Grant Information

SELECTION, MOLECULAR AND GENETIC ANALYSIS OF HLB TOLERANT/RESISTANT VARIANT CITRUS PLANTS

Sponsoring Institution Agricultural Research Service/USDA
Status ACTIVE
Funding Source USDA INHOUSE
Reporting Frequency Annual
Project Director DUAN Y
Accession Number 432389
Project Number 6034-22000-045-015R
Dates 2017-01-15 - 2023-01-14
Recipient Organization AGRICULTURAL RESEARCH SERVICE
219 SOUTH ROCK ROAD
FT PIERCE,FL 34945
Keywords (las)
candidatus-liberibacter-asiaticus
editing
genome
hlb
resistance/tolerance
selection
Research Effort Applied (30%)
Basic (60%)
Developmental (10%)
Classification Parameters
Knowledge AreaSubject of InvestigationField of SciencePercent
212 - Pathogens and Nematodes Affecting Plants 910 - Grapefruit 1040 - Molecular biology 25%
212 - Pathogens and Nematodes Affecting Plants 920 - Orange 1060 - Biology (whole systems) 25%
212 - Pathogens and Nematodes Affecting Plants 1114 - Peach 1040 - Molecular biology 10%
212 - Pathogens and Nematodes Affecting Plants 1122 - Strawberry 1060 - Biology (whole systems) 10%
212 - Pathogens and Nematodes Affecting Plants 1429 - Cucurbits, other (includes pumpkin, squash, gourd) 1040 - Molecular biology 10%
212 - Pathogens and Nematodes Affecting Plants 1460 - Tomato 1060 - Biology (whole systems) 10%
212 - Pathogens and Nematodes Affecting Plants 2110 - Ornamental trees and shrubs 1040 - Molecular biology 10%
Goals / Objectives
  1. Select variant citrus plants or bud sports with HLB tolerance/resistance.
  2. Identify citrus HLB-tolerant/resistant related genes for potential citrus genome editing targets through transcriptome profiling.
  3. Identify genetic variants that are associated to HLB-tolerance/resistance in variant citrus plants.
  4. Engineer HLB tolerance/resistance using genome editing technology.
Methods (unparsed)

1. Select volunteer seedlings from years of natural fruit drop and bud sports from sweet oranges, grapefruit, and mandarin hybrids with natural HLB resistance/tolerance from commercial groves in Florida. Sustained tolerance to HLB will be demonstrated in greenhouse studies and field trials in Florida, where HLB is endemic. The quantity and quality of the fruit produced during the field trials will also be evaluated. 2. Profile the dual transcriptomes of 30 resistant/tolerant citrus plants and their 30 susceptible siblings before and after HLB infection using RNA-seq. Bioinformatics and functional genomic analysis will be used to predict a list of HLB tolerance/resistance-related genes. Expressions of selected genes will be verified by reverse transcription quantitative PCR (RT-QPCR) on HLB challenged citrus varieties. 3. Re-sequence two tolerant/resistant and two susceptible sibling plants and their parents of a Duncan grapefruit line and a sour orange line. Bioinformatics and comparative genomics analysis will be used to identify HLB tolerance/resistance-related segment deletions, copy number variations (CNVs), structural variations (SVs), SNPs, and Indels in each citrus line. The identified variants will be further verified experimentally using RT-PCR.