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[学术文献 ] Activation of Induced Systemic Resistance in Cotton Plants Against Fusarium and Macrophomina by Microbial Antagonists 进入全文
JOURNAL OF PLANT GROWTH REGULATION
The use of microbial antagonists (MAs) against phytopathogens is a cost-effective, environmentally sustainable strategy that successfully enhances crop yield. In this study, we evaluated the in-planta efficacy of multistress-tolerant MAs isolated previously from the cotton rhizosphere showing high antagonistic activity against Macrophomina phaseolina and Fusarium oxysporum. During pathogenicity testing, M. phaseolina was found more aggressive compared to F. oxysporum as indicated by disease area percentage on cotton seeds but the use of MAs lowered the seed mortality rate (0-20%) in the pot experiment compared to pathogen control (47-60%) indicating their high antagonistic potential. The mode of antagonism was investigated by identifying antifungal metabolites and volatile organic compounds secreted by these agents using HPLC-MS and GC-MS coupled with SPME fiber, respectively, which revealed compounds like iturins, surfactins, mixirins, fengycins, undecanone, involved in the activation of induced systemic resistance (ISR) along with the antifungal activity. The increased levels of two defense enzymes, polyphenol oxidase [110-180% increase over absolute control (IOC)] and phenylalanine ammonia-lyase (22-58% IOC), and three antioxidant enzymes, catalase (36-98% IOC), peroxidase (44-71% IOC), and superoxide dismutase (72-145% IOC) in MA-treated plants confirmed the activation of ISR against both pathogens. The proline, total phenolic, and glycine betaine contents also increased in the MAs-treated plants, whereas a decreased malondialdehyde content was observed. These results indicate that these MAs are reliable and sustainable options for enhancing crop growth and that their bioformulations can be used to control fungal pathogens and help plants endure biotic and abiotic stresses.
[学术文献 ] Natural variations in the Cis-elements of GhRPRS1 contributing to petal colour diversity in cotton 进入全文
PLANT BIOTECHNOLOGY JOURNAL
The cotton genus comprises both diploid and allotetraploid species, and the diversity in petal colour within this genus offers valuable targets for studying orthologous gene function differentiation and evolution. However, the genetic basis for this diversity in petal colour remains largely unknown. The red petal colour primarily comes from C, G, K, and D genome species, and it is likely that the common ancestor of cotton had red petals. Here, by employing a clone mapping strategy, we mapped the red petal trait to a specific region on chromosome A07 in upland cotton. Genomic comparisons and phylogenetic analyses revealed that the red petal phenotype introgressed from G. bickii. Transcriptome analysis indicated that GhRPRS1, which encodes a glutathione S-transferase, was the causative gene for the red petal colour. Knocking out GhRPRS1 resulted in white petals and the absence of red spots, while overexpression of both genotypes of GhRPRS1 led to red petals. Further analysis suggested that GhRPRS1 played a role in transporting pelargonidin-3-O-glucoside and cyanidin-3-O-glucoside. Promoter activity analysis indicated that variations in the promoter, but not in the gene body of GhRPRS1, have led to different petal colours within the genus. Our findings provide new insights into orthologous gene evolution as well as new strategies for modifying promoters in cotton breeding.
[学术文献 ] Molecular traits of MAPK kinases and the regulatory mechanism of GhMAPKK5 alleviating drought/salt stress in cotton 进入全文
PLANT PHYSIOLOGY
Mitogen-activated protein kinase kinases (MAPKKs) play a critical role in the mitogen-activated protein kinase (MAPK) signaling pathway, transducing external stimuli into intracellular responses and enabling plant adaptation to environmental challenges. Most research has focused on the model plant Arabidopsis (Arabidopsis thaliana). The systematic analysis and characterization of MAPKK genes across different plant species, particularly in cotton (Gossypium hirsutum), are somewhat limited. Here, we identified MAPKK family members from 66 different species, which clustered into five different sub-groups, and MAPKKs from four cotton species clustered together. Through further bioinformatic and expression analyses, GhMAPKK5 was identified as the most responsive MAPKK member to salt and drought stress among the 23 MAPKKs identified in Gossypium hirsutum. Silencing GhMAPKK5 in cotton through virus-induced gene silencing (VIGS) led to quicker wilting under salt and drought conditions, while overexpressing GhMAPKK5 in Arabidopsis enhanced root growth and seed germination under these stresses, demonstrating GhMAPKK5's positive role in stress tolerance. Transcriptomics and Yeast-Two-Hybrid assays revealed a MAPK cascade signal module comprising GhMEKK (mitogen-activated protein kinase kinase kinases)3/8/31-GhMAPKK5-GhMAPK11/23. This signaling cascade may play a role in managing drought and salt stress by regulating transcription factor genes, such as WRKYs, which are involved in the biosynthesis and transport pathways of ABA, proline, and RALF. This study is highly important for further understanding the regulatory mechanism of MAPKK in cotton, contributing to its stress tolerance and offering potential in targets for genetic enhancement. Genome-wide identification and transcriptomic analyses indicate that a mitogen-activated protein kinase kinase signaling cascade plays a role in managing drought and salt stress in cotton.
