烟草NtPXG基因克隆、表达特征及其功能分析

Cloning,expression and functional analysis of NtPXG gene in tobacco

【目的】克隆烟草氧脂素合成关键基因NtPXG,探究该基因对生物/非生物胁迫以及植物生长调节剂的响应,为解析NtPXG基因响应烟草花叶病毒(tobacco mosaic virus,TMV)的作用机制提供参考。【方法】利用同源克隆法克隆NtPXG基因,采用生物信息学方法分析基因结构与蛋白质性质;通过qRT-PCR对不同发育期的组织以及机械损伤、干旱、不同植物生长调节剂处理下烟草NtPXG基因的表达模式进行分析;利用叶盘转化法获得过表达NtPXG基因烟草后,进行基因功能分析。【结果】NtPXG基因长度为744 bp,共编码247个氨基酸;NtPXG基因的表达模式分析显示,其在烟草不同时期部位的表达量具有明显的组织和发育特异性,对不同的非生物胁迫和植物生长调节剂也会产生响应;NtPXG基因过表达烟草表现出明显的TMV抗性。【结论】烟草NtPXG基因不仅参与烟草的生长发育,同时也参与烟草对生物胁迫和非生物胁迫的响应,推测NtPXG基因可能通过植物生长调节剂信号响应外界的胁迫。通过烟草中过表达NtPXG基因;证明了NtPXG基因可通过JA信号通路抑制TMV的增殖。

【Objective】The NtPXG gene was cloned in order to investigate the response of the tobacco PXG gene to biotic and abiotic stresses,as well as to plant growth regulators.This will provide a reference for the mechanism of action of the NtPXG gene in response to tobacco mosaic virus(TMV).【Method】The relevant proteins were screened using the protein structural domain(pfarm:PLN02648),and the NtPXG gene with high expression was selected and cloned to obtain its coding region sequence,which was analysed and predicted using bioinformatics software.The expression pattern of the NtPXG gene was analysed by qRT-PCR at different developmental stages,in different organs,and under mechanical damage,drought,and different plant growth regulators treatments.The gene function was verified by overexpressing the NtPXG gene in tobacco by leaf disc transformation technology.【Result】The NtPXG gene was cloned by homologous cloning method.The gene structure and protein properties were analyzed by bioinformatics method.The expression patterns of NtPXG gene in tobacco were analyzed by qRT-PCR under different growth stage tissues,mechanical injury,drought and plant growth regulators.NtPXG gene overexpressed tobacco was obtained by leaf disc transformation and gene function analysis was performed.【Conclusion】NtPXG plays a role in the growth and development of tobacco,as well as in the response of tobacco to biotic and abiotic stresses.It is postulated that NtPXG may respond to external stresses through plant growth regulator signaling.Furthermore,overexpression of the NtPXG gene in tobacco demonstrated its inhibitory effect on TMV proliferation through JA signalling.