Transcriptome Analysis of the Sm-Mediated Hypersensitive Response to Stemphylium lycopersici in Tomato.

Huanhuan Yang,Jingfu Li,Jingbin Jiang,Dongye Zhang,Songbo Wang,Xiuling Chen,Tingting Zhao,Chong Du,He Zhang,Xiangyang Xu,Guan Liu

doi:10.3389/fpls.2017.01257

Huanhuan Yang, Jingfu Li + Show 9 more

Open Access

https://doi.org/10.3389/fpls.2017.01257

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Abstract

Gray leaf spot disease caused by Stemphylium lycopersici is a major disease in cultivated tomato plants and threatens tomato-growing areas worldwide. Sm is a single dominant gene that confers resistance to tomato gray leaf spot disease agent. However, the underlying molecular mechanism remains unclear. Here, resistant (cv. Motelle, containing the Sm gene) and susceptible (cv. Moneymaker) plants were inoculated with virulent Stemphylium lycopersici isolate at a time point at which both cultivars showed a strong response to S. lycopersici infection. Transcriptome analyses were performed in both cultivars using RNA-seq. The number of differentially expressed genes (DEGs) was higher in Motelle than Moneymaker. Functional classification revealed that most DEGs were involved in plant–pathogen interactions, plant hormone signal transduction, regulation of autophagy, glycerophospholipid metabolism, and α-linolenic acid metabolism. Moreover, the genes that were significantly up-regulated in Sm tomatoes were involved in plant–pathogen interaction pathways. A total of 26 genes were selected for confirmation of differentially expressed levels by quantitative real-time PCR. This knowledge will yield new insights into the molecular mechanism of Sm responses to S. lycopersici infection.

Highlights

Gray leaf spot disease is considered one of the most devastating diseases in plants such as pepper (Cho et al, 2001), cotton (Francovig et al, 1999), and spinach (Koike et al, 2001)
RNA-seq was used to verify the transcriptome profiles of Sm tomato in response to S. lycopersici infection
Many significant DEGs were identified between the R and S cultivars in response to S. lycopersici infection

Summary

Introduction

Gray leaf spot disease is considered one of the most devastating diseases in plants such as pepper (Cho et al, 2001), cotton (Francovig et al, 1999), and spinach (Koike et al, 2001). Tomato gray leaf spot disease is caused by three species of Stemphylium: Stemphylium solani, Stemphylium floridanum, and Stemphylium lycopersici (Miranda et al, 2010). Gray leaf spot disease is considered a major disease in cultivated tomatoes and has threatened tomato-growing areas worldwide (Simmons, 2001). Tomato gray leaf spot disease symptoms appear as brownishblack specks, which later expand to necrotic lesions with gray centers and dark brown borders. S. lycopersici has been established as a cause tomato gray leaf spot disease based on morphology and molecular identification (Graham and Zeiders, 1960)

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