Detection of conserved microRNAs in Saccharum Officinarum Using Microarray

MicroRNAs (miRNAs) reported previously from Arabidopsis. thaliana and other seven plant species, by both experimental validation and prediction, were used to identify potential miRNAs in Saccharum officinarum which is an important food and bio-energy crop. A microfluidic microarray was developed for detecting plant miRNAs and used for the first experimental analyzing the mature miRNAs and miRNAs* in S. officinarum. Using probes corresponding to detect 231 miRNAs and 104 miRNAs*, a total of 114 conserved miRNAs and 11 miRNAs* were detected, following a set of strict criteria. The results suggest that miRNAs are highly conserved and divergent among plants. To validate the hybridization results, a RT-PCR assay of mature miRNA expression was performed, yielding the detection of five miRNAs selected. Comparison of expression profiles revealed that 80 miRNA and five miRNAs* expressed differentially between young seedlings and adult plants. We also found that three miRNA families, including miR394, 476 and 481 characteristically expressed in the seedling. The above studies provide an approach for large-scale experimental detection of conserved miRNAs in species with limited genome information available.