State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu, China.
Triticeae Research Institute, Sichuan Agricultural University, Chengdu, China.
Mol Plant Pathol. 2023 Oct;24(10):1205-1219. doi: 10.1111/mpp.13364. Epub 2023 Jun 12.
The dynamic balance and distribution of sphingolipid metabolites modulate the level of programmed cell death and plant defence. However, current knowledge is still limited regarding the molecular mechanism underlying the relationship between sphingolipid metabolism and plant defence. In this study, we identified a wheat RNA-binding protein 1 (TaRBP1) and TaRBP1 mRNA accumulation significantly decreased in wheat after infection by Puccinia striiformis f. sp. tritici (Pst). Knockdown of TaRBP1 via virus-induced gene silencing conferred strong resistance to Pst by enhancing host plant reactive oxygen species (ROS) accumulation and cell death, indicating that TaRBP1 may act as a negative regulator in response to Pst. TaRBP1 formed a homopolymer and interacted with TaRBP1 C-terminus in plants. Additionally, TaRBP1 physically interacted with TaGLTP, a sphingosine transfer protein. Knockdown of TaGLTP enhanced wheat resistance to the virulent Pst CYR31. Sphingolipid metabolites showed a significant accumulation in TaGLTP-silenced wheat and TaRBP1-silenced wheat, respectively. In the presence of the TaRBP1 protein, TaGLTP failed to be degraded in a 26S proteasome-dependent manner in plants. Our results reveal a novel susceptible mechanism by which a plant fine-tunes its defence responses by stabilizing TaGLTP accumulation to suppress ROS and sphingolipid accumulation during Pst infection.
鞘脂代谢物的动态平衡和分布调节细胞程序性死亡和植物防御的水平。然而，目前关于鞘脂代谢与植物防御之间关系的分子机制的知识仍然有限。在这项研究中，我们鉴定了一个小麦 RNA 结合蛋白 1（TaRBP1），在小麦感染小麦条锈菌（Pst）后，TaRBP1 的 mRNA 积累显著降低。通过病毒诱导的基因沉默（VIGS）敲低 TaRBP1 赋予小麦对 Pst 的强烈抗性，通过增强宿主植物活性氧（ROS）积累和细胞死亡，表明 TaRBP1 可能作为响应 Pst 的负调节剂。TaRBP1 在植物中形成同源聚合物并与 TaRBP1 C 末端相互作用。此外，TaRBP1 与鞘氨醇转移蛋白 TaGLTP 相互作用。敲低 TaGLTP 增强了小麦对毒性 Pst CYR31 的抗性。在 TaGLTP 沉默的小麦和 TaRBP1 沉默的小麦中，鞘脂代谢物分别表现出明显的积累。在 TaRBP1 蛋白存在的情况下，TaGLTP 不能以依赖 26S 蛋白酶体的方式在植物中降解。我们的结果揭示了一种新的易感机制，植物通过稳定 TaGLTP 积累来微调其防御反应，从而抑制 ROS 和鞘脂在 Pst 感染过程中的积累。
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