Lee Sung Chul, Hwang Byung Kook
Laboratory of Molecular Plant Pathology, College of Life and Environmental Sciences, Korea University, Sungbuk-ku, Anam-dong, Seoul, Republic of Korea.
Plant Mol Biol. 2006 May;61(1-2):95-109. doi: 10.1007/s11103-005-6102-6.
Pepper SAR8.2 gene (CASAR82A) was previously reported to be locally or systemically induced in pepper plants by biotic and abiotic stresses. In this study, the physiological and molecular functions of the pepper SAR8.2 protein in the plant defense responses were investigated by generating Arabidopsis transgenic lines overexpressing the CASAR82A gene. The transgenic Arabidopsis plants grew faster than the wild-type plants, indicating that the CASAR82A gene was involved in plant development. The ectopic expression of CASAR82A in Arabidopsis was accompanied by the expression of the Arabidopsis pathogenesis-related (PR)-genes including AtPR-1, AtPR-4 and AtPR-5. CASAR82A overexpression enhanced the resistance against infections by Pseudomonas syringae pv. tomato, Fusarium oxysporum f.sp. matthiolae or Botrytis cinerea. The transgenic plants also exhibited increased NaCl and drought tolerance during all growth stages. Moreover, the methyl viologen test showed that the transgenic plants were tolerant to oxidative stress. The purified recombinant CASAR82A protein and crude protein extracts of the transgenic plants exhibited antifungal activity against some phytopathogenic fungi, indicating that the enhanced resistance of the transgenic plants to fungal pathogen infection may be due to the antifungal effect of SAR8.2 protein.
辣椒SAR8.2基因（CASAR82A）此前报道在辣椒植株中会被生物和非生物胁迫局部或系统诱导。在本研究中，通过构建过表达CASAR82A基因的拟南芥转基因株系，对辣椒SAR8.2蛋白在植物防御反应中的生理和分子功能进行了研究。转基因拟南芥植株比野生型植株生长更快，表明CASAR82A基因参与植物发育。CASAR82A在拟南芥中的异位表达伴随着拟南芥病程相关（PR）基因如AtPR - 1、AtPR - 4和AtPR - 5的表达。过表达CASAR82A增强了对丁香假单胞菌番茄致病变种、尖孢镰刀菌香石竹专化型或灰葡萄孢菌感染的抗性。转基因植株在所有生长阶段对NaCl和干旱的耐受性也有所提高。此外，甲基紫精试验表明转基因植株对氧化胁迫具有耐受性。纯化的重组CASAR82A蛋白和转基因植株的粗蛋白提取物对一些植物病原真菌表现出抗真菌活性，表明转基因植株对真菌病原体感染抗性增强可能归因于SAR8.2蛋白的抗真菌作用。
