Project description:In this study, Solexa sequencing technology has been used to discover small RNA populations of self-grafted watermelon and grafted watermelon (bottle gourd and squash were used as rootstocks). A total of 11,458,476, 11,614,094 and 9,339,089 raw reads representing 2,957,751, 2,880,328 and 2,964,990 unique sequences were obtained from the scions of self-grafted watermelon and watermelon grafted on-to bottle gourd and squash at two true-leaf stage, respectively. 39 known miRNAs belonging to 30 miRNA families and 80 novel miRNAs were identified in our small RNA dataset. Compared with self-grafted watermelon, 20 (5 known and 15 novel miRNAs) and 51 (21 known miRNAs and 30 novel miRNAs) miRNAs were expressed significantly different with higher abundance or lower abundance in watermelon grafted on to bottle gourd and squash, respectively. The differentially expressed miRNA target various transcriptional factors and other genes which involved in a wide range of biological processes. This study was firstly conducted to identify and compare miRNAs on genome-wide scale in watermelon grafting system. The miRNAs expressed differentially when watermelon was grafted onto different rootstocks suggesting that miRNAs might play an important role in diverse biological and metabolic processes in watermelon and grafting may possibly by changing miRNAs expression to regulate plant growth and response to stresses. The small RNA transcriptomes obtained in this study provided insights into molecular basis of miRNA regulation of genes expressed in self-grafted and grafted watermelon.
