Transcriptomic Analysis of Maize Uncovers Putative Genes Involved in Metabolic Detoxification Under the Treatment of Four Herbicide Safeners

Herbicide safener have been widely used in agricultural production, but their specific mechanisms and causes of their chemical specificity remain unclear. In this study, we compared the effects of four safeners on the glutathione S-transferase (GST) activity, nicosulfuron metabolism and gene expression at the transcriptome level in maize. It was found that nicosulfuron degradation and GST activity in maize were accelerated by isoxadifen-ethyl and cyprosulfamide, but not by fenchlorazole-ethyl and mefenpyr-diethyl. Transcriptomic analysis showed that the number of genes induced by isoxadifen-ethyl and cyprosulfamide were larger than that induced by fenchlorazole-ethyl and mefenpyr-diethyl. 33 genes related to detoxification were identified. Moreover, GSTIV , GST6 , GST31 , UF3GT, MATE and ADH were up-regulated by isoxadifen-ethyl and/or nicosulfuron. These results indicate that the protection against nicosulfuron injury is linked to enhanced herbicide metabolism, and the chemical specificity of four safeners is attributed to the up-regulated genes related to the detoxification pathway.