Differential miRNA expression profiling reveals a correlation between hbr-miR156 and laticifer differentiation in rubber trees

A microRNA (miRNA) play a pivotal role in plant development and morphogenesis, as it can be involved in the cleavage of target genes and translational repression. Laticifer is a specific tissue in rubber trees that is used in the natural biosynthesis and storage of rubber and it differentiates from fusiform initials in the vascular cambia. However, current knowledge about the involvement of miRNAs in laticifer differentiation is limited. In the present study, the differential miRNA expression profiles in the cambial regions in response to coronatine (COR), a jasmonic acid (JA) mimic, were obtained using Illumina HiSeq-2000 technology. A total of 441 known mature miRNAs and 839 novel mature miRNAs were identified using the Mireap_v0.2 software, according to the miRBase database (Release 22.1) and CATAS7–33–97 genome. Of which, 119 miRNAs exhibited differential expression during the early and late-stage responses to COR, and the miRNAs differed between the two stages. Overexpression of hbr-miR156 caused a significant decrease in the number of laticifer cells in Russian dandelion (Taraxacum kok-saghyz. Rodin). The hbr-miR156 may be involved in coronatine-induced laticifer differentiation, providing a new perspective as to how miRNAs regulate the differentiation of the vascular cambia into laticifer cells.