褐飞虱卵巢SOD酶对高温胁迫的响应及作用机理研究

High temperature stress can significantly affect structure and development of insect ovary, but defense enzymes play an important role in protecting ovary of insect from high temperature stress. The highest activity of defense enzymes is super oxide dismutase (SOD) enzyme. However, the response and action mechanism of SOD enzyme to high temperature stress is poorly elucidated at present. The brown planthopper, Nilaparvata lugens Stål is a major insect pest of rice in China, even in South-east Asia and East Asia. Although our research has been pointed out that high temperature stress can significantly affect SOD enzyme activity of N. lugens, the response and action mechanism of SOD enzyme to high temperature need further understand carefully. Through ovarian dissection and kits, the SOD enzyme activity will be analysed under high temperature stress to clarify the sensitive period of N. lugens and the correlation of SOD enzyme activity and high temperature stress. Meanwhile, RT-qPCR and RNAi technologies will be used to reveal action mechanisms of SOD enzyme that plays roles in protecting ovary of N. lugens from high temperature stress. These results will reveal the response and action mechanism of SOD enzyme to high temperature stress, and this study contributes to provide a theoretical basis for reproductive strategies and migration of N. lugens under environment stess.

高温胁迫能显著影响昆虫卵巢的结构和发育，昆虫卵巢的抗逆性保护酶在保护卵巢免受高温胁迫伤害起到了重要作用。抗逆性保护酶中超氧化物歧化酶活性（SOD）最高，但是尚未阐明昆虫卵巢SOD酶对高温胁迫的响应及作用机理。基于前期研究发现高温胁迫能引起褐飞虱卵巢SOD酶活性显著变化，本项目组通过试剂盒和卵巢解剖方法解析褐飞虱卵巢SOD酶感受高温胁迫的敏感期，验证SOD酶活性与高温强度的相关性；采用RT-qPCR方法研究高温胁迫下SOD酶基因的相对表达量；同时结合RNAi技术阐明SOD酶基因在高温胁迫下对卵巢卵黄原蛋白等生理生化的影响，以及高温胁迫下卵细胞发育等卵巢发育的影响，揭示褐飞虱卵巢SOD酶在高温胁迫下的作用机理。本项目旨在揭示昆虫卵巢SOD酶对高温胁迫的响应及作用机理，其研究结果也可为解析褐飞虱繁殖策略和在逆境条件下迁飞研究提供科学依据。

高温胁迫能显著影响昆虫卵巢的结构和发育，超氧化物歧化酶活性（SOD）在保护卵巢免受高温胁迫伤害起到了重要作用。本项目组通过试剂盒和卵巢解剖方法解析了褐飞虱不同龄期和刚羽化的长翅雌虫经30、33、36、39、42°C条件处理羽化后卵巢SOD酶活性以及感受高温胁迫的敏感期；并采用RT-qPCR方法研究高温胁迫下sod基因和Nlvg基因的相对表达量。研究结果表明：褐飞虱低龄若虫（1st、2nd和3rd）经各温度处理羽化后卵巢SOD酶活性变化不大，其活性范围在20.29~28.30 u/mg之间；褐飞虱高龄若虫（4th和5th）和成虫卵巢SOD酶活性较低龄若虫（1st、2nd和3rd）更为敏感，且SOD酶活性随高温胁迫的增强而升高，且存在显著的相关性。30、33、36、39和42°C高温处理1-3龄褐飞虱若虫，对羽化后卵巢Vg含量没有影响；但是能显著降低4龄和5龄羽化后，及长翅雌虫卵巢Vg含量，Vg含量随温度升高呈下降趋势，且对4龄若虫影响尤为明显，经42°C处理羽化后Vg含量仅为16.82mg/g。RT-qPCR试验结果表明：高温胁迫对褐飞虱低龄若虫（1st、2nd和3rd）卵巢sod基因和Nlvg基因相对表达量均无显著影响；但是，高龄若虫（4th和5th）和成虫卵巢sod基因相对表达量随随高温胁迫的增强而升高，42°C处理后，4th、5th和长翅雌虫卵巢SOD酶相对表达量分别达到4.35倍、6.62倍和6.77倍；但是Nlvg酶相对表达量随温度升高有下降的趋势，其中4th若虫尤为明显，42°C条件下褐飞虱卵巢Nlvg酶相对表达量下调了16.70%。本项目旨在揭示昆虫卵巢SOD酶对高温胁迫的响应及作用机理，其研究结果也可为解析褐飞虱繁殖策略和在逆境条件下迁飞研究提供科学依据。