Search

Lint percentage is one of the most essential yield components and an important economic index for cotton planting. Improving lint percentage is an effective way to achieve high-yield in cotton breeding worldwide, especially upland cotton (Gossypium hirsutum L.). However, the genetic basis controlling lint percentage has not yet been systematically understood. Here, we performed a genome-wide association mapping for lint percentage using a natural population consisting of 189 G. hirsutum accessions (188 accessions of G. hirsutum races and one cultivar TM-1). The results showed that 274 single-nucleotide polymorphisms (SNPs) significantly associated with lint percentage were detected, and they were distributed on 24 chromosomes. Forty-five SNPs were detected at least by two models or at least in two environments, and their 5 Mb up- and downstream regions included 584 makers related to lint percentage identified in previous studies. In total, 11 out of 45 SNPs were detected at least in two environments, and their 550 Kb up- and downstream region contained 335 genes. Through RNA sequencing, gene annotation, qRT-PCR, protein–protein interaction analysis, the cis-elements of the promotor region, and related miRNA prediction, Gh_D12G0934 and Gh_A08G0526 were selected as key candidate genes for fiber initiation and elongation, respectively. These excavated SNPs and candidate genes could supplement marker and gene information for deciphering the genetic basis of lint percentage and facilitate high-yield breeding programs of G. hirsutum ultimately. [ABSTRACT FROM AUTHOR]

Sedoheptulose-1,7-bisphosphatase (SBPase, EC 3.1.3.37) is a key enzyme in the plant Calvin cycle and one of the main rate-limiting enzymes in the plant photosynthesis pathway. Many studies have demonstrated that the SBPase gene plays an important role in plant photosynthetic efficiency, yield, and stress responses; however, few studies have been conducted on the function and expression of the GhSBPase gene in upland cotton. In this study, our results showed that the coding sequence (CDS) of GhSBPase gene was 1182 bp, encoding a protein with 393 amino acids. The GhSBPase protein had adenosine monophosphate (AMP) binding site and a FIG (FBPase/IMPase/glpX) domain, and had six Cys residues and a CGGT(A/Q)C motif that were involved in redox regulation in plants. Evolutionarily, the GhSBPase protein clustered into the dicotyledon subgroup and was most closely related to the tomato SlSBPase protein. Western-blot analysis further indicated that the GhSBPase gene was indeed the gene encoding the SBPase protein in upland cotton. The GhSBPase protein was localized in chloroplast, which was consistent with its function as a key enzyme in photosynthesis. The GhSBPase gene was specifically highly expressed in leaves, and its expression level was significantly lower in a yellow-green leaf mutant than in the wild type. Moreover, the GhSBPase expression was in response to drought, salt, high- and low-temperature stress, and exhibits different expression patterns. The GhSBPase promoter had the cis-acting elements in response to abiotic stress, phytohormone, and light. In addition, the GhSBPase expression was positively correlated with the chlorophyll fluorescence parameters, suggesting that changes in the expression of the GhSBPase had potential applicability in breeding for enhanced cotton photosynthetic efficiency. These results will help to understand the function of the GhSBPase gene in photosynthesis and the adaptability of plants to external stress and provide important gene information for the high-yield breeding of crops in the future. [ABSTRACT FROM AUTHOR]

CIPK (calcineurin B-like-interacting protein kinase) is a kind of serine/threonine protein kinase widely existing in plants, and it plays an important role in plant growth and development and stress response. To better understand the biological functions of the GhCIPK23 gene in upland cotton, the coding sequence (CDS) of the GhCIPK23 gene was cloned in upland cotton, and its protein sequence, evolutionary relationship, subcellular localization, expression pattern and cis-acting elements in the promoter region were analyzed. Our results showed that the full-length CDS of GhCIPK23 was 1368 bp, encoding a protein with 455 amino acids. The molecular weight and isoelectric point of this protein were 50.83 KDa and 8.94, respectively. The GhCIPK23 protein contained a conserved N-terminal protein kinase domain and C-terminal regulatory domain of the CIPK gene family member. Phylogenetic tree analysis demonstrated that GhCIPK23 had a close relationship with AtCIPK23, followed by OsCIPK23, and belonged to Group A with AtCIPK23 and OsCIPK23. The subcellular localization experiment indicated that GhCIPK23 was located in the plasma membrane. Tissue expression analysis showed that GhCIPK23 had the highest expression in petals, followed by sepals, and the lowest in fibers. Stress expression analysis showed that the expression of the GhCIPK23 gene was in response to drought, salt, low-temperature and exogenous abscisic acid (ABA) treatment, and had different expression patterns under different stress conditions. Further cis-acting elements analysis showed that the GhCIPK23 promoter region had cis-acting elements in response to abiotic stress, phytohormones and light. These results established a foundation for understanding the function of GhCIPK23 and breeding varieties with high-stress tolerance in cotton. [ABSTRACT FROM AUTHOR]

