Professor Susan E Seal
Principal Scientist; Professor of Molecular Biology; Molecular Plant Pathologist
Agriculture, Health and Environment Department
Natural Resources Institute
After obtaining a BSc Honours Microbiology degree in 1984 from Imperial College (London, UK), Professor Susan Seal gained a preliminary training in molecular biology at Genentech Inc. (San Francisco, USA) carrying out research on an auto-immune disease. Further research experience in molecular biology was acquired through PhD studies at the University of Bath on identifying pathogenicity genes in the plant pathogen Xanthomonas campestris pv. vesicatoria. During this time she decided on a career in research to benefit agriculture in developing countries and obtained scholarship funding to do fieldwork in Indonesia, and then worked as a postdoctoral scientist at The Sainsbury Laboratory, John Innes Centre developing DNA-based diagnostic tests for Ralstonia solanacearum, one of the most important tropical plant pathogens. Several tests were developed and Professor Seal was employed by NRI in 1992 to transfer these tests to a range of overseas countries and develop new molecular diagnostic projects.
Since joining NRI, Professor Seal has overseen the molecular diagnostic laboratories at NRI, as well as establishing molecular-diagnostics laboratories in developing countries, and teaching MSc courses ('Molecular diagnostics', 'Plant pathology', 'Organisms and Systematics' and 'GM Crops'). In 2009, she became Leader of the Molecular Virology and Entomology Research Group at NRI, which focuses on applied as well as strategic research for controlling pests and diseases of tropical food crops especially those caused by viruses and insect vectors on cassava, sweet potato, yams and vegetables. These root and tuber crops play key roles in food security, poverty reduction, and income generation in Sub-Saharan Africa.
Professor Seal has led ~50 research projects at NRI (total value ~£5 million), the larger of which are outlined below in chronological order with their funding source given in brackets.
- Set up of molecular diagnostic laboratories in Asia and Africa (ODA)
- Cyprus national quarantine diagnostic services consultancy (EC, Govt. Cyprus)
- Yam potyvirus research (Worldbank, Gatsby Charitable Foundation, ODA)
- Identification of a banana bacterial wilt pathogenicity locus (ODA)
- Development of diagnostics for bacterial pathogens of vegetables (ODA)
- Molecular characterisation of aflatoxin producing fungi (ODA)
- Diagnostic tools for corn stunt complex (funding ODA)
- Diagnostics for a fungal pathogen (Mycospharella fijiensis) of banana (ODA)
- Diagnostics for Cassava brown streak virus, and sweet potato virus disease (DFID)
- Detection and characterisation of yam viruses (EC, CIRAD, Kebbi State, Nigeria)
- Genetic linkage map and molecular markers in groundnut (DFID)
- Review of suitability of transgenic crops for developing countries (DFID)
- Development of diagnostic tools for fish trematodes (INCO-DEV, EC)
- Identification of existing biosafety capacities and initiatives available in the CORAF sub-region and needs for research and training (FARA)
- 'Green, white, blue and red' biotechnologies in developing countries (EC)
- Molecular typing of begomoviruses (DFID)
- Transcriptomics/genomics of whiteflies (UoG and BMGF)
- Yam virus research (BMGF)
- Development of On-Farm Robust Diagnostic Toolkits for Yam Viruses (BMGF)
- Enabling research tools for cassava virologists and breeders (BMGF)
Research on the above projects has led to the publication of >75 refereed journal papers, reviews and book chapters, as well as several 'Briefing Papers'. The projects above have also incorporated supervising the research of a range of MSc (>10 overseas students) and PhD (>20 overseas students) studies.
Keywords: molecular biology, diagnostics, cassava, yam, virus, whitefly, PCR, genomics, transcriptomics
Current research interests focus on using molecular biology tools to generate an improved understanding of the factors contributing to the spread of cassava and yam disease epidemics in Africa and developing novel technologies for their control. The research ranges from using the latest next generation sequencing technologies to determine genome and transcriptome data for the vector (Bemisia tabaci) of the cassava viruses, to developing robust, low-cost diagnostic technologies for such plant viruses and specific populations of their vectors which appear to be driving the spread of epidemics.
