Transcriptome sequencing of Verticillium dahliae with different virulence

The V. dahliae could cause host obvious disease symptoms. Moreover, it was difficult to control, because of the rapidly genetic variation. Due to the rapidly genetic variation and complexity of the genetic background, the mechanism of pathogenicity differentiation of V. dahliae has still been unknown. To solve the problem, we isolated 24 strains of V. dahliae from a farmland of Shihezi city, Xinjiang province. Through ITS sequences and VCGs assay, the strains of SHZ-4, SHZ-5, and SHZ-9 had closer kinship. Moreover, the large difference was presented on the pathogenicity of SHZ-4, SHZ-5, and SHZ-9. Furthermore, a number of differentially expressed genes was identified through comparative transcriptome sequencing method and the genes were mainly centered on CWDEs and transport relative proteins. It was well understand that the CWDEs determined the source of nutrients of V. dahliae and the organic substance of host cell degraded by the CWDEs would induce the hyperosmosis of intercellular liquid. According to these, we proposed a hypothesis that the hyperosmosis induced the dehydration and death of host cell and contributed to absorb the nutrition for V. dahliae. The hyperosmosis promoting the nutrients scramble indicated that the V. dahliae could resist the hyperosmosis and the pathogenicity was positive associating with the tolerance. With regards to this, the sugar-induced-hyperosmotic resistance of the three V. dahliae isolates and cotton leaf tissue were analyzed through changing the sugar concentration. The result was entirely consistent with our hypothesis. It was firstly found that the pathogenicity of V. dahliae was relative to the resistance of sugar-induced-hyperosmosis, which could provide a new idea for cultivating a new varieties to resistant to the V. dahliae. Hypha mRNA profiles of three strains with different virulence were generated by deep sequencing, using Illumina Hiseq2500 PE125.