Incidence and transmission of Faba bean necrotic yellows virus (FBNYV) in Spain

V Ortiz,J Romero,S Castro,E Navarro,G Carazo

doi:10.5424/sjar/2006043-200

Abstract

Information on the distribution of Faba bean necrotic yellows virus (FBNYV) in Spain was gathered by sampling different legume crops (faba bean "Muchamiel", forage faba bean, pea and chickpea) in four regions (Murcia, Andalucía, Castilla y León, and Extremadura). The virus was detected by TAS-ELISA in faba bean "Muchamiel" and peas only in the Murcia region. A portion of 272 bp within the C5 component of a FBNYV from Murcia was amplified by IC-PCR and directly sequenced. The Spanish FBNYV was 93.75% identical to two previously sequenced isolates of FBNYV from Syria and Egypt. Periodic samplings of faba bean "Muchamiel" over one growing season (Oct. 1999 to Jan. 2000) in Murcia provided no clear evidence of any spread of the disease either within or beyond the affected fields. Mixed infections of FBNYV and Tomato spotted wilt virus (TSWV), Bean leaf roll virus (BLRV) and Bean yellow mosaic virus (BYMV) were commonly observed. The necrotic symptoms developed on the leaf borders were more pronounced in these mixed infections. Transmission experiments using a Spanish isolate as inoculum source and the aphid species Acyrthosiphon pisum and Aphis craccivora showed that both are efficient FBNYV vectors. In these experiments, the faba bean cvs. "Aguadulce", "Muchamiel" and "Valenciana"were all susceptible to FBNYV.

Highlights

Faba bean necrotic yellows virus (FBNYV; genus Nanovirus) causes severe yield losses and crop failure in food and fodder legumes in Western Asia and North Africa (Makkouk et al, 1992, 1994; Franz et al, 1995; Makkouk and Kumari, 2000)
FBNYV was detected in 85 samples from the Murcia region, but only from faba bean cv
FBNYV was first reported from Syria in 1988 and subsequently was recorded in many Arab countries of West Asia and North Africa as Syria, Jordan, Ethiopia, Egypt, Algeria and Morocco (Katul et al, 1993; Franz et al, 1996)

Summary

Introduction

Faba bean necrotic yellows virus (FBNYV; genus Nanovirus) causes severe yield losses and crop failure in food and fodder legumes in Western Asia and North Africa (Makkouk et al, 1992, 1994; Franz et al, 1995; Makkouk and Kumari, 2000). The virus has a wide host range—58 host legume species have been identified (Katul et al, 1993; Franz et al, 1997). FBNYV is persistently transmitted by aphids, most efficiently (in laboratory tests) by Acyrthosiphon pisum (Harris) and Aphis craccivora (Koch). V. Ortiz et al / Span J Agric Res (2006) 4(3), 255-260 considered the most efficient vector of Syrian FBNYV isolates and A. craccivora the most important vector under field conditions (Franz et al, 1995, 1998). The virus has a multipartite genome consisting of several circular ssDNA components that are similar in size (about 1 kb) and individually encapsidated in small isometric particles about 18 nm in diameter (Katul et al, 1993). Early-infected plants remain stunted, showing leaf yellowing followed by necrosis and plant death

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