Integrating transcriptomic, physiological, and biochemical studies revealing the role of endogenous ABA and GA3 in the germination of quinoa seed

Xueying LiXiuzhang WangAilin LiOu LuoYanxia SunXiaoyong Wu^*

• Chengdu University, Chengdu, China

Plant endogenous hormones play crucial roles in seed germination. Among them, abscisic acid (ABA) and gibberellin (GA), two antagonistic hormones, are central regulators. However, their precise mechanisms in quinoa seed germination remain incompletely understood. Thus, by combining physiological and transcriptome analyses, this study provides insights into the ABA/GA3-mediated regulatory mechanisms during seed germination in quinoa. employs quinoa seed germination as a model to simulate PHS, with a primary focus on analyzing the alterations in starch, protein, soluble sugar, and endogenous ABA and GA3 content in quinoa seeds pre-and post-germination. Additionally, the study investigates the enzymatic activities associated with these two hormones. Also, the transcriptome data analysis before and after seed germination elucidate the mechanisms by which endogenous ABA and GA3 regulate quinoa seed germination. The germination leads to an increase in the concentrations of soluble sugars, proteins, maltose, and glucose. Quinoa seeds exhibit insensitivity to ABA, while GA3 plays a significant role in promoting seed germination. Transcriptome revealed upregulation of starch and sucrose metabolism and the EMP pathway and TCA cycle were enhanced during seed germination. Fifteen crucial genes related to ABA, GA3, starch/sucrose metabolism, and EMP pathway in quinoa germination were identified. Notably, unlike most crops, the elevated endogenous ABA levels are inadequate to impede the germination of quinoa seeds or quinoa seeds exhibit insensitivity to ABA. The analysis of transcriptome data demonstrated an upregulation of the starch and sucrose metabolism pathways, as well as glycolysis and the tricarboxylic acid cycle, during the germination process of quinoa seeds. These findings provide a foundational theoretical framework for elucidating the intrinsic mechanisms underlying quinoa germination and preharvest sprouting.