Ultrastructure change and transcriptome analysis of GA3 treatment on seed germination of moso bamboo(Phyllostachys edulis)

Abstract

Exploring the mechanism of Gibberellic acid (GA₃) treatment on seed germination of moso bamboo can lay a foundation for its future breeding and research. In this study, the germination-related indicators (germination rate, germination potential, vigor index, respiration rate) with different content of GA₃ treatment were measured, and the ultrastructure of moso bamboo seeds treated with low and high GA₃ concentrations was observed during the germination process. In addition, the transcriptome data of the germination seeds, with and without GA₃ treatment were analyzed. The results showed that the low GA₃ concentration (10 mol/L) increased the germination rate, germination potential, vigor index and respiration rate, thus promoting the germination of moso bamboo seeds, but a high concentration of GA₃ (50 mol/L) inhibited the seed germination. The low GA₃ concentration accelerated the decomposition of starch and fat and promoted the vacuole formation of cells, but the high GA₃ concentration damaged organelles and increased the endocytosis of cells. Compared with untreated moso bamboo seeds, the seeds had fewer genes expressed after GA₃ treatment. Starch and carbon metabolism play a very important role in seed development and embryo viability, whether the seed is treated with GA₃ or not. After hormone treatment, GID1 and DELLA-related genes homologous to rice genes is not expressed, but the expression of PIF4, PIF5, GA₃ox2, GA₂oxs, etc., were up-regulated.

Keywords: GA3; Moso bamboo; TEM; key genes; respiration rate; seed germination; transcriptome analysis.