Microarray Analysis of Plant microRNAs

To identify miRNAs involved in the response of soybean to Phytophthora sojae, researchers examined expressional patterns of miRNAs upon infection by P. sojae by microarray analysis in three soybean cultivars: Williams (susceptible), Conrad (quantitative resistance), and Williams 82 (qualitative resistance)1. Expression of a number of miRNAs was significantly altered upon infection and (or) in the different genotypes. qRT–PCR data with some miRNAs further confirmed the microarray results. Comparative analysis of the selected miRNAs and their targeted gene expression datasets uncovered many reciprocally expressed miRNA–target pairs, which could proposed a feedback circuit between miRNA(s) and protein-coding genes. These results may serve as a basis for further in-depth studies of miRNAs involved in soybean resistance to P. sojae.

Apomixis or asexual seed formation represents a potentially important agronomic trait whose introduction into crop plants could be an effective way to fix and perpetuate a desirable genotype through successive seed generations. The potential function of microRNAs, which are known to play crucial roles in many aspects of plant growth and development, remains to be determined with regards to the switch from sexual to apomictic reproduction.  Using bioinformatics and microarray validation procedures, 51 miRNA families conserved among angiosperms were identified in Boechera2. Microarray assay confirmed 15 of the miRNA families that were identified by bioinformatics techniques. This study constitutes the first extensive insight into the conservation and expression of microRNAs in Boechera sexual and apomictic species.