关键词: 玉米大斑病菌, 聚酮体合成酶基因, DHN黑色素, RNA干扰

Abstract: 【Objective】RNA interference technology was used to investigate the function of a polyketide synthase gene (StPKS) in Setosphaeria turcica.【Method】The silent vector, pSilent-StPKS1-2, was constructed by inserting StPKS fragments into plasmid pSilent-1 then trandformed into S. turcica 01-23 protoplasts through PEG. Transformants were selected on potato dextrose agar (PDA) containing hygromycin and the expression levels of StPKS was analysised by Semiquantitative RT-PCR. The hypae morphology of transformants and wide type was observed by microscope.【Results】The RNAi vector was effective to reduce the gene expression. Thirty hygromycin-resistant transformants were isolated and five melanin-deficient transformants were analysised by Semiquantitative RT-PCR. The results showed that StPKS mRNA was weakly expressed in white-color phenotypes. The transformants hypae morphology was anomalistic, including intumescent, anamorphic and ramose.【Conclusion】StPKS gene involved in the DHN-melanin biosynthesis and related to the mycelial morphology. The DHN-melanin biosynthesis was readuced when StPKS gene weakly expression.

Key words: Setosphaeria turcica, Polyketide synthase gene, DHN-melanin, RNAi