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ARS Home » Pacific West Area » Riverside, California » National Clonal Germplasm Repository for Citrus » Research » Publications at this Location » Publication #316720
Title: Citrus Huanglongbing tolerance in Australian Citrus Relatives, Microcitrus and Eremocirus

Author
item RAMADUGU, CHANDRIKA - University Of California
item Keremane, Manjunath
item HALBERT, SUSAN - University Of Florida
item Stover, Eddie
item Hall, David
item McCollum, Thomas
item ROOSE, MIKEAL - University Of California
item LEE, RICHARD - Retired ARS Employee

Submitted to: American Phytopathological Society
Publication Type: Abstract Only
Publication Acceptance Date: 4/15/2015
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Tolerance, or resistance to citrus huanglongbing will be important as a long term solution for this disease. In a field trial conducted with over 1000 plants belonging to different genera in the sub-family Aurantioideae, we observed field tolerance in many Australian citrus relatives. To confirm these results in a controlled greenhouse setting, we have exposed 140 plants to Candidatus Liberibacter asiaticus via psyllid feeding under no-choice conditions for a period of two weeks. We have maintained these seedlings under greenhouse conditions and conducted detailed analysis on the presence of the pathogen and level of tolerance observed in various plants after exposure to the pathogen. We have analyzed the samples using qPCR and droplet digital PCR (ddPCR) to estimate the bacterial titer in accessions that were either susceptible, tolerant, or resistant in field studies. To confirm the presence or absence of the pathogen in plants with questionable qPCR results, ddPCR analysis was conducted targeting multiple genomic regions of Candidatus Liberibacter asiaticus. Since these experiments are conducted using open pollinated seeds where the pollen parent is not known, we have also conducted about 2000 pollinations using Microcitrus,Eremocitrus, pummelo, and mandarin as both seed and pollen parents. The targeted crosses were also conducted with known HLB tolerant cultivars of mandarins like Temple tangor and Fallglo mandarin.