Xinbin Gao1, Pei Guo1, Zhiyuan Wang1, Chunhua Chen2, Zhonghai Ren3. 1. State Key Laboratory of Crop Biology, Shandong Collaborative Innovation Center of Fruit and Vegetable Quality and Efficient Production, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops in Huang-Huai Region, College of Horticultural Science and Engineering, Shandong Agricultural University, Ministry of Agriculture, Tai'an, 271018, Shandong, China. 2. State Key Laboratory of Crop Biology, Shandong Collaborative Innovation Center of Fruit and Vegetable Quality and Efficient Production, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops in Huang-Huai Region, College of Horticultural Science and Engineering, Shandong Agricultural University, Ministry of Agriculture, Tai'an, 271018, Shandong, China. chenchunhua@sdau.edu.cn. 3. State Key Laboratory of Crop Biology, Shandong Collaborative Innovation Center of Fruit and Vegetable Quality and Efficient Production, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops in Huang-Huai Region, College of Horticultural Science and Engineering, Shandong Agricultural University, Ministry of Agriculture, Tai'an, 271018, Shandong, China. zhren@sdau.edu.cn.
Abstract
MAIN CONCLUSION: We discovered a potential defense pathway of cucumber to downy mildew. The signaling that activates the pathways of ROS and lignin accumulation may play an important role in the defense response. Many resistance genes were identified by transcriptome analysis. Downy mildew (DM), caused by Pseudoperonospora cubensis, is one of the most destructive diseases and causes severe yield losses of cucumber. However, the genes and pathways involved in regulating DM resistance were still poorly understood. In our study, we observed that the highly sensitive inbred line 53 (IL53) exhibited more severe disease symptoms than the highly resistant inbred line 51 (IL51) under P. cubensis infection. Furthermore, lignin, limiting the germination and extension of P. cubensis, and H2O2, as a signaling molecule during the resistant process, were both shown to increase, indicating that the signaling that activates these pathways might be responsible for the resistance divergence between IL51 and IL53. Transcriptome analysis, using the resistant and susceptible pools in F2 populations with IL51 and IL53 as parents, showed that a series of differentially expressed genes was involved in multiple functions of defense response: pathogen-associated molecular pattern recognition, signal transduction, reactive oxygen species and lignin accumulation, and transcription regulators. Combining physiological data with transcriptomes, we predicted a potential molecular mechanism of cucumber resistance to DM. Our research provided a foundation for further studies on the mechanism of cucumber resistance to DM.
MAIN CONCLUSION: We discovered a potential defense pathway of cucumber to downy mildew. The signaling that activates the pathways of ROS and lignin accumulation may play an important role in the defense response. Many resistance genes were identified by transcriptome analysis. Downy mildew (DM), caused by Pseudoperonospora cubensis, is one of the most destructive diseases and causes severe yield losses of cucumber. However, the genes and pathways involved in regulating DM resistance were still poorly understood. In our study, we observed that the highly sensitive inbred line 53 (IL53) exhibited more severe disease symptoms than the highly resistant inbred line 51 (IL51) under P. cubensis infection. Furthermore, lignin, limiting the germination and extension of P. cubensis, and H2O2, as a signaling molecule during the resistant process, were both shown to increase, indicating that the signaling that activates these pathways might be responsible for the resistance divergence between IL51 and IL53. Transcriptome analysis, using the resistant and susceptible pools in F2 populations with IL51 and IL53 as parents, showed that a series of differentially expressed genes was involved in multiple functions of defense response: pathogen-associated molecular pattern recognition, signal transduction, reactive oxygen species and lignin accumulation, and transcription regulators. Combining physiological data with transcriptomes, we predicted a potential molecular mechanism of cucumber resistance to DM. Our research provided a foundation for further studies on the mechanism of cucumber resistance to DM.
Authors: Bishwo N Adhikari; Elizabeth A Savory; Brieanne Vaillancourt; Kevin L Childs; John P Hamilton; Brad Day; C Robin Buell Journal: PLoS One Date: 2012-04-24 Impact factor: 3.240
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