College of Horticulture, Henan Agricultural University, 95 Wenhua Road, Zhengzhou 450002, China.
Int J Mol Sci. 2023 Apr 6;24(7):6789. doi: 10.3390/ijms24076789.
Controlling the tree size of fruit species such as peach can reduce the amount of labor and input needed for orchard management. The phytohormone gibberellin (GA) positively regulates tree size by inducing degradation of the GA signaling repressor DELLA. The N-terminal DELLA domain in this protein is critical for its GA-dependent interaction with the GA receptor GID1 and the resulting degradation of the DELLA protein, which allows for growth-promoting GA signaling. In this study, a DELLA family member, PpeDGYLA, contains a DELLA domain but has amino acid changes in three conserved motifs (DELLA into DGYLA, LEQLE into LERLE, and TVHYNP into AVLYNP). In the absence or presence of GA, the PpeDGYLA protein did not interact with PpeGID1c and was stable in 35S-PpeDGYLA peach transgenic callus. The overexpression of in both polar and Arabidopsis showed an extremely dwarfed phenotype, and these transgenic plants were insensitive to GA treatment. PpeDGYLA could interact with PpeARF6-1 and -2, supposed growth-promoting factors. It is suggested that the changes in the DELLA domain of PpeDGYLA may, to some extent, account for the severe dwarf phenotype of poplar and Arabidopsis transgenic plants. In addition, our study showed that the DELLA family contained three clades (DELLA-like, DELLA, and DGLLA). clustered into the DGLLA clade and was expressed in all of the analyzed tissues. These results lay the foundation for the further study of the repression of tree size by PpeDGYLA.
控制桃树等水果品种的树型大小可以减少果园管理所需的劳动力和投入。植物激素赤霉素（GA）通过诱导 GA 信号抑制物 DELLA 的降解来正向调节树型大小。该蛋白的 N 端 DELLA 结构域对于其与 GA 受体 GID1 的 GA 依赖性相互作用以及 DELLA 蛋白的降解至关重要，这允许生长促进的 GA 信号传导。在这项研究中，一个 DELLA 家族成员 PpeDGYLA 含有一个 DELLA 结构域，但在三个保守基序（DELLA 变为 DGYLA、LEQLE 变为 LERLE 和 TVHYNP 变为 AVLYNP）中存在氨基酸变化。在缺乏或存在 GA 的情况下，PpeDGYLA 蛋白与 PpeGID1c 不相互作用，并且在 35S-PpeDGYLA 桃转基因愈伤组织中稳定。在拟南芥的极性和中过表达 ，表现出极度矮小的表型，这些转基因植物对 GA 处理不敏感。PpeDGYLA 可以与假定的生长促进因子 PpeARF6-1 和 -2 相互作用。表明 PpeDGYLA 的 DELLA 结构域的变化在一定程度上解释了杨树和拟南芥转基因植物的严重矮小表型。此外，我们的研究表明，DELLA 家族包含三个分支（DELLA-like、DELLA 和 DGLLA）。PpeDGYLA 聚类到 DGLLA 分支中，并在所有分析的组织中表达。这些结果为进一步研究 PpeDGYLA 对树型大小的抑制作用奠定了基础。
