Agricultural Research Service

The Goal of This Proposal Is the Commercial Delivery of a Sustainable and Biologically-based Therapeutic Delivery Platform Called Symbiont Technology to Treat Citrus Trees in Production Fields to Provide Protection/symptom Alleviation From Citrus Greening Disease (aka Huanglongbing, HLB). a Symbiont Is Simply an Agrobacterium-induced Plant Gall (galls Are Abnormal Growths That Occur on Various Locations of Plants) That Is Modified to Produce Molecules That Benefit the Host Plant and Designed as a Solution That With Ultimately Reduced Regulatory Approval Time for Field Delivery. Agrobacterium Is a Common Soil Bacterium Found Globally That Is Well Studied and Shown to Be Able to Produce Galls on Plants When It Enters a Wound Site and Injects a Specific Piece of Dna Into Neighboring Plant Cells That Encode Proteins That Synthesis Plant Growth Regulators). Proof-of-concept of the Symbiont Platform Was Demonstrated in a Previous Nifa Grant 2020-08451 Cap: Therapeutic Molecule Evaluation and Field Delivery Pipeline for Solutions to HLB. a Recently Initiated Aphis Approved Field Trial Is Underway and Has Demonstrated Initial Symbiont Development on Mature Citrus Trees in a Florida Grove. These Trees Are Currently Being Monitored for Impact on Growth, Hlb-symptoms, and Fruit Production/quality Responses (inoculations Were Initiated in November). However, Current Methods of Establishing Symbionts on Trees in Production Groves Is Too Timely and Expensive. This Proposal Will Focus on Establishing Robust, Rapid and Economical Commercializable Methods of Symbiont Delivery and Maintenance (including Inoculum Delivery Device Fabrication Performed by the Irsc Advanced Manufacturing Hub). Data Will Also Be Developed During This Time to Continue to Support the Regulatory Requirements for Deregulation of Symbiont Use in Commercial Groves in Florida, Texas, and California. Specific Milestones: I) Commercial Delivery of an Economically Feasible Symbiont Production/maintenance System; Ii) Identify Strains of Agrobacterium That Produce Robust and Effective Symbionts; Iii) Evaluate the Potential of Switching to Symbiont Delivery Using Just Direct Dna Delivery.