论文部分内容阅读
为明确外源Bt基因的导入对玉米抗病性的影响,本研究以转Bt基因玉米株系和其受体亲本郑58为材料,比较了接种丝黑穗病菌(Sphacelotheca reiliana(Kühn)Clint.)后转Bt基因玉米防御酶系统、激素水平及次生代谢的变化情况,探讨了转Bt基因玉米对病害抗性的相关生理机制。研究结果表明:接种丝黑穗病菌后,转Bt基因玉米在吐丝期的发病率达到24%,单穗总粒重较对照下降18%,百粒重下降12%,而郑58发病率为15%,产量与对照无显著差异。转Bt基因玉米的超氧化物歧化酶(SOD),过氧化物酶(POD),过氧化氢酶(CAT)等防御酶活性比郑58玉米在抵御病害侵染时表现的较弱,丙二醛(MDA)含量显著增加,膜脂过氧化程度较为严重,这可能是造成转Bt基因玉米产量下降明显的原因之一。生育前期生长素(IAA)、赤霉素(GA)、玉米素核苷(ZR)含量明显下降,而脱落酸(ABA)含量明显升高使得转Bt基因玉米生长受限,同样造成产量的显著下降。此外,在各个生育时期体内的单宁和总酚的含量都低于其受体郑58玉米,生化防御机制受限也可能造成抗病性的降低,进而产量下降。
In order to clarify the effect of exogenous Bt gene introduction on the disease resistance of maize, the transgenic Bt corn and its parent Zheng 58 were compared to inoculate with Sphacelotheca reiliana (Kühn) Clint. ) To the Bt gene maize defensive enzyme system, hormone levels and secondary metabolism changes in transgenic Bt maize disease resistance related physiological mechanisms. The results showed that the incidence of Bt transgenic corn in silking stage was 24% after inoculation with S. gossypii, the total grain weight per panicle decreased by 18% and the weight of 100 kernels decreased by 12%, while the incidence of Zheng 58 was 15%, no significant difference in yield and control. The activities of SOD, POD, CAT and other defense enzymes in transgenic Bt corn were weaker than those in Zheng 58, Aldehyde (MDA) content increased significantly, membrane lipid peroxidation is more serious, which may be caused by transgenic Bt maize yield decreased significantly one of the reasons. The content of auxin (IAA), gibberellin (GA) and zeatin riboside (ZR) decreased significantly in early growth period, while the content of abscisic acid (ABA) increased significantly and the growth of transgenic Bt corn was also restricted decline. In addition, the contents of tannin and total phenols were lower than that of their receptor Zheng 58 maize in each growth period. The limited biochemical defense mechanism may also lead to the decrease of disease resistance and the decrease of yield.