FIRST REPORT OF BEET SOIL-BORNE VIRUS IN RHIZOMANIA-INFESTED SOILS OF SUGAR BEET FIELDS IN LEBANON

• Published in: Journal of plant pathology Vol. 91; no. 4; p. S4.108
• Main Authors: Mouhanna, A M, Choueiri, E
• Format: Journal Article
• Language: English
• Published: 01.12.2009
• Subjects: Beet soil-borne virus; Beta vulgaris; Chenopodium quinoa
• ISSN: 1125-4653

During spring 2007, 15 sugar beet (Beta vulgaris subsp. vulgaris var. altissima) fields with a history of rhizomania disease (Choueiri et al., 2001), were surveyed in the Bekaa Valley (Lebanon) to look for soil-borne fungal vectors of viral diseases (Mouhanna et al., 2008). Five soil samples were collected from each field, regardless of the crop planted at the time of collection. Each soil sample was distributed among three 12 x 12 cm pots, then placed in a greenhouse at 22-25 degree C, RH between 80-85%, and 16 h photoperiod. Sugar beet cv. Hilma seeds were sown in each pot. After eight weeks, leaves were harvested and the roots were left in the soil until they dried. After additional three weeks, sugar beet seeds were re-sown in the same pots. Eight weeks later the plants were collected, their roots were washed thoroughly and ELISA-tested using polyclonal antisera (DSMZ Plant Virus Collection, Germany) to Beet soil-borne virus (BSBV) and Beet necrotic yellow vein (BNYVV). BSBV was detected in the roots of plants grown in 9 soil samples primarily from the central and west Bekaa. Roots extracts in 0.1 M phosphate buffer, pH 7 and 2.5% nicotine were mechanically inoculated to Chenopodium quinoa. Necrotic ringspots developed on the leaves and BSBV presence was confirmed by ELISA. BNYVV was identified in the roots of plants grown in 32 soil samples. In the BSBV-infected soil samples, BNYVV was detected in seven samples whereas two samples were infected with BSBV alone. BNYVV has previously been reported from Lebanon (Choueiri et al., 2001). To our knowledge, this is the first report of BSBV occurring in Rhizomania-infested soils of sugar beet fields in Lebanon.