GmSBH1, a homeobox transcription factor gene, relates to growth and development and involves in response to high temperature and humidity stress in soybean.

KEY MESSAGE: GmSBH1 involves in response to high temperature and humidity stress. Homeobox transcription factors are key switches that control plant development processes. Glycine max H1 Sbh1 (GmSBH1) was the first homeobox gene isolated from soybean. In the present study, the full ORF of GmSBH1 was isolated, and the encoded protein was found to be a typical class I KNOX homeobox transcription factor. Subcellular localization and transcriptional activation assays showed that GmSBH1 is a nuclear protein and possesses transcriptional activation activity in the homeodomain. The KNOX1 domain was found to play a clear role in suppressing the transcriptional activation activity of GmSBH1. GmSBH1 showed different expression levels among different soybean tissues and was involved in response to high temperature and humidity (HTH) stress in developing soybean seeds. The overexpression of GmSBH1 in Arabidopsis altered leaf and stoma phenotypes and enhanced seed tolerance to HTH stress. Overall, our results indicated that GmSBH1 is involved in growth, development, and enhances tolerance to pre-harvest seed deterioration caused by HTH stress in soybean.