I am interested in understanding the response of the plant to a viral infection, so my lab studies virus-plant interactions using a variety of methods and plant-virus models.
Geminiviruses are the main subject of my research and arabidopsis is the plant model we favored, but we also do research in tomato, cassava and N. benthamiana. However, we also study potyviruses (Cassava brown streak disease) and use other viruses as vehicles for gene silencing (TRV for arabidopsis and tomato). We are also interested in using multispectral systems to scan leaves and identify early signatures of virus presence (way earlier than the onset of symptoms) to properly rogue or eliminate viral dispersion.
Our grants study virus evolution and diversity (PIRE-NSF) or molecules enhancing symptoms and mechanisms for resistance (Bill and Melinda Gates Foundation). We also have direct links with industry trying to define how to use aptamers to induce resistance against viruses in tomato (MicroPEP) or using small chemicals to inhibit replication functions (Atomwise).
Our Biochemistry Undergraduate Research and Training Program (BURT-P) hosts undergraduate researchers that are doing incredible work, among them:
They are investigating how geminivirus induces senescence in arabidopsis, using tubulin-GFP fusions to visualize the effect of different viruses in the leaves.
Another group is pursuing understanding the involvement of CDKs (Cyclin-dependent kinase like) in Arabidopsis response to geminivirus infection.
They are also using NMR to define binding properties of small molecules to Rep, a protein absolutely necessary for geminivirus replication.
Furthermore, they are also characterizing infectious clones of several geminiviruses using a small tomato variety (Lanai).
Our graduate students are determining the involvement of Arabidopsis response regulator 7 (ARR7) in the infection.
Area(s) of Expertise
Plant responses to virus infection. Virus evolution. Virus-induced Senescence. Multispectral virus detection. Virus inoculations. Biolistics.
- SEGS-1 a cassava genomic sequence increases the severity of African cassava mosaic virus infection in Arabidopsis thaliana , FRONTIERS IN PLANT SCIENCE (2023)
- Early detection of plant virus infection using multispectral imaging and spatial-spectral machine learning , SCIENTIFIC REPORTS (2022)
- Rapid Multilocus Adaptation of Clonal Cabbage Leaf Curl Virus Populations to Arabidopsis thaliana , PHYTOBIOMES JOURNAL (2022)
- A New Type of Satellite Associated with Cassava Mosaic Begomoviruses , JOURNAL OF VIROLOGY (2021)
- Conserved Structural Motif Identified in Peptides That Bind to Geminivirus Replication Protein Rep , BIOCHEMISTRY (2021)
- Geminivirus Resistance: A Minireview , FRONTIERS IN PLANT SCIENCE (2020)
- Immunohistochemical localization of Cassava brown streak virus and its morphological effect on cassava leaves , PHYSIOLOGICAL AND MOLECULAR PLANT PATHOLOGY (2019)
- Lanai: A small, fast growing tomato variety is an excellent model system for studying geminiviruses , JOURNAL OF VIROLOGICAL METHODS (2018)
- Sucrose Nonfermenting 1-Related Protein Kinase 1 Phosphorylates a Geminivirus Rep Protein to Impair Viral Replication and Infection , PLANT PHYSIOLOGY (2018)
- Infectivity of Deinbollia mosaic virus, a novel weed-infecting begomovirus in East Africa , ARCHIVES OF VIROLOGY (2017)
This proposal establishes a research and training partnership between scientists in the U.S. and East Africa to study the evolution of plant DNA viruses, which have emerged as leading pathogens and now threaten crops worldwide. AfricaÃƒÂ¢Ã¢â€šÂ¬Ã¢â€žÂ¢s future depends on increasing food production to feed its growing population. There has been dramatic growth in the investments by governments, nongovernmental organizations, international donors and the private sector to develop the scientific expertise and infrastructure necessary to find solutions to the problems that limit African agriculture. The Biosciences Eastern and Central Africa-International Livestock Research Institute (BecA-ILRI) Hub in Kenya and the Mikocheni Agricultural Research Institute (MARI) in Tanzania were created to solve problems facing African farmers and limiting food security. A U.S.-East Africa partnership represents an excellent international opportunity for research synergy and training of U.S. students and early career scientists. Key features include the establishment of a research exchange program between laboratories in the U.S. and East Africa. Postdoctoral researchers, graduate students and undergraduates will be mentored by a strong international research team, which includes experts on viral population genetics, insect vector transmission and population dynamics, virus/vector/plant interactions, and STEM education. The multidisciplinary nature of the research will provide trainees experience in laboratory and field-based research as well as bioinformatics. This will prepare them to become globally engaged, independent scientists with a solid foundation in a range of research methodologies and environments and first-hand experience in international and multidisciplinary collaborations.
