Oh Sang-Keun, Jang Hyun A, Lee Sang Sook, Cho Hye Sun, Lee Dong-Hee, Choi Doil, Kwon Suk-Yoon
Department of Plant Science, College of Agriculture and Life Sciences, Seoul National University, Seoul 151-742, Republic of Korea.
Korea Research Institute of Bioscience & Biotechnology, Plant Systems Engineering Research Center, Daejeon 305-806, Republic of Korea.
J Plant Physiol. 2014 Jun 15;171(10):817-22. doi: 10.1016/j.jplph.2014.02.002. Epub 2014 Mar 4.
Homologs of the cytoplasmic protein kinase Pti1 are found in diverse plant species. A clear role of Pti1 in plant defense response has not been established. We identified a Pti1 homolog in cucumber (CsPti1-L). CsPti1-L expression was induced when cucumber plants were challenged with the fungal pathogen Sphaerotheca fuliginea or with salt treatment. CsPti1-L expression in cucumber leaves also was induced by methyl jasmonate, salicylic acid, and abscisic acid. CsPti1-L exhibited autophosphorylation activity and was targeted to the cytoplasm. Transgenic Nicotiana benthamiana expressing CsPti1-L exhibited greater cell death and increased ion leakage in response to the bacterial pathogen Pseudomonas syringae pv. tomato DC3000, resistance to Botrytis cinerea infection, and higher tolerance to salt stress. RT-PCR analysis of transgenic N. benthamiana overexpressing CsPti1-L revealed constitutive upregulation of multiple genes involved in plant-defense and osmotic-stress responses. Our results suggest a functional role for CsPti1-L as a positive regulator of pathogen-defense and salt-stress responses.
在多种植物物种中都发现了细胞质蛋白激酶Pti1的同源物。Pti1在植物防御反应中的明确作用尚未确定。我们在黄瓜中鉴定出一种Pti1同源物（CsPti1-L）。当黄瓜植株受到真菌病原体白粉菌或盐处理挑战时，CsPti1-L的表达会被诱导。黄瓜叶片中CsPti1-L的表达也会被茉莉酸甲酯、水杨酸和脱落酸诱导。CsPti1-L表现出自身磷酸化活性，并定位于细胞质。表达CsPti1-L的转基因本氏烟草对细菌病原体番茄丁香假单胞菌pv. tomato DC3000表现出更大的细胞死亡和离子渗漏增加、对灰霉病菌感染具有抗性以及对盐胁迫具有更高的耐受性。对过表达CsPti1-L的转基因本氏烟草进行RT-PCR分析发现，参与植物防御和渗透胁迫反应的多个基因组成型上调。我们的结果表明CsPti1-L作为病原体防御和盐胁迫反应的正调控因子具有功能作用。
