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

Understanding and engineering host defense to a parasitic plant
This project is based on the idea that host plant defense systems can be improved to resist parasitism and this knowledge can be used to make crops that are not parasitized. We have evidence that host defense signaling networks influence the success of the parasitic plant Phelipanche aegyptiaca (Egyptian broomrape) attachment on host roots. We are using genetic and molecular tools to dissect the roles of host defense genes in the interactions with parasites using two hosts, the model plant Arabidopsis and tomato. We have also identified host gene promoters that are expressed with high specificity in response to parasite attack. We plan to generate transgenic plants expressing these promoters fused to the most effective defense genes. Ultimately, we aim to generate enhanced resistance to parasitism in both Arabidopsis and tomato hosts. This project will expand our understanding of host defense responses and host-parasitic plant communication.
Collaborator: Soyon Park, University of Missouri
Funded by: USDA NIFA award 2023-67013-39896

Collaborative Research: PlantTransform: Novel methods of plant genome editing enabled by theparasitic plant Cuscuta campestris
A major barrier to plant research and crop improvement is a scarcity of methods available for genetically manipulating plants. Techniques currently used include the culturing of plant tissues, the insertion or editing of DNA, and the regeneration of whole plants, but each of these steps represents a potential barrier because they don't work reliably in many species. To fill this gap, we propose that the parasitic plant dodder (Cuscuta species) can be used to deliver gene editing molecules to a wide range of plants. Dodder plants live by attaching themselves to the stems of host plants and forming connections to withdraw water and nutrients. The organs that form the connections are called haustoria, and function somewhat similar to the way a mosquito taps into a vein to feed, and dodder is able to transmit a variety of large molecules, including proteins and RNAs, to their hosts. Another key feature of dodder is its ability to connect to an unusually wide range of host species, including the most important broadleaf crops. We will evaluate the ability of dodder to mobilize genome editing molecules into its hosts, with the goal of producing gene-edited seeds. Success in this activity would establish a novel vehicle for genetic modification of plants that is relatively simple, rapid, and broadly applicable.
Collaborators: Soyon Park, University of Missouri; Michael Axtell, Penn State; Bastiaan Bargmann, Virginia Tech
Funded by: NSF (Plant Genome) IOS-2348321

