Cloning of GhPBL1 gene in cotton and its resistance function against Fusarium wilt

【Objective】 GhPBL1, a receptor-like cytoplasmic kinase(RLCK) gene from cotton, was cloned and its resistance to Fusarium wilt was studied, which provided new gene resources for cotton disease-resistant molecular breeding.【Method】 Using the gene expression profile data of cotton roots induced by Fusarium oxysporum and combined with the cotton database, the RLCK family gene GhPBL1 was screened and obtained. Bioinformatics software was used to analyze the sequence characteristics of GhPBL1 gene, and real-time quantitative fluorescence(qRT-PCR) was used to detect the gene expression in different tissues of different resistant varieties, F. oxysporum and exogenous hormone treatments. The anti-Fusarium wilt function of GhPBL1 gene was studied by virus-induced gene silencing(VIGS) technology.【Result】 The open reading frame(ORF) of GhPBL1 gene was 1116 bp. It encoded 371 amino acids residues, contained a STYKc conserved domain located in 81-360 amino acids. It belonged to RLCK family gene. Expression analysis showed that the gene was expressed in roots, stems and leaves of resistant and susceptible materials, but the expression in roots was the highest. After F. oxysporum treatment, the expression level of GhPBL1 gene in resistant materials was higher than that in susceptible materials. Both salicylic acid(SA) and methyl jasmonate(MeJA) could induce the expression of GhPBL1 gene, but the response time of the gene to SA stress was earlier than MeJA stress. Compared with control plants(TRV:00), TRV:GhPBL1-silenced plants were more susceptible to disease, and the relative expression levels of resistance related genes GhEDS1, GhCCR1, GhHCT1 and Gh4CL were significantly lower than the control(P<0.05), but the relative expression levels of GhPR5 were extremely significantly higher than the control(P<0.01).【Conclusion】 The expression of GhPBL1 differs among the resistant and susceptible materials and has obvious tissue specificity. The gene is up-regulated after F. oxysporum treatment and is able to respond to SA and MeJA stress. It is speculated that GhPBL1 gene plays a positive regulatory role in cotton resistance to Fusarium wilt and exogenous hormone stress.