Yang Yong, Wu Yushuang, Huang Jinling, Tang Huiquan, Gao Haoran, Yu Junyi, Chen Jiajun, Ji Han, Huang Mengshu, Wan Xiaorong, Tan Xiaodan
Guangzhou key laboratory for research and development of crop germplasm resources, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, Guangdong, China.
National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan 430070, Hubei, China.
Int J Biol Macromol. 2025 Jan;284(Pt 2):138189. doi: 10.1016/j.ijbiomac.2024.138189. Epub 2024 Nov 30.
A predicted peanut R. solanacearum T3E RS_T3E_Hyp6 was identified as a definite T3E and renamed as RipBU. It is relative conserved in 31 R. solanacearum strains. Deletion of RipBU in R. solanacearum HA4-1 strain caused the attenuate pathogenicity in peanut, and complementarity of RipBU recovered the virulence of ΔRipBU mutant strain. Transient expression of RipBU decreased the level of chlorophyll, resulting in leaf chlorosis and suppressed flg22-triggered reactive oxygen species (ROS) burst and the expression of pattern-triggered immunity (PTI) marker genes in the leaves of Nicotiania benthamiana. Subcellular localization observation showed that RipBU localizes to chloroplasts in tobacco cells. RipBU significantly increased the jasmonic acid (JA) content and the expressions of JA-signaling marker genes in tobacco leaves, while significantly decreased the salicylic acid (SA) level and the expressions of SA-signaling marker genes. RipBU contained a putative lipase domain, and mutation of which abolished the ability of RipBU to induce tobacco leaf chlorosis and peanut wilt, while still localized to chloroplasts. Our study reveals the virulence function of RipBU that suppresses plant immunity by inhibiting PTI and SA signaling, and promoting JA signaling.
一种预测的花生青枯雷尔氏菌Ⅲ型效应蛋白RS_T3E_Hyp6被鉴定为一种确定的Ⅲ型效应蛋白，并重新命名为RipBU。它在31株青枯雷尔氏菌菌株中相对保守。在青枯雷尔氏菌HA4-1菌株中缺失RipBU导致其对花生的致病性减弱，而RipBU的互补恢复了ΔRipBU突变菌株的毒力。RipBU的瞬时表达降低了叶绿素水平，导致叶片褪绿，并抑制了本氏烟草叶片中flg22触发的活性氧（ROS）爆发以及模式触发免疫（PTI）标记基因的表达。亚细胞定位观察表明，RipBU定位于烟草细胞的叶绿体中。RipBU显著增加了烟草叶片中茉莉酸（JA）的含量以及JA信号标记基因的表达，同时显著降低了水杨酸（SA）水平以及SA信号标记基因的表达。RipBU包含一个假定的脂肪酶结构域，其突变消除了RipBU诱导烟草叶片褪绿和花生枯萎的能力，但其仍定位于叶绿体中。我们的研究揭示了RipBU通过抑制PTI和SA信号传导以及促进JA信号传导来抑制植物免疫的毒力功能。
