Abstract:

microRNAs play the important roles in regulation of plant growth and development，
responding to biotic and abiotics tresses，and signal transduction. In this study，the seedlings of‘Jincheng’
orange（Citrus sinensis Osbeck），‘Ziyang Xiangcheng’（C. junos Sied. ex Tanaka），and Flying dragon
（Poncirus trifoliata Raf.），and the grafted plants of‘Jincheng/Ziyang Xiangcheng’，‘Jincheng/Flying
Dragon’were used as materials to analyze the expression profiles of microRNAs and their target genes
before and after grafting. Fluorescence quantitative PCRs were performed to compare the expression of
miRNAs and their target genes in the leaves and roots to identify the difference on miRNA expression
between scion and rootstock. The results indicated that the grafting significantly affected the expression of
microRNAs and their target genes in both scions and rootstocks. In the leaves of scion，effect of grafting
more likely prompted the expression of microRNAs and suppressed their target genes expression involved
in the regulation of plant growth and development，stress response and hormone signal transduction. In the
roots of rootstock，effect of grafting tended to suppress the expression of miRNAs related to the regulation of plant growth and development，and stress response. The varieties of microRNAs and the level of
expression were significantly different between the two rootstocks.

Key words: citrus, rootstock, scion, microRNAs