BTH诱导黄瓜幼苗对霜霉病的抗性与细胞壁HRGP和木质素含量的关系

【目的】苯并噻二唑（BTH）对黄瓜幼苗霜霉病的诱导抗性与苯丙氨酸解氨酶(PAL)活性、过氧化物酶（POD）活性、木质素和富含羟脯氨酸糖蛋白(HRGP)含量的关系。【方法】用比色法对BTH诱导或接种霜霉菌的植株进行PAL和POD活性以及木质素和HRGP含量的测定。【结果】BTH不仅能提高黄瓜幼苗对霜霉病的抗性，而且明显提高了PAL和POD的活性以及木质素和HRGP的含量。BTH诱导处理和霜霉菌侵染黄瓜叶片，细胞壁中HRGP的积累与木质素的沉积在时间进程中表现出明显的同步性。【结论】HRGP的积累和细胞壁的木质化与黄瓜对霜霉病的抗性反应有关，是寄主抗病反应的生化机制之一。

The Relationship Between BTH-Induced Resistance to Downy Mildew in Cucumber Seedlings and Content of HRGP and Lignin in Cell Wall

【Objective】 The relationship between the activity of phenylalanine ammonia lyase (PAL) or proxidase (POD) and the content of hydroxyproline-rich glycoprotein (HRGP) or lignin and benzothiadiazole (BTH) induced resistance to downy mildew in cucumber seedlings was studied. 【Method】Cucumber seedlings at two-leaf stage were inoculated with spores of Pseudoperonospora cubensis f.sp.cucumerinum before or after treated with BTH. The activities of PAL and POD and the contents of HRGP and Lignin were measured with colorimetric method in the following days. 【Result】BTH treatment not only enhanced the resistance of seedlings to downy mildew, but also increased both enzyme activities and the contents of HRGP and lignin. The accumulation of HRGP and the deposition of lignin synchronized in cucumber leaves after infection of Psedoperonospora cubensis. 【Conclusion】The results suggest that the accumulation of HRGP and the deposition of lignin in cell wall are related to resistant reaction of cucumber to downy mildew, and it is considered a biochemical response of cucumber to downy mildew.