.org/10.1186/s42397-020-00068-y

Global identification of genes associated with xylan biosynthesis in cotton fiber

[Background] Mature cotton fiber secondary cell wall comprises largely of cellulose (> 90%) and small amounts of xylan and lignin. Little is known about the cotton fiber xylan biosynthesis by far.

[Result] To comprehensively survey xylan biosynthetic genes in cotton fiber, we identified five IRX9, five IRX10, one IRX14, six IRX15, two FRA8, one PARVUS, eight GUX, four GXM, two RWA, two AXY9, 13 TBL genes by using phylogenetic analysis coupled with expression profile analysis and co-expression analyses. In addition, we also identified two GT61 members, two GT47 members, and two DUF579 family members whose homologs in Arabidopsis were not functionally characterized. These 55 genes were regarded as the most probable genes to be involved in fiber xylan biosynthesis. Further complementation analysis indicated that one IRX10 like and two FRA8 related genes were able to partially recover the irregular xylem phenotype conferred by the xylan deficiency in their respective Arabidopsis mutant. We conclude that these genes are functional orthologs of respective genes that are implicated in GX biosynthesis.

[Conclusion] The list of 55 cotton genes presented here provides not only a solid basis to uncover the biosynthesis of xylan in cotton fiber, but also a genetic resource potentially useful for future studies aiming at fiber improvement via biotechnological approaches.

[Title] Global identification of genes associated with xylan biosynthesis in cotton fiber

[Authors] CHEN Feng, GUO Yanjun, CHEN Li, GAN Xinli, LIU Min, LI Juan & XU Wenliang

Journal of Cotton Research 2020, 325

https://doi.org/10.1186/s42397-020-00063-3

Development and application of perfect SSR markers in cotton

[Background] This study aimed to develop a set of perfect simple sequence repeat (SSR) markers with a single copy in the cotton genome, to construct a DNA fingerprint database suitable for authentication of cotton cultivars. We optimized the polymerase chain reaction (PCR) system for multi-platform compatibility and improving detection efficiency. Based on the reference genome of upland cotton and 10× resequencing data of 48 basic cotton germplasm lines, single-copy polymorphic SSR sites were identified and developed as diploidization SSR markers. The SSR markers were detected by denaturing polyacrylamide gel electrophoresis (PAGE) for initial screening, then fluorescence capillary electrophoresis for secondary screening. The final perfect SSR markers were evaluated and verified using 210 lines from different sources among Chinese cotton regional trials.

[Result] Using bioinformatics techniques, 1 246 SSR markers were designed from 26 626 single-copy SSR loci. Adopting a stepwise (primary and secondary) screening strategy, a set of 60 perfect SSR markers was selected with high amplification efficiency and stability, easy interpretation of peak type, multiple allelic variations, high polymorphism information content (PIC) value, uniform chromosome distribution, and single-copy characteristics. A multiplex PCR system was established with ten SSR markers using capillary electrophoresis detection.

[Conclusion] A set of perfect SSR markers of cotton was developed and a high-throughput SSR marker detection system was established. This study lays a foundation for large-scale and standardized construction of a cotton DNA fingerprint database for authentication of cotton varieties.

[Title] Development and application of perfect SSR markers in cotton

[Authors] WU Yuzhen, HUANG Longyu, ZHOU Dayun, FU Xiaoqiong, LI Chao, WEI Shoujun, PENG Jun & KUANG Meng

Journal of Cotton Research 2020, 321

https://doi.org/10.1186/s42397-020-00066-0

Toward the efficient use of Beauveria bassiana in integrated cotton insect pest management

[Background] For controlling the resistance to insects, in particular carpophagous and phyllophagous caterpillars, using chemical pesticides has led to contamination of cotton area in Benin. Facing this problem, alternative methods including the use of entomopathogenic fungi as biopesticide could be a sound measure to preserve the environment, biodiversity and ensure good quality of crops. Previous studies have revealed the insecticidal potential of the entomopathogenic Beauveria bassiana on some insect pest species. However, little is known about its effectiveness on cotton Lepidopteran pests. This review is done to learn more about B. bassina for its application in controlling cotton insect pests, especially Lepidopteran species.

[Main body] Different sections of the current review deal with the related description and action modes of B. bassiana against insects, multi-trophic interactions between B. bassiana and plants, arthropods, soil and other microbes, and biological control programs including B. bassiana during last decade. Advantages and constraints in applying B. bassiana and challenges in commercialization of B. bassiana-based biopesticide have been addressed. In this review, emphasis is put on the application methods and targeted insects in various studies with regard to their applicability in cotton

[Conclusion] This review helps us to identify the knowledge gaps related to application of B. bassiana on cotton pest in general and especially in Lepidopteran species in Benin. This work should be supported by complementary laboratory bioassays, station and/or fields experiments for effective management of cotton Lepidopteran pests in Benin.
[Title] Toward the efficient use of Beauveria bassiana in integrated cotton insect pest management

[Authors] DANNON H. Fabrice, DANNON A. Elie, DOURO-KPINDOU O. Kobi, ZINSOU A. Valerien, HOUNDETE A. Thomas, TOFFA-MEHINTO Joëlle, ELEGBEDE I. A. T. Maurille, OLOU B. Dénis & TAMÒ Manuele

