Effects Of Exogenous Salicylic Acid And Jasmonic Acid On The Defense Response Of Bt Corn And Conventional Corn

Bt corn is one of the large-scale commercialized transgenic crops around the world.It is increasingly clear that the complementary durable approaches for pest control,which combine the endogenous defense of the crop with the introduction of foreign genes,are promisingly alternative strategies for pest resistance management and the next generation of insect-resistant transgenic crops.In the present study,we tested the Bt protein content,defense chemicals(DIMBOA and total phenol)contents,defense enzymes(polyphenol oxidase,peroxidase,catalase and superoxide dismutase)activities changes in both leaves and roots of Bt corn and conventional corn,which in the period of corn lobes by inducing 2.5 mM salicylic acid and 100 ?M jasmonic acid to aboveground part,inducing 1.0 mM salicylic acid and 1.0 ?M jasmonic acid to belowground part after 24 h.The objectives were to study the effect of chemical defense in Bt corn and conventional corn and the interactions between Bt genes and exogenous chemicals-mediated induced defense,in the hope of further providing some scientific bases for the comprehensive management of Bt crop's resistance.The main results are as follows.(1)Induced by 2.5 mM salicylic acid to the aboveground part,the leaf inductive defense response in Bt corn 5422 CBCL is stronger than that in conventional corn,and the root systematic inductive defense response in Bt corn 5422 CBCL is stronger than that in conventional corn 5422 and Bt corn 5422Bt1.After the aboveground part of Bt corn and conventional corn was treated by SA,the leaf polyphenol oxidase activity of conventional corn 5422 increased significantly;leaf Bt protein content and peroxidase activity of Bt corn 5422Bt1 increased significantly;leaf polyphenol oxidase and peroxidase activity of Bt corn 5422 CBCL increased significantly.After the aboveground part was treated by SA,the root polyphenol oxidase and peroxidase activity of conventional corn 5422 increased significantly and systematically;root polyphenol oxidase and catalase activity of Bt corn 5422Bt1 increased significantly and systematically;root DIMBOA content and polyphenol oxidase,peroxidase,catalase,superoxide dismutase activity of Bt corn 5422 CBCL increased significantly and systematically.(2)Induced by 1.0 mM salicylic acid to the belowground part,the root inductive defense response in Bt corn 5422 CBCL is weaker than that in conventional corn 5422 and Bt corn 5422Bt1,and the leaf systematic inductive defense response in both Bt corn types and conventional corn.After the belowground part of Bt corn and conventional corn was treated by SA,the root DIMBOA,total phenol content and polyphenol oxidase,peroxidase,superoxide dismutase activity of conventional corn 5422 increased significantly;root DIMBOA content and polyphenol oxidase,peroxidase,catalase,superoxide dismutase activity of Bt corn 5422Bt1 increased significantly;root polyphenol oxidase and catalase activity of Bt corn 5422 CBCL increased significantly.After the belowground part was treated by SA,the leaf total phenol content and polyphenol oxidase,peroxidase,catalase activity of conventional corn 5422 increased significantly and systematically;leaf Bt protein content and polyphenol oxidase,peroxidase activity of Bt corn 5422Bt1 increased significantly and systematically;leaf Bt protein content and polyphenol oxidase,peroxidase,superoxide dismutase activity of Bt corn 5422 CBCL increased significantly and systematically.(3)Induced by 100 ?M jasmonic acid to the aboveground part,the leaf inductive defense response in Bt corn 5422Bt1 is stronger than that in conventional corn,and the root systematic inductive defense response in conventional corn is stronger than that in Bt corn.After the aboveground part of Bt corn and conventional corn was treated by JA,the leaf polyphenol oxidase and catalase activity of conventional corn 5422 increased significantly;leaf Bt protein content and polyphenol oxidase,peroxidase activity of Bt corn 5422Bt1 increased significantly;leaf polyphenol oxidase,peroxidase,catalase activity of Bt corn 5422 CBCL increased significantly.After the aboveground part was treated by JA,the root polyphenol oxidase and peroxidase activity of conventional corn 5422 increased significantly and systematically.(4)Induced by 1.0 ?M jasmonic acid to the belowground part,the root inductive defense response in Bt corn 5422Bt1 is stronger than that in conventional corn 5422 and Bt corn 5422 CBCL,the leaf systematic inductive defense response in Bt corn 5422 CBCL is weaker than that in conventional corn 5422 and Bt corn 5422Bt1.After the belowground part of Bt corn and conventional corn was treated by JA,the root polyphenol oxidase and peroxidase activity of Bt corn 5422Bt1 increased significantly.After the belowground part was treated by JA,the leaf DIMBOA content and polyphenol oxidase,peroxidase,catalase activity of conventional corn 5422 increased significantly and systematically;leaf Bt protein content and polyphenol oxidase,peroxidase,catalase activity of Bt corn 5422Bt1 increased significantly and systematically;leaf polyphenol oxidase and peroxidase activity of Bt corn 5422 CBCL increased significantly and systematically.Therefore,in the process of exogenous salicylic acid and jasmonic acid induced defense response,there is a synergistic effect between the Bt gene introduction and inductive defense response in corn.