Mealybug Transmission of Grapevine Leafroll Viruses: An Analysis of Virus–Vector Specificity

• Published in: Phytopathology 2010-08, Vol.100 (8), p.830-834
• Main Authors: Tsai, Chi-Wei, Rowhani, Adib, Golino, Deborah A, Daane, Kent M, Almeida, Rodrigo P.P
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Closteroviridae - physiology; Closterovirus; Fundamental and applied biological sciences. Psychology; Grapevine leafroll-associated virus; Hemiptera - virology; Host-Parasite Interactions; insect pests; insect vectors; Insect Vectors - virology; mixed infection; Phytopathology. Animal pests. Plant and forest protection; Planococcus ficus; Plant Diseases - virology; plant pests; plant viruses; Pseudococcus; Pseudococcus longispinus; species differences; Species Specificity; vector competence; vectorial capacity; virus transmission; Vitaceae; Vitis - parasitology; Vitis - virology
• ISSN: 0031-949X; 1943-7684
• DOI: 10.1094/phyto-100-8-0830

To understand ecological factors mediating the spread of insect-borne plant pathogens, vector species for these pathogens need to be identified. Grapevine leafroll disease is caused by a complex of phylogenetically related closteroviruses, some of which are transmitted by insect vectors; however, the specificities of these complex virus–vector interactions are poorly understood thus far. Through biological assays and phylogenetic analyses, we studied the role of vector-pathogen specificity in the transmission of several grapevine leafroll-associated viruses (GLRaVs) by their mealybug vectors. Using plants with multiple virus infections, several virus species were screened for vector transmission by the mealybug species Planococcus ficus and Pseudococcus longispinus. We report that two GLRaVs (-4 and -9), for which no vector transmission evidence was available, are mealybug-borne. The analyses performed indicated no evidence of mealybug–GLRaV specificity; for example, different vector species transmitted GLRaV-3 and one vector species, Planococcus ficus, transmitted five GLRaVs. Based on available data, there is no compelling evidence of vector–virus specificity in the mealybug transmission of GLRaVs. However, more studies aimed at increasing the number of mealybug species tested as vectors of different GLRaVs are necessary. This is especially important given the increasing importance of grapevine leafroll disease spread by mealybugs in vineyards worldwide.