Evaluation of peanut genotypes for resistance to Tomato spotted wilt virus by mechanical and thrips inoculation

Luciana Cordeiro Do Nascimento,Carl Michael Deom,Gilvan Pio-Ribeiro,Francisco Miguel De Assis Filho,Viboon Pensuk,John Sherwood,Nivânia Pereira Da Costa

doi:10.1590/s0100-204x2006000600006

Abstract

The objective of this work was to evaluate the reactions of three peanut breeding lines (IC-10, IC-34, and ICGV 86388) to Tomato spotted wilt virus (TSWV) by mechanical and thrips inoculation, under greenhouse conditions, and compare them to the reactions of cultivars SunOleic, Georgia Green, and the breeding line C11-2-39. TSWV infection by mechanical inoculation was visually assessed using an index ranging from 0 (no symptoms) to 4 (apical death). Enzyme-linked immunosorbent assay was used to confirm TSWV infection from both mechanical and thrips inoculations. IC-10, IC-34, ICGV 86388, and C11-2-39 were more resistant than the cultivars SunOleic and Georgia Green based on mechanical inoculation. Upon thrips inoculation only IC-34 and ICGV-86388 were infected by TSWV, as demonstrated by reverse transcription polymerase chain reaction (RT-PCR), although no symptoms of infection were observed. The peanut breeding lines IC-10, IC-34, and ICGV 86388 show higher level of resistance to TSWV than cultivar Georgia Green considered a standard for TSWV resistance.

Highlights

Peanut (Arachis hypogaea L.) is an important oilseed crop throughout the world, and one of the main limiting factors to its production is the infection by Tomato spotted wilt virus (TSWV) (Culbreath et al, 2003)
The peanut breeding lines IC-10, IC-34, and ICGV-86388 were tested for TSWV resistance and showed field resistance to the TSWV-related tospovirus Peanut bud necrosis virus under natural infection in Thailand (Pensuk et al, 2002)
Plants from all peanut genotypes tested became systemically infected with TSWV by mechanical inoculation

Summary

Introduction

Peanut (Arachis hypogaea L.) is an important oilseed crop throughout the world, and one of the main limiting factors to its production is the infection by Tomato spotted wilt virus (TSWV) (Culbreath et al, 2003). Tomato spotted wilt disease was first described in Australia on tomato (Lycopersicon esculentum Miller) (Brittleblank, 1919), and its viral etiology was confirmed in 1930 (Samuel et al, 1930). TSWV is capable of infecting more than 800 species of plants, monocot and dicot, within more than 70 families (Goldbach & Peters, 1994). Epidemics of TSWV occur in many parts of the world causing losses in several crops (Culbreath et al, 2003). TSWV is the type member of the genus Tospovirus in the family Bunyaviridae (Van Regenmortel et al, 2000). The virions are spherical enveloped particles, Pesq. agropec. bras., Brasília, v.41, n.6, p.937-942, jun. 2006

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