State Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Landscaping, Ministry of Agriculture and Rural Affairs, Key Laboratory of Biology of Ornamental Plants in East China, National Forestry and Grassland Administration, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China.
Plant Physiol. 2022 Nov 28;190(4):2484-2500. doi: 10.1093/plphys/kiac437.
YABBY (YAB) genes are specifically expressed in abaxial cells of lateral organs and determine abaxial cell fate. However, most studies have focused on few model plants, and the molecular mechanisms of YAB genes are not well understood. Here, we identified a YAB transcription factor in chrysanthemum (Chrysanthemum morifolium), Dwarf and Robust Plant (CmDRP), that belongs to a distinct FILAMENTOUS FLOWER (FlL)/YAB3 sub-clade lost in Brassicaceae. CmDRP was expressed in various tissues but did not show any polar distribution in chrysanthemum. Overexpression of CmDRP resulted in a semi-dwarf phenotype with a significantly decreased active GA3 content, while reduced expression generated the opposite phenotype. Furthermore, plant height of transgenic plants was partially rescued through the exogenous application of GA3 and Paclobutrazol, and expression of the GA biosynthesis gene CmGA3ox1 was significantly altered in transgenic plants. Yeast one-hybrid, luciferase, and chromatin immunoprecipitation-qPCR analyses showed that CmDRP could directly bind to the CmGA3ox1 promoter and suppress its expression. Our research reveals a nonpolar expression pattern of a YAB family gene in dicots and demonstrates it regulates plant height through the GA pathway, which will deepen the understanding of the genetic and molecular mechanisms of YAB genes.
YABBY（YAB）基因特异性地在侧生器官的背腹细胞中表达，并决定背腹细胞命运。然而，大多数研究都集中在少数几个模式植物上，因此 YAB 基因的分子机制还不太清楚。在这里，我们在菊花（Chrysanthemum morifolium）中鉴定出一个 YAB 转录因子，即矮化健壮植物（Dwarf and Robust Plant，CmDRP），它属于在十字花科中丢失的丝状花（FILAMENTOUS FLOWER，FlL）/YAB3 亚科。CmDRP 在各种组织中表达，但在菊花中没有表现出任何极性分布。过表达 CmDRP 导致半矮化表型，其中活性 GA3 含量显著降低，而表达减少则产生相反的表型。此外，通过外源施加 GA3 和多效唑，转基因植物的株高部分得到挽救，并且转基因植物中 GA 生物合成基因 CmGA3ox1 的表达也发生了显著改变。酵母单杂交、荧光素酶和染色质免疫沉淀-qPCR 分析表明，CmDRP 可以直接结合 CmGA3ox1 启动子并抑制其表达。我们的研究揭示了二倍体中 YAB 家族基因的非极性表达模式，并证明其通过 GA 途径调节植物的高度，这将加深对 YAB 基因遗传和分子机制的理解。