In the past value of Professor Seal's research is indicated by the following examples
- Selected by the EC/Cyprus Government as the consultant to advise on improving the molecular diagnostic capability and infrastructure of Cyprus' national quarantine laboratories.
- Approached by John Innes Centre and Gatsby Charitable Foundation to develop tests for yam potyviruses, and awarded two postdoctoral grants.
- Awarded a 1-year CIRAD 'poste d'accueil'; these grants promote collaboration with targeted foreign scientists whose knowledge will benefit CIRAD.
- Publishing the first full-length yam badnavirus sequence and evidence of endogenous pararetroviruses in host plant genomes. Selected currently to provide yam virology expertise for a Bill & Melinda Gates Foundation (BMGF) proposal (~US$12 million) to improve yam productivity in Africa, as well as leading a US$1.5 million yam virus toolkits project (BMGF).
- Expertise in begomovirus/whitefly characterisation recognised by Imperial College and employed to review factors influencing the worldwide emergence of whitefly-transmitted begomovirus epidemics. The review published was position 4 (2006-2009) in most cited Critical Reviews in Plant Sciences reviews.
It is hoped in the future that the value of Professor Seal's research will be to deliver research outputs that reduce the impact of root and tuber crop virus diseases in sub-Saharan Africa, and hence improve food security for smallholder farmers for whom cassava and yam are their major staple crop.
Current and Previous Funded Research Projects
Project Leader for project entitled 'Enabling research tools for cassava virologists and breeders' (2013-2017, £0.5 million funded by The Bill and Melinda Gates Foundation )
Cassava is an essential food security crop, but its production is greatly limited by cassava virus diseases driven by super-abundant populations of the whitefly vector, B. tabaci, which appear to be an invasive form. In order to develop novel whitefly-management technologies and to ensure their successful adoption by resource-poor farmers, an improved understanding of the mechanisms generating the super-abundance cassava whitefly populations is required. A key step in this process is the development of accurate, robust and easy-to-use diagnostic tools that differentiate the different African cassava whitefly species. At present, population identification is based on the partial sequence of the mitochondrial cytochrome-oxidase 1 gene (mtCO1). This diagnostic has several drawbacks, the most serious being that it is a mitochondrial marker and hence is inherited maternally. The proposed project will address the need for improved whitefly diagnostics by studying biological properties and nuclear gene sequences for the different cassava 'mt-CO1' populations, focusing on identifying diagnostic targets (i.e. gene sequence differences) present in the super-abundant whitefly populations infesting cassava in sub-Saharan Africa. The knowledge and new diagnostic tools will improve our understanding of the mechanisms driving plant-virus epidemics and for identifying key intervention points. As such they have the potential to create significant impact both in the scientific community and through improved African cassava whitefly, and hence virus disease control.
This project will also assess the suitability of a novel method to develop infectious clones (ICs) of cassava brown streak viruses (CBSV, UCBSV) and NRI is coordinating an international team to share resources and draw up standard operating procedures (SOPs) for the use of ICs in SSA. This will link directly with the 'Disease diagnostics for sustainable cassava productivity in Africa' proposal at the Mikocheni Agricultural Research Institute (MARI) Tanzania, which aims to minimize both the occurrence as well as impact of cassava virus diseases and their associated insect (whitefly) vectors.
