Grant Information

PATHOGEN-VECTOR RELATIONS BETWEEN ASIAN CITRUS PSYLLID AND LIBERIBACTER ASIATICUS

Sponsoring Institution Agricultural Research Service/USDA
Status ACTIVE
Funding Source USDA INHOUSE
Reporting Frequency Annual
Project Director HALL D G
Accession Number 420109
Project Number 6034-22320-001-13R
Dates 2010-07-01 - 2012-08-31
Recipient Organization AGRICULTURAL RESEARCH SERVICE
219 SOUTH ROCK ROAD
FT PIERCE,FL 34945
Keywords asian
citri
citrus
diaphorina
disease
greening
huanglongbing
psyllid
Research Effort Applied (30%)
Basic (45%)
Developmental (25%)
Classification Parameters
Knowledge AreaSubject of InvestigationField of SciencePercent
215 - Biological Control of Pests Affecting Plants 2110 - Ornamental trees and shrubs 1130 - Entomology and acarology 20%
211 - Insects, Mites, and Other Arthropods Affecting Plants 910 - Grapefruit 1130 - Entomology and acarology 15%
215 - Biological Control of Pests Affecting Plants 920 - Orange 1130 - Entomology and acarology 15%
216 - Integrated Pest Management Systems 1460 - Tomato 1130 - Entomology and acarology 15%
216 - Integrated Pest Management Systems 2122 - Potted plants 1130 - Entomology and acarology 15%
211 - Insects, Mites, and Other Arthropods Affecting Plants 1429 - Cucurbits, other (includes pumpkin, squash, gourd) 1130 - Entomology and acarology 10%
211 - Insects, Mites, and Other Arthropods Affecting Plants 1499 - Vegetables, general/other 1130 - Entomology and acarology 10%
Goals / Objectives
To examine the specific interactions between Asian citrus psyllid (ACP) and Candidatus Liberbacter asiaticus (Las), the bacterium responsible for huanglongbing (HLB) or citrus greening disease. Substantial gaps and conflicting reports exist in our knowledge of the relationship between ACP and LAS. Thus, our research objectives are: a) to study cellular interactions, transmission barriers, and other factors affecting vector specificity and vector competence; and b) to clarify various acquisition and transmission parameters between ACP and Las.
Methods (unparsed)

Q-PCR and fluorescence In situ hybridization (FISH) will be used to identify ACP organs and tissues that are infected by LAS. A time-course study will be used to find out if Las replicates or just accumulates in these tissues during the nymphal or adult stages. Traditional transmission experiments will be conducted to assess disease acquisition and transmission parameters.

Methods
Q-PCR and fluorescence In situ hybridization (FISH) will be used to identify ACP organs and tissues that are infected by LAS. A time-course study will be used to find out if Las replicates or just accumulates in these tissues during the nymphal or adult stages. Traditional transmission experiments will be conducted to assess disease acquisition and transmission parameters.
Project Timeline Tracking

Outputs

Q-PCR and fluorescence In situ hybridization (FISH) will be used to identify Asian citrus psyllid (ACP) organs and tissues that are infected by LAS. A time-course study will be used to find out if Las replicates or just accumulates in these tissues during the nymphal or adult stages. Traditional transmission experiments will be conducted to assess disease acquisition and transmission parameters. This project is related to Objective 3c: Investigate basic biology and ecology of the Asian citrus psyllid and its natural enemies in Florida citrus. Huanglongbing (HLB) is caused by a bacterium vectored by Asian citrus psyllid (ACP). This project was conducted to elucidate the biological relationships between the disease and vector. We found the HLB bacterium in the ACP alimentary canal, filter chamber, midgut, Malpighian tubules, hemolymph, salivary glands, and ovaries and in muscle and fat tissues. The bacterium appears to replicate or accumulate in both the alimentary canal and salivary glands. The proportion of infected salivary glands was significantly lower than that of infected alimentary canals or other organs. However, titers of the bacterium were high in the salivary glands. Relatively low percentages of infected psyllids transmit the bacterium. The salivary glands therefore appear to constitute a significant barrier to infection and/or transmission by ACP. A new detached-leaf assay method was developed that speeds up inoculativity tests on psyllids from 3-12 months to 2-3 weeks.