Rloes Of AtCCOAMT And AtGSTU3 In The Resistance To Sclerotinia Sclerotiorum

Sclerotinia sclerotiorum can infect more than 500 kinds of plants, such as rapeseed, sunflower, soybean, causing significant economic losses.Oxalic acid (OA) plays an important role in the pathogenicity of Sclerotinia sclerotiorum. Using Arabidopsis microarray, we got the differentially expressed gene profile under the stress of OA, we identified that two of the genes was significantly upregulated by oxalic acid, AtCCoAOMT (Atlg67980) and AtGSTU3 (At2g29470), which encodes Caffeoyl-CoA 3-O-Methyltransferase and Glutathione S-Transferase tau 3 respectively, and confirmed by qRT-PCR analysis. These results indicate that AtCCoAOMT and AtGSTU3 may play important roles in the resistance to Sclerotinia sclerotiorum.To elucidate the functions of two genes, we firstly performed bioinformatic analysis of two genes in the aspect of the expression pattern, cis-acting elements of promoter and amino acid sequence alignment. Meanwhile, we generated transgenic overexpression lines of these two genes respectively and obtained the T3 homozygous seeds by genetic screening for further study. Treatment with oxalic acid shown that both the OE-Atlg67980 and OE-At2g29470 lines possess some resistance to 1.2mM OA, the resistance of OA in OE-Atlg67980 is more significant. JA, SA and NaCl sensitivity assay shown that only the OE-At2g29470 lines are insensitive to SA treatment.5 week-old OE transgenic Arabidopsis seedlings were inoculated with Sclerotinia sclerotiorum in planta, compared with wild-type Co10 plants, transgenic plants OE-Atlg67980 lesion area is small, and has less mycelium and smaller of the end of hyphae; transgenic OE-At2g29470 also has the similar phenotypes. Therefore, we suggested that transgenic plants OE-At1g67980 and OE-At2g29470 conferred resisitance to Sclerotinia. Protective enzyme activity and defense-related gene expression analysis showed that the protective enzyme activity of two OE plants is significant higher than that of wild-type Arabidopsis, and the expression of the marker gene of SA pathway PR1, and the expression of the marker gene of JA pathway-PDF1.2 is up regulated in OE plants compared with wild type Arabidopsis. Taken together, AtCCoAOMT and AtGSTU3 may regulate the active oxygen metabolism, JA and SA signaling pathways, and thus possess the resistance to Sclerotinia sclerotiorum...