Survival, Persistence, and Infection Efficiency of Verticillium dahliae Passed Through the Digestive System of Sheep.

Abstract

The present study was carried out to determine the survival, persistence, and infection efficiency of Verticillium dahliae passed through the digestive tract of sheep. Eggplant, turnip, tomato, and pepper plants were artificially inoculated with 32 V. dahliae isolates. At 33 days postinoculation, the disease incidence and severity for eggplant, turnip, tomato, and pepper plants were 99.6, 96.2, 62.9, and 18.0% and 80.1, 49.8, 19.8, and 7.8%, respectively. The infected plant material was used to feed four 1-year-old sheep. Polymerase chain reaction assays revealed the presence of V. dahliae DNA in fecal samples received from animals' rectum on days 1, 2, 3, 4, and 5, whereas the pathogen DNA was not detected on 0, 6, and 7 days after feeding. Pathogenicity tests were conducted by transplanting eggplant plants into soil substrate amended with 20% decomposed manure, collected from the four animals fed with the infested forage. At 52 days after transplanting, manure-treated plants exhibited Verticillium wilt symptoms whereas, 2 months later, disease incidence, disease severity, and percentage of positive V. dahliae isolations from stem tissues were 58.3, 30.7, and 48.3%, respectively. Symptoms or positive isolations were not observed in control plants (transplanted in 100% soil substrate). This is the first report of the active role of V. dahliae passed through the digestive system of sheep as effective inoculum for host plants, in relation to the span persistence and transmission via the sheep carrier.