Transcriptome Analysis of Sunflower Genotypes with Contrasting Oxidative Stress Tolerance Reveals Individual- and Combined- Biotic and Abiotic Stress Tolerance Mechanisms.

Anjugam Paramanantham,Makarla Udayakumar,Vemanna S Ramu,Venkategowda Ramegowda,Basavaiah Mohan-Raju,Debasis Chakrabarty,Muthappa Senthil-Kumar

doi:10.1371/journal.pone.0157522

Anjugam Paramanantham, Makarla Udayakumar + Show 5 more

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https://doi.org/10.1371/journal.pone.0157522

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Abstract

In nature plants are often simultaneously challenged by different biotic and abiotic stresses. Although the mechanisms underlying plant responses against single stress have been studied considerably, plant tolerance mechanisms under combined stress is not understood. Also, the mechanism used to combat independently and sequentially occurring many number of biotic and abiotic stresses has also not systematically studied. From this context, in this study, we attempted to explore the shared response of sunflower plants to many independent stresses by using meta-analysis of publically available transcriptome data and transcript profiling by quantitative PCR. Further, we have also analyzed the possible role of the genes so identified in contributing to combined stress tolerance. Meta-analysis of transcriptomic data from many abiotic and biotic stresses indicated the common representation of oxidative stress responsive genes. Further, menadione-mediated oxidative stress in sunflower seedlings showed similar pattern of changes in the oxidative stress related genes. Based on this a large scale screening of 55 sunflower genotypes was performed under menadione stress and those contrasting in oxidative stress tolerance were identified. Further to confirm the role of genes identified in individual and combined stress tolerance the contrasting genotypes were individually and simultaneously challenged with few abiotic and biotic stresses. The tolerant hybrid showed reduced levels of stress damage both under combined stress and few independent stresses. Transcript profiling of the genes identified from meta-analysis in the tolerant hybrid also indicated that the selected genes were up-regulated under individual and combined stresses. Our results indicate that menadione-based screening can identify genotypes not only tolerant to multiple number of individual biotic and abiotic stresses, but also the combined stresses.

Highlights

Sunflower (Helianthus annuus) is one of the most important oilseed crops worldwide
Sunflower growing regions are characterized by constant occurrence of multiple individual biotic and abiotic stresses, and simultaneous drought, pathogen infection and temperature stresses resulting in substantial loss of crop productivity [1,2,3,4]
The data from plants exposed to drought, heat, NaCl, oxidative stress, cold stress and an oomycete pathogen, Plasmopara halstedii infection were collected to identify stress responsive genes shared among these stresses (S2 Table)

Summary

Introduction

Sunflower (Helianthus annuus) is one of the most important oilseed crops worldwide. Sunflower growing regions are characterized by constant occurrence of multiple individual biotic and abiotic stresses, and simultaneous drought, pathogen infection and temperature stresses resulting in substantial loss of crop productivity [1,2,3,4]. Recent climate changes lead to unpredictable rainfall pattern, temperature and pathogen spread [5,6,7,8]. This lead to increased interaction of pathogens with different abiotic stresses in the plant interphase [9,10]. Research in the past had largely focused on understanding plant responses to individual stresses with a limited emphasis on combined stresses [11,12,13,14,15]. Uncovering the shared mechanisms using information from large number of individual stress based studies will be useful for understanding the role of commonly regulated genes under combined and individual stresses

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