James Westwood

Program Focus

My research focuses on parasitic plants, which I find to be the most intriguing of organisms. Parasitic plants are fascinating subjects because they possess unusual characteristics that reveal the extremes of plant growth and development.  For example, the parasite haustorium has the capacity to attach to a host, invade host tissues to reach the host vascular system and form a connection that then serves as a conduit for transfer of host resources.  An essential element of this process is the communication between host and parasite by which the haustorial cells navigate through the host tissue, suppress host defenses, and induce metabolic changes in the host to facilitate transfer of nutrients to the growing parasite.  By elucidating the mechanisms underlying these host-parasite interactions I will identify processes that can be targeted to sever the continuity between parasite and host.

My research focus on basic parasite biology is necessitated by the fact that parasitic plants are Federal Noxious Weeds and their importation and movement within the US is restricted by law.  Important parasite genera Orobanche, Phelipanche and Striga devastate crops in many parts of the world, and present a constant threat to become established in the US.  Orobanche and Phelipanche species infest fields from North Africa to Eastern Europe and the Middle East, reducing yields and forcing farmers to stop growing susceptible crops.  Striga species are a major constraint to cereal production in Africa where they cause annual yield losses exceeding $10 billion.  The USDA imposes tight restrictions on importation of these species, so my research is confined to the plant quarantine facility in my laboratory.  My long-term strategy for translating my research findings into practical control systems is to collaborate with overseas colleagues who can provide a field research component to our work and a link to farmers affected by parasitic weeds.

My interest in the host-parasite exchange of materials led me to also work on the parasitic plant genus, Cuscuta (dodders), which form exceptionally open haustorial connections with their hosts, resulting in the cross-species movement of macromolecules.  My group was the first to report that messenger RNA (mRNA) from host plants can move into Cuscuta and continues to be a leader in characterizing the exchange of RNAs between plants. 

Current Projects

The Parasitic Plant Genome Project (PPGP).  This NSF-Funded project is a collaboration with colleagues at UC Davis, Penn State, and the University of Virginia.  Together we are using a comparative framework of the family Orobanchaceae, which includes species representing the full range of parasitic dependence: a facultative parasite (Triphysaria versicolor), a photosynthetically-competent obligate parasite (Striga hermonthica), an obligate holoparasite [Phelipanche (=Orobanche) aegyptiaca], and their closest non-parasitic relative, Lindenbergia philippensis, which provides a point of contrast to the parasitic species. Transcriptome sequence data generated from these species will be used, along with metabolite profiles from key stages of parasite and host tissues, to identify gene and metabolic networks that function uniquely in parasitic plants. The project aims to identify and characterize genes that are essential for haustoria function in connecting to host tissues and extracting host nutrients such as amino acid and sugar transporters and transcription factors. More information and data are available at http://ppgp.huck.psu.edu/.

Characterization of Mobile RNAs in a Host-Parasite Interaction.  This NSF-funded project is studying Cuscuta pentagona, which has a remarkable ability to communicate with its host plants.  During parasitism it develops a haustorium, which penetrates the host, establishes vascular connections, and serves as a conduit for obtaining water and nutrients from the host.  This is all the more striking because our research has demonstrated the movement of specific messenger RNAs (mRNAs) from the host into Cuscuta.  The project is investigating mRNA trafficking in the host-parasite system, focusing on tomato and Arabidopsis as model host species.  New mobile mRNAs are being identified and characterized using next-gen sequencing of RNAs from parasite and host tissues.

Investigating the Basis for Germination Specificity in Orobanche.  Among the most amazing abilities of parasitic plants is the host detection mechanism of the root parasitic Orobanchaceae.  The seeds of these plants persist for years in the soil, only germinating when the root of an acceptable host plant grows near the seed.  The germination signals are primarily strigolactones (although other compounds exuded from host roots may be involved), but the mechanism by which this signal is perceived by the parasite remains unknown.  Our project is funded by BARD (US – Israel Binational Agricultural Research and Development Fund) with the goal of elucidating the basis for germination specificity in Orobanchespecies. Working with our collaborators in Israel, we are applying RNA-seq approaches to investigate the genetic differences between two closely related species, O. cumana and O. ceruna, that differ in host preference and in response to specific germination stimulants.

• PPWS 3754: Weeds that Shape Our World. Co-instructor: Dr. Jacob Barney.
• PPWS 5984: Molecular Biology for Applied Plant Science. Co-instructors Drs. David Haak and Hillary Mehl.
• PPWS 5704: Weed Science and Management. Online course.

