The present reporting period runs from June 16 – September 15, 2019. Mr. Chad Vosburg is the M.S. degree student in the Penn State Department of Plant Pathology graduate program who is working on the project. Chad took a trip to Fort Pierce, FL, September 12 – 15, 2019. During this trip, he set up plant propagations sufficient for 1-2 runs of an HLB resistance test for all the FT-scFv grapefruit lines. Existing propagated plants were cut back to induce a new flush of growth, which is essential for a successful HLB infection test. Personnel at the USHRL will initiate the HLB screenhouse test when the plants have reached the optimal stage of re-growth. Chad also worked with personnel at the USHRL to set up a field test of two of the FT-scFv lines. Chad is now working on mastering PCR skills for CLas detection that will be part of the HLB infection tests in the lab at Penn State. We anticipate that the first run of an HLB resistance test will beinitiated during the next reporting period. Mr. Jeremy Held, a Ph.D. student in the Intercollege Graduate Program in Plant Biology at Penn State, continued his studies of the stabilty and expression of the FT-scFv protein in the grapefruit lines. He optimized western blotting and antibody selection and plans to test for movement of FT-scFv across the graft union using immunoprecipitation during the next reporting period. Finally, we initiated tests to check whether FT-scFv plants are fertile. Initial fruits obtained from the FT-scFv plants were seedless, possibly because they are being grown in greenhouses or growth chambers. Jeremy performed some cross-pollinations of FT-scFv flowers in the spring of 2019, and one of these fruits was cut open during the reporting period and found to have normal seed set. This is good news if the FT-scFv construct were ever to be used as a citrus breeding acceleration tool, since precocity is one of the phenotypes of FT-scFv plants. Jeremy also tested pollen viability from FT-scFv plants and found the pollen to be viable and able to germinate in the laboratory in pollen germination medium.