College of Horticulture, Henan Agricultural University, Zhengzhou, China.
Plant Biotechnol J. 2019 Sep;17(9):1723-1735. doi: 10.1111/pbi.13094. Epub 2019 Mar 6.
Plant stature is one important factor that affects the productivity of peach orchards. However, little is known about the molecular mechanism(s) underlying the dwarf phenotype of peach tree. Here, we report a dwarfing mechanism in the peach cv. FenHuaShouXingTao (FHSXT). The dwarf phenotype of 'FHSXT' was caused by shorter cell length compared to the standard cv. QiuMiHong (QMH). 'FHSXT' contained higher endogenous GA levels than did 'QMH' and did not response to exogenous GA treatment (internode elongation). These results indicated that 'FHSXT' is a GA-insensitive dwarf mutant. A dwarf phenotype-related single nucleotide mutation in the gibberellic acid receptor GID1 was identified in 'FHSXT' (GID1c ), which was also cosegregated with dwarf phenotype in 30 tested cultivars. GID1c was unable to interact with the growth-repressor DELLA1 even in the presence of GA. 'FHSXT' accumulated a higher level of DELLA1, the degradation of which is normally induced by its interaction with GID1. The DELLA1 protein level was almost undetectable in 'QMH', but not reduced in 'FHSXT' after GA treatment. Our results suggested that a nonsynonymous single nucleotide mutation in GID1c disrupts its interaction with DELLA1 resulting in a GA-insensitive dwarf phenotype in peach.
植株高度是影响桃园生产力的一个重要因素。然而，人们对桃树矮化性状的分子机制知之甚少。本研究报道了桃品种‘丰华寿仙桃’（FHSXT）的矮化机制。与标准品种‘秋蜜红’（QMH）相比，‘FHSXT’的矮化表型是由于细胞长度较短引起的。‘FHSXT’的内源 GA 水平高于‘QMH’，且对外源 GA 处理（节间伸长）没有反应。这些结果表明，‘FHSXT’是一种 GA 不敏感的矮化突变体。在‘FHSXT’中发现了一个与矮化表型相关的单个核苷酸突变，该突变位于赤霉素受体 GID1 中（GID1c），在 30 个测试品种中，该突变与矮化表型共分离。即使存在 GA，GID1c 也无法与生长抑制剂 DELLA1 相互作用。‘FHSXT’积累了更高水平的 DELLA1，而其与 GID1 的相互作用通常会诱导 DELLA1 的降解。在‘QMH’中，DELLA1 蛋白水平几乎检测不到，但在‘FHSXT’中，GA 处理后并未减少。我们的结果表明，GID1c 中的非同义单核苷酸突变破坏了其与 DELLA1 的相互作用，导致桃的 GA 不敏感矮化表型。