Professor | 2018 to present
School of Plant and Environmental Sciences
Virginia Polytechnic Institute and State University, Blacksburg, Va. 

Professor | 2012 to 2018
Department of Plant Pathology, Physiology and Weed Science (PPWS)
Virginia Polytechnic Institute and State University, Blacksburg, Va. 

Associate Professor |  2005 to 2012
Department of Plant Pathology, Physiology and Weed Science (PPWS)
Virginia Polytechnic Institute and State University, Blacksburg, Va. 

Assistant Professor | 1999 to 2005
Department of Plant Pathology, Physiology and Weed Science (PPWS)
Virginia Polytechnic Institute and State University, Blacksburg, Va. 

Research Scientist | 1997 to 1998
Department of Plant Pathology, Physiology and Weed Science (PPWS)
Virginia Polytechnic Institute and State University, Blacksburg, Va. 

Research Associate | 1994 to 1996
Department of Plant Pathology, Physiology and Weed Science (PPWS)
Virginia Polytechnic Institute and State University, Blacksburg, Va. 

Graduate Research Assistant | 1989 to 1994
Department of Horticulture
Purdue University, West Lafayette, In. 

Agricultural Extension Agent |  1986 to 1988
(US Peace Corps) Mauritanian National Rural Development Society 
Dar Salam, Mauritania.

Graduate Teaching Assistant | 1982 to 1985
Botany Department
University of Minnesota, St. Paul, Mn. 

• Fulbright Scholar, Laboratoire des Interactions Plantes‐Microorganismes, INRA, Toulouse, France. 2019-2020. 
• Virginia Tech College of Agriculture and Life Sciences Excellence in Basic Research Award, 2016.
• Visiting Professor, Inner Mongolia University, Hohhot, China. 2015-2018.
• Honorary Member, International Parasitic Plant Society, 2013.
• Henderson Award for outstanding faculty member in the Department of Plant Pathology, Physiology and Weed Science, 2013.

