Acta Horticulturae Sinica ›› 2022, Vol. 49 ›› Issue (5): 958-972.doi: 10.16420/j.issn.0513-353x.2021-0103

• Research Papers • Previous Articles     Next Articles

Molecular Evolution of MiR168 Family and Their Expression Profiling During Dormancy of Pyrus pyrifolia

LIANG Qin1,2, ZHANG Yanhui3, KANG Kaiquan4, LIU Jinhang1, LI Liang1, FENG Yu1, WANG Chao1, YANG Chao1,*(), LI Yongyu1,*()   

  1. 1College of Horticulture,Fujian Agriculture and Forestry University,Fuzhou 350002,China
    2Guang’an Modern Agricultural Park Service Center,Guang’an,Sichuan 638500,China
    3Economic Crop Station,Agricultural and Rural Bureau of Yongtai County,Fuzhou 350700,China
    4Lianjiang State-Owned Forest Farm in Fujian Province,Fuzhou 350500,China
  • Received:2022-01-11 Revised:2022-04-01 Online:2022-05-25 Published:2022-05-25
  • Contact: YANG Chao,LI Yongyu;


To explore the evolutionary characteristics of miR168 gene family and its expression pattern in dormancy process of pear,the mature and precursor sequences of all miR168 family members in plants were obtained from miRBase 22.0 and miRNA library of pear(‘Huanghua’)created by our laboratory. We cloned two precursors of miR168 from the pear flower buds,which contained two mature sequences. Bioinformatics analysis and real-time quantitative PCR(qRT-PCR)were used to analyze the mature sequences and the pre-miR168 sequences of the miR168 family of pear. The phylogenetic tree was constructed with known plant miR168,and based on target genes prediction,the expression of miR168 and target genes during dormancy development in pear was analyzed. RNAfold prediction analysis showed that the pre-miR168 sequence of pear could form stable hairpin structure. Further analysis showed that the sequences of both ends of plant pre-miR168 were conservative,while the intermediate sequences were not. The mature miR168 was highly conserved,and the evolutionary tree analysis was mainly divided into two categories. Phylogenetic analysis found that the affinity of pre-miR168 of pear was closely related to apple,which showed that species affinity is the main factor for the evolutionary characteristics of the precursor of miR168 family. PsRNA target prediction showed that a total of 21 potential mRNAs of target genes were regulated by miR168 by means of cleavage,which mainly contained protein argonaute 1AGO1)and callose synthase 3CalS3). qRT-PCR analysis showed that a dynamic change of “rise-decline expression pattern of miR168a was observed during the dormancy process of pear bud. In addition,the expression of target gene AGO1 showed an increase trend,while the expression of target gene CalS3 showed a decrease trend. Furthermore,the expression of CalS3 showed a negative correlation with germination rate of pear bud,declined with the increase of germination rate. Taken together,the work also showed that the sequence of plant miR168s was highly conserved,and may regulate flower bud dormancy together with AGO1 through ABA. The up-regulated expression of miR168a in pear may inhibit the expression of CalS3 and thus promote the release of dormancy in pear during dormancy in winter.

Key words: pear, microRNA168, evolutionary characteristics, dormancy, expression pattern

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