Heterologous expression of the maize transcription factor ZmbHLH36 enhances abiotic stress tolerance in .

Unlabelled: Basic helix-loop-helix (bHLH) transcription factors are widely distributed in eukaryotes, and in plants, they regulate many biological processes, such as cell differentiation, development, metabolism, and stress responses. Few studies have focused on the roles of bHLH transcription factors in regulating growth, development, and stress responses in maize (), even though such information would greatly benefit maize breeding programs. In this study, we cloned the maize transcription factor gene (Gene ID: 100193615, GRMZM2G008691). ZmbHLH36 possesses conserved domains characteristic of the bHLH family. RT-qPCR analysis revealed that was expressed at the highest level in maize roots and exhibited different expression patterns under various abiotic stress conditions. Transgenic () plants heterologously expressing had significantly longer roots than the corresponding non-transgenic plants under 0.1 and 0.15 mol L NaCl treatment as well as 0.2 mol L mannitol treatment. Phenotypic analysis of soil-grown plants under stress showed that transgenic plants harboring exhibited significantly enhanced drought tolerance and salt tolerance compared to the corresponding non-transgenic plants. Malondialdehyde contents were lower and peroxidase activity was higher in -expressing plants than in the corresponding non-transgenic plants. ZmbHLH36 localized to the nucleus when expressed in maize protoplasts. This study provides a systematic analysis of the effects of ZmbHLH36 on root growth, development, and stress responses in transgenic , laying a foundation for further analysis of its roles and molecular mechanisms in maize.

Supplementary Information: The online version contains supplementary material available at 10.1007/s42994-024-00159-3.