EjGASA6 promotes flowering and root elongation by enhancing gibberellin biosynthesis1

The gene family, Gibberellic Acid-Stimulated Arabidopsis (GASA), is involved in the regulation of gene expression and plant growth, development, and stress response. To investigate the function of the loquat GASA genes in growth and development regulation of plants, a loquat EjGASA6 gene homologous to Arabidopsis AtGASA6 was cloned. EjGASA6 expression was induced by gibberellin, and ectopic transgenic plants containing this gene exhibited earlier bloom and longer primary roots as these phenotypic characteristics are related to higher gibberellin content. Transcriptome analysis and qRT-PCR results showed that the expressions of GA3ox1 and GA20ox1 that encodes key enzymes in gibberellin biosynthesis significantly increased. Furthermore, we confirmed that EjGASA6 could promote the expression of GA20ox1 via the luciferase reporter system. Overall, our results suggest that EjGASA6 promotes blooming and main-root elongation by positively regulating gibberellin biosynthesis. Our findings broaden the understanding of GASAs role in plant development and growth and sets the groundwork for future research into the functions of EjGASA6 in regulating loquat growth and development.