Maize ZmLAZ1-3 gene negatively regulates drought tolerance in transgenic Arabidopsis

Molecular mechanisms in response to drought stress are important for the genetic improvement of maize. In our previous study, nine ZmLAZ1 members were identified in the maize genome, but the function of ZmLAZ1 was largely unknown.

The ZmLAZ1-3 gene was cloned from B73, and its drought-tolerant function was elucidated by expression analysis in transgenic Arabidopsis. The expression of ZmLAZ1-3 was upregulated by drought stress in different maize inbred lines. The driving activity of the ZmLAZ1-3 promoter was induced by drought stress and related to the abiotic stress-responsive elements such as MYB, MBS, and MYC. The results of subcellular localization indicated that the ZmLAZ1-3 protein localized on the plasma membrane and chloroplast. The ectopic expression of the ZmLAZ1-3 gene in Arabidopsis significantly reduced germination ratio and root length, decreased biomass, and relative water content, but increased relative electrical conductivity and malondialdehyde content under drought stress. Moreover, transcriptomics analysis showed that the differentially expressed genes between the transgenic lines and wild-type were mainly associated with response to abiotic stress and biotic stimulus, and related to pathways of hormone signal transduction, phenylpropanoid biosynthesis, mitogen-activated protein kinase signaling, and plant-pathogen interaction.

The study suggests that the ZmLAZ1-3 gene is a negative regulator in regulating drought tolerance and can be used to improve maize drought tolerance via its silencing or knockout.