title: Application of a modified EDTA-mediated exudation technique and guttation fluid analysis for Potato spindle tuber viroid RNA detection in tomato plants (Solanum lycopersicum).
abstract: Potato spindle tuber viroid (PSTVd) is a small plant pathogenic circular RNA that does not encode proteins, replicates autonomously, and traffics systemically in infected plants. Long-distance transport occurs by way of the phloem; however, one report in the literature describes the presence of viroid RNA in the xylem ring of potato tubers. In this study, a modified method based on an EDTA-mediated phloem exudation technique was applied for detection of PSTVd in the phloem of infected tomato plants. RT-PCR, nucleic acid sequencing, and Southern blot analyses of RT-PCR products verified the presence of viroid RNA in phloem exudates. In addition, the guttation fluid collected from the leaves of PSTVd-infected tomato plants was analyzed revealing the absence of viroid RNA in the xylem sap. To our knowledge, this is the first report of PSTVd RNA detection in phloem exudates obtained by the EDTA-mediated exudation technique.
authors.affiliation: Molecular Plant Pathology Laboratory, U.S. Department of Agriculture, Agricultural Research Service, Beltsville, MD 20705, USA; Institute of Ecological Soil Science of MV Lomonosov Moscow State University, Moscow 119991, Russia.
authors.forename: Natalia
authors.initials: N
authors.lastname: Kovalskaya
authors.affiliation: Molecular Plant Pathology Laboratory, U.S. Department of Agriculture, Agricultural Research Service, Beltsville, MD 20705, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Owens
authors.affiliation: Molecular Plant Pathology Laboratory, U.S. Department of Agriculture, Agricultural Research Service, Beltsville, MD 20705, USA.
authors.forename: C Jacyn
authors.initials: CJ
authors.lastname: Baker
authors.affiliation: Genetic Improvement of Fruits and Vegetables Laboratory, U.S. Department of Agriculture, Agricultural Research Service, Beltsville, MD 20705, USA.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Deahl
authors.affiliation: Molecular Plant Pathology Laboratory, U.S. Department of Agriculture, Agricultural Research Service, Beltsville, MD 20705, USA. Electronic address: rose.hammond@ars.usda.gov.
authors.forename: Rosemarie W
authors.initials: RW
authors.lastname: Hammond
mesh_terms: D004492:Edetic Acid / Q000737:chemistry*; D018551:Solanum lycopersicum / Q000821:virology*; D052585:Phloem / Q000821:virology; D010935:Plant Diseases / Q000235:genetics*; D018515:Plant Leaves / Q000821:virology; D012313:RNA / Q000235:genetics*; D000079962:RNA, Circular; D014772:Viroids / Q000235:genetics*
chemical_list: D000079962:RNA, Circular; D012313:RNA; D004492:Edetic Acid
keywords: EDTA-mediated phloem exudation; Guttation fluid; Potato spindle tuber viroid; Solanum lycopersicum