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Washington State University Molecular Plant Sciences


President Sam Smith Distinguished Professor in Plant Virology
Department of Plant Pathology Ph.D. 1990, University of Alberta, Edmonton

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Viruses offer a simple yet elegant model systems to study the molecular basis of their interactions with host plants as these interactions could result in varying degrees of disease development, in some cases, a lethal response in their hosts. Understanding the basis of these interactions would provide clues to developing strategies for managing virus infections and virus epidemics in crops.

My research activities are focused on genomics and proteomcis of DNA and RNA viruses that are pathogenic to economically important crops: molecular characterization, gene structure-function relationships (Pappu et al. PNAS 90:3641); molecular evolutionary studies using viral genes as markers for attribution (Pappu et al. Arch. Virol. 151:1015); identification and development of novel promoters from plant pararetroviruses for expression of foreign genes in plants; molecular studies on plant pararetroviruses that exist as integrants in their host plant genomes (Pahalawatta et al., Virology 376:253), and use of RNA and DNA viruses of plants as tools for studying virus-host and virus-vector interactions.

Specific research interests/expertise include

* Molecular and biotechnological approaches for characterization and control of viral diseases of crop plants.
* Specific areas of interest are genomics, proteomics, molecular epidemiology, conventional and transgenic resistance, virus detection and diagnosis, and host-virus interactions.
* Current focus is on tospoviruses, luteoviruses, potyviruses, and caulimoviruses
* Crops include vegetables, nursery/ landscape/ ornamentals, legumes, and cereals.
* Other areas of expertise include environmental impact assessments, and regulatory framework for transgenic plants/GM crops; impact of plant biotechnology on society; adoption trends of plant biotechnology in the US and other parts of the world

Ongoing projects include the following

* Thrips and tospoviruses in various vegetable and legume cropping systems
* New and emerging viruses affecting nursery and landscape industry
* Biological and molecular studies of Dahlia mosaic caulimovirus
* Molecular basis of viral pathogenecity using potato-PVS as a model sytstem
* Ecology, epidemiology, and molecular studies on legume viruses

Selected Publications

Review Articles/Book Chapters (Invited and peer-reviewed)

Mandal, B., R. K. Jain, M. Krishnareddy, N.K. Krishna Kumar, K.S. Ravi, and H. R. Pappu. 2012. Emerging Problems of Tospoviruses (Bunyaviridae) and their Management in the Indian Subcontinent. Plant Disease 96:468-479.

Makkouk, K., H.R. Pappu and S.G. Kumari. 2012. Virus Diseases of Peas, Beans and Faba Bean in the Mediterranean Region. Advances in Virus Research 84:367-402.

Chastagner, G., G.R. Hanks, M.L. Daughtrey, I. Yedidia, T.Miller, and H.R. Pappu. 2012. Sustainable Production and Integrated Management: Environmental Issues Pp. 363-420. In: Kamenetsky, R., and H. Okubo (Eds), Ornamental Geophytes: From Basic Science to Sustainable Horticultural Production. Taylor and Francis. 553 pp.

Pappu, H.R., R.A.C. Jones, and R.K. Jain. 2009. Global status of tospovirus epidemics in diverse cropping systems: Successes gained and challenges that lie ahead. Virus Research 141:219–236.

Pappu, H.R. 2008. Tomato spotted wilt virus (Bunyaviridae). In: Encyclopedia of Virology. 3rd edition. Brian Mahy and Marc van Regenmortel (Eds.). Elsevier Ltd, Oxford, UK. pp. 133-138.

Refereed Journal Publications

Mitter, N., V. Koundal, S. Williams, and H.R. Pappu. 2013. Differential expression of virus-specific small RNAs in Tomato spotted wilt virus (Tospovirus:Bunyaviridae)-infected experimental and commercial hosts. PLoS ONE. Accepted for publication.

Sundaraj, S., R. Srinivasan, A.K. Culbreath, D.G. Riley, and H.R. Pappu. 2013. Host plant resistance against Tomato spotted wilt virus (TSWV) in peanut (Arachis hypogaea) and its impact on virus transmission, virus population genetics, and vector feeding behavior and survival. Phytopathology. Accepted for publication.

