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Pierce's Disease
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What is Pierce's Disease?

Pierce's Disease is a bacterial infection, which is spread by bugs that feed on grapevines, particularly the "glassy winged sharpshooter." Grapevines that become infected with PD can quickly become sick and die.

glassy-winged sharpshooter

GENETIC STUDIES OF GONATOCERUS METANOTALIS POPULATIONS FROM ARGENTINA UNCOVER DIVERGENT CLADES: A PROSPECTIVE EGG PARASITOID CANDIDATE AGENT FOR THE GLASSY-WINGED SHARPSHOOTER IN CALIFORNIA

  • Author(s): de Le?n, Jesse; Logarzo, Guillermo; Triapitsyn, Serguei; Morgan, David;
  • Abstract: Two molecular methods were utilized to genetically distinguish geographic populations of Gonatocerus metanotalis (Ogloblin) (Hymenoptera: Mymaridae) from Argentina and to begin to test the possibility that this South American species could exist as a cryptic species complex. Gonatocerus metanotalis is a prospective egg parasitoid candidate agent for a neoclassical biological control program in California against the invasive glassy-winged sharpshooter (GWSS), Homalodisca vitripennis (Germar) [=H. coagulata (Say)]. Six populations were analyzed: Campo Grande (Misiones Province), Tartagal (Salta), Taf Viejo (Tucumn), near PROIMI (Tucumn), Santa Clara (Jujuy), Clorinda (Formosa). As a first approach, inter-simple sequence repeat-polymerase chain reaction (ISSR-PCR) DNA fingerprinting was performed with a 5-anchored ISSR primer. Several distinct banding patterns were identified among the populations with some band sharing and in certain populations (Tartagal and Santa Clara) there was extensive variation. Next, a phylogeographic analysis inferred by the mitochondrial cytochrome oxidase subunit I (COI) gene was performed. A neighbor-joining distance tree clustered the G. metanotalis populations into three main distinct clades supported by very strong bootstrap values (100%), uncovering haplotype or phylogeographic structure. With the exception of one population (Campo Grande), all individuals from the populations fell into one of the three clades. Individuals from Campo Grande clustered into the three clades, suggesting that three sympatric strains may be present in this location. A phylogenetic analysis performed by the neighbor-joining algorithmic method along with other named and two unnamed Gonatocerus Nees species (15) confirmed species boundaries and again uncovered three main distinct clades in G. metanotalis. Very strong bootstrap support (100%) was seen for both the G. metanotalis clades and for all of the Gonatocerus species. Understanding possible cryptic variation in this prospective GWSS egg parasitoid candidate agent is critical to the biological control program in California.
  • Publication Date: Nov 2006
  • Journal: 2006 Pierce's Disease Research Symposium

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