A Rapid Protocol for Evaluating Prunus Germplasm for Tomato Ringspot Virus Resistance

Abstract

Rooted cuttings of `Halford' and `Redhaven' peaches [Prunus persica (L.) Batsch] and `Stanley' (Prunus domestica L.) and `Marianna 2624' (P. cerasifera × P. munsoniana) plums were planted in soil containing ≈38 tomato ringspot virus-(TomRSV) infested nematodes (Xiphinema americanum sensu lato Cobb) per 100 cc. Test- and control-plant sap extracts were made from root and leaf tissues after 10, 22, and 34 weeks. Aliquots of these samples were assayed by mechanical inoculation to Chenopodium quinoa Willd. Total nucleic-acid extracts prepared from the remainder of each sample were analyzed by dot blot hybridization using a cRNA probe for TomRSV. The bioassay identified one `Stanley' and two `Redhaven' infected plants. Hybridization results indicated that two of two `Stanley', three of three `Halford', five of five `Redhaven', and zero of six `Marianna 2624' were infected. Our results demonstrate the sensitivity of molecular hybridization for TomRSV detection in Prunus and substantiate the TomRSV resistance of `Marianna 2624'.