Time-resolved transcriptomic analysis suggests candidate hub gene modules and putative regulatory pathways in tobacco under dicamba stress

Abstract

Introduction Widespread dicamba use poses challenges of resistance and phytotoxicity. To investigate the temporal molecular response mechanisms of tobacco, this study performed a time-resolved transcriptomic analysis of tobacco seedlings exposed to dicamba. Methods Samples were collected at 6, 24, and 72 h after treatment. Results Results indicated that tobacco exhibits a putative three-phase transcriptional adaptation pattern of “perception-defense-repair”. In the early stage (6h), NtIAA genes were rapidly induced alongside activation of the glutathione system, potentially alleviating oxidative stress; at the mid-stage (24h), enhanced carotenoid synthesis and thylakoid reconstruction appeared to protect photosynthetic structures; at the late stage (72h), the transcriptional response shifted toward systemic repair through secondary metabolism, including phenylpropanoid biosynthesis. Predictive regulatory network analysis suggested that the ERF transcription factor Nitab4.5_0000015g0020 may act as a candidate hub, potentially linking auxin signaling and ribosomal protein genes. Discussion Taken together, this study provides transcriptomic evidence that the NtIAA family may serve as candidate genes in response to dicamba, offering potential genetic candidates for breeding herbicide-resistant crops.