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

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.

Acknowledgements

The research was supported by the Fundamental Research Funds for the Central Universities (No. QNTD202306), National Natural Science Foundation of China (No. 32371947, 32071816), Beijing High-Precision Discipline Project, Discipline of Ecological Environment of Urban and Rural Human Settlements and the Special Fund for Beijing Common Construction Project.

Author contributions

W.L., Q.Z., and T.Z. planned and designed the research. T.Z. and W.L. conducted experiments and material collection. W.L. and T.Z. analysed data. W.L., L.Q., X.G., L.P., X.Y., L.L., J.W., and T.C. conducted fieldwork and material maintenance. S.A. modified the language. W.L. and T.Z. wrote the manuscript. T.Z. and Q.Z. revised the manuscript and finalized the manuscript. All authors have read and approved the final manuscript.

Data availability

The raw sequence data of BSA-seq is available in the National Genomics Data Center (NGDC) with the accession number PRJCA017066.The DAP-seq data have been deposited to the National Genomics Data Center (NGDC) with the accession number PRJCA017094.

Conflict of interest statement

The authors declare no conflict of interest.

Supplementary data

Supplementary data is available at Horticulture Research online.

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