Project Leader for project entitled 'Development of On-farm Robust Diagnostic Toolkits for Yam Virus Diseases' (2012-2016, ~US$1.5 million funded by The Bill and Melinda Gates Foundation)
Yams are propagated vegetatively through their tubers, which leads to an accumulation of tuber-borne diseases in farmers' planting material and subsequent serious crop yield losses. The economically-important tuber-borne diseases are caused by viruses, and the only effective method of controlling these virus diseases is to use virus-free planting material. The scarcity and associated high expense of such material has been identified as one of the most important critical constraints to increasing yam production and productivity in W.Africa. A separate Bill and Melinda Gates Foundation funded project 'Yam Improvement for Incomes and Food Security in W.Africa (YIIFSWA)' (of which NRI/Professor Seal is also a partner) will address this by supporting the supply of high quality breeder and foundation seeds, and promoting a seed yam certification system to support the production and sustainable supply of high quality seed yams through farmer seed growers and commercial seed entrepreneurs. There is a resulting urgent need to develop on-farm diagnostic kits for yam viral diseases to enable this certification in the field.
The 26 virus species that have been reported to infect yams worldwide fall into nine taxonomic genera, but only three of these genera (badnaviruses, potyviruses and cucumoviruses) have been shown to cause important diseases and be widespread in recent surveys (2004-2009) across 100 yam growing locations in W.Africa. In addition to the normal virus infection process, some of the 12 yam badnavirus species appear to be integrated into the host genome of some of the widely cultivated Dioscorea species. Integrated badnavirus sequences are termed 'endogenous pararetroviruses' (EPRVs). Of particular concern is that EPRVs can be 'activatable', i.e. able to replicate and initiate virus infections de novo from their sequences integrated in the host genome. This poses serious problems for virus-indexing facilities as material free from virus particles and symptoms can, when stressed, become infected. Therefore it is essential to improve existing diagnostic tools for broad-specific detection of viruses and EPRVs, particularly in germplasm selected for wide dissemination in YIIFSWA. The yam lines containing 'activatable' EPRVs will need to be removed from the multiplication process as they cannot be 'cleaned' of badnaviruses and will pose a serious long term threat to the genuinely virus-free yam lines.
Responsibilities within the University
- Leader of the Molecular Virology and Entomology Research Group (NRI)
- Faculty Research Degrees Committee representative
- Biological and Genetic Manipulations Safety Committee
- Plant Pathogen Import Licence holder
- AGRINATURA GM Biosafety NRI representative
- Laboratory and Glasshouse responsibility
- Collins C, Patel M, Colvin J, Bailey D, Seal S. (2013). Identification and evaluation of suitable reference genes for gene expression in the whitefly, Bemisia tabaci, by reverse transcription quantitative real-time RT-PCR. Journal of Insect Science (accepted).
- Seal, Susan, Patel, Mitulkumar V., Collins, Carl, Colvin, John and Bailey, David (2012) Next generation transcriptome sequencing and quantitative real-time PCR technologies for characterisation of the Bemisia tabaci Asia 1 mtCOI phylogenetic clade. Journal of Integrative Agriculture, 11 (2). pp. 281-292. ISSN 2095-3119 (doi:10.1016/S2095-3119(12)60012-4)
- Black, Robert, Fava, Fabio, Mattei, Niccolo, Seal, Susan and Verdier, Valerie (2011) Case studies on the use of biotechnologies and on biosafety provisions in four African countries. Journal of Biotechnology, 156. pp. 370-381. ISSN 0168-1656 (doi:10.1016/j.jbiotec.2011.06.036)
