Accumulation of raffinose in rice seedlings overexpressing OsWRKY11 in relation to desiccation tolerance

We previously reported that transgenic rice (Oryza sativa L.) lines overexpressing OsWRKY11 showed significant desiccation tolerance, as indicated by their slower water loss in detached leaves. Here we examined the contents of sucrose, glucose, fructose and raffinose. Raffinose was shown to accumulate at a significantly higher level in the transgenic plants overexpressing OsWRKY11. Microarray analysis of gene expression profile indicated that the gene expression of Os07g0209100 encoding raffinose synthase and that of Os07g0687900 encoding galactinol synthase were up-regulated. These results suggest that OsWRKY11 induced activation of these genes involved in raffinose synthesis and the accumulated raffinose played an important role in the desiccation tolerance of the OsWRKY11-overexpressed plants.