Grant Information
| Knowledge Area | Subject of Investigation | Field of Science | Percent |
|---|---|---|---|
| 204 - Plant Product Quality and Utility (Preharvest) | 920 - Orange | 1080 - Genetics (excludes breeding) | 40% |
| 203 - Plant Biological Efficiency and Abiotic Stresses Affecting Plants | 910 - Grapefruit | 1080 - Genetics (excludes breeding) | 30% |
| 212 - Pathogens and Nematodes Affecting Plants | 999 - Citrus, general/other | 1080 - Genetics (excludes breeding) | 30% |
USDA-ARS in Fort Pierce has undertaken a major effort to genetically transform citrus varieties to contain genes that produce chemical defenses (antimicrobial peptides) against huanglungbing (HLB). The Citrus Research and Development Foundation is currently funding two projects to generate transformed plants, and large numbers of plants have been and continue to be produced. USDA-ARS has dedicated a greenhouse to expedite testing of these transgenics, appointed a program manager and enlisted the assistance of the Subtropical Insects Research Unit to supply infected psyllids. With respect to producing infected psyllids, infected psyllids are continually produced in each of five cages on infected citrus, and approximately 5,000 infected psyllids are produced monthly. The following is a review of the current screening program. Stage 1: A colony of HLB-infected psyllids is used to challenge the plants to psyllid infestations and HLB. Individual plants growing in conetainers are caged and infested by hot psyllids (20 adults per plant depending on the percentage of psyllids in the colony that test positive) for a week, then cages are removed and the plants are maintained in the greenhouse for two months in the midst of an open infestation of infected psyllids. Stage 2: The plants are transplanted into larger pots (D-c) and maintained in the greenhouse for six to eight months in the midst of an open infestation of infected psyllids. Stage 3: The plants are transplanted into Ruck¿s pots and grown out for an additional four to six months in the midst of an open infestation of infected psyllids. The plants are then evaluated for resistance to HLB, which requires growth measurements and real-time polymerase chain reaction assays (RT-PCR) analyses.
USDA-ARS in Fort Pierce has undertaken a major effort to genetically transform citrus varieties to contain genes that produce chemical defenses (antimicrobial peptides) against huanglungbing (HLB). The Citrus Research and Development Foundation is currently funding two projects to generate transformed plants, and large numbers of plants have been and continue to be produced. USDA-ARS has dedicated a greenhouse to expedite testing of these transgenics, appointed a program manager and enlisted the assistance of the Subtropical Insects Research Unit to supply infected psyllids. With respect to producing infected psyllids, infected psyllids are continually produced in each of five cages on infected citrus, and approximately 5,000 infected psyllids are produced monthly. The following is a review of the current screening program. Stage 1: A colony of HLB-infected psyllids is used to challenge the plants to psyllid infestations and HLB. Individual plants growing in conetainers are caged and infested by hot psyllids (20 adults per plant depending on the percentage of psyllids in the colony that test positive) for a week, then cages are removed and the plants are maintained in the greenhouse for two months in the midst of an open infestation of infected psyllids. Stage 2: The plants are transplanted into larger pots (D-c) and maintained in the greenhouse for six to eight months in the midst of an open infestation of infected psyllids. Stage 3: The plants are transplanted into Ruck�s pots and grown out for an additional four to six months in the midst of an open infestation of infected psyllids. The plants are then evaluated for resistance to HLB, which requires growth measurements and real-time polymerase chain reaction assays (RT-PCR) analyses. This project is related to Objective 1: Create new genetic combinations of citrus, Objective 2: Screen germplasm for important traits and select superior individuals, Sub objective 1 D: Create new scions and rootstocks with potential resistance to huanglongbing (HLB) and citrus bacterial canker (CBC) by genetic transformation. USDA-ARS-U.S. HOrticultural Research Laboratory, Fort Pierce Florida is producing thousands of scion or rootstock plants transformed to express peptides that might mitigate huanglongbing (HLB). The more rapidly this germplasm can be evaluated, the sooner we will be able to identify transgenic strategies for controlling HLB. The purpose of this project is to support a high-throughput facility to evaluate transgenic citrus for HLB-resistance. This screening program supports two U.S. Horticultural Research Lab's projects funded by Citrus Research Development Foundation (CRDF) for transforming citrus. Non-transgenic citrus can also be subjected to the screening program. CRDF funds are being used for the inoculation steps of the program. Briefly, individual plants are caged with infected psyllids for two weeks, and then housed for six months in a greenhouse with an open infestation of infected psyllids. Plants are then moved into a psyllid-free greenhouse and evaluated for growth, HLB- symptoms and Las titer. This report marks the end of the first year of the project, during which we have achieved large-scale production of Candidatus Liberibacter (CLas) positive Asian citrus psyllid (ACP). To date on this project, a technician dedicated to the project has been hired, a second career technician has been assigned part-time, two small air-conditioned greenhouses for rearing psyllids are in use, and 18 individual CLas- infected ACP colonies are being used for caged infestations. A total of 3, 583 transgenic plants have passed through the screening program. A total of 71,760 psyllids have been used in no-choice inoculations.