- Abarshi, M.M., Mohammed, I.U., Wasswa, P., Hillocks, R.J., Holt, J., Legg, J.P., Seal, S.E. and Maruthi, M.N. (2010) Optimization of diagnostic RT-PCR protocols and sampling procedures for the reliable and cost-effective detection of Cassava brown streak virus. Journal of Virological Methods, 163 (2). pp. 353-359. ISSN 0166-0934 (doi:10.1016/j.jviromet.2009.10.023)
- Bousalem, Mustapha, Durand, O., Scarcelli, N., Lebas, B.S.M., Kenyon, L., Marchand, J.-L., Lefort, F. and Seal, S.E. (2009) Dilemmas caused by endogenous pararetroviruses regarding the taxonomy and diagnosis of yam (Dioscorea spp.) badnaviruses: Analyses to support safe germplasm movement. Archives of Virology, 154 (2). pp. 297-314. ISSN 0304-8608 (Print), 1432-8798 (Online) (doi:10.1007/s00705-009-0311-2)
- Bousalem, M., Douzery, E.J.P. and Seal, S.E. (2008) Taxonomy, molecular phylogeny and evolution of plant reverse transcribing viruses (family Caulimoviridae) inferred from full-length genome and reverse transcriptase sequences. Archives of Virology, 153 (6). pp. 1085-1102. ISSN 0304-8608 (Print), 1432-8798 (Online) (doi:10.1007/s00705-008-0095-9)
- Kenyon, Lawrence, Lebas, B.S.M. and Seal, S.E. (2008) Yams (Dioscorea spp.) from the South Pacific Islands contain many novel badnaviruses: Implications for international movement of yam germplasm. Archives of Virology, 153 (5). pp. 877-889. ISSN 0304-8608 (Print), 1432-8798 (Online) (doi:10.1007/s00705-008-0062-5)
- Seal SE, Karunasagar I, Paiboon S, Melhorn H, Zheng F. (2008). Development of a diagnostic tool for the detection of fish-borne trematodes. Pages 49-53 In: Catalogue of synopses of International S&T Cooperation (INCO) projects on challenges in fisheries, coastal zones, wetlands and aquaculture. (Estrella Santon N., and Nauen C.E. eds) ACP-EU Fish. Res. Rep. (17): 292 pp.
- Seal, Susan and Muller, Emanuelle (2007) Molecular analysis of a full-length sequence of a new yam badnavirus from Dioscorea sansibarensis. Archives of Virology, 152 (4). pp. 819-825. ISSN 0304-8608 (Print) 1432-8798 (Online) (doi:10.1007/s00705-006-0888-7)
- Seal, Susan, Jeger, M.J. and vandenBosch, F. (2006) Factors influencing begomovirus evolution and their increasing global significance: implications for sustainable control. Critical Reviews in Plant Sciences, 25 (1). pp. 23-46. ISSN 0735-2689 (doi:10.1080/07352680500365257)
- Seal S, Jeger MJ and vandenBosch F. (2006). Disease management and begomovirus evolution. Advances in Virus Research 67, 297-316.
- van den Bosch F, Akudibilah G, Seal S and Jeger M. (2006). Host resistance and the evolutionary response of plant viruses. Journal of Applied Ecology 43, 506-516.
- Chowda Reddy RV, Colvin J, Muniyappa V, and Seal S. (2005). Diversity and distribution of begomoviruses infecting tomato in India. Archives of Virology 150, 845-867.
- Herselman L, Thwaites R, Kimmins FM, Courtois B, van der Merwe PJA and Seal SE. (2004). Identification and mapping of AFLP markers linked to peanut (Arachis hypogaea L.) resistance to the aphid vector of groundnut rosette disease. Theoretical and Applied Genetics 109, 1426-1433.
- Maruthi, M.N., Colvin, John, Gibson, Gabriella, Thwaites, Richard M., Banks, Gina K. and Seal, Susan (2004) Reproductive incompatibility and cytochrome oxidase I gene sequence variability amongst host-adapted and geographically separate Bemisia tabaci populations (Hemiptera: Aleyrodidae). Systematic Entomology, 29 (4). pp. 560-568. ISSN 0307-6970 (doi:10.1111/j.0307-6970.2004.00272.x)
- Monger W.A., S. Seal, S. Cotton and G.D. Foster (2001). Identification of different strains of Cassava brown streak virus, and development of a diagnostic RT-PCR test. Plant Pathology 50, 768-775.
- Monger W.A , S. Seal, A.M. Isaac and G.D. Foster (2001). Molecular characterisation of Cassava brown streak virus coat protein. Plant Pathology 50, 527-534.
