miR166e/ZmATHB14 module contributes to drought tolerance in maize root

MicroRNAs significantly influence abiotic stress responses. A species-conserved miRNA implicated in the response to abiotic stress is maize miR166. Therefore, it is unknown whether miR166e plays a role in maize roots' reaction to drought stress. According to this study, drought stress lowers the expression of the miR166e precursor. According to genetic data, miR166e knockdown (KO) improved drought tolerance, while miR166e overexpression decreased it. Additionally, 5'-RACE and double luciferase tests have identified ZmATHB14, an HD-Zip III transcription factor, as a target of miR166e. Under drought stress, KO-miR166e alters ZmATHB14 expression and exhibits the opposite properties of miR166e. ZmATHB14 positively regulates the tolerance to drought stress. Furthermore, ZmATHB14, linked to the GTAATGATTAC cis-element, can activate transcription within the nucleus. Under drought stress, miR166e and ZmATHB14 contribute to vascular development and control ROS homeostasis. We discovered through metabolic targeting tests (Liquid chromatography-mass spectrometry, HPLC-MS) that ZmATHB14 modifies signaling pathways and hormone levels. Our findings strongly imply that the miR166e-ZmATHB14 module regulates drought tolerance.