小麦 TaPIM1 基因的克隆及其转基因烟草的抗病性分析

In plants,MYB transcription factors play various roles in developmental processes and in responses to biotic and abiotic stresses. In this paper, a pathogen-induced MYB gene of wheat, TaPIM1, protein TaPIM1 consisting of 323 amino acids. TaPIM1 protein contains two MYB DNA binding domains (R2, R3), two nuclear localization sites and two transcription activation domains. The entire sequence of TaPIM1 protein shares a low identity of below 43.69% with other plant MYB proteins. TaPIM1 is a new member of R2R3 type of MYB transcription factors of transcription families. The transcript of TaPIM1 was obviously upregulated after challenge with fungal pathogens Rhizoctonia cerealis or Bipolaris sorokiniana, respectively. The gene transformation vector pBI-35S: TaPIM1 was constructed, in which the TaPIM1 was driven by the CaMV 35S promoter. The vector pBI-35S: TaPIM1 wastransferred into tobacco cultivar W38 by Agrobacterium -mediated transformation method. Twelve TaPIM1 transgenic tobacco lines, such as M66, M102 and M110, were obtained through screening. The T 1 plants of these transgenic lines were subjected to PCR, RT-PCR analyses and evaluated for Ralstonia solanacearum resistance. The results showed that three transgenic lines, including M66, M102, and M110, overexpressed TaPIM1 and showed significantly enhanced resistance to R.  solanacearum compared with the host tobacco W38 plants.The resistance degree was correlated with the transcript level of the TaPIM1 inthese transgenic lines . These results suggested that TaPIM1 may positively modulate defense response to certain pathogens. was isolated from cDNAs of wheat leaves inoculated with Rhizoctonia cerealis . TaPIM1 gene encodes a