Identification and characterization of microRNAs in tree peony during chilling induced dormancy release by high-throughput sequencing

Shupeng Gai,Chunying Liu,Yanyan Wang,Xuekai Gao,Yuxi Zhang

doi:10.1038/s41598-018-22415-5

Abstract

Tree peony, one of the most valuable horticultural and medicinal plants in the world, has to go through winter to break dormancy. Growing studies from molecular aspects on dormancy release process have been reported, but inadequate study has been done on miRNA-guided regulation in tree peony. In this study, high-throughput sequencing was employed to identify and characterize miRNAs in three libraries (6 d, 18 d and 24 d chilling treatments). There were 7,122, 10,076 and 9,097 unique miRNA sequences belonging to 52, 87 and 68 miRNA families, respectively. A total of 32 conserved miRNAs and 17 putative novel miRNAs were identified during dormancy release. There were 771 unigenes as potential targets of 62 miRNA families. Total 112 known miRNAs were differentially expressed, of which 55 miRNAs were shared among three libraries and 28 miRNAs were only found in 18 d chilling duration library. The expression patterns of 15 conserved miRNAs were validated and classified into four types by RT-qPCR. Combining with our microarray data under same treatments, five miRNAs (miR156k, miR159a, miR167a, miR169a and miR172a) were inversely correlated to those of their target genes. Our results would provide new molecular basis about dormancy release in tree peony.

Highlights

Tree peony (Paeonia suffruticosa Andrews) is one of the earliest and most well-known horticultural and medicinal plants in the world
To discover transcriptional pathways associated with dormancy release in Prunus persica, Fu et al explored the chilling-dependent expressions of 11 genes involved in endoplasmic reticulum stress and the unfolded protein response signal pathways[6]
Gai et al obtained over 15,000 high quality unigenes by RNA sequencing during chilling requirement fulfillment through Roche 454 GS FLX platform[10], of which 3,174 genes were significantly differentially expressed during endo-dormancy release in tree peony[11]

Summary

Introduction

Tree peony (Paeonia suffruticosa Andrews) is one of the earliest and most well-known horticultural and medicinal plants in the world. Liu et al obtained 190 significantly differentially expressed genes associated with bud dormancy in pear[4]. Gai et al obtained over 15,000 high quality unigenes by RNA sequencing during chilling requirement fulfillment through Roche 454 GS FLX platform[10], of which 3,174 genes were significantly differentially expressed during endo-dormancy release in tree peony[11]. We aimed to identify and characterize miRNAs by high-throughput sequencing technology in tree peony during the period of bud dormancy release after 6 d, 18 d and 24 d chilling requirement fulfilling, which included three physiological status, endo-dormancy, endo-dormancy release and eco-dormancy[10]. Our results increase the available information on miRNA-guided regulation mechanism and physiological changes during chilling induced dormancy release in tree peony

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Conclusion