• 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. Kaur, S., M. Ibdah, R. Sakioka, K. Nagano, K. Yoneyama, P. Simon, J. Westwood and D. Tholl. Reduced strigolactone exudation as a key resistance mechanism in wild carrots against Phelipanche aegyptiaca. Plant & Cell Physiology. In press.
2. Cerda-Herrera, J., H. Zhang, E. Wafula, S. Adhikari, S.-Y. Park, S.B. Carey, A. Harkess, P. Ralph, J.H. Westwood, M.J. Axtell, and C.W. dePamphilis. 2025. Chromosome level assembly and annotation of Cuscuta campestris Yunck. ("dodder") a model parasitic plant. G3:Genes Genomes Genetics. https://doi.org/10.1093/g3journal/jkaf193
3. Adhikari, S., Mudalige, A., Phillips, L., Lee, H., Bernal-Galeano, V., Gruszewski, H., Westwood, J.H., and Park, S-Y. 2025. Agrobacterium-mediated Cuscuta campestris transformation as a tool for understanding plant–plant interactions. New Phytologist 245: 1774–1786. DOI: 10.1111/nph.20140
4. Sharma, G.; D. Haak, J. Westwood, S. Askew, and J. Barney. 2024. Transgenerational adaptation to herbicide stress is more rapid than to ecological stress in Arabidopsis. The Plant Journal 119:2375-2384. http://doi.org/10.1111/tpj.16923
5. PLANTCOM network: Claude Becker, Richard Berthomé, Philippe Delavault, Timothée Flutre, Hélène Fréville, Stéphanie Gibot-Leclerc, Valérie Le Corre, Jean-Benoit Morel, Nathalie Moutier, Stéphane Muños, Céline Richard-Molard, James Westwood, Pierre-Emmanuel Courty, Alexandre de Saint Germain, Gaëtan Louarn, Fabrice Roux. 2023. The ecologically relevant genetics of plant-plant interactions. Trends in Plant Science. https://doi.org/10.1016/j.tplants.2022.08.014
6. Bendaoud, F., G. Kim, H. Larose, J.H. Westwood, N. Zermane* and D.C. Haak*. 2022. GBS analysis of Orobanche crenata populations in Algeria reveals genetic differentiation. Ecology and Evolution 12:e8750 DOI: 10.1002/ece3.8750
7. Bernal-Galeano, V. K. Beard and J.H. Westwood. 2022. An artificial host system enables the obligate parasitic plant Cuscuta campestris to grow and complete its life cycle in vitro. Plant Physiology 189:687-702. DOI: 10.1093/plphys/kiac106
8. Park, S.-Y., K. Shimizu, J. Brown, K. Aoki and J.H. Westwood. 2022. Mobile host mRNAs are translated to protein in the associated parasitic plant Cuscuta campestris. Plants 11, 93. DOI: 10.3390/plants11010093
9. Sharma, G., J.N. Barney, J.H. Westwood and D.C. Haak. 2021. Into the weeds: new insights in plant stress. Trends in Plant Science 26:1050-106.  https://doi.org/10.1016/j.tplants.2021.06.003
10. Gu, X., I.G. Chen, S.A. Harding, B. Nyamdari, M.A. Ortega, K. Clermont, J.H. Westwood and C.-J. Tsai. 2021. Plasma membrane phylloquinone biosynthesis in non-photosynthetic parasitic plants. Plant Physiology 185:1443-1456. DOI: 10.1093/plphys/kiab031
11. Clarke, C.R., S.-Y. Park, R. Tuosto, X. Jia, A. Yoder, J.H. Van Mullekom and J. Westwood. 2020. Multiple immune pathways control susceptibility of Arabidopsis thaliana to the parasitic weed Phelipanche aegyptiaca. PeerJ 8:e9268. DOI: 10.7717/peerj.9268
12. Dor, E., D. Plakhine, D.M. Joel, H. Larose, J.H. Westwood, E. Smirnov, H. Ziadna and J. Hershenhorn. 2020. A new race of sunflower broomrape (Orobanche cumana) with a wider host range due to changes in seed response to strigolactones. Weed Science 68:134-142. DOI: 10.1017/wsc.2019.73
13. Ennami, M., J. Mbasani-mansi, F.Z. Briache, N. Oussible, F. Gaboun, L. Ghaouti, L. Belqadi, M.E. Ghanem, K. Aberkani, J. Westwood and R. Mentag. 2020. Growth-defense tradeoffs and source-sink relationship during both faba bean and lentil interactions with Orobanche crenata Forsk. Crop Protection 127:104924. DOI: 10.1016/j.cropro.2019.104924
14. One Thousand Plant Transcriptomes Initiative. 2019. A phylogenomic view of evolutionary complexity in green plants. Nature 574: 679–685. DOI: 10.1038/s41586-019-1693-2
15. Clarke, C.R., M.P. Timko, J.I. Yoder, M.J. Axtell and J.H. Westwood. 2019. Molecular dialog between parasitic plants and their hosts. Annual Review of Phytopathology 57: 279-299. DOI: 10.1146/annurev-phyto-082718-100043 (Invited review)
16. Yang, Z., E. Wafula, G. Kim, S. Shahid, J.R. McNeal, P.E. Ralph, P.R. Timilsena, W.-B. Yu, E. Kelly, H. Zhang, T.N. Person, N.S. Altman, M.J. Axtell, J.H. Westwood and C.W. dePamphilis. 2019. Convergent horizontal transfer and crosstalk of mobile nucleic acids in parasitic plants. Nature Plants. 5: 991–1001. DOI: 10.1038/s41477-019-0458-0
17. Clermont, K., Y. Wang, S. Liu, Z. Yang, C.W. dePamphilis, J.I. Yoder, E. Collakova, and J.H. Westwood. 2019. Comparative metabolomics of early development of the parasitic plants Phelipanche aegyptiaca and Triphysaria versicolor. Metabolites 9: 114. DOI:10.3390/metabo9060114
18. 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
19. 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
20. 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
21. 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
22. 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
23. 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
24. 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
25. 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.
26. 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.
27. 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
28. 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.
29. 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
30. 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
31. Westwood, J.H. 2015. Parasitic Plant. Encyclopedia Britannica. http://www.britannica.com/topic/parasitic-plant
32. 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.
33. 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. 
34. 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. 
35. 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.
36. 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.
37. 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.
38. 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.
39. 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.
40. 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.
41. 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.
42. 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.  
43. 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.
44. 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. 
45. 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.
46. 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.
47. 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.
48. 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. 
49. 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.
50. 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.