Copyright of Plant Journal is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Cotton is one of the most important economic and fiber crops in the world. KNOX is one class of universal transcription factors, which plays important roles in plant growth and development as well as response to different stresses. Although there are many researches on KNOXs in other plant species, there are few reports on cotton. In this study, we systematically and comprehensively identified all KNOX genes in upland cotton and its two ancestral species; we also studied their functions by employing RNA-seq analysis and virus-induced gene silence (VIGS). A total of 89 KNOX genes were identified from three cotton species. Among them, 44 were from upland cotton, 22 and 23 were found in its ancestral species G. raimondii and G. arboreum , respectively. Plant polyploidization and domestication play a selective force driving KNOX gene evolution. Phylogenetic analysis displayed that KNOX genes were evolved into three Classes. The intron length and exon number differed in each Class. Transcriptome data showed that KNOX genes of Class II were widely expressed in multiple tissues, including fiber. The majority of KNOX genes were induced by different abiotic stresses. Additionally, we found multiple cis -elements related to stress in the promoter region of KNOX genes. VIGS silence of GhKNOX4-A and GhKNOX22-D genes showed significant growth and development effect in cotton seedlings under salt and drought treatments. Both GhKNOX4-A and GhKNOX22-D regulated plant tolerance; silencing both genes induced oxidative stresses, evidenced by reduced SOD activity and induced leave cell death, and also enhanced stomatal open and water loss. Thus, GhKNOX4-A and GhKNOX22-D may contribute to drought response by regulating stomata opening and oxidative stresses. • A total of 89 KNOX genes were identified from upland cotton and its two ancestral species • Plant polyploidization and domestication play a selective force driving KNOX gene evolution • VIGS silence of GhKNOX4-A Gh and GhKNOX22-D genes showed significant growth and development effect in cotton seedlings under salt and drought treatment • Silencing GhKNOX4-A and GhKNOX22-D induced oxidative and abiotic stresses • GhKNOX4-A and GhKNOX22-D may contribute to drought response by regulating stomata opening and oxidative stresses [ABSTRACT FROM AUTHOR]

Grafting is a classical technique to increase plant stress resistance and yield in horticultural crops. This review takes cotton (Gossypium spp.) as an example to summarize the application of grafting in sustainable development for the following subjects: (1) cotton production, such as improving stress tolerance, increasing nutrient and water use efficiency, and cultivating cotton perennially for high yield; (2) cotton breeding, such as conserving and propagating special germplasms, utilizing heterosis, breeding new varieties, improving the survival rate of transplanted plantlets, and accelerating virus-induced gene silencing (VIGS); and (3) cotton physiology and molecular biology research, such as the mechanism underlying root-shoot communication. In particular, cotton is a unique non-horticultural field crop, which can grow annually or perennially, depending on winter temperature. Therefore, cotton grafting has some unique aspects, e.g., annual cotton cultivars can be used in perennial cultivation when grafted on cold-resistant rootstocks to improve the over-winter survival abilities, and graft-propagated male sterile plants can be used for multi-year heterosis utilization in near tropics, which could be used to build a sustainable agricultural system. Moreover, future promises associated with grafting have been presented and discussed, such as whether cotton grafting could promote the exchange of genetic material (especially DNA) between rootstock and scion, resulting in stable inheritable variations that remains to be verified by molecular genetics. • Cotton grafting has been widely used to study root-shoot communication mechanism. • Grafting may become a new technology for cotton germplasm innovation. • Grafting can be applied to sustainable production and perennial cultivation. • Grafting is important for reproduction of sterile cotton. [ABSTRACT FROM AUTHOR]

• Around 340 circRNAs were identified from leaf, fiber and ovule in upland cotton. • Single parent expressed circRNAs played an essential role in heterosis. • Thirty-two key circRNAs related to formation of heterosis were identified. • A cotton fiber development related potential ceRNA-PPI network were established. Circular RNA (CircRNA) is a type of single-stranded RNA that plays a vital role in gene regulation during and after transcription. However, the functional role of circRNA in polyploid crop hybridization has not yet been reported. In this study, a high-yield elite upland cotton (Gossypium hirsutum) inbred line, 4133Bt, crossed with a high-quality elite inbred line, J02–247, produced a high -yield and high-quality F 1 hybrid. An RNA-sequence library was constructed from three biological replicates of the parents and F 1 hybrids in the vegetative and reproductive growth periods. A total of 340 high-confidence circRNAs were identified. Our results showed that the circRNAs were more active in ovules than in fiber and leaves and that the host genes of ovule-specific circRNAs were involved in nucleoside metabolic processes. In addition, single parent expressed (SPE) circRNAs and extremely nonadditively expressed (ENAE) circRNAs had different expression patterns in the F 1 hybrid. Moreover, 32 out of the 340 circRNAs were found to be dominant (expression level dominance, ELD) or overdominant (transgressive) at the expression level. These circRNAs might regulate the expression of their host genes through competitive inhibition. Eight of these 32 circRNAs might regulate gene expression through a putative ceRNA network. At 0 days post-anthesis (0 DPA) ovule, five circRNAs were found to interact with six miRNAs that are associated with the regulation of cytoskeleton- and plant cell wall-related genes during the initiation stage of cotton fiber development. Two circRNAs that interacted with two miRNAs to regulate vesicle transport and signal transduction pathways during the fiber elongation stage were identified at 10 DPA (fiber). These results indicate that circRNA may regulate the initiation and elongation stages of cotton fiber via a sponge model during the hybridization process. This study provides a deeper understanding of the molecular mechanism of hybrid breeding from a new perspective. [ABSTRACT FROM AUTHOR]