Functional Analysis Of Chitin Synthase Chs1 And Chs2 Through RNAI In Fusarium Graminearum

Fusarium head blight(FHB) of wheat, caused by Fusarium pathogens, is a serious harmfull disease worldwide. As the second largest food crop wheat, natural resistance of wheat against FHB is inadequate, so it is so easily that FHB of wheat may break out extensively, it will result in yield loss greatly. So new strategies for controlling the disease and enhancing zhe resistance of wheat aganist FHB are required. RNA interference give us a new way to slove the problem. Chitin is a important component of fungal cell wall and is synthesized by chitin synthases(Chs). Plant pathogenic fungi normally have multiple chitin sunthase genes, moreover chitin synthases is an ideal target for antifungal drugs. In the study, using the Gatway, I constracted a series of RNA interference vector for small gene fragment of chitin synthases(Chs1,Chs2), so that we can get the important small gene fragment for Fusarium asiaticum development and pathogenesis. As a result, it provides transgenic wheat breeding for disease resistance.1. The Chs1 was divided into five sections, every section forms a hairpin structure into the fungal RNA interference vector. Then protoplast transformation into the specific PLS locus of F. asiaticum 5035. Detecting the positive transformants, compared with the wild-type strain 5035, there are a different degree distinction in the extent of conidiation, in a 48.2%-68.6% reduction of pathogenicity, accompanied by decreases of 11%-23% in chitin content. Cell wall is the frist protective barrier to withstand changes in osmtic pressure and PH imposed by environment. Because the obstruction of chitin synthesis in the positive transformants, the positive transformants grow slowly clearly compared with the wild-type strain 5035 in a hypertonic and acidic environment.2.The same with RNAi vector contruction of Chs1, the Chs2 was divided into five sections, every section forms a hairpin structure into the fungal RNA interference vector. Then protoplast transformation into the specific PLS locus of F. asiaticum 5035. In high osmotic pressure and acidic environment, the positive transformants grow slowly clearly compared with the wild-type strain 5035. There are a different degree distinction in the extent of conidiation, accompanied by decreases of 9%-25.3% in chitin content of △Chs2-3, △Chs2-4, △Chs2-5, in a 61.1%-73.6% reduction of pathogenicity.