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

Ning Jiang,Yushi Luan,Guangxin Sun,Jun Meng,Jun Cui

doi:10.1038/s41438-018-0017-2

Ning Jiang, Yushi Luan + Show 3 more

Open Access

https://doi.org/10.1038/s41438-018-0017-2

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Abstract

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.

Highlights

Tomato, as an important horticultural and economic crop cultivated worldwide, always suffers from the aggression of various pathogens[1,2,3]
The result of multiple nucleic acid sequence alignments showed that the sequence of the pre-miR482b and mature-miR482b were identical to the miR482b from cultivated tomato S. lycopersicum in miRbase (Figure S1)
To verify whether miR482b was involved in the response to P. infestans infection, the expression of miR482b in P. infestans-treated leaves at different dpi was measured

Summary

Introduction

As an important horticultural and economic crop cultivated worldwide, always suffers from the aggression of various pathogens[1,2,3]. Phytophthora infestans, the agent that causes late blight, has become one of the most devastated pathogens[4] and can cause great losses in tomato production[5]. In Inner Mongolia of China and the USA, late blight caused the loss of tomato production in early 2000s6,7. The molecular mechanisms of tomato–P. infestans interaction are beyond understanding and the method for controlling tomato late blight is still not effective enough. It is necessary to study tomato resistance mechanisms against. P. infestans and identify the key resistance genes which are used in disease-resistance breeding of tomato transgene. The major methods to study miRNA functions are to generate and analyze the transgenic lines overexpressing miRNAs11,12. In our previous studies, overexpression of miR172 in tomato enhanced its susceptibility to P. infestans[13]

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