Frederick E. Gildow, Jr., Ph.D.

Area of Research Expertise:

Virus-Vector biology associated with transmission of plant infecting viruses and disease epidemiology.  Research expertise in plant virology, aphid biology, and ultrastructural and immunocytochemical transmission electron microscopy.

Teaching Program:

Dr. Gildow taught Microbe-Plant Interactions: Plant Disease and Biological Control (PPATH 405) an undergraduate senior level and introductory graduate level course.This course surveys  biological interactions of plants with microbial organisms and viruses that are associated with causes of plant disease or that are involved in maintaining plant health (biological controls).  The goal of the course is to educate students with the fundamental knowledge needed to apply basic plant pathology concepts for designing plant disease management strategies.  Dr. Gildow was also adviser to the undergraduate Minor in Plant Pathology program.

Research Program:

Dr. Gildow's  research was focused on three areas: (1) virus-cell membrane interactions associated with  virus transport through insect vectors that determine vector-specificity; and (2) virus microevolution associated with infection of new plant host species and adaptation to new aphid vector species; (3) Studies of vector efficiency of aphids transmitting viruses of epidemiological importance;

Luteovirus vector-specificity mechanisms:  Plant viruses in the family Luteoviridae, such as barley yellow dwarf virus (BYDV), potato leaf roll virus (PLRV), and soybean dwarf virus (SbDV), cause important diseases in major crops worldwide.  Luteoviruses are small icosahedral ss-RNA viruses characterized by extreme host plant tissue-specificity infecting only phloem cells of plants within a limited host range and by vector-specificity limiting transmission by only one or a few aphid species.  This extreme specificity for host tissue and vectors makes the luteoviruses excellent models for experimental studies of mechanisms regulating infection, cellular transport, virus transmission, and viral evolution associated with adaptations to new hosts and vectors.   Much of his work has been on ultrastructural studies to identify the cellular mechanisms regulating luteovirus  transport through aphid cell systems and identifying barriers to transmission that determine vector-specificity.  Recent work in collaborations with Dr. Stewart Gray (USDA-ARS) at Cornell University is focused on identifying virus and aphid proteins associated with host tissue specificity  and vector specificity. 

Microevolution of Soybean Dwarf  Virus and host/vector selection: Soybean dwarf luteovirus is an important pathogen on soybeans throughout Asia.  In N. America, related SbDV strains occur commonly in perennial clovers but do not generally infect soybean at epidemic levels. Why clover isolates of SbDV do not infect soybeans has been unknown, but is believed to be due to the fact that until recently no N. American species of potential aphid vectors colonized soybean.  In 2000, the soybean aphid (Aphis glycines) was introduced to N. America and soon thereafter, clover strains of SbDV were identified infecting soybean crops in several states.  We have initiated studies to determine the likelihood of clover SbDV adapting to transmission by the soybean aphid and becoming epidemic in soybean crops.  In general we are interested in how a virus responds when first introduced to a new host plant and adapts to that plant species, and how virus mutations may be selected for during adaptation to new aphid vector species.  These studies are being done in collaboration with Dr. Bill Schneider and Dr. Vern Damsteegt (USDA-ARS; Ft Detrick, MD).      

Identification of economically important aphid vectors : Recent virus transmission studies have centered on identifying the aphid species responsible for spreading plant viruses causing economically important crop diseases.  Plum  pox virus (PPV) in the virus family Potyviridae is a serious pathogen infecting stone fruits, like peaches, resulting in greatly reduced yields and killed trees.   PPV was first identified in North America in Adams County, Pennsylvania in September, 1999.  Surveys conducted in 2000 delineated the geographical range of the virus.  My lab, with support from the Pa Dept. of Agr and the USDA-ARS, was responsible for identifying indigenous aphid species capable of transmitting the virus and determining which species were epidemiologically significant for spreading the virus.  We were also involved in studies with Bill Schneider and colleagues  (USDA-ARS, Foreign Disease and Weed Research Unit, Ft. Detrick, MD) to identify the host range of PPV in native and ornamental plant species that could function as reservoir hosts aiding PPV survival, and verified that infected fruits could play a role in spreading disease.  Since 2010, PPV has been considered eradicated from Pennsylvania.  More recently, strains of CMV capable of infecting legumes have become epidemic in many eastern US states.  Significant yield losses have been reported in CMV-infected snap bean crops.  Our research, supported by the PA Department of Agriculture in collaboration with Dr. Shelby Fleischer (Dept. Entomology) and colleagues at Cornell University, verified the major aphid vectors responsible for spreading CMV in snap bean fields.  As part of this study we also developed experimental models for estimating vector efficiency in order to identify the most significant vectors responsible for CMV spread and allowing for more targeted control strategies.   

Selected Publications

 Cilia, M., K.A. Peter, M.S. Bereman, K. Howe, T. Fish, D. Smith, F. Gildow, M. Maccoss, and S. Gray.  2012.  Discovery and targeted LC-MS/MS of purified polerovirus reveals differences in the virus-host interactome associated with altered aphid transmission. PLOS ONE  Volume 7 Issue 10: Article Number e48177 DOI: 10.1371/journal.pone.0048177 .

Damsteegt V.D., Stone, A.L1., Kuhlmann, M., Gildow, F.E., Domier, L.L., Sherman, D.J. ,Tian, B., Schneider, W.L. 2011.  Acquisition and transmissibility of United States Soybean dwarf virus isolates by the soybean aphid Aphis glycines.  Plant Disease: 95: 945-950.

