A 49-bp deletion of PmAP2L results in a double flower phenotype in Prunus mume

Weichao Liu; Tangchun Zheng; Like Qiu; Xiaoyu Guo; Ping Li; Xue Yong; Lulu Li; Sagheer Ahmad; Jia Wang; Tangren Cheng; Qixiang Zhang

doi:10.1093/hr/uhad278

A 49-bp deletion of PmAP2L results in a double flower phenotype in Prunus mume

Hortic Res. 2023 Dec 19;11(2):uhad278. doi: 10.1093/hr/uhad278. eCollection 2024 Feb.

Authors

Weichao Liu¹, Tangchun Zheng¹, Like Qiu¹, Xiaoyu Guo¹, Ping Li¹, Xue Yong¹, Lulu Li¹, Sagheer Ahmad², Jia Wang¹, Tangren Cheng¹, Qixiang Zhang¹

Affiliations

¹ Beijing Key Laboratory of Ornamental Plants Germplasm Innovation & Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and Rural Ecological Environment, Engineering Research Center of Landscape Environment of Ministry of Education, Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants of Ministry of Education, School of Landscape Architecture, Beijing Forestry University, Beijing, China.
² Key Laboratory of National Forestry and Grassland Administration for Orchid Conservation and Utilization at College of Landscape Architecture, Fujian Agriculture and Forestry University, Fuzhou, China.

Abstract

The double flower is an important trait with substantial ornamental value. While mutations in PETALOSA TOE-type or AG (AGAMOUS) genes play a crucial role in enhancing petal number in ornamental plants, the complete mechanism underlying the formation of double flowers remains to be fully elucidated. Through the application of bulked segregant analysis (BSA), we identified a novel gene, APETALA2-like (PmAP2L), characterized by a 49-bp deletion in double-flowered Prunus mume. β-Glucuronidase (GUS) staining and luciferase reporter assays confirmed that the 49-bp deletion in PmAP2L reduced its binding with Pmu-miRNA172a. Phylogenetic analysis and microsynteny analysis suggested that PmAP2L was not a PETALOSA TOE-type gene, and it might be a new gene controlling the formation of double flower in P. mume. Subsequently, overexpression of PmAP2L-D in tobacco led to a significant rise in the number of stamens and the conversion of stamens to petals. Furthermore, silencing of the homologue of RC5G0530900 in rose significantly reduced the number of petals. Using transient gene expression in P. mume flower buds, we determined the functional differences between PmAP2L-D and PmAP2-S in controlling flower development. Meanwhile, DNA-affinity purification sequencing (DAP-seq), yeast hybrid assays and luciferase reporter assays indicated that PmAP2L negatively regulated the floral organ identity genes by forming a repressor complex with PmTPL and PmHDA6/19. Overall, these findings indicate that the variation in PmAP2L is associated with differences in the regulation of genes responsible for floral organ identity, providing new insights into the double-flower trait and double-flower breeding in plants.