Key Laboratory of Horticultural Plant Biology, Ministry of Education, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, Hubei, PR China.
PLoS One. 2013 May 15;8(5):e63389. doi: 10.1371/journal.pone.0063389. Print 2013.
The identification of mutants in model plant species has led to the isolation of the floral homeotic function genes that play crucial roles in flower organ specification. However, floral homeotic C-function genes are rarely studied in basal eudicots. Here, we report the isolation and characterization of the AGAMOUS (AG) orthologous gene (PaAG) from a basal eudicot London plane tree (Platanus acerifolia Willd). Phylogenetic analysis showed that PaAG belongs to the C- clade AG group of genes. PaAG was found to be expressed predominantly in the later developmental stages of male and female inflorescences. Ectopic expression of PaAG-1 in tobacco (Nicotiana tabacum) resulted in morphological alterations of the outer two flower whorls, as well as some defects in vegetative growth. Scanning electron micrographs (SEMs) confirmed homeotic sepal-to-carpel transformation in the transgenic plants. Protein interaction assays in yeast cells indicated that PaAG could interact directly with PaAP3 (a B-class MADS-box protein in P. acerifolia), and also PaSEP1 and PaSEP3 (E-class MADS-box proteins in P. acerifolia). This study performed the functional analysis of AG orthologous genes outside core eudicots and monocots. Our findings demonstrate a conserved functional role of AG homolog in London plane tree, which also represent a contribution towards understanding the molecular mechanisms of flower development in this monoecious tree species.
在模式植物物种中鉴定突变体，导致了在花器官特化中起关键作用的花同源性功能基因的分离。然而，在基本真双子叶植物中很少研究花同源性 C 功能基因。在这里，我们报告了从基本真双子叶植物悬铃木（Platanus acerifolia Willd）中分离和鉴定 AGAMOUS（AG）同源基因（PaAG）的情况。系统发育分析表明，PaAG 属于 C- 枝 AG 基因群。发现 PaAG 主要在雄性和雌性花序的后期发育阶段表达。PaAG-1 在烟草（Nicotiana tabacum）中的异位表达导致了外部两轮花被片的形态改变，以及一些营养生长缺陷。扫描电子显微镜（SEM）证实了转基因植物中同源性的花萼到心皮的转化。酵母细胞中的蛋白相互作用测定表明，PaAG 可以与 PaAP3（悬铃木中的 B 类 MADS 盒蛋白）直接相互作用，也可以与 PaSEP1 和 PaSEP3（悬铃木中的 E 类 MADS 盒蛋白）相互作用。本研究在外核真双子叶植物和单子叶植物中进行了 AG 同源基因的功能分析。我们的发现表明，AG 同源基因在伦敦悬铃木中具有保守的功能作用，这也为理解该雌雄同株树种的花发育分子机制做出了贡献。
