2008 Robert Cary (Novel Immunocapture …..)

Novel Immunocapture Technology for Field Deployable Nucleic Acid-Based Detection of Citrus Pathogens

The primary hypothesis guiding this project is that a highly simplified and field deployable sample preparation system can be realized using low cost and easily used lateral flow chromatography technologies. Specifically, we proposed the development of a nucleic acid analysis system making use of Lateral Flow Microarray technology (LFM) and supporting field deployable sample preparation and amplification methods. Toward this end we are developing and testing lateral flow chromatographic immuno-capture methods, novel passive fluid exchange systems, and integration of these systems to form the basis of a field deployable diagnostic platform.

2008 N W Schaad (Cultivation and Sequencing of HLB)

Cultivation and Rapid Detection of the Causal Agent of Huanglongbing Disease of Citrus

Huanglongbing (HLB), an insect-transmitted disease of citrus, also known as citrus greening, results in a green blotchy mottle on foliage, small, lopsided fruit with tree decline and eventual tree death. The causal organism has been identified as a bacterium, however no organism had been previously cultured. The protocol for identifying disease agents is to follow Koch’s postulates: isolate the pathogen from the diseased host and grow the pathogen in culture, use the culture to infect a healthy host plant and observe typical symptoms of the disease, and re-isolate the pathogen from symptomatic tissue and grow in culture.

2008 Kentaro Inoue (Molecular Analysis of Greening….)

Molecular Analysis of Degreening and Regreening in ValenciaOrange

Mature orange fruits change their peel color from green to orange during ripening. This degreening is an important process to determine the commercial quality of fruits. After reaching the full-ripe stage, some late season varieties such as Valencia turn their fruit peel color from orange to green. The regreened fruits are ripe inside, but cannot sell well due to their unripe-like appearance. The funded project aims to understand the molecular bases of this peel color development of citrus fruit, and to use the outcomes to develop efficient strategies to enhance color development and prevent regreening from happening.

2008 Jianchi Chen (Fingerprinting of HLB Strains)

Genetic Diversity and Fingerprinting of HLB Bacteria

This is the first year report of the two-year project on the genetic diversity and fingerprinting of Huanglongbing- associated bacteria. The project involves three objectives: 1). Analyses of historically and currently available literature data on HLB and identify important issues to address; 2). Study what microorganisms are involved in HLB in addition to what we currently know; and, 3). Use genomic information to study the variation of HLB-associated bacteria and their source of origins.

2008 Henry Fisk (Genetic Engineering of Citrus )

Genetic Engineering of Citrus

The main goal of this project has been to develop genetic transformation methods for the improvement of citrus cultivars important to the California industry. The two major scion cultivars of lemon (Lisbon and Eureka) were selected to serve as the primary focus for these experiments during the initial years of the program. As a result, two functional transformation systems based on organogenic regeneration were developed. One began with three- to five-week-old nucellar seedlings, whereas the other started with flush growth from mature trees. The seedling system applied only to the Eureka cultivar due to the fact that Lisbon epicotyl tissue did not regenerate.

2008 Eduardo Blumwald (Determinants of Sugar and Acid)

Characterization of Determinants in Citrus Fruit Development and Identification of Key Processes Affecting Fruit Quality

Citrus fruit quality standards have been determined empirically, depending on species and on the particular growing regions. In general, the TSS (total soluble solids) to total acidity (TA) ratio determines whether citrus fruit can be marketed. The TSS/TA ratio in citrus fruits is dominated by two main components: (i) overall vacuolar juice cell acidity and the juice cell sugar content.

2008 Abhaya Dandekar (Improving Peel Quality ..

Improving Peel Quality of California Citrus Fruit

An essential component of high quality citrus fruit is an external finish free of blemishes, defects, and disease. The peel or rind of citrus fruit, composed of flavedo and albedo layers, is a highly physiologically active tissue prone to injury and environmental influence.

2008 Hailing Jin (Identification of Candidatus…)

Identification of Candidatus Liberobacter-induced Small RNAs for early diagnosis of HLB CitrusGreening

Citrus greening or “Huanglongbing” (HLB), caused by bacteria Candidatus Liberobacter, is one of the most devastating diseases of citrus. The serious spread of HLB in Florida is of great concern to the citrus industry as well as scientists. Recent detection of Asian citrus psyllids in several additional states, including California, makes it an urgent need for scientist to develop effective measures to prevent its further spread.

2008 Georgios & Hailing (Identification of Spiroplasma…)

Identification of Spiroplasma citri-induced Small RNAs for Early Diagnosis of Citrus Stubborn Disease

The fundamental control method for the stubborn disease, like most of the graft-transmissible diseases of citrus, is the use of disease tested propagative material. Modern diagnostic techniques that increase the capacity of quarantine programs such as the Citrus Clonal Protection Program (CCPP) to test source plants of citrus germplasm and improve the overall scheme of diagnostics necessary for the safe release of new varieties to the industry are essential for a sustainable and viable California citriculture.

2007 Timothy Close (EST Libraries and Bioinformatics)

EST Libraries and Bioinformatics for California Citrus

This project produced fundamental resources and information in the area of “Genomics”, which facilitates other research and practical applications. Using information developed in earlier years of the project or released by others, an Affymetrix citrus GeneChip® was designed by this project and made commercially available.