- Author: Barbara Alonso
Scientists are studying the interaction between citrus trees and the bacterium Candidatus Liberibacter asiaticus (CLas) associated with huanglongbing (HLB) at the molecular level. In particular, they are investigating how CLas interacts with citrus proteins to cause disease, hoping to disrupt this interaction and ultimately develop new resistant or tolerant varieties using a genome-editing technology called CRISPR/Cas.
Download the Research Snapshot to learn more, and visit our Research Snapshots page.
We have developed short, descriptions of research projects that aim to help in the fight against HLB. These projects include traditional breeding and genetic engineering to create resistant citrus varieties, psyllid modification, using other organisms to deliver HLB-resistance genes, and early detection of the bacterium in trees.
- Author: Barbara Alonso
- Author: Elizabeth E Grafton-Cardwell
- Author: Peggy G. Lemaux
Plants defend themselves from pathogens and insect feeding by producing proteins that enhance their resistance to these organisms. This is called systemic acquired resistance (SAR). Specific defense genes code for pathogenesis-related (PR) proteins that protect plants from microorganisms and are induced by a plant hormone called salicylic acid. The defense genes from resistant or tolerant plants can be inserted into less tolerant plants, thereby improving their resistance to diseasesResearch is underway to transform the rootstock with the hope that it will boost the immunity of the entire tree.
Download the Research Snapshot to learn more, and visit our Research Snapshots page.
About Research Snapshots
- Author: Barbara Alonso
- Author: Elizabeth E Grafton-Cardwell
- Author: Peggy G. Lemaux
Dr. Johan Leveau, a Professor of Plant Pathology at UC Davis, is comparing the differences between healthy citrus trees and citrus trees infected with the bacterium Candidatus Liberibacter asiaticus (CLas), that causes Huanglongbing disease (HLB). The most obvious difference is the presence of CLas DNA in infected plants. Polymerase Chain Reaction (PCR) is a test that can detect CLas DNA and is currently the only way to confirm the presence of the bacterium in trees.
Download the Research Snapshot to learn more, and visit our Research Snapshots page.
We have developed short, descriptions of research projects that aim to help in the fight against HLB. These projects include traditional breeding and genetic engineering to create resistant citrus varieties, psyllid modification, using other organisms to deliver HLB-resistance genes, and early detection of the bacterium in trees.
- Author: Barbara Alonso
- Author: Elizabeth E Grafton-Cardwell
- Author: Peggy G. Lemaux
Download the Research Snapshot to learn more, and visit our Research Snapshots page.
We have developed short, descriptions of research projects that aim to help in the fight against HLB. These projects include traditional breeding and genetic engineering to create resistant citrus varieties, psyllid modification, using other organisms to deliver HLB-resistance genes, and early detection of the bacterium in trees.
- Author: Elizabeth E Grafton-Cardwell
- Author: Peggy G. Lemaux
- Author: Lukasz Stelinski
- Author: Barbara Alonso
CLas is spreading in Texas and in the past year has begun to accelerate its spread in Southern California. It is imperative to inform growers and consumers about the research and approaches that are being pursued to control the spread of the disease. Through both the NIFA-sponsored NuPsyllid and RNAi-based strategy projects, we are developing extension and education information for growers and end-users, which address the use of genetics and other tools to lessen the impact of HLB on citrus.
We developed a plan that enhances existing citrus extension educator programming with three primary outreach approaches.
Citrus outreach website
This site is specifically designed to provide grower information on genetic and non-genetic strategies for control and detection of huanglongbing/citrus greening, and hosts the following three outreach resources.
PowerPoint slides
Research Snapshots
Snapshots are created to provide the latest information on various approaches being used to combat HLB. We work directly with researchers to obtain detailed information what they are doing, how they are doing it and the current status of their efforts. Research Snapshots, available on the website, can be used as fact sheets at educational venues. Snapshots are put into one of four categories, which are color-coded and interlinked to make use easier. New snapshots are being added each month.
- Nupsyllid: Approaches aimed at altering the psyllid's ability to transmit HLB
- Replants: HLB resistance strategies requiring replanting of citrus trees
- Established orchards: Approaches that could be applied to existing orchards
- EDTs: Methods used to detect HLB disease early in the infection of trees
Fact Sheets
A fact sheet, which addresses general aspects of citrus genetics, “What Makes Lemon, Oranges and Limes Look and Taste Different?”, is available for download on the website.
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