Abstract:

In order to understand the evolution characteristics of miR166 gene family and its expression pattern in different tissues of Dimocarpus longan，we analyzed the mature sequences，and the phylogenetic of miR166 in longan and some other fruit plants，predicted the secondary structure of precursor miR166（pre-miR166）family members，analyzed their targets，as well as their expression patterns. The results showed that the longan miR166 family contained 12 mature sequences and 7 precursor sequences. Mfold analysis showed that these pre-miR166 members could form a typical stable stem loop structures，and their minimal folding free energies（ΔG）ranged from–35.30 to–83.30 kal ? mol-1. Multiple sequence alignment of these pre-miR166 members showed that the regions generating mature miRNA were highly conservative. Phylogenetic tree analysis showed that the genetic relationship of pre-miR166 family in longan was closer to those from grape and peach. Target gene prediction of longan miR166 family revealed that their targets were homeobox-leucine zipper protein，pentatricopeptide repeat-containing protein，hypothetical protein，DNA-directed RNA polymerase Ⅲ subunit，and Ultraviolet-B receptor UVR8. Real-time quantitative PCR showed that diffierent pre-miR166 family members，had different expression patterns，and more or less expressed at different development stages on vegetative and reproductive growth of longan，suggesting that they may be widely participate in the regulation of longan organs development，and may have function division in longan.

Key words: Dimocarpus longan, miR166 family, evolution, real-time quantitative PCR