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…

The Agricultural Research Service (ARS), Southeast Area, received a $1,499,977 Project Grant from the National Institute of Food and Agriculture (NIFA) under the Specialty Crop Research Initiative (SCRI, CFDA 10.309) awarded September 15, 2025, through September 14, 2028. The grant funds the development and commercialization of Symbiont Technology, a biologically-based therapeutic delivery platform designed to treat citrus trees in production fields for protection against Citrus Greening Disease (Huanglongbing, HLB). The Symbiont platform leverages Agrobacterium-induced plant galls modified to produce beneficial molecules for the host plant, building on proof-of-concept demonstrated under a previous NIFA award and an ongoing APHIS-approved field trial in Florida.

The project focuses on establishing robust, rapid, and economically viable methods for Symbiont delivery and maintenance in commercial citrus groves, including the development of inoculum delivery devices through partnership with the IRSC Advanced Manufacturing Hub. Deliverables include a commercially feasible Symbiont production and maintenance system and supporting regulatory data to advance deregulation approval for Symbiont use across commercial citrus operations in Florida, Texas, and California. Research activities and monitoring conducted at the Stoneville, MS facility will assess impacts on tree growth, HLB symptom alleviation, and fruit production and quality metrics.

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.