Center for Plant Cell Biology


A. L. N. RaoA. L. N. Rao


Mailing Address:

Plant Pathology and Microbiology
Webber Hall /3264A
University of California
Riverside, CA 92521

Phone: (951) 827-3810
Fax: (951) 827-3264
Email: arao@ucr.edu


PhD 1982 University of Adelaide
MS 1976 Indian Agrl Res. Inst

College/Division Affiliation:

College of Natural and Agricultural Sciences

Center/Inst Affiliation(s):

Center for Plant Cell Biology

Areas Of Expertise:

Molecular Plant Virology; Virus Replication; Virus-host Interactions; Virus Cell-to-cell Movement and Mechanism of Genome Packaging in Positive-strand RNA Viruses

Research Summary:

Assembly of infectious virions has long been recognized to be an important phase in the life cycle of a given virus pathogenic to plants, humans and animals. Viral genome packaging is considered to be a highly specific process since the majority of purified virions contain exclusively viral RNAs. However the mechanism by which viruses assemble and package their genomes (RNA or DNA) into stable virions is poorly understood. To unravel the mechanism of RNA packaging in eukaryotic RNA viruses, my laboratory is using brome mosaic virus (BMV) and flock house virus (FHV) as model systems.  Bipartite FHV, an RNA virus of insects and a member of Nodaviridae family, shares viral replication features with a tripartite BMV, an RNA virus infecting plants and a member of Bromoviridae family. Although FHV is an insect virus, it efficiently replicates and forms infectious virions in several plant species. Furthermore, BMV replicates on ER while FHV on outer mitochondrial membranes. Others and we have demonstrated that in these two viruses genome packaging is functionally coupled to replication, a widely conserved mechanism among positive-strand RNA viruses of diverse origin. To shed more light on replication-coupled packaging mechanism, we exploited the unique features of BMV and FHV and developed an agrobacterium-mediated transient expression system (agroinfiltration) for DNA-directed expression of functional BMV and FHV RNA components in plants. This agroinfiltration system is being used to delineate various events that lead to regulate replication-coupled RNA packaging. To complement this ongoing research endeavor, recently we initiated a new project involving non-invasive fluorophore-based bimolecular fluorescence complementation (BiFC) approach for studying protein-protein interactions in plants.

Figure 1. Confocal laser scanning microscopy of enhanced green fluorescent protein (eGFP). Top panels: Macroscopic images of Nicotiana benthamiana leaves infiltrated with indicated cultures of agrotransformants. The infiltrated leaf harvested at 5 dpi was scanned through Typhoon 9410 equipped with emission filter 670 bp 30-633 nm (red laser) and emission filter 520 BP-488 nm (blue laser).  Dotted circles indicate infiltration patches. Bottom panels: Confocal laser scanning microscopic images showing subcellular localization of eGFP. Note that mock infiltrated leaf (left) emits reddish auto-fluorescence; in leaf infiltrated with DI-eGFP alone (middle) the transiently expressed green fluorescence was confined to epidermal cells whereas in leaf infiltrated with FHV RNA1 (F1)+eGFP (right) green fluorescence was seen in mesophyll cells.  


Figure 2  Immunogold EM localization of FHV protein A (replicase). (A) Electron micrographic image of a section of healthy N. benthamiana leaf showing vacuole (V), chloroplast (Ch), cytoplasm (Cy) and mitochondria (M). (B) Electron micrograph showing a section of F1 infiltrated N. benthamiana leaf treated with pre-immune serum. (C) Electron micrograph showing localization of FHV protein A to mitochondria of N. benthamiana infiltrated with F1 agrotransformant. The arrows show the location of gold particles on outer mitochondrial membrane. (D) Electron micrograph (higher magnification, 50X) reveals localization of gold particles to outer double-walled mitochondrial membrane (indicated by double arrows).  Scale bars = 0.5 μm (A and B) and 0.2 μm (C).







Selected Publications:

List of publications from HubMed

Lab Personnel: 

Bamunusinghe, Devinka
Graduate Student — Molecular Plant Virology
Chaturvedi, Sonali
Graduate Student —  Molecular Plant Virology
Choi, Soon
Graduate Student —  Molecular Plant Virology

More Information

General Campus Information

University of California, Riverside
900 University Ave.
Riverside, CA 92521
Tel: (951) 827-1012

Career OpportunitiesUCR Libraries
Campus StatusDirections to UCR

Center Information

Center for Plant Cell Biology
Botany & Plant Sciences Department
2150 Batchelor Hall

Tel: (951) 827-7177
Fax: (951) 827-5155
E-mail: genomics@ucr.edu