巴西橡胶树HbEPSPS基因逆境响应功能解析

草甘膦除草剂的靶标酶为5-烯醇式丙酮莽草酸-3-磷酸合成酶(EPSPS)。为研究HbEPSPS基因在橡胶树中的逆境响应功能，分析其在草甘膦、机械伤害、白粉菌侵染和不同激素处理下的表达模式。结果表明：草甘膦、机械伤害和IAA处理诱导HbEPSPS显著上调；干旱、ABA、SA和ETH处理亦能诱导HbEPSPS显著上调；H2O2处理橡胶树叶片中HbEPSPS表达呈现双峰规律；白粉菌侵染叶片，HbEPSPS表达显著下调。不同部位表达分析结果表明，HbEPSPS基因在花中表达量最高，其次是树皮和叶，在胶乳中表达量最低。此结果表明，HbEPSPS基因在橡胶树草甘膦药害和激素信号响应中具有重要作用，为研究其在橡胶树抗逆机制中的作用奠定良好基础。

Functional Analysis of HbEPSPS in Stress Response in Rubber Tree (Hevea brasiliensis Muell. Arg.)

The target enzyme of herbicide Glyphosate is 5-enolpyruvylshikimate-3-phosphatesynthase (EPSPS). In order to study the function of HbEPSPS in stress response of rubber tree, we analyzed HbEPSPS expression patterns in rubber tree treated with glyphosate, mechanical wounding, powdery mildew infection and different hormones. Results show that glyphosate, mechanical wounding and IAA treatment induced significant upregulation of HbEPSPS; drought, ABA, SA and ETH treatment also upregulated HbEPSPS expression obviously. In rubber tree leaves treated with H2O2, HbEPSPS expression showed a bimodal pattern. Rubber tree leaves infected with powdery mildew had a significant downregulation of HbEPSPS expression. Expression analysis in different parts of rubber tree showed that HbEPSPS was most highly expressed in flower, followed by the bark and leaves, the lowest in latex. This study indicates that HbEPSPS plays an important role in the response to glyphosate phytotoxicity and hormone signal, which lay a good foundation for further study of the stress resistance mechanism in rubber tree.