Function identification of miR482b, a negative regulator during tomato resistance to Phytophthora infestans

摘要

Tomato is an important horticultural and economic crop cultivated worldwide. As Phytophthora infestans becomes a huge threat to tomato production, it is necessary to study the resistance mechanisms of tomato against P. infestans . Our previous research has found that miR482 might be involved in tomato– P . infestans interaction. In this study, miR482b precursor was cloned from Solanum pimpinellifolium “L3708” and miR482b was shown to decrease in abundance in tomato following P . infestans infection. Compared to wild-type tomato plants, tomato plants that overexpressed miR482b displayed more serious disease symptoms after P . infestans infection, with more necrotic cells, longer lesion diameters, and increased P . infestans abundance. Meanwhile, silencing of miR482b was performed by short tandem target mimic (STTM), resulting in enhancement of tomato resistance to P . infestans . Using miRNA and degradome data sets, NBS–LRR disease-resistance genes targeted by miR482b were validated. Negative correlation between the expression of miR482b and its target genes was found in all miR482b -overexpressing and -silencing tomato plants. Our results provide insight into tomato miR482b involved in the response to P . infestans infection, and demonstrate that miR482b– NBS–LRR is an important component in the network of tomato– P . infestans interaction.