AUTHOR=Lu Yanan , Wang Hanhui , Liu Zhi , Zhang Tianxu , Li Zongjian , Cao Li , Wu Siyao , Liu Yueying , Yu Song , Zhang Qingzhu , Zheng Zhimin 

TITLE=A naturally-occurring phenomenon of flower color change during flower development in Xanthoceras sorbifolium

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.1072185

DOI=10.3389/fpls.2022.1072185

ISSN=1664-462X

ABSTRACT=<p><italic>Xanthoceras sorbifolium</italic> (yellowhorn) is originated in China and is a unique tree in northern China. Yellowhorn is very popular because of the gradual color change of its flower at different flower developmental stages. During flowering development, the color at the base of yellowhorn flower petals gradually changes from yellow to purple. The mechanism of this miraculous phenomenon is still unclear. Here we show that anthocyanin accumulation during flowering development is the main reason for this color change. RT-PCR results show that the expression level of a variety of anthocyanin biosynthesis genes changes in different flower developmental stages. Realtime results show that the expression changes of these anthocyanin biosynthesis genes are positively regulated by a cluster of <italic>R2R3-MYB</italic> transcription factor genes, <italic>XsMYB113s</italic>. Furthermore, the DNA methylation analysis showed that CHH methylation status on the transposon element near the <italic>XsMYB113-1</italic> influence its transcript level during flowering development. Our results suggest that dynamic epigenetic regulation of the <italic>XsMYB113-1</italic> leads to the accumulation of anthocyanins during yellowhorn flower color change. These findings reemphasize the role of epigenetic regulation in flower development and provide a foundation for further studies of epigenetic regulation in long-lived woody perennials.</p>