State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, Shaanxi 712100, PR China.
J Exp Bot. 2012 Jul;63(12):4571-84. doi: 10.1093/jxb/ers140. Epub 2012 Jun 13.
BAX inihibitor-1 (BI-1) is proposed to be a cell death suppressor conserved in both animals and plants. The ability of BI-1 genes to inhibit programmed cell death (PCD) has been well studied in animals, but the physiological importance of BI-1 in plant-microbe interactions remains unclear. This study characterized BI-1 from wheat infected by Puccinia striiformis f. sp. tritici (Pst). The deduced TaBI-1 protein contained a Bax inhibitor domain and seven transmembrane regions conserved among members of the BI-1 family. Transcription of TaBI-1 was detected in all wheat tissues tested (culms, roots, leaves, anthers, and spikelets). Furthermore, TaBI-1 exhibited positive transcriptional responses to Pst infection and abiotic stresses. Overexpression of TaBI-1 in tobacco blocked Bax-induced cell death. Silencing TaBI-1 in plants of a resistant wheat genotype converted a resistant reaction to a relatively susceptible reaction when inoculated with an avirulent pathotype of the pathogen, and increased the area per infection site, but the percentage of necrotic cells did not change significantly, indicating that TaBI-1, a negative cell death regulator, contributes to wheat resistance to stripe rust. These results provide a better understanding of the molecular mechanism of wheat resistance to stripe rust.
BAX 抑制剂-1（BI-1）被认为是一种在动物和植物中保守的细胞死亡抑制剂。BI-1 基因抑制程序性细胞死亡（PCD）的能力在动物中得到了很好的研究，但 BI-1 在植物-微生物相互作用中的生理重要性仍不清楚。本研究对感染条锈菌（Puccinia striiformis f. sp. tritici，Pst）的小麦中的 BI-1 进行了特征描述。推导的 TaBI-1 蛋白包含 Bax 抑制剂结构域和 BI-1 家族成员之间保守的七个跨膜区域。在所有测试的小麦组织（茎、根、叶、花药和小穗）中均检测到 TaBI-1 的转录。此外，TaBI-1 对 Pst 感染和非生物胁迫表现出正转录响应。在烟草中过表达 TaBI-1 可阻止 Bax 诱导的细胞死亡。在接种非毒性病原菌小种时，沉默小麦抗性基因型中的 TaBI-1 将抗性反应转化为相对敏感反应，并增加了每个感染部位的面积，但坏死细胞的百分比没有显著变化，表明负细胞死亡调节剂 TaBI-1 有助于小麦对条锈病的抗性。这些结果提供了对小麦抗条锈病分子机制的更好理解。
