Identification and comparative profiling of microRNAs in an early flowering mutant of trifoliate orange (Poncirus trifoliata (L.) Raf.) and its wild type by genome-wide high throughput sequencing
Solexa sequencing was performed at different developmental stages both an early flowering mutant of trifoliate orange (precocious trifoliate orange, Poncirus trifoliata L. Raf.) and its wild-type in this study, resulting in the obtainment of a total of 143 known miRNAs belonging to 99 families and 75 novel miRNAs in four libraries. A total of 317 potential target genes were predicted based on the 50 novel miRNAs families, GO and KEGG annotation revealed that high ranked miRNA-target genes are those implicated in diverse cellular processes in plants, including development, transcription, protein degradation and cross adaptation. To characterize those miRNAs expressed at the juvenile and adult development stages of the mutant and its wild-type, further analysis on the expression profiles of several miRNAs through real-time PCR was performed. The results revealed that most miRNAs were down-regulated at adult stage compared with juvenile stage both the mutant and its wild-type. These results indicate that both conserved and novel miRNAs may play important roles in citrus growth and development, stress responses and other physiological processes. Overall design: To understand whether miRNA was involved in the lowering process, the miRNA levels was investigated in juvenile and adult precocious trifoliate orange and its wild-type by Solexa sequencing.