National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei, PR China.
J Exp Bot. 2011 Nov;62(15):5607-21. doi: 10.1093/jxb/err245. Epub 2011 Aug 23.
The incompatible pathosystem between resistant cotton (Gossypium barbadense cv. 7124) and Verticillium dahliae strain V991 was used to study the cotton transcriptome changes after pathogen inoculation by RNA-Seq. Of 32,774 genes detected by mapping the tags to assembly cotton contigs, 3442 defence-responsive genes were identified. Gene cluster analyses and functional assignments of differentially expressed genes indicated a significant transcriptional complexity. Quantitative real-time PCR (qPCR) was performed on selected genes with different expression levels and functional assignments to demonstrate the utility of RNA-Seq for gene expression profiles during the cotton defence response. Detailed elucidation of responses of leucine-rich repeat receptor-like kinases (LRR-RLKs), phytohormone signalling-related genes, and transcription factors described the interplay of signals that allowed the plant to fine-tune defence responses. On the basis of global gene regulation of phenylpropanoid metabolism-related genes, phenylpropanoid metabolism was deduced to be involved in the cotton defence response. A closer look at the expression of these genes, enzyme activity, and lignin levels revealed differences between resistant and susceptible cotton plants. Both types of plants showed an increased level of expression of lignin synthesis-related genes and increased phenylalanine-ammonia lyase (PAL) and peroxidase (POD) enzyme activity after inoculation with V. dahliae, but the increase was greater and faster in the resistant line. Histochemical analysis of lignin revealed that the resistant cotton not only retains its vascular structure, but also accumulates high levels of lignin. Furthermore, quantitative analysis demonstrated increased lignification and cross-linking of lignin in resistant cotton stems. Overall, a critical role for lignin was believed to contribute to the resistance of cotton to disease.
采用对棉花具有抗性的品种（Gossypium barbadense cv. 7124）和棉花黄萎病菌菌株 V991 组成的不亲和共生体系，通过 RNA-Seq 研究病原菌接种后棉花转录组的变化。通过将标签映射到组装的棉花连续体，共检测到 32774 个基因，其中鉴定到 3442 个防御应答基因。差异表达基因的基因聚类分析和功能分配表明转录组具有显著的复杂性。对具有不同表达水平和功能分配的选定基因进行定量实时 PCR（qPCR），以证明 RNA-Seq 可用于研究棉花防御反应过程中的基因表达谱。详细阐明富含亮氨酸重复受体样激酶（LRR-RLKs）、植物激素信号相关基因和转录因子的反应，描述了允许植物精细调节防御反应的信号相互作用。基于苯丙烷代谢相关基因的全局基因调控，推断苯丙烷代谢参与了棉花的防御反应。对这些基因的表达、酶活性和木质素水平进行更深入的研究，揭示了抗性和感病棉花之间的差异。接种黄萎病菌后，两种类型的植物均表现出木质素合成相关基因表达水平的增加和苯丙氨酸解氨酶（PAL）和过氧化物酶（POD）酶活性的增加，但抗性品系的增加更大且更快。木质素的组织化学分析表明，抗性棉花不仅保留其维管束结构，而且还积累高水平的木质素。此外，定量分析表明抗性棉花茎中的木质素发生了增加的木质化和交联。总的来说，木质素的关键作用被认为有助于棉花对疾病的抗性。
