Pea streak virus recorded in Europe

Abstract

Sarkisová T., Bečková M., Fránová J., Petrzik K. (2016): Pea streak virus recorded in Europe. Plant Protect. Sci., Alfalfa (Medicago sativa L.) is concluded to be the principal reservoir of Pea streak virus (PeSV, genus Carlavirus) which induces necrotic streaking symptoms in pea. This virus is prevalent in pea growing areas in the USA, but in Europe it was recorded only once almost 60 years ago. Recently, filamentous virus particles 600-700 nm long have been observed in examined plant sap of alfalfa with leaf malformation, local necrotic lesions and yellow spots on leaves. Four kilo base pairs nucleotide sequence of PeSV including partial replicase gene, triple gene block, and capsid protein (CP) gene has been determined. On the nucleotide level, the sequence of the CP has about 80% identity with the North American isolates of PeSV, however, on the amino acid level the sequence has more than 94% identity. This is the first sequence-based proof of PeSV presence in Europe.Keywords: carlavirus; alfalfa; Pea streak virus; partial sequence Alfalfa (Medicago sativa L.) represents one of the most important and widely planted leguminous crops. In the Czech Republic there are 18 registered cultivars growing mainly as fodder crop representing about 36% of perennial green fodder produced (Czech Statistical Office, release November 2010). Beside many fungal diseases causing the highest damage of alfalfa, there are more than 30 viruses of 15 viral families listed to be able to infect alfalfa (Brunt et al. 1996) Pea streak virus (PeSV, genus Carlavirus) was first described in 1938 (Zaumeyer 1938) and was found in pea growing areas in the USA. Alfalfa latent virus has been described in 1977 (Veerisetty & Brakke 1977), but recently it is recognised as a mild strain of PeSV causing mostly symptomless infections and distinguishable from PeSV only by typical symptoms on pea plants (Hampton 1981). PeSV is presumed to be widespread in most alfalfa growing areas (Rahman & Paeden 1993), but outside America it was recorded only once by electron microscopy and by serology in white sweet clover (Melilotus alba) in Germany (Brandes & Quantz 1957;Wetter & Quantz 1958). Only sequences of American isolates are represented in GenBank now -two identified as ALV and originated from alfalfa host, and two identified as PeSV from pea and from unknown host (Table 1). In this work we firstly describe sequence of a PeSV isolate coming from Europe. 165Plant Protect. Sci. Vol. 52, 2016, No. 3: 164-166 doi: 10.17221/157/2015-PPS MAtERiAl And MEthodsAlfalfa (Medicago sativa) plant originally designated as sample "V4" with leaves malformation (yellow spots becoming local necrotic lesion) has been found in Želešice (SE of the Czech Republic). Crude plant sap preparation from symptomatic leaves was negatively stained with uranyl acetate and inspected using transmission electron microscopy (JEM 1010; JEOL USA, Peabody, USA). RNA was isolated from the symptomatic plants with Nucleospin RNA II kit (Macherey-Nagel, Düren, Germany) according to the...