Journal of Cotton Research 2020, 324

https://doi.org/10.1186/s42397-020-00061-5

Heritability and correlation analysis of morphological and yield traits in genetically modified cotton

[Background] Cotton is known for fiber extraction and it is grown in tropical and sub-tropical areas of the world due to having hot weather. Cotton crop has a significant role in GDP of Pakistan. Therefore, the two-years research was conducted to estimate heritability and association among various yield contributing parameters of cotton, i.e., plant height, number of bolls per plant, number of sympodial branches per plant, seed cotton yield, boll weight, seed index, ginning outturn (GOT), fiber length, fiber strength, and fiber fineness.

[Result] Association analysis revealed that seed cotton yield had a significant positive correlation with plant height, number of bolls per plant, number of sympodial branches per plant, GOT, staple length and fiber strength. Staple length and fiber strength were negatively linked with each other. Estimates of heritability were high for all of the traits except the number of sympodial branches per plant and boll weight.

[Conclusion] The parent IUB-222 was found to be the best for plant height, the number of bolls per plant, boll weight, GOT, seed cotton yield, and seed index. The genotypes namely, NIAB-414 and VH-367 were identified as the best parents for fiber length, strength, and fineness. Among the crosses NIAB-414 × IUB-222 was the best for the number of bolls per plant, seed index, seed cotton yield and fiber fineness, whereas, the cross of NIAB-414 × CIM-632 was good for plant height. The combination of A555 × CIM-632 was the best for the number of sympodial branches per plant, boll weight, fiber length, and strength, and VH-367 × CIM-632 proved the best for GOT.
[Title] Heritability and correlation analysis of morphological and yield traits in genetically modified cotton

[Authors] REHMAN Abdul, MUSTAFA Nida, DU Xiongming & AZHAR Muhammad Tehsee

Journal of Cotton Research 2020, 323

https://doi.org/10.1186/s42397-020-00067-z

QTL and genetic analysis controlling fiber quality traits using paternal backcross population in upland cotton

[Background] Genetic improvement in fiber quality is one of the main challenges for cotton breeders. Quantitative trait loci (QTL) mapping provides a powerful approach to dissect the molecular mechanism in fiber quality traits. In present study, F14recombinant inbred line (RIL) population was backcrossed to paternal parent for a paternal backcross (BC/P) population, deriving from one upland cotton hybrid. Three repetitive BC/P field trials and one maternal backcross (BC/M) field trial were performed including both two BC populations and the original RIL population.

[Result] In total, 24 novel QTLs are detected for fiber quality traits and among which 13 QTLs validated previous results. Thirty-five QTLs in BC/P populations explain 5.01%–22.09% of phenotype variation (PV). Among the 35 QTLs, 23 QTLs are detected in BC/P population alone. Present study provides novel alleles of male parent for fiber quality traits with positive genetic effects. Particularly, qFS-Chr3–1 explains 22.09% of PV in BC/P population, which increaseds 0.48 cN·tex− 1 for fiber strength. A total of 7, 2, 8, 2 and 6 QTLs explain over 10.00% of PV for fiber length, fiber uniformity, fiber strength, fiber elongation and fiber micronaire, respectively. In RIL population, six common QTLs are detected in more than one environment: qFL-Chr1–2qFS-Chr5–1qFS-Chr9–1qFS-Chr21–1qFM-Chr9–1 and qFM-Chr9–2. Two common QTLs of qFE-Chr2–2(TMB2386-SWU12343) and qFM-Chr9–1 (NAU2873-CGR6771) explain 22.42% and 21.91% of PV. The region between NAU4034 and TMB1296 harbor 30 genes (379 kb) in A05 and 42 genes (49 kb) in D05 for fiber length along the QTL qFL-Chr5–1 in BC/P population, respectively. In addition, a total of 142 and 46 epistatic QTLs and QTL × environments (E-QTLs and QQEs) are identified in recombinant inbred lines in paternal backcross (RIL-P) and paternal backcross (BC/P) populations, respectively.

[Conclusion] The present studies provide informative basis for improving cotton fiber quality in different populations.
[Title] QTL and genetic analysis controlling fiber quality traits using paternal backcross population in upland cotton

[Authors] MA LingLing, SU Ying, NIE Hushuai, CUI Yupeng, CHENG Cheng, IJAZ Babar & HUA  Jinping

Journal of Cotton Research 2020, 322

https://doi.org/10.1186/s42397-020-00060-6

Overexpressing rice lesion simulating disease 1-like gene (OsLOL1) in Gossypium hirsutum promotes somatic embryogenesis and plant regeneration

[Background] Cotton somatic embryogenesis is difficult or rarely frequent to present, which has limited gene function identification and biotechnological utility. Here, we employed a rice key somatic embryogenesis-related gene, rice lesion simulating disease 1-like gene (OsLOL1), to develop transgenic cotton callus for evaluating its function in ectopic plants.

