异三聚体G蛋白参与小麦抗叶锈病反应的研究

 【目的】研究异三聚体G蛋白是否参与小麦抗叶锈病反应的过程，为更深入地了解小麦抗叶锈病的反应机制奠定基础。【方法】用异三聚体G蛋白的效应剂处理离体培养的小麦叶片后接种叶锈菌观察侵染型的变化。测量经异三聚体G蛋白的效应剂诱导后防卫反应酶活性值，观察变化趋势。另外用半定量RT-PCR方法检测接种毒性菌株和无毒性菌株后异三聚体G蛋白α亚基基因的表达情况。【结果】用激活剂（GTPγS、Mastoparan-7）处理后明显可以推迟叶片发病,而抑制剂百日咳毒素（PTX）作用不明显。用G蛋白的激活剂（GTPγS、Mastoparan-7）处理后防卫反应酶的活性升高，而用抑制剂百日咳毒素（PTX）处理后24 h再接种无毒性叶锈菌菌株，防卫反应酶的活性却无明显的变化。无毒性叶锈菌菌株可以诱导叶片中G蛋白基因表达量升高，毒性菌株抑制G蛋白基因的表达。【结论】异三聚体G蛋白可能参与了小麦抗叶锈病的反应过程。

Involvement of the Heterotrimeric G Protein in the Defense Responses of Wheat to Puccinia triticina

【Objective】 The objective of the paper is to investigate if the heterotrimeric G protein is involved in the defense responses of wheat to Puccinia triticina. 【Method】 After 24h of treating the detached-leaf with the regulators of heterotrimeric G protein (activator and inhibitor), the infection types at the 9th day were evaluated by inoculating Puccinia triticina. The activities of defensive enzymes POD (peroxidase), PAL (phenylalanine ammonia lyase), and PPO (polyphenoloxidase) were tested after the leaves induced by the regulators of heterotrimeric G protein. In addition, the expression of the heterotrimeric G protein α subunit gene was evaluated by semi-quantitative RT-PCR after inoculating the virulent race and avirulent race, respectively. 【Result】 The activators delayed the disease occurrence, however the inhibtor had no effect on the development of wheat leaf rust. The activity of defensive enzymes was enhanced after treating with activators GTPγS and Mastoparan-7. Inhibitor PTX (pertussis toxin) inhibited the enhancement of defensive enzymes induced by the avirulent race. The avirulent race enhanced the expresstion of the heterotrimeric G protein α subunit gene, but virulent race inhibited its expression. 【Conclusion】 The results suggest that G protein may play a role in the resistance to Puccinia triticina.