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ARS Home » Southeast Area » Fort Pierce, Florida » U.S. Horticultural Research Laboratory » Citrus and Other Subtropical Products Research » Research » Research Project #435031

Research Project: Development of Huanglongbing Resistant/tolerant Citrus Through Genomic Approaches

Location: Citrus and Other Subtropical Products Research

Project Number: 6034-21000-019-003-R
Project Type: Reimbursable Cooperative Agreement

Start Date: Jun 1, 2019
End Date: May 31, 2024

Through traditional breeding, we have generated populations of novel citrus hybrids with Huanglongbing (HLB) resistant Australian citrus parentage. The hybrids segregating for resistance traits will be used for association of genetic markers with disease resistance. Candidate genes identified as valuable will be used to transform elite citrus cultivars to incorporate resistance traits. Specific objectives are: to generate reference sequences of three HLB resistant citrus relative species, identification of genetic differences between resistant and susceptible hybrids by low depth whole genome sequencing of 100 hybrid lines, pooled genome (bulk segregant) analysis and transcriptome study of selected individuals. Combination of these techniques will enable identification of candidate genes associated with resistance.

Genes conferring HLB resistance/tolerance will be identified in citrus relative genera and incorporated into commercial citrus types. We have already generated hybrid populations exhibiting a range of phenotypes from complete HLB resistance to tolerance and susceptibility. The resistant parents have now been in the field for ten years in Florida, and the resistant hybrids are under continued monitoring for over two years after HLB challenges in the greenhouses. We propose using genomic tools to identify disease resistance genes from these hybrids and transfer these genes into cultivated citrus through biotechnology methods.