Cassava mosaic disease (CMD) is one of the most important diseases of cassava and a serious constraint on production across Africa. We identified and characterized two DNA sequences designated as SEGS-1 and SEGS-2 that enhance CMD symptoms and break resistance. A better understanding of the origins of the SEGS and how they alter disease etiology is necessary to develop sustainable CMD control measures for cassava. In this project, we will use cassava and Arabidopsis to address the following questions with the ultimate goal of translating the information to cassava. (1) How are the SEGS activated/transmitted in cassava? (2) What infection/defense processes are altered by the SEGS to enhance symptoms and break resistance? (3) What is the nature of the begomovirus resistance in Arabidopsis? (4) How our findings be translated to cassava to improve resistance to CMD?
The main goal of this project is to generate a series of optimized synthetic transcriptional reporters to simultaneously monitor the activity of up to nine major plant hormones (auxin, ethylene, ABA, cytokinins, gibberellins, brassinosteroids, salicylic acid, jasmonate, and strigolactones) in a single plant. Single-hormone synthetic reporters (e.g., DR5 and EBS) have been shown to work across a broad range of plant species, making the proposed new tool useful for many plant species, from Arabidopsis to tomato and maize. By applying the synthetic biology principles of standardization and reusability to all ÃƒÂ¢Ã¢â€šÂ¬Ã…â€œgenetic partsÃƒÂ¢Ã¢â€šÂ¬Ã‚Â (e.g., synthetic minimal promoters, CDSs, or terminators) and ÃƒÂ¢Ã¢â€šÂ¬Ã…â€œmodulesÃƒÂ¢Ã¢â€šÂ¬Ã‚Â (whole transcriptional units, or TUs) generated, these new tools will be highly customizable and upgradable whenever new fluorescent proteins or promoters become available. Thus, in addition to producing a single-locus multi-hormone reporter, this project will also: A) popularize synthetic biology tools, such as the GoldenBraid1 (GB) gene assembly technology, among plant biologists; B) streamline rapid and quantitative pipeline to evaluate the function of individual genetic parts and modules; C) test the limit on the number of genes that can be routinely monitored simultaneously by ÃƒÂ¢Ã¢â€šÂ¬Ã…â€œgenericÃƒÂ¢Ã¢â€šÂ¬Ã‚Â labs not specialized in imaging techniques; D) explore new approaches that combine CRISPR-Cas9 and recombineering to stack multiple genes (up to 150 Kb) in a single TAC clone.
Geminiviruses represent a serious threat to food security in Africa. This proposal is a subcontract of a larger proposal entitled "Disease Diagnostics for Sustainable Cassava Productivity in Africa" submitted by Dr. Joseph Ndunguru of Tanzania. The proposed research will identify a resistance gene for geminiviruses that loses effectiveness in the presence of DNA satellites isolated from cassava. Standard QTL mapping of a segregating population will be used to fine map the gene, followed by targeted disruptions of candidate loci. No resistance gene has ever been identified at the molecular level for a plant DNA virus. This information is expected to help determine the mechanism of action for resistance-breaking DNA satellites and may uncover new ways to safeguard cassava against viruses.