Role of methylation in vernalization and photoperiod pathway: a potential flowering regulator?

Abstract

Recognized as a pivotal developmental transition, flowering marks the continuation of a plant’s life cycle. Vernalization and photoperiod are two major flowering pathways orchestrating numerous florigenic signals. Methylation, including histone, DNA and RNA methylation, is one of the recent foci in plant development. Considerable studies reveal that methylation seems to show an increasing potential regulatory role in plant flowering via altering relevant gene expression without altering the genetic basis. However, little has been reviewed about whether and how methylation acts on vernalization- and photoperiod-induced flowering before and after FLOWERING LOCUS C (FLC) reactivation, what role RNA methylation plays in vernalization- and photoperiod-induced flowering, how methylation participates simultaneously in both vernalization- and photoperiod-induced flowering, the heritability of methylation memory under the vernalization/photoperiod pathway, and whether and how methylation replaces vernalization/photoinduction to regulate flowering. Our review provides insight about the crosstalk among the genetic control of the flowering gene network, methylation (methyltransferases/demethylases) and external signals (cold, light, sRNA and phytohormones) in vernalization and photoperiod pathways. The existing evidence that RNA methylation may play a potential regulatory role in vernalization- and photoperiod-induced flowering has been gathered and represented for the first time. This review speculates about and discusses the possibility of substituting methylation for vernalization and photoinduction to promote flowering. Current evidence is utilized to discuss the possibility of future methylation reagents becoming flowering regulators at the molecular level.

Acknowledgements

This work was supported by the National Key Research and Development Program (2018YFD1000800); the National Natural Science Foundation of China (31160398, 31560563, 31860568, 32072559, and 32102370); the Key Research and Development Program of Gansu Province, China (21YF5WA096); the Natural Science Foundation of Gansu Province, China (1606RJZA073 and 1606RJZA077); and the Research Fund of Higher Education of Gansu, China (2018C-14 and 2019B-082). We are grateful to members of our laboratory for helpful criticism and advice.

Author contributions

W.L. designed the article; M.S. wrote the manuscript; W.L. and C.W. guided the completion of the manuscript text; P.W., F.H.Y., Z.L., F.J.Y., L.W., and M.Z. guided the completion of the figures and table.

Data Availability

No data was used for the research described in the article.

Conflict of interest

The authors declared that they have no conflict of interest.

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