马铃薯StMAPK4响应低温胁迫的功能解析

Functional analysis of StMAPK4 in response to low temperature stress in potato

马铃薯易受低温危害,造成减产。MAPK基因广泛参与多种环境胁迫,研究发现其参与低温调控。为探究马铃薯StMAPK4在响应低温胁迫过程中的功能,本研究以马铃薯栽培品种‘Atlantic’为试验材料,分析其在低温(4℃)胁迫下不同时间点在马铃薯根茎叶中的表达特性,并对StMAPK4基因进行生物信息学分析及对其编码的蛋白进行亚细胞定位分析,构建StMAPK4的过表达和RNAi干扰表达载体,转化马铃薯获得转基因植株,并分析了在4℃处理下非转基因(NT)、过表达和RNAi干扰表达转基因植株的超氧化物歧化酶(SOD)和过氧化物酶(POD)活性、脯氨酸(Pro)和丙二醛(MDA)含量的变化。结果显示,StMAPK4蛋白的等电点为4.97,属于酸性蛋白,该蛋白定位于细胞核和细胞膜;低温胁迫下,StMAPK4在根茎叶中的表达量显著升高;StMAPK4过表达植株的SOD、POD活性和脯氨酸含量较NT植株明显升高,而MDA含量明显降低;StMAPK4干扰表达植株的SOD、POD活性和脯氨酸含量较NT植株明显降低,而MDA含量明显升高;通过表型观察发现,非转基因和RNAi干扰表达植株的叶片萎蔫严重,而过表达植株的叶片受影响较小。因此,过表达StMAPK4基因可以增强马铃薯植株对低温胁迫的耐受性。

Potato is vulnerable to low temperatures resulting in reduced yield production.MAPK gene is widely involved in a variety of environmental stress,and it has been detected to be involved in low temperature regulation.In this present study,to explore StMAPK4 function in response to low temperature stress,potato cultivar‘Atlantic’as the experimental material,the expression characteristics of StMAPK4 gene were analyzed in potato root,stem,and leaf at the different time under low temperature(4℃)stress.StMAPK4 gene was analyzed using bioinformatics and its encoded protein subcellular localization was assayed.StMAPK4 overexpression and RNA interference expression vectors were constructed and obtained transgenic potato plants.The activities of superoxide dismutase(SOD)and peroxidase(POD),and the contents of proline(Pro)and malondialdehyde(MDA)in non-transgenic(NT),overexpressed and RNAi interfered transgenic plants were analyzed under 4℃.The results showed that the isoelectric point(pI)of StMAPK4 was 4.97 and it was acidic protein localized in the nucleus and cell membrane.The relative expression levels of StMAPK4 in roots,stems,and leaves significantly increased under low temperature stress.Compared with non-transgenic plants,the activities of SOD and POD and the content of proline in StMAPK4 overexpressed plants were significantly increased,while the content of MDA was significantly decreased.Compared with NT plants,the activities of SOD and POD,and the content of Pro in StMAPK4 overexpression plants were significantly decreased,while the content of MDA was significantly increased.Phenotypic observation revealed that the leaves of non-transgenic and RNAi interfered expression plants wilted seriously,while the leaves of overexpressed plants were less affected.In summary,the overexpression of StMAPK4 gene can enhance the tolerance of low temperature stress in potato plants.