Kalischuk, M., B. Müller, A. Fusarod, D. Prüferc, P.M. Waterhoused, H.R. Pappu, and L.M. Kawchuk.2013. Molecular characterization of Rubus yellow net virus reveals that open reading frame 1 exhibits pathogenicity determinant properties. Virus Research. Accepted for publication.

Sengoda, V.G., J.L. Buchman, D.C. Henne, H.R. Pappu, and J.E. Munyaneza. 2013.“Candidatus Liberibacter solanacearum” titer over time in the potato psyllid, Bactericera cockerelli (Hemiptera: Triozidae), following acquisition from infected potato and tomato plants. Journal of Economic Entomology. In press.

Birithia, R., S. Subramanian, H. R. Pappu, J. Muthomi and R. D. Narla. 2013. Analysis of Iris yellow spot virus (IYSV, genus Tospovirus) replication in vector and non-vector thrips species. Plant Pathology DOI: 10.1111/ppa.12057

Bag, S., N. Mitter, S. Eid., and H.R. Pappu. 2012. Genetic complementation between two tospoviruses facilitates the systemic movement of a plant virus silencing suppressor in an otherwise restrictive host. PLoS ONE

Media release: Sorensen, E. Viral alliances overcome plant defenses, WSU research finds. WSU Today

Mandal, B., R. K. Jain, M. Krishnareddy, N.K. Krishna Kumar, K.S. Ravi, and H. R. Pappu. 2012. Emerging problems of tospoviruses (Bunyaviridae) and their management in the Indian subcontinent. Plant Disease 96:468-479.

Srinivasan, R., S. Sundaraj, H.R. Pappu, S. Diffie, D.G. Riley, and R.D Gitaitis. 2012. Transmission of Iris yellow spot virus by Frankliniella fusca and Thrips tabaci (Thysanoptera: Thripidae). Journal of Economic Entomology 105:40-47.

Eid, S., C. V. Almeyda, D.E. Saar, K.L. Druffel, and H.R. Pappu. 2011. Genomic characterization of para-retroviral sequences in wild Dahlia spp. in natural habitats. Archives of Virology 156:2079–2084. DOI 10.1007/s00705-011-1076-y

Eid, S., D.E. Saar, K.L. Druffel, and H.R. Pappu. 2011. Plant para-retroviral sequences in wild Dahlia species in their natural habitats in Mexican mountain ranges. Plant Pathology 60, 378–383. DOI: 10.1111/j.1365-3059.2010.02367.x

Bag, S., K.L. Druffel and H.R. Pappu. 2010. Structure and genome organization of the large RNA of Iris yellow spot virus (genus Tospovirus, family Bunyaviridae). Archives of Virology 155:275–279 (DOI 10.1007/s00705-009-0568-5).

Sengoda, V.S., J.E. Munyaneza, J.M. Crosslin, J.L. Buchman, and H.R. Pappu. 2010. Phenotypic and etiological differences between psyllid yellows and zebra chip diseases of potato. American Journal of Potato Research 87:41–49 (DOI 10.1007/s12230-009-9115-x).

Lin, Y-H., K.L. Druffel, J. Whitworth, M.J. Pavek, and H.R. Pappu. 2009. Molecular characterization of two Potato Virus S isolates from late blight resistant genotypes of potato (Solanum tuberosum). Archives of Virology 154:1861-1863. DOI 10.1007/s00705-009-0486-6.

Bag, S., K.L. Druffel, T. Salewsky, and H.R. Pappu. 2009.  Nucleotide sequence and genome organization of the medium RNA of Iris yellow spot virus (genus Tospovirus, family Bunyaviridae) from the United States. Archives of Virology 154:715-718.

Pappu, H.R., R.A.C. Jones, and R.K. Jain. 2009. Global status of tospovirus epidemics in diverse cropping systems: Successes gained and challenges that lie ahead. Virus Research 141:219–236.