Li Fei, Zhang Yi, Tian Chang, Wang Xinhui, Zhou Lijie, Jiang Jiafu, Wang LiKai, Chen Fadi, Chen Sumei
State Key Laboratory of Crop Genetics and Germplasm Enhancement / Key Laboratory of Flower Biology and Germplasm Innovation, Ministry of Agriculture and Rural Affairs / Key Laboratory of Biology of Ornamental Plants in East China, National Forestry and Grassland Administration / College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China.
New Phytol. 2023 Mar;237(5):1776-1793. doi: 10.1111/nph.18643. Epub 2022 Dec 25.
Lignin is a major component of plant cell walls and a conserved basic defense mechanism in higher plants deposited in response to aphid infection. However, the molecular mechanisms of lignin biosynthesis in response to aphid infection and the effect of lignin on aphid feeding behavior remain unclear. We report that 4-Coumarate:coenzyme A ligase 2 (Cm4CL2), a gene encoding a key enzyme in the lignin biosynthesis pathway, is induced by aphid feeding, resulting in lignin deposition and reduced aphid attack. Upstream regulator analysis showed that the expression of Cm4CL2 in response to aphid feeding was directly upregulated by CmMYB15-like, an SG2-type R2R3-MYB transcription factor. CmMYB15-like binds directly to the AC cis-element in the promoter region of Cm4CL2. Genetic validation demonstrated that CmMYB15-like was induced by aphid infection and contributed to lignin deposition and cell wall thickening, which consequently enhanced aphid resistance in a Cm4CL2-dependent manner. This study is the first to show that the CmMYB15-like-Cm4CL2 module regulates lignin biosynthesis in response to aphid feeding.
木质素是植物细胞壁的主要成分，也是高等植物中一种保守的基本防御机制，在受到蚜虫感染时会沉积下来。然而，木质素生物合成对蚜虫感染的分子机制以及木质素对蚜虫取食行为的影响仍不清楚。我们报告称，4-香豆酸：辅酶A连接酶2（Cm4CL2），一种编码木质素生物合成途径关键酶的基因，受蚜虫取食诱导，导致木质素沉积并减少蚜虫侵害。上游调控因子分析表明，响应蚜虫取食时Cm4CL2的表达由CmMYB15-like直接上调，CmMYB15-like是一种SG2型R2R3-MYB转录因子。CmMYB15-like直接结合到Cm4CL2启动子区域的AC顺式元件上。遗传验证表明，CmMYB15-like受蚜虫感染诱导，并有助于木质素沉积和细胞壁加厚，从而以Cm4CL2依赖的方式增强蚜虫抗性。这项研究首次表明，CmMYB15-like-Cm4CL2模块调节响应蚜虫取食的木质素生物合成。
