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ARS Home » Pacific West Area » Riverside, California » National Clonal Germplasm Repository for Citrus » Research » Publications at this Location » Publication #409271

Research Project: Conservation, Management and Distribution of Citrus and Date Genetic Resources and Associated Information

Location: National Clonal Germplasm Repository for Citrus

Title: Analyzing Huanglongbing-resistant pummelo from India.

item Keremane, Manjunath
item SINGH, K - University Of California, Riverside
item AKELLA, V - Icar - Indian Institute Of Horticultural Research
item SUBBAIH, MT - Icar - Indian Institute Of Horticultural Research
item SULLADMATH, V - Icar - Indian Institute Of Horticultural Research
item RAMADUGU, C - University Of California, Riverside
item Krueger, Robert

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 11/8/2023
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: There is no appreciable resistance to huanglongbing (HLB) disease reported in cultivated citrus. We have identified a pummelo variety resistant to citrus HLB from the Gonikopal area in the Coorg district of Southern India. HLB has devastated the once thriving Coorg mandarin industry in this area where the disease has been present for nearly a hundred years. While most citrus types were affected by HLB in the area, some native pummelos showed no HLB symptoms and continued to grow well and produce healthy trees in spite of both the disease and the vector being present in the area. Real-time PCR analysis conducted in 2013 showed the absence of the HLB-associated bacterium, Candidatus Liberibacter asiaticus in the tested pummelo tree, but the presence of the pathogen in the surrounding Coorg mandarin trees. A clone of this pummelo, “Cariappa” was imported at the USDA Repository under valid permits in 2013 and maintained under quarantine. After therapy followed by testing the plant material for the absence of multiple citrus pathogens, the accession was released from quarantine in 2019. In general, most pummelo varieties are highly susceptible to HLB. We have inoculated the putative HLB-resistant “Cariappa” and a susceptible Siamese pummelo variety with two isolates of CLas, “Hacienda Heights” (HH) from California and “Psy62” from Florida in contained research facilities in Riverside. Tissue from these plants was subjected to transcriptome analysis. The symptomatology of inoculated plants and analysis of transcriptome studies will be discussed. Possible uses of “Cariappa” pummelo for breeding novel HLB-resistant varieties will be addressed.