AcMYB266, a key regulator of the red coloration in pineapple peel: a case of subfunctionalization in tandem duplicated genes

Abstract

Red fruit peel is an attractive target for pineapple breeding. Various pineapple accessions with distinct red coloration patterns exist; however, the precise molecular mechanism accounting for these differences remains unknown, which hinders the pineapple breeding process from combining high fruit quality with red peel. In this study, we characterized a transcription factor, AcMYB266, which is preferentially expressed in pineapple peel and positively regulates anthocyanin accumulation. Transgenic pineapple, Arabidopsis, and tobacco plants overexpressing AcMYB266 exhibited significant anthocyanin accumulation. Conversely, transient silencing of this gene led to decreased anthocyanin accumulation in pineapple red bracts. In-depth analysis indicated that variations of AcMYB266 sequences in the promoter instead of the protein-coding region seem to contribute to different red coloration patterns in peels of three representative pineapple varieties. In addition, we found that AcMYB266 was located in a cluster of four MYB genes exclusive to and conserved in Ananas species. Of this cluster, each was proved to regulate anthocyanin synthesis in different pineapple tissues, illustrating an interesting case of gene subfunctionalization after tandem duplication. In summary, we have characterized AcMYB266 as a key regulator of pineapple red fruit peel and identified an MYB cluster whose members were subfunctionalized to specifically regulate the red coloration of different pineapple tissues. The present study will assist in establishing a theoretical mechanism for pineapple breeding for red fruit peel and provide an interesting case for the investigation of gene subfunctionalization in plants.

Acknowledgements

This work was supported by Major Science and Technology Projects of Hainan Province (ZDKT2021014), the National Natural Science Foundation of China: National Key R&D Program of China (2019YFD100050), Special Fund for Rural Revitalization Strategy of Guangdong Province (2022NPY00031), and Central Public-interest Scientific Institution Basal Research Fund for Chinese Academy of Tropical Agricultural Sciences (No.1630032024001), National Natural Science Foundation of China (No. 32101584). The authors gratefully acknowledge experimental material support from National Tropical Plants Germplasm Resource Center.

Author contributions

W.Z. designed and performed the experiments, and conducted data analysis. W.Z. and A.L. wrote the manuscript. J.W., C.L., and W.Y. performed some experiments. J.X., Y.W., and C.C. helped with data analysis. T.X., J.M., Z.Z., M.Y., and J.H. performed the experiments. Y.H. designed the experiment, conceived the project, and supervised the study. All authors have read and approved the final manuscript.

Data availability

The data underlying this article are available in the Sequence Read Archive (SRA) at NCBI under Project ID PRJNA483249 and PRJNA1094551.

Conflict of interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Supplementary data

Supplementary data are available at Horticulture Research online.

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