[Vesicular transport protein VdSec22 is involved in secretion of extracellular protein and pathogenicity in Verticillium dahliae].

The aim of this study was to characterize VdSec22 of Verticillium dahliae, which is an intracellular vesicle fusion protein involved in fungal secretory pathway, and to provide a potential gene target for controlling Verticillium wilt disease.VdSec22 deletion mutant ΔQF and functional complementation strain CΔQF by reintroducing the VdSec22 intoAQF were constructed. Secretion ability of extracellular protein (including pectinase, cellulose, and phytotoxin protin) and pathogenicity of ΔQF and CΔQF were studied compared with that of wild type strain Vd991. Expression level of ER molecular chaperones by quantitative PCR was also performed to infer whether ER stress was induced in ΔQF.We successfully constructed VdSec22 deletion mutant strain ΔQF and functional complementation strain CΔQF. VdSec22 deficiencies did disturb secretion ability of extracellular protein such as pectinase, cellulose, and phytotoxin protin. Pathogenicity of ΔQF was dramatically reduce accordingly. We also found loss of VdSec22 resulted in ER stress in V. dahliae cells. Reintroducing functional VdSec22 into ΔQF can compensate for the deficiencies mentioned above.VdSec22 is an important secretion pathway protein involved in secretion of extracellular protein and pathogenicity in V. dahliae. VdSec22 provides a potential gene target for controlling the devastating disease.