Silencing GhNDR1 and GhMKK2 compromises cotton resistance to Verticillium wilt

• Published in: The Plant journal : for cell and molecular biology 2011-04, Vol.66 (2), p.293-305
• Main Authors: Gao, Xiquan, Wheeler, Terry, Li, Zhaohu, Kenerley, Charles M., He, Ping, Shan, Libo
• Format: Article
• Language: English
• Subjects: Arabidopsis; Biofuels; Biological and medical sciences; Cotton; Cotyledons; Crop diseases; Crops; DNA, Plant - genetics; Fibers; Flagellin; Food; Fundamental and applied biological sciences. Psychology; Gene expression; Gene Expression Regulation, Plant; Gene Silencing; Genes, Plant; Genetic engineering; genomics; Gossypium - genetics; Gossypium - microbiology; Gossypium hirsutum; Immunity, Innate; Infection; Inoculation; Leaves; MAP kinase; Mitogen-Activated Protein Kinase Kinases - genetics; Mitogen-Activated Protein Kinase Kinases - metabolism; Oil; pathogen elicitors; Pathogens; Perception; Plant biology; Plant breeding; Plant Diseases - genetics; Plant Diseases - immunology; Plant Diseases - microbiology; Plant physiology and development; Plant Proteins - genetics; Plant Proteins - metabolism; Plant resistance; protoplast transient gene expression assay; Protoplasts; Protoplasts - metabolism; resistance; Seedlings; Sustainable yield; Transcription Factors - genetics; Transcription Factors - metabolism; Transfection; Verticillium; Verticillium - pathogenicity; Verticillium dahliae; verticillium wilt; virus‐induced gene silence (VIGS)
• ISSN: 0960-7412; 1365-313X
• DOI: 10.1111/j.1365-313X.2011.04491.x

Summary Cotton is an important cash crop worldwide, and is a significant source of fiber, feed, foodstuff, oil and biofuel products. Considerable effort has been expended to increase sustainable yield and quality through molecular breeding and genetic engineering of new cotton cultivars. Given the recent availability of the whole‐genome sequence of cotton, it is necessary to develop molecular tools and resources for large‐scale analysis of gene functions at the genome‐wide level. We have successfully developed an Agrobacterium‐mediated virus‐induced gene silencing (VIGS) assay in several cotton cultivars with various genetic backgrounds. The genes of interest were potently and readily silenced within 2 weeks after inoculation at the seedling stage. Importantly, we showed that silencing GhNDR1 and GhMKK2 compromised cotton resistance to the infection by Verticillium dahliae, a fungal pathogen causing Verticillium wilt. Furthermore, we developed a cotton protoplast system for transient gene expression to study gene functions by a gain‐of‐function approach. The viable protoplasts were isolated from green cotyledons, etiolated cotyledons and true leaves, and responded to a wide range of pathogen elicitors and phytohormones. Remarkably, cotton plants possess conserved, but also distinct, MAP kinase activation with Arabidopsis upon bacterial elicitor flagellin perception. Thus, using gene silencing assays, we have shown that GhNDR1 and GhMKK2 are required for Verticillium resistance in cotton, and have developed high throughput loss‐of‐function and gain‐of‐function assays for functional genomic studies in cotton.