- Mumford R. A., and Seal SE (1997). Rapid single-tube immunocapture RT-PCR for the detection of two yam potyviruses. Journal of Virological Methods 69, 73-79.
- Seal S.E., L.A. Jackson, J. P. W. Young and M.J. Daniels. (1993). Differentiation of P. solanacearum, P. syzygii, P. pickettii and the Blood disease bacterium by partial 16S rRNA sequencing. Journal of General Microbiology 139:1587-1594.
- Seal S., L. Jackson and M. Daniels. (1992). Isolation of a Pseudomonas solanacearum-specific DNA probe by subtraction hybridization and construction of species-specific oligonucleotide primers for sensitive detection by the polymerase chain reaction. Applied Environmental Microbiology 58: 3751-3758.
Recent Conference Presentations
- A.Turaki, P. L. Kumar, A. Lopez-Montes, M. Bomer, G. Silva, and S. E. Seal. 2013. Developing diagnostics to detect badnavirus and endogenous pararetrovirus DNA sequences in West African yam breeding lines. Abstract at Yams2013, first global conference on yam (Dioscorea spp.), 3-6/10/2013, Accra, Ghana.
- M. Hema, P. Ogunsanya, S. E. Seal and P. L. Kumar. 2013. Expression of the coat protein genes of Yam mosaic virus and Yam mild mosaic virus in Escherichia coli and production of polyclonal antibodies. Abstract at Yams2013, first global conference on yam (Dioscorea spp.), 3-6/10/2013, Accra, Ghana
- C. K. Nkere, G.I. Atiri, S. E. Seal and P. L. Kumar. 2013. Preservation of yam (Dioscorea spp.) leaf samples for epidemiological investigations on yam viruses. Abstract at Yams2013, first global conference on yam, 3-6/10/2013 in Accra, Ghana
- C. K. Nkere, T. Oviasuyi, G. I. Atiri, E. Otoo, E. Chamba, J. T. Onyeka, S. E. Seal and P. L. Kumar. 2013. Assessment of major disease threats to yam (Dioscorea spp.) cultivation in Ghana and Nigeria. Abstract at Yams2013, first global conference on yam (Dioscorea spp.), 3-6/10/2013 in Accra, Ghana
- M. V. Patel, S Cain, M. Febrer, M. Caccamo, J. Colvin, D. Bailey, S. Seal. 2013. Characterization of next generation transcriptomic and genomic sequence data from the Asia1 mtCOI genetic clade of Bemisia tabaci. 19-24 May, 2013 First International Whitefly Symposium, Kolymbari, Greece
- A. Turaki, P. L. Kumar, A. Lopez-Montes and S. E. Seal. 2013. Characterisation of badnaviruses and endogenous pararetroviruses in West African yam breeding lines. 12th International Plant Virology Congress, Tanzania, 27-31 January 2013.
- Member of the Royal College of Science, Imperial College, London
- Editor for Annals of Applied Biology
- Biotechnology Business Fellow for London Technology Network
- Associate Adviser for British Council Scholarships
- Nominated as Leader of AGRINATURA GM Biosafety group
- 2013 Societal Impact Award – received at The Sainsbury Laboratory 25 year anniversary from Lord David Sainsbury
- 2001-2002 Awarded 1-year 'scholarship' from CIRAD (Montpellier, France) paying for me to work at CIRAD and transfer capability in yam virus diagnostics
- 1989 Royal Bath and West 'Prince Charles Medallion' for most productive use of one of their scholarships
- 1988 Royal Bath and West 1 year Travel scholarship for research into vegetables and insecticide use in Indonesia
- 1985-1988 University of Bath scholarship funding to carry out PhD studies
Professor Susan E Seal
Natural Resources Institute
University of Greenwich
Central Avenue, Chatham Maritime, Kent ME4 4TB, United Kingdom.
Tel: +44 (0)1634 883602