外源茉莉酸处理对Bt玉米直接防御物质含量及其相关基因表达的影响

 【目的】Bt（Bacillus thuringiensis）玉米（Zea mays L.）是全球商品化程度最快的抗虫转基因作物之一，协调利用其内在防御机制和人工导入抗性是目标害虫抗性风险综合管理和第2代抗虫转基因作物培育的主要策略之一。【方法】采用基因表达分析、化学物质分析和ELISA蛋白定量方法，研究外施信号物质茉莉酸对Bt玉米34B24 (Mon810)及其同源常规玉米34B23幼苗叶片直接防御物质含量及其相关基因表达的影响。【结果】外源茉莉酸处理能诱导34B24和34B23处理叶（第1叶）中LOX、PR-2a、MPI和PR-1基因的表达，第1叶丁布含量分别比对照增加63％和18％、总酚含量分别增加24％和12％。茉莉酸处理使34B24第1叶中的Bt蛋白含量增加了13%，但第2叶中的显著降低了27%。与34B23相比，茉莉酸对34B24的诱导作用更强，并具有系统性。【结论】人工外施茉莉酸的条件下，Bt玉米人工导入抗性（Bt基因）和自身化学防御过程之间的互作关系是协同的。

Effects of Exogenous Jasmonic Acid on Concentrations of Direct Defense Chemicals and Expression of Related Genes in Bt (Bacillus thuringiensis) Corn (Zea mays)

【OBJECTIVE】Bt corn is one of the top three large-scale commercialized transgenic pest resistance crops around the world. It is increasingly clear that the complementary durable pest control approaches, which combine the endogenous defense of the crop and the foreign genes introduction, are the promising alternative strategies for the target pest resistance management and the next generation of insect-resistant transgentic crops.【METHOD】In the present study, we tested the inducible effects of exogenous jasmonic acid (JA) on direct defense chemicals content, Bt protein concentration and related genes expression in the leaves of Bt corn cultivar 34B24 and Non-Bt cultivar 34B23 by chemical analysis, ELISA and RT-PCR.【RESULTS】The results shown that the expression of LOX,PR-2a,MPI and PR-1 genes in the treated leaf (first leaf ) was promoted by exogenous JA both in 34B24 and 34B23. As compared with the control, the concentration of DIMBOA in the treated leaf was significantly increased by 63% and 18% for 34B24 and 34B23 respectably. The total phenolic acid was also increased by 24% and 12% for 34B24 and 34B23 either. The Bt protein content of 34B24 in the treated leaf was increased by 13%, but decreased by 23% in the second leaf. The induced response of 34B24 is in a systemic way and much stronger than that of 34B23.【CONCLUSION】Those findings indicated that there is a synergistic interactions between Bt gene and jasmonic acid mediate induced defense in Bt corn.