Identification and functional analysis of the CqGID1 homologs in quinoa

Abstract

Silencing of CqGID1s from quinoa resulted in severely dwarfed plants, whereas CqGID1 overexpression significantly increased GA sensitivity and plant height in Arabidopsis thaliana. Gibberellin (GA) is an important phytohormone that regulates seed germination and growth, and the GIBBERELLIN-INSENSITIVE DWARF1 (GIDI) is a key mediator of GA. In this study, we identified three quinoa GID1 genes: the expression level of CqGID1c was low during the germination of quinoa seeds, whereas those of CqGID1b1 and CqGID1b2 were high, suggesting that CqGID1b1 and CqGID1b2 may play important roles in the germination of quinoa seeds. The silencing of CqGID1s in quinoa resulted in severe plant dwarfism, whereas CqGID1-overexpressing Arabidopsis had significantly increased plant heights. Overexpression of CqGID1s increased the sensitivity of plants to GA. CqGID1s-overexpressed Arabidopsis showed a significant increase in root length, hypocotyl length, seed germination rate, internode number, and flowering time. Both overexpression and silencing of CqGID1s caused changes in the endogenous hormone contents and the expression of genes related to GA biosynthesis and degradation, suggesting that GA-mediated plant growth and development is influenced by its signaling, biosynthesis, and degradation genes. Overall, our study identified and investigated quinoa CqGID1s, established a foundation for understanding the role of GID1 in plant growth and development, and provided a theoretical basis for elucidating the mechanism by which the GA signaling pathway regulates seed germination and plant height in quinoa.

Keywords: GID1; Gibberellin; Gibberellin signaling; Quinoa.