An NGS-based system for unambiguous detection of HLB pathogen

Citrus HLB control in California is on eradication of “Candidatus Liberbacter asiaticus” (CLas). Current detection of CLas is based on PCR, resulting in a Ct value that measuring the amount of amplified pathogen DNA. The higher the Ct, the lower the CLas concentration in the sample. However, interpretation of an extremely high Ct value, say Ct=38, could be problematic, because it could mean extremely low CLas concentration, or no CLas at all but the presence of non-CLas bacteria. This uncertainty creates a problem in HLB management, particularly in the practice of early CLas detection. This proposal is to develop a system, not to rely on Ct value, but to directly recognize CLas DNA sequences to eliminate ambiguity in CLas detection using the recent next generation sequencing (NGS) technology.