AUTHOR=Xu Wanyu , Bao Wenquan , Liu Huimin , Chen Chen , Bai Haikun , Huang Mengzhen , Zhu Gaopu , Zhao Han , Gou Ningning , Chen Yixiao , Wang Lin , Wuyun Ta-na 

TITLE=Insights Into the Molecular Mechanisms of Late Flowering in Prunus sibirica by Whole-Genome and Transcriptome Analyses

JOURNAL=Frontiers in Plant Science

VOLUME=12

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2021.802827

DOI=10.3389/fpls.2021.802827

ISSN=1664-462X

ABSTRACT=<p>Freezing during the flowering of <italic>Prunus sibirica</italic> is detrimental to fruit production. The late flowering (LF) type, which is delayed by 7–15 days compared with the normal flowering (NF) type, avoids damages at low temperature, but the molecular mechanism of LF remains unclear. Therefore, this study was conducted to comprehensively characterize floral bud differentiation. A histological analysis showed that initial floral bud differentiation was delayed in the LF type compared to the NF type. Genome-wide associated studies (GWAS) showed that a candidate gene (PaF106G0600023738.01) was significantly associated with LF type. It was identified as <italic>trehalose-6-phosphate phosphatase</italic> (<italic>PsTPPF</italic>), which is involved in trehalose-6-phosphate (Tre6P) signaling pathway and acts on floral transition. A whole-transcriptome RNA sequencing analysis was conducted, and a total of 6,110 differential expression (DE) mRNAs, 1,351 DE lncRNAs, and 148 DE miRNAs were identified. In addition, 24 DE mRNAs related with floral transition were predicted, and these involved the following: three interactions between DE lncRNAs and DE mRNAs of photoperiod pathway with two mRNAs (<italic>COP1</italic>, PaF106G0400018289.01 and <italic>CO3</italic>, MXLOC_025744) and three lncRNAs (<italic>CCLR</italic>, LTCONS_00031803, <italic>COCLR1</italic>, LTCONS_00046726, and <italic>COCLR2</italic>, LTCONS_00046731); one interaction between DE miRNAs and DE mRNAs with one mRNA, encoding <italic>trehalose-6-phosphate synthase</italic> (<italic>PsTPS1</italic>, PaF106G0100001132.01), and one miRNA (miRNA167h). Combined with the expression profiles and Tre6P levels, functions of <italic>PsTPPF</italic> and <italic>PsTPS1</italic> in Tre6P regulation were considered to be associated with flowering time. A new network of ceRNAs correlated with LF was constructed, and it consisted of one mRNA (<italic>PsTPS1</italic>), one lncRNA (<italic>TCLR</italic>, LTCONS_00034157), and one miRNA (miR167h). This study provided insight into the molecular regulatory mechanism of LF in <italic>Prunus sibirica</italic>.</p>