条锈菌诱导的小麦MBF1转录辅激活因子基因的克隆及其特征分析

Cloning and Characterization of a MBF1 Transcriptional Coactivator Factor in Wheat Induced by Stripe Rust Pathogen

应用电子克隆和RT-PCR方法,从小麦叶片中分离出一个条锈菌诱导的编码MBF1基因的cDNA序列,暂被命名为TaMBF1a。TaMBF1a包含一个完整的429 bp的开放阅读框,编码142个氨基酸,具有MBF1保守结构域;小麦TaMBF1a氨基酸序列与水稻OsMBF1相似性达92%,与拟南芥AtMBF1a相似性达80%。TaMBF1a编码的蛋白可能是核蛋白,且该基因在小麦根、茎、叶组织中表达量基本一致。在小麦与条锈菌的亲和、非亲和互作中,TaMBF1a基因均受条锈菌诱导高水平表达,且非亲和组合表达量高于亲和组合。外源植物激素水杨酸、乙烯、脱落酸也可诱导该基因快速上调表达,表明TaMBF1a可能通过水杨酸、乙烯等信号途径参与小麦对条锈菌的防御反应。

To better understand wheat （Triticum aestivurn L.） defense responses to Puccinia striiformis f. sp. tritici, the compatible interaction cDNA library of wheat leaves infected by Puccinia striiformis f. sp. tritici is constructed in our laboratory. A total of 594 genes have been identified and 399 genes have been annotated. On the basis of previous study, a new MBF1 gene was isolated from this cDNA library through in silico cloning and RT-PCR approaches. The gene was tentatively designated as TaMBFla whose open reading frame was 429 bp in length and encoded 142 amino acids containing a conserved MBF1 transcription activation domain. The amino acid sequence of TaMBFla shares 92% identify with OsMBF1 in rice and 80% identify with AtMBFla in Arabidopsis thaliana. The expression of TaMBFla gene was at a similar level in leaves, stems, and roots. TaMBFla protein is possibly a nuclear protein in wheat. The expression patterns results revealed that TaMBFla was up-regulated in both compatible and incompatible interactions. However, the expression in incompatible interaction was higher than that in compatible interaction. The expression of TaMBFla was also induced by salicylic acid （SA）, ethylene, and abscisic acid （ABA）, suggesting that the SA and ethylene pathways might be involved in regulating the host defence responses.