Isolation And Characterization Of Cotton PR10-like Gene Responsive To Infection By Verticillium Dahliae

Upland cotton (Gossypium hirsutum L.) is one of the most important economic crops in our country. Verticillium wilt, a soil-borne fungal disease, causes serious wilt phenotype for cotton and results in severe loss of cotton production as well as downgrade of fiber quality. At present few remarkable research progress was made in the control and breeding against the pathogen. In this study, we isolated and characterized a cotton PR10-like gene which would be down-regulated when cotton was infected by Verticillium dahliae. We provided some important experimental evidences for understanding of the molecular mechanism of cotton responsive to the infection of V. dahliae.BD18 is a breeding line of upland cotton that is characterized by high tolerance to V. dahliae. Using the PCR-Selected cDNA Substractive kit, a cDNA library was generated from the roots of infected upland cotton cultivar BD18 infected by the highly aggressive defoliating strain T9 of V. dahliae.62 induced and 15 repressed cDNA clones by the pathogen infection were isolated through two rounds of reverse northern. The PR10-like gene sequence down-regulated by the infection of V. dahliae was isolated using northern blot, which encodes a polypeptide of 158 amino acids. PR10-like proteins were mainly localized in the nucleus and cell membrane. Signal molecules including SA and ABA, can supress the expression of PR10-like gene. But JA can activated the expression of this gene.We constructed the plant expression vector of this gene and transformated the model plant tobacco. Semi-quantitative RT-PCR and Real time PCR revealed that the overexpression of the PR10-like genes supressed the pathogenesis-related genes (npr1 and pr5) in the transgenic tobacco. The nprl plays a key role in the pathway of SAR of plant. In additional, the RNA degradation assays indicated the inclusion protein of PR10-like gene can degrade RNA in vitro. This chemistry activity maybe involve in regulation of the expression of other gene in nucleus through degrating the transcriptions of those genes. The RNase activity of PR10 proteins also suggests a potential role in defense response against pathogenic infections.In conclusion, the cotton PR10-like gene maybe down-regulate the pathway of plant SAR resulting in the defense response against the infection of V. dahliae.