Detection of beet necrotic yellow vein virus in Lithuania.

A survey of sugar beet crops for the presence of Beet necrotic yellow vein virus (BNYVV) in Lithuania was undertaken from 1998 using DAS-ELISA as a detection method. In 2004 in one area of the South-west region of Lithuania, sugar beet roots with branched tips and enlarged quantities of small rootlets were collected and samples of rootlets reacted positively for BNYVV using the kits from BIOREBA AG and LOEWE. When sugar beet seeds were sown in soil collected from the rhizomania infected field, the germinated plants rootlets appeared thicker and had brown discoloration. The samples of rootlets gave a positive reaction with BNYVV in DAS-ELISA tests. These samples in immunosorbent electron microscopy with trapped antibodies from the BIOREBA AG kit revealed the presence of straight, very short and longer particles, about 20 nm in diameter. Mechanical inoculations to Chenopodium amaranticolor resulted in development of local chlorotic lesions. These sugar beet rootlets were used for RT-PCR detection BNYVV with primer pairs as recommended by V.Harju from Central Science Laboratory (UK) in Protocol for the diagnosis of the quarantine organism Beet necrotic yellow vein virus (2003) and a slightly modified one-step protocol. Using both RT-PCR protocols, amplified products of the expected size were obtained. Thus, detection of BNYVV in Lithuania was confirmed by ELISA in naturally infected sugar beet roots, in rootlets of plants grown in soil from rhizomania infected field, by mechanical transmission to plant-indicator, by morphology of detected virus particles in ISEM, and according to RT-PCR amplification products.