Zhang Qiong, Zhang Xinmei, Zhuang Rui, Wei Zetong, Shu Weixue, Wang Xiaojie, Kang Zhensheng
State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, China.
College of Life Sciences, Northwest A&F University, Yangling, China.
Front Plant Sci. 2020 Jun 30;11:716. doi: 10.3389/fpls.2020.00716. eCollection 2020.
Rac/Rop proteins play important roles in the regulation of cell growth and plant defense responses. However, the function of Rac/Rop proteins in wheat remains largely unknown. In this study, a small G protein gene, designated as , was characterized from wheat () in response to f. sp. () and was found to be highly homologous to the Rac proteins identified in other plant species. Transient expression analyses of the TaRac6-GFP fusion protein in leaves showed that TaRac6 was localized in the whole cell. Furthermore, transient expression of TaRac6 inhibited Bax-triggered plant cell death (PCD) in . Transcript accumulation of was increased at 24 h post-inoculation (hpi) in the compatible interaction between wheat and , while it was not induced in an incompatible interaction. More importantly, silencing of by virus induced gene silencing (VIGS) enhanced the resistance of wheat (Suwon 11) to (CYR31) by producing fewer uredinia. Histological observations revealed that the hypha growth of was markedly inhibited along with more HO generated in the -silenced leaves in response to . Moreover, transcript levels of were significantly down-regulated, while those of and were significantly up-regulated. These results suggest that functions as a potential susceptibility factor, which negatively regulate the reactive oxygen species (ROS) burst in the wheat- interaction.
Rac/Rop蛋白在细胞生长调控和植物防御反应中发挥着重要作用。然而，Rac/Rop蛋白在小麦中的功能仍 largely未知。在本研究中，从小麦（）中鉴定出一个小G蛋白基因，命名为，该基因对 f. sp. （）有响应，且被发现与其他植物物种中鉴定出的Rac蛋白高度同源。TaRac6-GFP融合蛋白在叶片中的瞬时表达分析表明，TaRac6定位于整个细胞中。此外，TaRac6的瞬时表达抑制了Bax触发的植物细胞死亡（PCD）。在小麦与的亲和互作中，接种后24小时（hpi）时的转录积累增加，而在非亲和互作中未被诱导。更重要的是，通过病毒诱导基因沉默（VIGS）沉默后，小麦（苏旺11）对（CYR31）的抗性增强，产生的夏孢子堆减少。组织学观察表明，在沉默的叶片中，响应时，的菌丝生长受到显著抑制，同时产生更多的HO。此外，的转录水平显著下调，而和的转录水平显著上调。这些结果表明，作为一个潜在的感病因子，在小麦与的互作中对活性氧（ROS）爆发起负调控作用。
