VIEW ARTICLE

Etiology

Association of Single-Stranded DNA with the Foliar Decay Disease of Coconut Palm in Vanuatu. J. W. Randles, Department of Plant Pathology, Waite Agricultural Research Institute, University of Adelaide, Glen Osmond, South Australia 5064; J. F. Julia(2), C. Calvez(3), and M. Dollet(4). (2)(3)IRHO-CIRAD, Saraoutou Station, B.P. 89, Santo, Vanuatu; (4)IRHO-CIRAD, B.P. 5035 34032 Montpellier Cedex, France. Phytopathology 76:889-894. Accepted for publication 17 January 1986. Copyright 1986 The American Phytopathological Society. DOI: 10.1094/Phyto-76-889.

Foliar decay disease induced by feeding of the cixiid plant hopper, Myndus taffini, is a disease of unknown etiology that develops in coconut palms in Vanuatu. Extraction of diseased leaf tissue with or without a cellulase digestion treatment, followed by a precipitation step with 8% polyethylene glycol 6000, and high-speed centrifugation, yielded a sedimentable component containing a single-stranded DNA. This component has an estimated sedimentation coefficient of less than 75 S. and buoyant densities in Nycodenz and Cs₂SO₄ of 1.21-1.25 g/ml and about 1.36 g/ml, respectively, but no virus-like particles were specifically associated with this component. An assay for the DNA, based on polyacrylamide gel electrophoresis and silver staining, showed that it was disease specific. It has an estimated mol wt between 2 and 3 x 10⁶ in 3.3% polyacrylamide gels and therefore appears not to be typical of DNA from any plant virus taxonomic group. The use of this DNA for the diagnosis of foliar decay disease and the possibility that it indicates a virus etiology is discussed.