DNA-based Tissue Diagnostics for Lettuce Fusarium

Fusarium wilt of lettuce continues to be a growing threat to the competitiveness of the Arizona iceberg lettuce industry, and unlike most plant diseases, there is no known treatment to control this soil-borne disease completely.  The Yuma Center of Excellence for Desert Agriculture (YCEDA) is leading multiple projects conducting research to find solutions to this plaguing problem.  The objectives of this project were developed based upon findings from our 2016 study, “Advancing Fusarium wilt management in lettuce",  which revealed the need for more precise and reproducible methods for inoculating greenhouse lettuce with Fusarium wilt to support continued study on disease epidemiology, interactions with soil, and rapid cultivar evaluations.  Additionally, findings revealed the value of precise diagnostic methods for the detection of Fusarium DNA in lettuce tissue and the need for additional development of more sensitive diagnostic PCR primers for these DNA-based techniques that can be used by producers. 

Precision plant disease diagnostics is currently experiencing a very exciting period with the introduction of new techniques and products, all of which are targeting faster and more sensitive detection of pathogens.  The more quickly a grower is able to detect a potential problem, the more options are available for improved management decisions.  Perhaps equally important, improved early and sensitive detection of Fusarium in iceberg lettuce tissue will enable researchers to conduct important studies on the epidemiology of the disease and answer a number of critical questions that impact disease management.  

Experiments will be conducted on methods of inoculation used to artificially infect lettuce with Fusarium, and on the interaction of soil conditions with disease development.  Additional experiments will be conducted to further develop two promising diagnostic techniques; each technique requiring the refinement of unique PCR primers that are specific to the Fusarium wilt pathogen and sensitive to low DNA concentrations in lettuce tissue.  Web content and informational videos will be developed and disseminated to the production industry that will present an introduction to and step-by-step instructions for these novel diagnostic methods.