抑制GhSAMS基因表达降低陆地棉对棉铃虫的抗性

Suppressed expression of GhSAMS gene reduced the Helicoverpa armigera resistance in Gossypium hirsutum

【目的】探究陆地棉S-腺苷甲硫氨酸合成酶(S-adenosylmethionine synthetase,SAMS)基因在棉花对棉铃虫抗性响应中的功能。【方法】利用实时荧光定量聚合酶链式反应(real-time quantitative polymerase chain reaction,qRT-PCR)分析GhSAMS基因在棉铃虫取食下的表达模式。利用病毒诱导的基因沉默(virus-induced gene silencing,VIGS)技术抑制GhSAMS基因的表达,通过分析棉铃虫的生长发育(体重和体长的变化量)、取食偏好性以及棉花叶片受害等级等,初步探究GhSAMS基因的抗虫功能。【结果】qRT-PCR结果表明,棉花叶片中的GhSAMS基因在棉铃虫取食后表达量增加。利用VIGS技术获得了pTRV2::GhSAMS沉默棉株。与饲喂野生型棉花叶片的棉铃虫相比,饲喂pTRV2::GhSAMS棉花叶片的棉铃虫生长发育更快;棉铃虫对pTRV2::GhSAMS棉花叶片表现出更强的取食偏好;二氨基联苯胺(3,3’-diaminobenzidine,DAB)染色结果分析表明,与野生型棉花相比,沉默GhSAMS基因的棉花叶片细胞中H_(2)O_(2)的累积量增多。【结论】抑制GhSAMS基因表达降低了陆地棉对棉铃虫的抗性,GhSAMS可作为提高棉花对棉铃虫抗性的候选基因。

[Objective]This research aims to investigate the function of S-adenosylmethionine synthetase(SAMS)gene in the resistant response to Helicoverpa armigera in Gossypium hirsutum.[Method]Real-time quantitative polymerase chain reaction(qRT-PCR)was used to analyze the expression pattern of GhSAMS gene under the H.armigera attack.Virus-induced gene silencing(VIGS)technology was adopted to suppress the expression of GhSAMS gene.The insect-resistant function of GhSAMS gene was preliminally investigated by analyzing the growth and development(changes in body weight and body length)as well as feeding preference of H.armigera,and the damage profile of cotton leaves.[Result]qRT-PCR results showed that the expression level of GhSAMS gene was increased during H.armigera feeding process.Compared with those fed with wild-type(WT)cotton leaves,H.armigera fed with pTRV2::GhSAMS leaves grew and developed faster.And H.armigera exhibited stronger feeding preferences towards pTRV2::GhSAMS leaves.3,3'-diaminobenzidine(DAB)staining showed that pTRV2::GhSAMS cotton leaves accumulated more H_(2)O_(2)compared with WT cotton.[Conclusion]Inhibiting the expression of GhSAMS gene reduces the resistance of G.hirsutum to H.armigera,and GhSAMS can be used as a candidate gene to improve the cotton resistance to H.armigera.