Biotechnology to Generate Disease Resistant Mature Citrus as a Service

Biotechnology to Generate Disease Resistant Mature Citrus as a Service

Report Date: 10/08/2020
Project: 18-067C   Year: 2020
Category: Plant Improvement
Author: Janice Zale
Sponsor: Citrus Research and Development Foundation

1. Please state project objectives and what work was done this quarter to address them:           The objectives of this project are to produce disease resistant, commercially & agronomically acceptable, mature citrus transgenics & intragenics that will flower & fruit naturally using Agrobacterium & biolistics as a service for customers. The research focus of this project is to increase Agrobacterium & biolistic transformation efficiency of mature citrus, so that biotech products produced in our facility for commercialization can reach the Florida Citrus Growers sooner, at less expense.          During this quarter, we tested two new, citrus selectable markers in Agrobacterium transformation & produced ~55 transgenics that survived micrografting. The number of transgenics produced with these citrus genes appeared to be higher than the standard nptII selectable marker although we have to finish data analyses to conclusively make this statement. These selectable markers are important for intragenics using all citrus sequences. The next step will be to characterize these transgenics at the molecular level, & to determine whether extra doses of these genes have any effect on phenotype, particularly the fruit. In addition, ~70 transgenics were produced for another CRDF project, however our portion of that funding is set to expire by the year’s end.         We introduced OLL-20 from FDACS, which is a favorite of the juice industry, but the mother plants produced from shoot-tip grafts & all of the budded plants were chimeric. We are currently trying to resolve the chimeras by cutting off the chimeric tissue. FDACS has been alerted to this issue in the event that their trees were chimeric.        The Educational Business Account (EBA) has been completed & it is now up to UF officials to approve it.  Once approved, our new price list will be implemented, which should allow for a more reasonable fee collection that contributes more to salaries & consumables.         Currently UF labs have limited return to work schedules as the Covid-19 pandemic in FL is still causing a significant number of cases & deaths.  Our lab continues to work in shifts. Once the pandemic subsides, we will hopefully return to a more normal work schedule with people able to work together in one lab. Wearing masks, social distancing & disinfecting surfaces are directives that we must follow in the workplace now. 2. Please state what work is anticipated for next quarter:          We will continue to produce transgenics for clients. For one client, this has involved testing different, commercially important mature grapefruit cultivars (Marsh, Flame, and Ray Ruby). Thus far, one mature grapefruit cultivar regenerated the most shoots in tissue culture & might have the highest transformation efficiency. We are also performing experiments to increase the efficiency of biolistic transformation of mature citrus by altering the osmotic pretreatment & finding cultivars amenable to the process. The two citrus selectable markers are being tested in biolistic transformation. The USDA APHIS BRS does not examine cis/intragenic trees, because the new federal SECURE RULE states that intragenic trees, without vector sequences, will be considered similar to trees produced through traditional plant breeding.   3. Please state budget status (underspend or overspend, and why):  We are on track monetarily.   


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