Fruit development is orchestrated by a complex network of interactions between hormone signaling pathways. The phytohormone gibberellin (GA) is known to regulate a diverse range of developmental processes; however, the mechanisms of GA action in perennial fruit species are yet to be elucidated. In the current study, a GA signaling gene PslSLY1, encoding a putative F-box protein that belongs to the SLY1 (SLEEPY1)/GID2 (gibberellin-insensitive dwarf2) gene family, was isolated from Japanese plum (Prunus salicina). PslSLY1 transcript abundance declined as fruit development progressed, along with potential negative feedback regulation of PslSLY1 by GA. Subcellular localization and protein–protein interaction assays suggested that PslSLY1 functions as an active GA signaling component that interacts with the ASK1 (Arabidopsis SKP1) subunit of an SCF–ubiquitin ligase complex and with PslDELLA repressors, in a GA-independent manner. By using a domain omission strategy, we illustrated that the F-box and C-terminal domains of PslSLY1 are essential for its interactions with the downstream GA signaling components. PslSLY1 overexpression in wild-type and Arabidopsissly1.10 mutant backgrounds resulted in a dramatic enhancement in overall plant growth, presumably due to triggered GA signaling. This includes germination characteristics, stem elongation, flower structure, and fertility. Overall, our findings shed new light on the GA strategy and signaling network in commercially important perennial crops.

中文翻译：

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李子果实发育过程中赤霉素F-box蛋白PslSLY1的功能表征

通过激素信号传导途径之间相互作用的复杂网络来协调水果的发育。已知植物激素赤霉素（GA）调节多种发育过程。然而，GA在多年生果树种中的作用机理尚待阐明。在当前的研究中，从日本李子（Prunus salicina）中分离了一个GA信号基因PslSLY1，该信号编码一个假定的F-box蛋白，该蛋白属于SLY1（SLEEPY1）/ GID2（对赤霉素不敏感的dwarf2）基因家族。随着水果的发展，PslSLY1转录本的丰度下降，同时潜在的负反馈调节PslSLY1由GA。亚细胞定位和蛋白质-蛋白质相互作用测定表明，PslSLY1作为活性GA信号成分起作用，以GA独立的方式与SCF-泛素连接酶复合体的ASK1（拟南芥SKP1）亚基以及PslDELLA阻遏物相互作用。通过使用域省略策略，我们说明了PslSLY1的F-box和C-末端域对于其与下游GA信号组件的相互作用至关重要。PslSLY1在野生型和拟南芥sly1.10中的过表达突变的背景导致总体植物生长显着增强，可能是由于触发了GA信号传导。这包括发芽特性，茎伸长，花结构和繁殖力。总体而言，我们的发现为商业上重要的多年生作物的遗传资源战略和信号网络提供了新的思路。