First Report on the Natural Occurrence of Beet chlorosis virus in Poland.

Yellowing symptoms on sugar beet (Beta vulgaris L.) are caused by several viruses, especially those belonging to the genus Polerovirus of the family Luteoviridae, including Beet mild yellowing virus (BMYV) and Beet western yellows virus (BWYV), and recently, a new species, Beet chlorosis virus (BChV), was reported (2). To identify Polerovirus species occurring in beet crops in Poland and determine their molecular variability, field surveys were performed in the summer and autumn of 2005. Leaves from symptomatic beet plants were collected at 26 localities in the main commercial sugar-beet-growing areas in Poland that included the Bydgoszcz, Kutno, Lublin, Poznań, Olsztyn, and Warszawa regions. Enzyme-linked immunosorbent assay (ELISA) tests (Loewe Biochemica GmbH, Sauerlach, Germany) detected poleroviruses in 23 of 160 samples (approximately 20 samples from each field). Multiplex reverse-transcription polymerase chain reaction (RT-PCR) (1) (GE Healthcare S.A.-Amersham Velizy, France) confirmed the presence of poleroviruses in 13 of 23 samples. Nine of twenty sugar beet plants gave positive reactions with BChV-specific primers and three with primers specific to the BMYV P0 protein. Two isolates reacted only with primer sets CP+/CP, sequences that are highly conserved for all beet poleroviruses. Leaf samples collected from three plants infected with BChV were used as inoculum sources for Myzus persicae in transmission tests to suitable indicator plants including sugar beet, red beet (Beta vulgaris L. var. conditiva Alef.), and Chenopodium capitatum. All C. capitatum and beet plants were successfully infected with BChV after a 48-h acquisition access period and an inoculation access period of 3 days. Transmission was confirmed by the presence of characteristic symptoms and by ELISA. Amino acid sequences obtained from each of four purified (QIAquick PCR Purification kit, Qiagen S.A., Courtaboeuf, France) RT-PCR products (550 and 750 bp for CP and P0, respectively) were 100% identical with the CP region (GenBank Accession No. AAF89621) and 98% identical with the P0 region (GenBank Accession No. NP114360) of the French isolate of BChV. To our knowledge, this is the first report of BChV in Poland. References: (1) S. Hauser et al. J. Virol. Methods 89:11, 2000. (2) M. Stevens et al. Mol. Plant Pathol. 6:1, 2005.