玉米热激转录因子基因ZmHSF-Like对逆境胁迫响应的信号途径

Signal Transduction Pathway of ZmHSF-Like Gene Responding to Different Abiotic Stresses

在前期对玉米热激转录因子基因ZmHSF-Like克隆、表达特性和亚细胞定位分析的基础上,对基因响应不同逆境胁迫的信号途径进行了研究。结果显示,H2O2处理能显著上调ZmHSF-Like基因的表达,42℃热激上调ZmHSF-Like基因的表达依赖于H2O2的存在,ABA上调基因表达部分依赖于H2O2的存在,而PEG-6000诱导基因表达不依赖于H2O2;外源Ca2+处理也能上调ZmHSF-Like基因表达,而螯合胞外钙离子并阻断其内流并不能降低上述逆境胁迫诱导的ZmHSF-Like基因的表达水平。表明ZmHSF-Like基因通过H2O2信号途径实现对热激和ABA胁迫的响应。在H2O2处理过程中,热激蛋白基因HSP704的表达与ZmHSF-Like基因的表达同步,可能是该途径中ZmHSF-Like结合的下游热激蛋白。单独钙离子诱导处理,热激蛋白基因HSP701、HSP702和HSPeu701的表达均与ZmHSF-Like基因的表达同步,可能是ZmHSF-Like基因响应Ca2+反应的下游结合蛋白。ZmHSF-Like通过与下游不同热激蛋白的结合实现对不同逆境胁迫的响应。

Based on our previous findings of cloning, expression characteristics, and subcellular-location of gene ZmHSF-Like, we analyzed the signal transduction pathway responding to different abiotic stresses. The results showed that the relative expression of gene ZmHSF-Like was up-regulated by H2O2. Up-regulating gene expression by heat shock of 42℃ was dependent on exis- tence of H2O2, while that PEG-6000 treatment was not. Up-regulating gene expression with ABA was partially dependent on H2O2. The relative expression of gene ZmHSF-Like was also up-regulated by Ca2＋, and chelating Ca2＋ with methyleneglycol-bis- （2-aminoethylether）-N,N,N＇,N＇-tetraacetic acid （EGTA） and blocking Ca2＋ intracellular transport with verapamil （Vp） did not decrease gene expression up-regulated by heat shock, PEG and ABA treatments. Those results illustrated that ZmHSF-Like rea- lizes the response to heat shock and ABA through H2O2 signal transduction pathway. While treated with H2O2, the HSP704 gene expression was synchronous with that of ZmHSF-Like gene, HSP704 might be the downstream binding protein of ZmHSF-Like in this signal transduction pathway. HSP701, HSP702, and HSPeu701 had the synchronous gene expression with that of ZmHSF-Like gene after Ca2＋ treatment, suggesting that they are the downstream binding proteins of ZmHSF-Like responding to Ca2＋. These results further indicated that ZmHSF-Like makes response to different stresses through binding different HSPs.