Large-scale transcriptome comparison of sunflower genes responsive to Verticillium dahliae

Shuchun Guo,Yanfang Zhang,Wenxia Su,Chengyan Wu,Qianzhong Li,Yulin An,Yongchun Zuo,Haifeng Yu,Wen Jin

doi:10.1186/s12864-016-3386-7

Abstract

BackgroundSunflower Verticillium wilt (SVW) is a vascular disease caused by root infection with Verticillium dahliae (V. dahlia). It is a serious threat to the yield and quality of sunflower. However, chemical and agronomic measures for controlling this disease are not effective. The selection of more resistant genotypes is a desirable strategy to reduce contamination. A deeper knowledge of the molecular mechanisms and genetic basis underlying sunflower Verticillium wilt is necessary to accelerate breeding progress.ResultsAn RNA-Seq approach was used to perform global transcriptome profiling on the roots of resistant (S18) and susceptible (P77) sunflower genotypes infected with V. dahlia. Different pairwise transcriptome comparisons were examined over a time course (6, 12 and 24 h, and 2, 3, 5 and 10 d post inoculation). In RD, SD and D datasets, 1231 genes were associated with SVW resistance in a genotype-common transcriptional pattern. Moreover, 759 and 511 genes were directly related to SVW resistance in the resistant and susceptible genotypes, respectively, in a genotype-specific transcriptional pattern. Most of the genes were demonstrated to participate in plant defense responses; these genes included peroxidase (POD), glutathione peroxidase, aquaporin PIP, chitinase, L-ascorbate oxidase, and LRR receptors. For the up-regulated genotype-specific differentially expressed genes (DEGs) in the resistant genotype, higher average fold-changes were observed in the resistant genotype compared to those in the susceptible genotype. An inverse effect was observed in the down-regulated genotype-specific DEGs in the resistant genotype. KEGG analyses showed that 98, 112 and 52 genes were classified into plant hormone signal transduction, plant-pathogen interaction and flavonoid biosynthesis categories, respectively. Many of these genes, such as CNGC, RBOH, FLS2, JAZ, MYC2 NPR1 and TGA, regulate crucial points in defense-related pathway and may contribute to V. dahliae resistance in sunflower.ConclusionsThe transcriptome profiling results provided a clearer understanding of the transcripts associated with the crosstalk between sunflower and V. dahliae. The results identified several differentially expressed unigenes involved in the hyper sensitive response (HR) and the salicylic acid (SA)/jasmonic acid (JA)-mediated signal transduction pathway for resistance against V. dahliae. These results are useful for screening resistant sunflower genotypes.

Highlights

Sunflower Verticillium wilt (SVW) is a vascular disease caused by root infection with Verticillium dahliae (V. dahlia)
Based on the above discussion of the physiological indexes, we concluded that the resistant genotype performed better in resistance to V. dahliae infection
When we focused on the average fold-change of each differentially expressed genes (DEGs) for each functional category in genotype-common DEGs, most of the upregulated DEGs in the resistant genotype showed a higher average FC than the susceptible genotype, and several down-regulated DEGs in the resistant genotype displayed lower average FCs than the susceptible genotype (Additional file 7: Table S8)

Summary

Introduction

Sunflower Verticillium wilt (SVW) is a vascular disease caused by root infection with Verticillium dahliae (V. dahlia). Because sunflowers have the characteristics of drought resistance and strong salinity tolerance, these plants have been widely planted throughout the world. SVW, a serious soil-borne vascular disease is caused by Verticillium dahliae [3], which is harmful to more than 200 plant species worldwide [4, 5]. This disease causes sunflower leaves to become yellow or withered, followed by the eventual death of seriously infected plants (Fig. 1a)

Methods

Results

Discussion

Conclusion