roger beachy, ph.d. member
rnbeachy@danforthcenter.org
Research in my laboratory is directed to understanding mechanisms of virus replication and developing strategies to control gene expression to increase disease resistance and metabolic processes in transgenic plants.
Virus replication is regulated by both host-encoded and virus-encoded genes and the battle between host and pathogen determines whether or not disease occurs. Te Beachy lab is engaged in studies to determine how sites of virus infection are established, and developing strategies to control infection of plant viruses. Our targets include rna-containing viruses of peanut and sweet potato and rice tungro bacilliform virus (rtbv), a pararetrovirus. Knowledge from studies of gene expression of the latter are used to develop a chemically controlled gene switching system to regulate biological process in transgenic plants.
molecular virology and biotechnology: Our previous studies of tobacco mosaic virus revealed that replication and local cell-cell spread of tmv are regulated in part by the capsid protein (cp). Te outcome of these studies suggested a role for the cp in regulating production of the viral movement protein which in turn regulates the mobilization of virus replication complexes through the plasmodesmata that interconnect adjacent leaf cells. Current goals of this project are include to characterize the proteome(s) of vrc’s that assemble in the presence and absence of mp. Tese studies include a collaboration with Dr. Howard Berg (Integrated Microscopy Facility) to establish ultrastructural characteristics of the vrc’s using high resolution transmission electron microscopy and tomography.
We have established collaborations to develop and test virus resistance in several crops that serve as important food sources for peoples in Africa and Asia. In a collaboration with the International Crops Re- search Institute for the Semi-Arid Tropics (icrisat; Patencheru, India) coat protein mediated resistance is being used to develop peanuts with resistance to tobacco streak virus. In collaboration with the Interna- tional Potato Center (cip; Lima, Peru) and the National Agricultural Research Organization (Namulonge, Uganda) we are applying both protein- and rnai-mediated strategies to control sweet potato virus dis- ease. Tis disease is most severe when plants are doubly infected with sweet potato feathery mottle virus and sweet potato chlorotic stunt virus. Transgenic lines that contain different constructs are currently being challenged by inoculation with single or multiple viruses identify those with resistance. Our goal is to transfer lines with resistance to collaborators in target countries for further evaluation. In collaboration with Phil Rice (Los Banos, Philippines) we are extending the results of recent studies which revealed that expression of rice transcription factors RF2a or RF2b led to resistance to rtbv (Dai et al, 2008). In future studies we hope to extend the work to elite breeding materials followed by tests for resistance to rice tungro disease in countries where the disease is endemic.
gene regulation and biotechnology: Rice transcription activators rf2a and rf2b, and rlp1 (a repressor; work in progress) each contain
Model of the predicted structure of the acidic domain of RF2a, a rice transcription factor.
Ordiz, M.I., Yang, J., Barbazuk, W.B.. and Beachy, R.N. (2010) Functional analysis of the activation domain of RF2a, a rice transcription factor Plant Biotechnol J issue 8 Published Online: Apr 7 2010 DOI: 10.1111/j.1467-7652.2010.00520.x
protein domains that bind target dna and control expression of selected genes. We recently characterized the functional domains of each protein and are using the information to develop a robust system to control gene expression in transgenic plants using a gene switching system that uses methoxyfenozide as the activating ligand (described in Koo et al, Te Plant Journal, 37:439-448). In ongoing research we are using gene switching to modulate metabolic pathways that control production of epidermal waxes, and to regulate production of cellulose and lignin in plants. With Dr. H. Nonogaki (Oregon State University) the gene switch system is being adapted to control seed development and germi- nation. If successful these studies will lead to new uses for production of biomass and limit growth of future transgenic crops that will be used for non-food/feed purposes.
lab members: Maria Soto-Aguilar, Ph.D., Research Scientist / Brian Kelly, Laboratory Technician / Isabel Ordiz, Ph.D., Research Scien- tist / Jaemo Yang, Ph.D., Postdoctoral Associate/ Zhonglian (Julie) Huang, Postdoctoral Associates / Hiro Nonogaki, Visiting Scientist
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2009 scientific report the donald danforth plant science center
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