1.  Randhawa, R., J.H. Westwood, C.W. Cahoon and M.L. Flessner. 2018. Interference and control of ALS-resistant mouse-ear cress (Arabidopsis thaliana) in winter wheat. Weed Technology 32:671-677 DOI:10.1017/wet.2018.69
2. Westwood, J.H., R. Charudattan, S.O. Duke, S.A. Fennimore, P. Marrone, D.C. Slaughter, C. Swanton and R. Zollinger. 2018. Weed control in 2050: Perspectives on the future of weed science. Weed Science 66:275-285. DOI:org/10.1017/wsc.2017.78
3. Tran, H.T., H. Zhu, X. Wu, G. Kim, C.R. Clarke, H. Larose, D. Haak, S. Askew, J. Barney, J. Westwood and L. Zhang. 2018. Identification of differentially methylated sites with weak methylation effect. Genes 9:75. DOI:10.3390/genes9020075
4. Shahid, S., G. Kim, N.R. Johnson, E. Wafula, F. Wang, C. Coruh, V. Bernal-Galeano, T. Phifer, C.W. dePamphilis, J.H. Westwood and M.J. Axtell. 2018. MicroRNAs from the parasitic plant Cuscuta campestris target host messenger RNAs. Nature 553:82–85. DOI: 10.1038/nature25027
5. Weisberg, A.J., G. Kim, J. Westwood and J.G. Jelesko. 2017. Sequencing and de novo assembly of the Toxicodendron radicans (poison ivy) transcriptome. Genes 8:317. DOI: 10.3390/genes8110317
6. Kim G., C.R. Clarke, H. Larose, H.T. Tran, D.C. Haak, L. Zhang, S. Askew, J.  Barney and J.H. Westwood. 2017. Herbicide injury induces DNA methylome alterations in Arabidopsis. PeerJ. 5:e3560. DOI: org/10.7717/peerj.3560
7. Westwood, J.H. and G. Kim. 2017. RNA mobility in parasitic plant – host interactions. RNA Biology 14:450-455. DOI: 10.1080/15476286.2017.1291482
8. Ennami, M., F.Z. Briache, F. Gaboun, R. Abdelwahd, L. Ghaouti, L. Belqadi, J. Westwood and R. Mentag. 2017. Host differentiation and variability of Orobanche crenata populations from legume species in Morocco as revealed by cross infestation and molecular analysis. Pest Management Science 73:1753-1763. DOI: 10.1002/ps.4536.
9. Yang, Z., Y. Zhang, E.K. Wafula, L.A. Honaas, P.E. Ralph, S. Jones, C.R. Clarke, S. Liu, C. Su, H. Zhang , N.S. Altman, S.C. Schuster, M.P. Timko, J.I. Yoder, J.H. Westwood and C.W. dePamphilis. 2016. Horizontal gene transfer is more frequent with increased heterotrophy and contributes to parasite adaptation. Proceedings of the National Academy of Sciences, USA 113 (45) E7010-E7019. DOI:10.1073/pnas.1608765113.
10. Kim, G. and J.H. Westwood. 2015. Macromolecule exchange in Cuscuta-host plant interactions. Current Opinion in Plant Biology. 26:20-25. DOI: 10.1016/j.pbi.2015.05.012
11. Conn C.E., R. Bythell-Douglas, D. Neumann, S. Yoshida, B. Whittington, J.H. Westwood, K. Shirasu, C.S. Bond, K.A. Dyer, and D.C. Nelson. 2015. Convergent evolution of strigolactone perception enabled host detection in parasitic plants. Science 349:540-543. DOI: 10.1126/science.aab1140.
12. Das, M., M. Fernandez-Aparicio, Z. Yang, K. Huang, N.J. Wickett, S. Alford, E.K. Wafula, C. dePamphilis, H. Bouwmeester, M.P. Timko, J.I. Yoder and J.H. Westwood. 2015. Parasitic plants Striga and Phelipanche that depend on exogenous strigolactones for germination have retained genes for strigolactone biosynthesis. American Journal of Plant Sciences 6:1151-1166. DOI: 10.4236/ajps.2015.68120
13. Yang Z., E.K. Wafula, L.A. Honaas, H. Zhang, M. Das, M. Fernandez-Aparicio, K. Huang, P.C.G. Bandaranayake, B. Wu, J.P. Der, C.R. Clarke, P.E. Ralph, L. Landherr, N.S. Altman, M.P. Timko, J.I. Yoder, J.H. Westwood and C.W. dePamphilis. 2015. Comparative transcriptome analyses reveal core parasitism genes and suggest gene duplication and repurposing as sources of structural novelty. Molecular Biology and Evolution 32:767-790. DOI: 10.1093/molbev/msu343
14. Westwood, J.H. 2015. Parasitic Plant. Encyclopedia Britannica. http://www.britannica.com/topic/parasitic-plant
15. Kim G., M.L. LeBlanc, E.K. Wafula, C.W. dePamphilis and J.H. Westwood. 2014. Genomic-scale exchange of mRNA between a parasitic plant and its hosts. Science 345: 808-811. DOI: 10.1126/science.1253122.
16. Liu, Q., Y. Zhang, R. Matusova, T. Charnikhova, M. Amini, M. Jamil, M. Fernandez-Aparicio, K. Huang, M. Timko, J.H. Westwood, C. Ruyter-Spira, S. van der Krol and H.J. Bouwmeester. 2014. Striga hermonthica MAX2 restores branching but not the Very Low Fluence Response in the Arabidopsis thaliana max2 mutant. New Phytologist 202: 531–541. DOI: 10.1111/nph.12692. 
17. LeBlanc, M., G. Kim, B. Patel, V. Stromberg and J. Westwood. 2013. Quantification of tomato and Arabidopsis mobile RNAs trafficking into the parasitic plant Cuscuta pentagona. New Phytologist 200:1225-1233. DOI: 10.1111/nph.12439. 