Simmons, H. E., Holmes, E. C., Gildow, F. E., Bothe-Goralczyk, M. A., and Stephenson, A. G. 2011.  Experimental verification of seed transmission of Zucchini yellow mosaic virus. Plant Dis. 95:751-754.

Schneider, W.L., V.D. Damsteegt, F.E. Gildow, A.L. Stone, D.J. Sherman, L.E. Levy, V.Mavrodieva, N. Richwine, R.Welliver, and D.G. Luster. 2011. Molecular, Ultrastructural, and Biological Characterization of Pennsylvania Isolates of Plum Pox virus. Phytopathology 101:627-636. 

Nault, B., D. A. Shah, K. E. Straight, A. C. Bachmann, W. M. Sackett, H. R. Dillard, S.J. Fleischer and F. E. Gildow. 2009. Modeling temporal trends in aphid vector dispersal and Cucumber mosaic virus epidemics in snap bean. Environmental Entomology 38: 1347-1359.

Peter, K. A., Gildow, F., Palukaitis, P. and Gray, S. M. 2008. Phloem limitation of a plant virus is an asset and not a liability. J. Virology 83: 5419-5429. 

Gildow, F.E., D.A. Shah, W.M. Sackett, T. Butzler, B.A. Nault, and S.J. Fleischer. 2008. Transmission efficiency of Cucumber mosaic virus by aphids associated with epidemics in snap beans. Phytopathology 98: 1233-1241.

Yang, X., T. W. Thannhauser, M. Burrows, D. Cox-Foster, F. E. Gildow, and Stewart M. Gray. 2008. Coupling Genetics and Proteomics To Identify Aphid Proteins Associated with Vector-Specific Transmission of Polerovirus (Luteoviridae). J. Virology 82: 291-299.

Wallis, C.M., A.L. Stone, D.J. Sherman, V.D. Damsteegt, F.E. Gildow, and W. L. Schneider. 2007. Adaptation of plum pox virus to a herbaceous host (Pisum sativum) following serial passages. J. Gen. Virol. 88:2839-2845. 

Kaplan, I.B., L.Lee, D.R. Ripoll, P. Palukaitis, F. Gildow, and S.M. Gray. 2007. Point mutations in the potato leafroll virus major capsid protein alter virion stability and aphid transmission. J. Gen. Virol. 88:1821-1830. 

Burrows, M.E., M.C. Caillaud, D.M. Smith, E.C. Benson, F.E. Gildow, and S.M. Gray. 2006. Genetic regulation of polerovirus and luteovirus transmission in the aphid Schizaphis graminum. Phytopathology 96: 828-837.

Strenger, D.C., R. French, and F.E. Gildow. 2005. Complete deletion of Wheat Streak Mosaic Virus HC-Pro: a null mutant is viable for systemic infection. J. of Virology 79: 12077-12080.

Wallis, C., S. Fleischer, D. Luster, and F.E. Gildow. 2005. Aphid (Homoptera: Aphididae) species composition and potential aphid vectors of Plum pox virus in Pennsylvania peach orchards. J. Econ. Entomol. 98: 1441-1450.

Damsteegt, V.D., A.L. Stone, F.E. Gildow, W.L. Schneider, and D.G. Luster. 2004. Prunus host range of Pennsylvania isolates of plum pox virus by aphid transmission. Acta Hort. : 657: 201-205

Gildow, F.E. 2004. Plum pox in North America : Identification of aphid vectors and a potential role for fruit in virus spread. Phytopathology : 94: 868-874.

Gray, S.M., and Gildow, F.E . 2003. Luteovirus-Aphid Interactions. Ann. Rev. Phytopathology 41: 539-566.

Gildow, F.E. 2001. Virus Detection – Electron Microscopy. Pages: 1088-92; In: Encyclopedia of Plant Pathology, O.C. Maloy and T.D. Murray (eds.), John Wiley and Sons, Inc. 

Li, Chao-Yang, D. Cox-Foster, and F. E. Gildow. 2001. Vector-specificity of Barley Yellow Dwarf Virus (BYDV) transmission: Identification of potential cellular receptors binding BYDV-MAV in the aphid, Sitobion avenae. Virology: 286: 125-133. 

Reinbold, C., Gildow, F.E., Herrback, E., Ziegler-Graff, V., M.C. Goncalves, van den Heuvel, J.E.J.M., and Brault, V. 2001. Studies on the role of the minor capsid protein in transport of Beet western yellows virus through Myzus persicae. J. Gen. Virology: 82: 1995-2007. 

Garcia-Salazar, F. E. Gildow, S. J. Fleischer, D. Cox-Foster, and F. L. Lukezic. 2000." Immunolocalization of Erwinia tracheiphila in Acalymma vittata." Environ. Entomol. 29:542-550. 

Gildow, F. E. 2000. "Virus detection: electron microscopy." In: The Encyclopedia of Plant Pathology, O.C. Maloy and T.D. Murray, eds., John Wiley & Sons, New York.

Gildow, F. E., V. D. Damsteegt, A. L. Stone, O. P. Smith, and S. M. Gray. 2000. "Virus-vector cell interactions regulating transmission specificity of soybean dwarf  luteoviruses." J Phytopathology : 148:333-342.

Gildow, F. E., B. Reavy, M. A. Mayo, G. H. Duncan, J. A. T. Woodford, J. W. Lamb and R. T. Hay. 2000. "Aphid acquisition and cellular transport of potato leafroll virus-like particles lacking P5 readthrough protein." Phytopathology 90:1153-1161.

Gildow, F. E.  1999.  Luteovirus transmission and mechanisms regulating vector-specificity.  pages 88-113, In: The Luteoviridae,  H. G. Smith and H. Barker, eds., CAB International .