AUTHOR=Qian Minjie , Ni Junbei , Niu Qingfeng , Bai Songling , Bao Lu , Li Jianzhao , Sun Yongwang , Zhang Dong , Teng Yuanwen 

TITLE=Response of miR156-SPL Module during the Red Peel Coloration of Bagging-Treated Chinese Sand Pear (Pyrus pyrifolia Nakai)

JOURNAL=Frontiers in Physiology

VOLUME=8

YEAR=2017

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2017.00550

DOI=10.3389/fphys.2017.00550

ISSN=1664-042X

ABSTRACT=<p>MicroRNA156 is an evolutionarily highly conserved plant micro-RNA (miRNA) that controls an age-dependent flowering pathway. miR156 and its target <italic>SQUAMOSA PROMOTER BINDING PROTEIN-LIKE</italic> (<italic>SPL</italic>) genes regulate anthocyanin accumulation in plants, but it is unknown whether this process is affected by light. Red Chinese sand pear (<italic>Pyrus pyrifolia</italic>) fruits exhibit a unique coloration pattern in response to bagging treatments, which makes them appropriate for studying the molecular mechanism underlying light-induced anthocyanin accumulation in fruit. Based on high-throughput miRNA and degradome sequencing data, we determined that miR156 was expressed in pear fruit peels, and targeted four <italic>SPL</italic> genes. Light-responsive elements were detected in the promoter regions of the miR156a and miR156ba precursors. We identified 19 <italic>SPL</italic> genes using the “Suli” pear (<italic>Pyrus pyrifolia</italic> Chinese White Pear Group) genome database, of which seven members were putative miR156 targets. The upregulated expression of anthocyanin biosynthetic and regulatory genes and downregulated expression of <italic>PpSPL2, PpSPL5, PpSPL7, PpSPL9, PpSPL10, PpSPL13, PpSPL16, PpSPL17</italic>, and <italic>PpSPL18</italic> were observed in pear fruits after bags were removed from plants during the anthocyanin accumulation period. Additionally, miR156a/ba/g/s/sa abundance increased after bags were removed. Yeast two-hybrid results suggested that PpMYB10, PpbHLH, and PpWD40 could form a protein complex, probably involved in anthocyanin biosynthesis. Additionally, PpSPL10 and PpSPL13 interacted with PpMYB10. The results obtained in this study are helpful in understanding the possible role of miR156 and its target <italic>PpSPL</italic> genes in regulating light-induced red peel coloration and anthocyanin accumulation in pear.</p>