[学术文献 ] GhEXL3 participates in brassinosteroids regulation of fiber elongation in Gossypium hirsutum 进入全文
PLANT JOURNAL
Cotton fiber (Gossypium hirsutum) serves as an ideal model for investigating the molecular mechanisms of plant cell elongation at the single-cell level. Brassinosteroids (BRs) play a crucial role in regulating plant growth and development. However, the mechanism by which BR influences cotton fiber elongation remains incompletely understood. In this study, we identified EXORDIUM-like (GhEXL3) through transcriptome analysis of fibers from BR-deficient cotton mutant pagoda 1 (pag1) and BRI1-EMS-SUPPRESSOR 1 (GhBES1.4, encoding a central transcription factor of BR signaling) overexpression cotton lines. Knockout of GhEXL3 using CRISPR/Cas9 was found to impede cotton fiber elongation, while its overexpression promoted fiber elongation, suggesting a positive regulatory function for GhEXL3 in fiber elongation. Furthermore, in vitro ovule culture experiments revealed that the overexpression of GhEXL3 partially counteracted the inhibitory effects of brassinazole (BRZ) on cotton fiber elongation, providing additional evidence of GhEXL3 involvement in BR signaling pathways. Moreover, our findings demonstrate that GhBES1.4 directly binds to the E-box (CACGTG) motif in the GhEXL3 promoter region and enhances its transcription. RNA-seq analysis revealed that overexpression of GhEXL3 upregulated the expression of EXPs, XTHs, and other genes associated with fiber cell elongation. Overall, our study contributes to understanding the mechanism by which BR regulates the elongation of cotton fibers through the direct modulation of GhEXL3 expression by GhBES1.4.
[学术文献 ] Development of an Agrobacterium-mediated CRISPR/Cas9 gene editing system in jute (Corchorus capsularis) 进入全文
CROP JOURNAL
Jute (Corchorus capsularis L.) is the second most important natural plant fiber source after cotton. However, developing an efficient gene editing system for jute remains a challenge. In this study, the transgenic hairy root system mediated by Agrobacterium rhizogenes strain K599 was developed for Meifeng 4, an elite jute variety widely cultivated in China. The transgenic hairy root system for jute was verified by subcellular localization and bimolecular fluorescence complementation (BiFC) assays. The CHLOROPLASTOS ALTERADOS 1 (CcCLA1) gene, which is involved in the development of chloroplasts, was targeted for editing at two sites in Meifeng 4. Based on this hairy root transformation, the gRNA scaffold was placed under the control of cotton ubiquitin GhU6.7 and -GhU6.9 promoters, respectively, to assess the efficiency of gene editing. Results indicated the 50.0% (GhU6.7) and 38.5% (GhU6.9) editing events in the target 2 alleles (gRNA2), but no mutation was detected in the target 1 allele (gRNA1) in transgenic-positive hairy roots. CcCLA1 gene editing at gRNA2 under the control of GhU6.7 in Meifeng 4 was also carried out by Agrobacterium tumefaciens-mediated transformation. Two CcCLA1 mutants were albinic, with a gene editing efficiency of 5.3%. These findings confirm that the CRISPR/Cas9 system, incorporating promoter GhU6.7, can be used as a gene editing tool for jute.
[学术文献 ] Apical meristem transcriptome analysis identifies a role for the blue light receptor gene GhFKF1 in cotton architecture development 进入全文
CROP JOURNAL
Cotton architecture is determined by the differentiation fate transition of axillary meristem (AM), and influences cotton yield and the efficiency of mechanized harvesting. We observed that the initiation of flowering primordium was earlier in early-maturing than that in late-maturing cultivars during the differentiation and development of AM. The RNA-Seq and expression level analyses showed that genes FLAVIN BINDING, KELCH REPEAT, F-BOX1 (GhFKF1), and GIGANTEA (GhGI) were in response to circadian rhythms, and involved in the regulation of cotton flowering. The gene structure, predicted protein structure, and motif content analyses showed that in Arabidopsis, cotton, rapseed, and soybean, proteins GhFKF1 and GhGI were functionally conserved and share evolutionary origins. Compared to the wild type, in GhFKF1 mutants that were created by the CRISPR/Cas9 system, the initiation of branch primordium was inhibited. Conversely, the knocking out of GhGI increased the number of AM differentiating into flower primordium, and there were much more lateral branch differentiation and development. Besides, we investigated that proteins GhFKF1 and GhGI can interact with each other. These results suggest that GhFKF1 and GhGI are key regulators of cotton architecture development, and may collaborate to regulate the differentiation fate transition of AM, ultimately influencing plant architecture. We describe a strategy for using the CRISPR/Cas9 system to increase cotton adaptation and productivity by optimizing plant architecture.