18. LeBlanc, M.L., T. Merritt, J. McMillan, J.H. Westwood and G. Khodaparast. 2013. Optoperforation of single, intact Arabidopsis cells for uptake of extracellular dye-conjugated dextran. Optics Express 21:14662-14673. (Selected by editors for inclusion in the Virtual Journal for Biomedical Optics). DOI: 10.1364/OE.21.014662.
19. Honaas, L.A., E.K. Wafula, Z. Yang, J.P. Der, N.J. Wickett, N.S. Altman, C.G. Taylor, J.I. Yoder, M.P. Timko, J.H. Westwood and C.W. dePamphilis. 2013. Functional genomics of a generalist parasitic plant: Laser microdissection of host parasite interface cells reveals host-specific patterns of parasite gene expression. BMC Plant Biology 13:9. DOI: 10.1186/1471-2229-13-9.
20. Zhang Y., M. Fernandez-Aparicio, E. Wafula, M. Das, Y. Jiao, N.J. Wickett, L.A. Honaas, P.E. Ralph, M.F. Wojciechowski, M.P. Timko, J.I. Yoder, J.H. Westwood and C. dePamphilis. 2013. Evolution of a horizontally acquired legume gene, albumin 1, in the parasitic plant Phelipanche aegyptiaca and related species. BMC Evolutionary Biology 13:48. DOI: 10.1186/1471-2148-13-48.
21. Fernández-Aparicio, M., K. Huang, E.K. Wafula, L.A. Honaas, N.J. Wickett, M.P. Timko, C.W. dePamphilis, J.I. Yoder and J.H. Westwood. 2013. Application of qRT-PCR and RNA-Seq analysis for the identification of housekeeping genes useful for normalization of gene expression values during Striga hermonthica development.  Molecular Biology Reports 40:3395-3407. DOI: 10.1007/s11033-012-2417-y.
22. Westwood, J.H. 2013. The physiology of the established parasite-host association. Pp. 87-114 In: Parasitic Orobanchaceae: Parasitic Mechanisms and Control Strategies (Joel, D.M., Musselman, L.J. and Gressel, J., eds.) Springer, Heidelberg.
23. LeBlanc, M., G. Kim and J.H. Westwood. 2012. RNA trafficking in parasitic plant systems. Frontiers in Plant Science 3:203.  DOI: 10.3389/fpls.2012.00203.
24. Westwood, J.H., C.W. dePamphilis, M. Das, M. Fernandez-Aparicio, L. Honaas, M.P. Timko, E. Wafula, N. Wickett and J.I. Yoder. 2012. The parasitic plant genome project: new tools for understanding the biology of Orobanche and Striga. Weed Science 60:295-306. DOI: 10.1614/WS-D-11-00113.1.
25. Joel, D.M., H. Bar, A.M. Mayer, D. Plakhine, H. Ziadne, J.H. Westwood and G. E. Welbaum. 2012. Seed ultrastructure and water absorption pathway of the root-parasitic plant Phelipanche aegyptiaca (Orobanchaceae). Annals of Botany 109:181-195 DOI: 10.1093/aob/mcr261.  
26. Wickett, N.J., L.A. Honaas, E.K. Wafula, M. Das, K. Huang, B. Wu, L. Landherr, M.P. Timko, J. Yoder, J.H. Westwood and C. W. dePamphilis. 2011. Expression of the chlorophyll synthesis pathway in a non-photosynthetic plant revealed by the transcriptomes of above ground structures from three parasitic plants from the family Orobanchaceae. Current Biology 21:2098-2104. DOI:10.1016/j.cub.2011.11.011.
27. Fernández-Aparicio, M., J.H. Westwood and D. Rubiales. 2011. Agronomic, breeding and biotechnological approaches for parasitic plant management by manipulating strigolactone levels in agricultural soils. Botany 89:813-826. DOI:10.1139/B11-075. 
28. Fernández-Aparicio, M., D. Rubiales, P.C.G. Bandaranayake, J.I. Yoder and J.H. Westwood. 2011. Transformation and regeneration of the holoparasitic plant Phelipanche aegyptiaca. Plant Methods 7:36. DOI: 10.1186/1746-4811-7-36.
29. Aly, R., N. Hamamouch, J. Abu-Nassar, S. Wolf, D.M. Joel, H. Eizenberg, E. Kaisler, C. Cramer, A. Gal-On and J.H. Westwood. 2011. Movement of protein and macromolecules between host plants and the parasitic weed Phelipanche aegyptiaca Pers. Plant Cell Reports 30:2233-2241. DOI: 10.1007/s00299-011-1128-5.
30. Westwood, J.H., J.I Yoder, M.P. Timko and C.W. dePamphilis. 2010. The evolution of parasitism in plants. Trends in Plant Science 15:227-235. DOI: http://dx.doi.org/10.1016/j.tplants.2010.01.004.
31. Davis, A. S., J.C. Hall, M. Jasieniuk, M.A. Locke, E.C. Luschei, D.A. Mortensen, D.E. Riechers, R.G. Smith, T.M. Sterling and J.H. Westwood. 2009. Weed Science Research and Funding: A Call to Action. Weed Science 57:442-448. DOI: 10.1614/WS-09-020.1. 
32. Stewart Jr, C.N., P.J. Tranel, D.P Horvath, J.V. Anderson, L.H. Rieseberg, J.H. Westwood, C.A. Mallory-Smith, M.L. Zapiola and K.M. Dlugosch. 2009. Evolution of Weediness and Invasiveness: Charting the Course for Weed Genomics. Weed Science 57: 451-462. DOI: 10.1614/WS-09-011.1.
33. Westwood J.H., J.K. Roney, P.A. Khatibi and V.K. Stromberg. 2009. RNA translocation between parasitic plants and their hosts. Pest Management Science 65: 533-539. DOI: 10.1002/ps.1727.