Articles
Quick convergent evolution of MBW complex for pomegranate fruit coloration
Article number
1254_21
Pages
135 – 142
Language
English
Abstract
Integration of a series of biochemical processes that enable eudicot plants such as pomegranate to successfully accumulate anthocyanins requires diverse and intricate transcription factor activity, among which the R2R3MYB, BHLH and WD40 complex (MBW) performs a crucial role.
MBW transcription factors activate the downstream operators that are necessary for anthocyanin biosynthesis.
Conversely, monocots such as pineapple and banana only utilize MYB transcription factors to regulate this biosynthetic pathway.
We therefore formulate a convergent evolution hypothesis which claims that eudicots and monocots independently developed the ability to synthesize compounds that would fulfill the same biological function.
To elucidate the evolution pattern of MBW complex, RNA-sequencing of peel tissue, followed by de novo assembly and near-full annotation of the Taishanhong pomegranate transcriptome was carried out.
Phylogenetic analyses revealed that the R2R3MYB gene tree consistently matched the e-PCR tree, indicating a species-specific R2R3MYB evolution.
Pan-angiosperm R2R3MYB comparisons suggested similar motif features in plants, providing a phylogenetic evidence for convergent evolution of MBW complex.
Selective evolution analysis showed that R2R3MYB had undergone a quick positive selection, presumably due to the evolutionary need of producing special colors to attract seed dispersers and to recruit pollinators.
Combined comparative transcriptomics and phylogenetics analyses suggest that the MBW complex might have convergently evolved to co-regulate anthocyanin biosynthesis.
Our hypothesis offers a novel evolutionary insight into fruit color development, and will be a valuable resource for fruit breeding, especially pomegranates.
MBW transcription factors activate the downstream operators that are necessary for anthocyanin biosynthesis.
Conversely, monocots such as pineapple and banana only utilize MYB transcription factors to regulate this biosynthetic pathway.
We therefore formulate a convergent evolution hypothesis which claims that eudicots and monocots independently developed the ability to synthesize compounds that would fulfill the same biological function.
To elucidate the evolution pattern of MBW complex, RNA-sequencing of peel tissue, followed by de novo assembly and near-full annotation of the Taishanhong pomegranate transcriptome was carried out.
Phylogenetic analyses revealed that the R2R3MYB gene tree consistently matched the e-PCR tree, indicating a species-specific R2R3MYB evolution.
Pan-angiosperm R2R3MYB comparisons suggested similar motif features in plants, providing a phylogenetic evidence for convergent evolution of MBW complex.
Selective evolution analysis showed that R2R3MYB had undergone a quick positive selection, presumably due to the evolutionary need of producing special colors to attract seed dispersers and to recruit pollinators.
Combined comparative transcriptomics and phylogenetics analyses suggest that the MBW complex might have convergently evolved to co-regulate anthocyanin biosynthesis.
Our hypothesis offers a novel evolutionary insight into fruit color development, and will be a valuable resource for fruit breeding, especially pomegranates.
Authors
T.K. Zhang, Z.H. Yuan
Keywords
pomegranate, MBW complex, convergent evolution, RNA-seq, anthocyanin biosynthesis
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