Ding Li-Na, Hu Ying-Hui, Li Teng, Li Ming, Li Yue-Tao, Wu Yuan-Zhen, Cao Jun, Tan Xiao-Li
College of Life Sciences, Jiangsu University, Zhenjiang 212013, China.
Plant Physiol. 2024 Dec 2;196(4):2973-2988. doi: 10.1093/plphys/kiae500.
Sclerotinia stem rot (SSR) caused by Sclerotinia sclerotiorum (Lib.) De Bary is a devastating disease infecting hundreds of plant species. It also restricts the yield, quality, and safe production of rapeseed (Brassica napus) worldwide. However, the lack of resistance sources and genes to S. sclerotiorum has greatly restricted rapeseed SSR-resistance breeding. In this study, a previously identified GDSL motif-containing lipase gene, B. napus GDSL LIPASE-LIKE 1 (BnaC07.GLIP1), encoding a protein localized to the intercellular space, was characterized as functioning in plant immunity to S. sclerotiorum. The BnaC07.GLIP1 promoter is S. sclerotiorum-inducible and the expression of BnaC07.GLIP1 is substantially enhanced after S. sclerotiorum infection. Arabidopsis (Arabidopsis thaliana) heterologously expressing and rapeseed lines overexpressing BnaC07.GLIP1 showed enhanced resistance to S. sclerotiorum, whereas RNAi suppression and CRISPR/Cas9 knockout B. napus lines were hyper-susceptible to S. sclerotiorum. Moreover, BnaC07.GLIP1 affected the lipid composition and induced the production of phospholipid molecules, such as phosphatidylethanolamine, phosphatidylcholine, and phosphatidic acid, which were correlated with decreased levels of reactive oxygen species (ROS) and enhanced expression of defense-related genes. A B. napus bZIP44 transcription factor specifically binds the CGTCA motif of the BnaC07.GLIP1 promoter to positively regulate its expression. BnbZIP44 responded to S. sclerotiorum infection, and its heterologous expression inhibited ROS accumulation, thereby enhancing S. sclerotiorum resistance in Arabidopsis. Thus, BnaC07.GLIP1 functions downstream of BnbZIP44 and is involved in S. sclerotiorum resistance by modulating the production of phospholipid molecules and ROS homeostasis in B. napus, providing insights into the potential roles and functional mechanisms of BnaC07.GLIP1 in plant immunity and for improving rapeseed SSR disease-resistance breeding.
由核盘菌（Sclerotinia sclerotiorum (Lib.) De Bary）引起的菌核病是一种毁灭性病害，可感染数百种植物。它还限制了全球油菜（Brassica napus）的产量、品质和安全生产。然而，缺乏对核盘菌的抗性资源和基因极大地限制了油菜菌核病抗性育种。在本研究中，一个先前鉴定的含有GDSL基序的脂肪酶基因，即甘蓝型油菜GDSL脂酶类似物1（BnaC07.GLIP1），编码一种定位于细胞间隙的蛋白质，其功能被鉴定为在植物对核盘菌的免疫中发挥作用。BnaC07.GLIP1启动子受核盘菌诱导，在核盘菌感染后BnaC07.GLIP1的表达显著增强。异源表达BnaC07.GLIP1的拟南芥（Arabidopsis thaliana）和过表达BnaC07.GLIP1的油菜株系对核盘菌表现出增强的抗性，而RNA干扰抑制和CRISPR/Cas9敲除的甘蓝型油菜株系对核盘菌高度敏感。此外，BnaC07.GLIP1影响脂质组成并诱导磷脂分子如磷脂酰乙醇胺、磷脂酰胆碱和磷脂酸的产生，这些与活性氧（ROS）水平降低和防御相关基因表达增强相关。一个甘蓝型油菜bZIP44转录因子特异性结合BnaC07.GLIP1启动子的CGTCA基序以正向调节其表达。BnbZIP44对核盘菌感染有响应，其异源表达抑制ROS积累，从而增强拟南芥对核盘菌的抗性。因此，BnaC07.GLIP1在BnbZIP44下游发挥作用，并通过调节甘蓝型油菜中磷脂分子的产生和ROS稳态参与对核盘菌的抗性，为BnaC07.GLIP1在植物免疫中的潜在作用和功能机制以及改善油菜菌核病抗性育种提供了见解。
