National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan, 430070, China.
Key Laboratory of Potato Biology and Biotechnology (HZAU), Ministry of Agriculture and Rural Affairs, Wuhan, 430070, China.
Plant J. 2023 Dec;116(5):1342-1354. doi: 10.1111/tpj.16428. Epub 2023 Aug 23.
Miraculin-like proteins (MLPs), members of the Kunitz trypsin inhibitor (KTI) family that are present in various plants, have been discovered to have a role in defending plants against pathogens. In this study, we identified a gene StMLP1 in potato that belongs to the KTI family. We found that the expression of StMLP1 gradually increases during Ralstonia solanacearum (R. solanacearum) infection. We characterized the promoter of StMLP1 as an inducible promoter that can be triggered by R. solanacearum and as a tissue-specific promoter with specificity for vascular bundle expression. Our findings demonstrate that StMLP1 exhibits trypsin inhibitor activity, and that its signal peptide is essential for proper localization and function. Overexpression of StMLP1 in potato can enhance the resistance to R. solanacearum. Inhibiting the expression of StMLP1 during infection accelerated the infection by R. solanacearum to a certain extent. In addition, the RNA-seq results of the overexpression-StMLP1 lines indicated that StMLP1 was involved in potato immunity. All these findings in our study reveal that StMLP1 functions as a positive regulator that is induced and specifically expressed in vascular bundles in response to R. solanacearum infection.
Miraculin-like 蛋白（MLPs）是 Kunitz 胰蛋白酶抑制剂（KTI）家族的成员，存在于各种植物中，已被发现在植物抵御病原体方面发挥作用。在本研究中，我们在马铃薯中鉴定出一个属于 KTI 家族的基因 StMLP1。我们发现，StMLP1 的表达在茄科雷尔氏菌（R. solanacearum）感染过程中逐渐增加。我们将 StMLP1 的启动子表征为可被茄科雷尔氏菌触发的诱导启动子，以及具有血管束表达特异性的组织特异性启动子。我们的研究结果表明，StMLP1 表现出胰蛋白酶抑制剂活性，其信号肽对于正确的定位和功能是必不可少的。在马铃薯中过表达 StMLP1 可以增强对茄科雷尔氏菌的抗性。在感染过程中抑制 StMLP1 的表达在一定程度上加速了感染。此外，过表达-StMLP1 系的 RNA-seq 结果表明，StMLP1 参与了马铃薯的免疫反应。我们研究中的所有这些发现都表明，StMLP1 作为一种正调控因子，在受到茄科雷尔氏菌感染时被诱导并特异性表达在血管束中。
