title: Combined small RNA and degradome sequencing reveals complex microRNA regulation of catechin biosynthesis in tea (Camellia sinensis).
abstract: MicroRNAs are endogenous non-coding small RNAs playing crucial regulatory roles in plants. Tea, a globally popular non-alcoholic drink, is rich in health-enhancing catechins. In this study, 69 conserved and 47 novel miRNAs targeting 644 genes were identified by high-throughout sequencing. Predicted target genes of miRNAs were mainly involved in plant growth, signal transduction, morphogenesis and defense. To further identify targets of tea miRNAs, degradome sequencing and RNA ligase-mediated rapid amplification of 5'cDNA ends (RLM-RACE) were applied. Using degradome sequencing, 26 genes mainly involved in transcription factor, resistance protein and signal transduction protein synthesis were identified as potential miRNA targets, with 5 genes subsequently verified. Quantitative real-time PCR (qRT-PCR) revealed that the expression patterns of novel-miR1, novel-miR2, csn-miR160a, csn-miR162a, csn-miR394 and csn-miR396a were negatively correlated with catechin content. The expression of six miRNAs (csn-miRNA167a, csn-miR2593e, csn-miR4380a, csn-miR3444b, csn-miR5251 and csn-miR7777-5p.1) and their target genes involved in catechin biosynthesis were also analyzed by qRT-PCR. Negative and positive correlations were found between these miRNAs and catechin contents, while positive correlations were found between their target genes and catechin content. This result suggests that these miRNAs may negatively regulate catechin biosynthesis by down-regulating their biosynthesis-related target genes. Taken together, our results indicate that miRNAs are crucial regulators in tea, with the results of 5'-RLM-RACE and expression analyses revealing the important role of miRNAs in catechin anabolism. Our findings should facilitate future research to elucidate the function of miRNAs in catechin biosynthesis.
authors.affiliation: College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Sun
authors.affiliation: College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou, China.
authors.forename: Chunzhen
authors.initials: C
authors.lastname: Cheng
authors.affiliation: College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou, China.
authors.forename: Yuling
authors.initials: Y
authors.lastname: Lin
authors.affiliation: College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou, China.
authors.forename: Qiufang
authors.initials: Q
authors.lastname: Zhu
authors.affiliation: College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou, China.|Anxi College of Tea Science, Fujian Agriculture and Forestry University, Fuzhou, China.
authors.forename: Jinke
authors.initials: J
authors.lastname: Lin
authors.affiliation: College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou, China.
authors.forename: Zhongxiong
authors.identifier: http://orcid.org/0000-0002-8523-621X
authors.initials: Z
authors.lastname: Lai
mesh_terms: D028241:Camellia sinensis / Q000235:genetics / Q000378:metabolism*; D002392:Catechin / Q000096:biosynthesis*; D018506:Gene Expression Regulation, Plant; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism*; D017423:Sequence Analysis, RNA
chemical_list: D035683:MicroRNAs; D018749:RNA, Plant; D002392:Catechin