Integrated analysis of miRNAs and their targets reveals that miR319c/TCP2 regulates apical bud burst in tea plant (Camellia sinensis)
The roles of microRNA-mediated epigenetic regulation were highlighted in the bud dormancy–activity cycle, implying that certain differentially expressed miRNAs play crucial roles in apical bud burst, such as csn-miR319c/TCP2.
microRNAs (miRNAs) are a class of small non-coding RNAs that regulate gene expression by targeting mRNA transcripts for cleavage or directing translational inhibition. To investigate whether miRNAs regulate bud dormancy–activation transition in tea plant, which largely affects the yield and price of tea products and adaptability of tea trees, we constructed small RNA libraries from three different periods of bud dormancy–burst transition. Through sequencing analysis, 262 conserved and 83 novel miRNAs were identified, including 118 differentially expressed miRNAs. Quantitative RT-PCR results for randomly selected miRNAs exhibited that our comprehensive analysis is highly reliable and accurate. The content of caffeine increased continuously from the endodormancy bud to flushing bud, and differentially expressed miRNAs coupling with their targets associated with bud burst were identified. Remarkably, csn-miR319c was downregulated significantly from the quiescent bud to burst bud, while its target gene CsnTCP2 (TEOSINTE BRANCHED/CYCLOIDEA/PROLIFERATING CELL FACTOR 2) displayed opposite expression patterns. Co-transformation experiment in tobacco demonstrated that csn-miR319c can significantly suppress the functions of CsnTCP2. This study on miRNAs and the recognition of target genes could provide new insights into the molecular mechanism of the bud dormancy–activation transition in tea plant.
KeywordsBud dormancy Bud burst Caffeine biosynthesis miRNAs Phytohormones Tea plant
Auxin response factor
Dormant/opened/swollen apical bud
TEOSINTE BRANCHED/CYCLOIDEA/PROLIFERATING CELL FACTOR
This work was supported by the National Natural Science Foundation of China (31800585), the China Postdoctoral Science Foundation (2017M621991), the Anhui Provincial Natural Science Foundation (1808085QC92) and the Natural Science Foundation of Anhui Provincial Department of Education (KJ2018A0131). We appreciate the anonymous reviewers for constructive comments on this manuscript.
Compliance with ethical standards
The authors declare that they have no competing interests.
- Du QG, Wang K, Zou C, Xu C, Li WX (2018) The PILNCR7-miR399 regulatory module is important for low phosphate tolerance in maize. Plant Physiol 177:1743–1753Google Scholar
- Hao XY, Yang YJ, Yue C, Wang L, Horvath DP, Wang XC (2017) Comprehensive transcriptome analyses reveal differential gene expression profiles of Camellia sinensis axillary buds at para-, endo-, ecodormancy, and bud flush stages. Front Plant Sci 8:553Google Scholar
- Jeyaraj A, Zhang X, Hou Y, Shangguan MZ, Gajjeraman P, Li YY, Wei CL (2017b) Genome-wide identification of conserved and novel microRNAs in one bud and two tender leaves of tea plant (Camellia sinensis) by small RNA sequencing, microarray-based hybridization and genome survey scaffold sequences. BMC Plant Biol 17:212CrossRefGoogle Scholar
- Koyama T, Sato F, Ohme-Takagi M (2017) Roles of miR319 and TCP transcription factors in leaf development. Plant Physiol 175:874–885Google Scholar
- Lang GA (1987) Dormancy: a new universal terminology. HortScience 22:817–820Google Scholar
- Liu LL, Li YY, She GB, Zhang XC, Jordan B, Chen Q, Zhao J, Wan XC (2018a) Metabolite profiling and transcriptomic analyses reveal an essential role of UVR8-mediated signal transduction pathway in regulating flavonoid biosynthesis in tea plants (Camellia sinensis) in response to shading. BMC Plant Biol 18:233CrossRefGoogle Scholar
- Ríos G, Leida C, Conejero A, Badenes ML (2014) Epigenetic regulation of bud dormancy events in perennial plants. Front Plant Sci 5:247Google Scholar
- Schommer C, Bresso EG, Spinelli SV, Palatnik JF (2012) Role of microRNA miR319 in plant development. In microRNAs in plant development and stress responses. Signaling and Communication in Plants 15:29–47. Springer-Verlag Berlin HeidelbergGoogle Scholar
- Sharma D, Tiwari M, Pandey A, Bhatia C, Sharma A, Trivedi PK (2016) MicroRNA858 is a potential regulator of phenylpropanoid pathway and plant development. Plant Physiol 171:944–959Google Scholar
- Wang YX, Wang Q, Gao LP, Zhu BZ, Ju Z, Luo YB, Zuo JH (2017) Parsing the regulatory network between small RNAs and target genes in ethylene pathway in tomato. Front Plant Sci 8:527Google Scholar