662 / 2019-04-30 11:04:46

Identification and Expression Analysis of MicroRNAs Involved in Age-related Flowering Pathway in Ginkgo biloba

age-related flowering pathway; gene.Gb_15227; microRNAs; transcriptome

Growth and Development > Growth and Development

The age-related flowering pathway is one of the most important pathways concerning flowering initiation in plant kingdom. It has been proposed that microRNA plays an important role in the age-related flowering pathway. However, the molecular mechanism underlying age-related flowering pathway remains unclear, although microRNA156 and microRNA172 have been identified as key mediators in this process. Ginkgo biloba has a particularly long juvenile phase, which severely restricted its breeding study, indicating the specificity of its age-related flowering pathway. In order to reveal the molecular mechanism underlying flowering initiation in Ginkgo biloba, transcriptome and microRNAs analysis were performed in samples of the stem apex from a juvenile tree, from a tree flowering for the first year, and from a tree flowering for many years, respectively. A total of 594 microRNAs were identified, including 89 known microRNAs and 505 new microRNAs. Then 12,762 target genes were identified based on known and newly predicted microRNAs. By comparing the expression patterns of microRNAs among the stem apex samples at different stages, 6 microRNAs with continuous up-regulation or down-regulation patterns were screened. Consequently, the target genes of these microRNAs were mainly enriched in the transcriptional regulation and signal transduction pathways. The expression levels of those selected genes were confirmed by quantitative real-time PCR.