Understanding corm development in flower bulbs is of importance for securing the quality of cut flowers and propagation of commercial stocks. Gladiolus is one of the most popular bulb plants worldwide. Its corm development is characterized by starch accumulation. Previous research has shown that phytohormones (especially gibberellin (GA)) are involved in tuber development. However, the relationship between abscisic acid (ABA)/GA and starch during corm development remains unclear. To gain deeper insights into the biological process of corm development, we performed a detailed anatomical characterization of different stages of corm development and analyzed phytohormone levels. Our study showed that corm development is linked to hormones (ABA and GA) and carbohydrates (sucrose and starch). Exogenous hormone treatment and silencing of endogenous hormone biosynthesis genes indicated that ABA positively regulates corm development, while GA acts as an antagonist of ABA function. A sucrose synthase gene (GhSUS2) was shown to be involved in the antagonism between ABA and GA. GhSUS2 was upregulated by ABA and downregulated by GA. The increase in the transcript level of GhSUS2 coincided with the development of corm/cormels. Silencing of GhSUS2 repressed corm development and starch accumulation. In conclusion, we propose that GhSUS2, an essential enzyme in sucrose degradation, is differentially regulated by ABA and GA and controls corm development in Gladiolus.

中文翻译：

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脱落酸与赤霉素的拮抗作用调控唐菖蒲淀粉合成和球茎发育

了解球茎的球茎发育对于确保切花的质量和商业种群的繁殖具有重要意义。唐菖蒲是世界上最受欢迎的球茎植物之一。其球茎发育的特点是淀粉积累。先前的研究表明，植物激素（尤其是赤霉素 (GA)）与块茎发育有关。然而，在球茎发育过程中脱落酸 (ABA)/GA 与淀粉之间的关系仍不清楚。为了更深入地了解球茎发育的生物学过程，我们对球茎发育的不同阶段进行了详细的解剖学表征，并分析了植物激素水平。我们的研究表明，球茎发育与激素（ABA 和 GA）和碳水化合物（蔗糖和淀粉）有关。外源激素处理和内源激素生物合成基因的沉默表明 ABA 正向调节球茎发育，而 GA 作为 ABA 功能的拮抗剂。蔗糖合酶基因（GHSUS2) 被证明参与了 ABA 和 GA 之间的拮抗作用。GHSUS2ABA上调，GA下调。转录水平的提高GHSUS2恰逢corm/cormels的发展。沉默GHSUS2抑制球茎发育和淀粉积累。总之，我们提出 GhSUS2 是蔗糖降解中的一种必需酶，它受 ABA 和 GA 的差异调节，并控制唐菖蒲的球茎发育。