[Result] Overexpressing OsLOL1 can promote cotton callus to form embryogenic callus, not only shortening time but also increasing transition of somatic callus cells to embryogenic callus cells. And the regenerating plantlets per transgenic OsLOL1 embryogenic callus were significantly higher than those in the control transformed with empty vector. Analysis of physiological and biochemical showed that OsLOL1 can repress cotton superoxide dismutase 1 gene (GhSOD1) expression, possibly resulting in reactive oxidant species (ROS) accumulation in transgenic callus cells. And OsLOL1-overexpressed embryogenic callus exhibited higher α-amylase activity compared with the control, resulting from the promotion of OsLOL1 to cotton amylase 7 gene (GhAmy7) and GhAmy8 expression.

[Conclusion] The data showed that OsLOL1 could be used as a candidate gene to transform cotton to increase its somatic embryogenesis capacity, facilitating gene function analysis and molecular breeding in cotton.
[Title] Overexpressing rice lesion simulating disease 1-like gene (OsLOL1) in Gossypium hirsutum promotes somatic embryogenesis and plant regeneration

[Authors] WANG Zhian, WANG Peng, HU Guang, XIAO Juanli, ZHANG Anhong, LUO Xiaoli & WU Jiahe

Journal of Cotton Research 2020, 319

https://doi.org/10.1186/s42397-020-00062-4

The impact of plant density and spatial arrangement on light interception on cotton crop and seed cotton yield: an overview

[Abstract] Light attenuation within a row of crops such as cotton is influenced by canopy architecture, which is defined by size, shape and orientation of shoot components. Level of light interception causes an array of morpho-anatomical, physiological and biochemical changes. Physiological determinants of growth include light interception, light use efficiency, dry matter accumulation, duration of growth and dry matter partitioning. Maximum light utilization in cotton production can be attained by adopting cultural practices that yields optimum plant populations as they affect canopy arrangement by modifying the plant canopy components. This paper highlights the extent to which spatial arrangement and density affect light interception in cotton crops. The cotton crop branches tend to grow into the inter-row space to avoid shade. The modification of canopy components suggests a shade avoidance and competition for light. Maximum leaf area index is obtained especially at flowering stage with higher populations which depicts better yields in cotton production.
[Keywords] Light interception, Plant populations, Spatial arrangement, Canopy architecture

[Title] The impact of plant density and spatial arrangement on light interception on cotton crop and seed cotton yield: an overview

[Authors] CHAPEPA Blessing, MUDADA Nhamo & MAPURANGA Rangarirai

Journal of Cotton Research 2020, 318

https://doi.org/10.1186/s42397-020-00059-z

Unraveling the puzzle of the origin and evolution of cotton A-genome

[Abstract] Gossypium hirsutum, the most widely planted cotton species, its evolution has long been an unsolved puzzle because of its hybrid origin from D-genome and A-genome species. To better understand the genetic component of cotton, Huang et al. recently sequenced and assembled the first A1-genome G. herbaceum, and updated the A2-genome G. arboreum and (AD)1-genome G. hirsutum. On the basis of the three reference genomes, they resolved existing controversial concepts and provided novel evolutionary insights surrounding the A-genome.

[Title] Unraveling the puzzle of the origin and evolution of cotton A-genome

[Authors] MA Zhiying

Journal of Cotton Research 3, Article number: 17 (2020)

https://doi.org/10.1186/s42397-020-00056-2

Applying plant-based irrigation scheduling to assess water use efficiency of cotton following a high-biomass rye cover crop

[Background] This study addressed the potential of combining a high biomass rye winter cover crop with predawn leaf water potential (ΨPD) irrigation thresholds to increase agricultural water use efficiency (WUE) in cotton. To this end, a study was conducted near Tifton, Georgia under a manually-controlled, variable-rate lateral irrigation system using a Scholander pressure chamber approach to measure leaf water potential and impose varying irrigation scheduling treatments during the growing season. ΨPD thresholds were − 0.4 MPa (T1), − 0.5 MPa (T2), and − 0.7 MPa (T3). A winter rye cover crop or conventional tillage were utilized for T1-T3 as well.

[Results] Reductions in irrigation of up to 10% were noted in this study for the driest threshold (− 0.7 MPa) with no reduction in lint yield relative to the − 0.4 MPa and − 0.5 MPa thresholds. Drier conditions during flowering (2014) limited plant growth and node production, hastened cutout, and decreased yield and WUE relative to 2015.

[Conclusions] We conclude that ΨPD irrigation thresholds between − 0.5 MPa and − 0.7 MPa appear to be viable for use in a ΨPD scheduling system with adequate yield and WUE for cotton production in the southeastern U.S. Rye cover positively impacted water potential at certain points throughout the growing season but not yield or WUE indicating the potential for rye cover crops to improve water use efficiency should be tested under longer-term production scenarios.

[Title] Applying plant-based irrigation scheduling to assess water use efficiency of cotton following a high-biomass rye cover crop

[Authors] MEEKS Calvin D., SNIDER John L., CULPEPPER Stanley and HAWKINS Gary
Journal of Cotton Research 3, Article number: 16 (2020)

https://doi.org/10.1186/s42397-020-00057-1