Alteration of tomato microRNAs expression during fruit development upon Cucumber mosaic virus and Tomato aspermy virus infection.

The economic importance of Solanaceae plant species is well documented, and tomato has become a model for fleshy fruit development and ripening studies. Plant microRNAs (miRNAs) are small endogenous RNAs that are involved in a variety of activities including plant development, signal transduction and protein degradation, as well as response to environment stress and pathogen invasion. Here in this study, we aimed at quantifying the expression alterations of nine miRNAs and target mRNAs in tomato flower and fruit development upon Cucumber mosaic virus (CMV) and Tomato aspermy virus infections. Three different CMV strains CMV-Fny, CMV-FnyΔ2b and CMV-Fny-satT1 were used in our investigation, and the miRNA/mRNA expression alterations were analyzed by real-time quantitative RT-PCR. The results shown the levels of several miRNA/mRNA pairs were increased upon virus infections. However, the increased level of individual miRNA differed for different virus strains, reflecting differences in severity of symptom phenotypes. The altered expression patterns of these miRNA/mRNA pairs and their predicted functions indicate the possible roles in flower and fruit development, and provide experimental data for understanding the miRNA-mediated phenotype alterations in tomato fruit.