Grant Information

INVESTIGATING MECHANISMS OF PATHOGENESIS AND NATURAL DEFENSE RESPONSES OF CITRUS GREENING (HLB) BY CHARACTERIZING HOST SMALL RNAS AND MRNAS

Sponsoring Institution Agricultural Research Service/USDA
Status ACTIVE
Funding Source USDA INHOUSE
Reporting Frequency Annual
Project Director BOWMAN K D
Accession Number 424116
Project Number 6034-21000-014-17R
Dates 2012-10-01 - 2015-06-30
Recipient Organization AGRICULTURAL RESEARCH SERVICE
219 SOUTH ROCK ROAD
FT PIERCE,FL 34945
Keywords asiaticus
candidatus
citrus
disease
greening
huanglongbing
liberibacter
rna
small
tristeza
virus
Research Effort Applied (50%)
Basic (50%)
Developmental (0%)
Classification Parameters
Knowledge AreaSubject of InvestigationField of SciencePercent
204 - Plant Product Quality and Utility (Preharvest) 920 - Orange 1080 - Genetics (excludes breeding) 40%
203 - Plant Biological Efficiency and Abiotic Stresses Affecting Plants 910 - Grapefruit 1000 - Biochemistry and biophysics 30%
212 - Pathogens and Nematodes Affecting Plants 999 - Citrus, general/other 1160 - Pathology 30%
Goals / Objectives
To identify the mechanisms of pathogenesis and natural defense in citrus to citrus greening disease or huanglongbing.
Methods (unparsed)

Complete greenhouse inoculation of citrus with huanglongbing (Candidatus Liberibacter asiaticus). Assess plant response and analyze changes in host plant small RNAs and mRNAs.

Methods
Complete greenhouse inoculation of citrus with huanglongbing (Candidatus Liberibacter asiaticus). Assess plant response and analyze changes in host plant small RNAs and mRNAs.
Project Timeline Tracking

Outputs

This research related to all of the objectives of the inhouse project: 1. Create new genetic combinations of citrus germplasm via conventional breeding, mutation, and transformation. 2. Screen germplasm for important traits and select superior individuals. 3. Evaluate selections for field performance and other traits. This cooperative research is focused on a study of the mechanisms by which trees become infected with the diseases Candidatus Liberibacter asiaticus (Las) and citrus tristeza virus (CTV). The approach of the project is to use changes in host small RNAs and mRNAs as indicators of infection process and host plant reaction to the diseases. We have inoculated three genotypes, representing a range of host responses to the two diseases, and have collected tissue every ten weeks after infection. One rootstock clone, Cleopatra, becomes infected with both pathogens very quickly, while there is a long delay after inoculation before either pathogen can be detected in a second rootstock clone, US-942. Similarities in the responses of the host genotypes to both diseases suggest that there may be some similarities in the mechanisms and genetic basis of tolerance. Tissue is being prepared for small RNA analysis. Progress was monitored by conference calls, emails, meetings, and reports to the original funding agency.