Feng Yuanjiao, Wang Xiaoyi, Du Tiantian, Shu Yinghua, Tan Fengxiao, Wang Jianwu
Key Laboratory of Agro-Environment in the Tropics, Ministry of Agriculture, South China Agricultural University, Guangzhou 510642, China.
Guangdong Provincial Key Laboratory of Eco-Circular Agriculture, South China Agricultural University, Guangzhou 510642, China.
Plants (Basel). 2022 Aug 20;11(16):2162. doi: 10.3390/plants11162162.
Bt () corn is one of the top three large-scale commercialized anti-insect transgenic crops around the world. In the present study, we tested the Bt protein content, defense chemicals contents, and defense enzyme activities in both the leaves and roots of Bt corn varieties 5422Bt1 and 5422CBCL, as well as their conventional corn 5422 seedlings, with two fully expanded leaves which had been treated with 2.5 mM exogenous salicylic acid (SA) to the aboveground part for 24 h. The result showed that the SA treatment to the aboveground part could significantly increase the polyphenol oxidase activity of conventional corn 5422, the Bt protein content, and peroxidase activities of Bt corn 5422Bt1, as well as the polyphenol oxidase and peroxidase activity of Bt corn 5422CBCL in the leaves. In the roots, the polyphenol oxidase and peroxidase activity of conventional corn 5422, the polyphenol oxidase and superoxide dismutase activities of Bt corn 5422Bt1, the DIMBOA (2,4-dihydroxy-7-methoxy-2H, 1, 4-benzoxazin-3 (4H)-one) content, and four defense enzymes activities of Bt corn 5422CBCL were systematically increased. These findings suggest that the direct effect of SA application to aboveground part on the leaf defense responses in Bt corn 5422CBCL is stronger than that in non-Bt corn. Meanwhile, the systemic effect of SA on the root defense responses in Bt corn 5422CBCL is stronger than that in conventional corn 5422 and Bt corn 5422Bt1. It can be concluded that the Bt gene introduction and endogenous chemical defense responses of corns act synergistically during the SA-induced defense processes to the aboveground part. Different transformation events affected the root defense response when the SA treatment was applied to the aboveground part.
转Bt基因玉米是全球三大大规模商业化种植的抗虫转基因作物之一。在本研究中，我们检测了转Bt基因玉米品种5422Bt1和5422CBCL及其常规玉米5422幼苗（两片完全展开叶）在地上部分用2.5 mM外源水杨酸（SA）处理24小时后，叶片和根中的Bt蛋白含量、防御性化学物质含量以及防御酶活性。结果表明，地上部分进行SA处理可显著提高常规玉米5422的多酚氧化酶活性、转Bt基因玉米5422Bt1的Bt蛋白含量和过氧化物酶活性，以及转Bt基因玉米5422CBCL叶片中的多酚氧化酶和过氧化物酶活性。在根中，常规玉米5422的多酚氧化酶和过氧化物酶活性、转Bt基因玉米5422Bt1的多酚氧化酶和超氧化物歧化酶活性、转Bt基因玉米5422CBCL的DIMBOA（2,4 - 二羟基 - 7 - 甲氧基 - 2H,1,4 - 苯并恶嗪 - 3(４H)-酮）含量以及四种防御酶活性均有系统性增加。这些发现表明，地上部分施用SA对转Bt基因玉米5422CBCL叶片防御反应的直接影响强于非转基因玉米。同时，SA对转Bt基因玉米5422CBCL根防御反应的系统影响强于常规玉米5422和转Bt基因玉米5422Bt1。可以得出结论，玉米中Bt基因的导入与内源化学防御反应在SA诱导的地上部分防御过程中协同作用。当对地上部分进行SA处理时，不同的转化事件会影响根的防御反应。
