Biochemical aspects of the soybean response to herbivory injury by the brown stink bug Euschistus heros (Hemiptera: Pentatomidae).

Renata Velozo Timbó,Débora Pires Paula,Angela Mehta,Marcelo Hermes-Lima,Luciano Paulino Silva,Maria Carolina Blassioli Moraes

doi:10.1371/journal.pone.0109735

Renata Velozo Timbó, Débora Pires Paula + Show 4 more

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https://doi.org/10.1371/journal.pone.0109735

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Abstract

Plant defense response is an elaborate biochemical process shown to depend on the plant genetic background and on the biological stressor. This work evaluated the soybean biochemical foliar response to brown stink bug herbivory injury through an analysis of redox metabolism and proteomic 2DE profiles of susceptible (BRS Silvania RR) and resistant (IAC-100) varieties. The activity of lipoxygenase-3, guaiacol peroxidase, catalase and ascorbate peroxidase was monitored every 24 h up to 96 h. In the susceptible variety, injury caused an increase in the activities of lipoxygenase 3 and guaiacol peroxidase, no change in ascorbate peroxidase, and a decrease in catalase. In the resistant variety, injury did not cause an alteration of any of these enzymes. The proteomic profiles were evaluated after 24 h of injury and revealed to have a similar proportion (4–5%) of differential protein expression in both varieties. The differential proteins, identified by mass spectrometry, in the susceptible variety were related to general stress responses, to plant defense, and to fungal infections. However, in the resistant variety, the identified change in protein profile was related to Calvin cycle enzymes. While the susceptible variety showed adaptive changes in redox metabolism and expression of stress-responsive proteins, the resistant showed a defense response to circumvent the biological stressor.

Highlights

Stink bugs (Hemiptera: Pentatomidae) are one of the most important pests of soybean in Brazil [1]
Plant defense to herbivory injury involves two major systems: (i) the direct defense, involving structural components, and production of primary metabolites and non-volatile secondary metabolites [9,10]; and (ii) the indirect defense, which is related to the production of volatile organic compounds (VOCs), such as (E,E)-a-farnesene, methyl salicylate and cis-jasmone, which attract natural enemies of the herbivores that feed on the plants, or in some cases act as herbivore repellents [6,11]
The herbivory injury by the brown stink bug did not affect the foliar activity of any of the enzymes evaluated even after 96 h of injury (Fig. 2) for the resistant IAC-100 variety, suggesting that the redox metabolism was not affected in this variety under E. heros feeding injury

Summary

Introduction

Stink bugs (Hemiptera: Pentatomidae) are one of the most important pests of soybean in Brazil [1]. Information about the soybean defense mechanisms to this herbivore when it colonizes in the late vegetative stages is important to support pest management. Several varieties of soybean have been studied regarding their defense response to herbivores in order to identify herbivory resistant varieties [5,6,7,8]. These studies have mostly focused on primary and secondary metabolite production as parts of the plant defense strategy aiming to support environmentally friendly soybean production. Plant defense to herbivory injury involves two major systems: (i) the direct defense, involving structural components (e.g. thorns, trichomes), and production of primary metabolites (e.g. proteinase inhibitors, antioxidant enzymes) and non-volatile secondary metabolites (e.g. phenolic acids and isoflavonoids) [9,10]; and (ii) the indirect defense, which is related to the production of volatile organic compounds (VOCs), such as (E,E)-a-farnesene, methyl salicylate and cis-jasmone, which attract natural enemies (predators and parasitoids) of the herbivores that feed on the plants, or in some cases act as herbivore repellents [6,11]

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