New Honorary Member of BSPP

Abstract

In almost 40 years of research and teaching John Mansfield has made several outstanding contributions to our understanding of plant-pathogen interactions and mechanisms of plant innate immunity. He has had an important impact as an inspirational teacher and supervisor, passing on his enthusiasm for the all-embracing subject of plant pathology. His interest in pathology was kindled as an undergraduate at University College of North Wales, Bangor (1965–68) following lectures and project supervision by Dave Shaw and Bob Whitbread. He was fortunate to move to Imperial College London for his PhD (1968–72) with Brian Deverall, during a period of focus on the role of newly identified phytoalexins in disease resistance. His challenge was to examine the role of antifungal plant metabolites in the differential pathogenicity of Botrytis species to Vicia faba. The concept of a balance operating between phytoalexin production by the plant and degradation by the adapted pathogen emerged from his early work. Research on phytoalexins and host specificity with Botrytis spp. including the epidemiology of narcissus smoulder, was continued as a lecturer in plant pathology at the University of Stirling (1972–80). Working with excellent postgraduate students and collaborating colleagues led to the identification of novel phytoalexins in bean (nine in total) and daffodil. The book, Phytoalexins, published in 1982, edited with John Bailey a contemporary at Imperial College, remains the definitive text on the antimicrobial secondary metabolites. At Stirling, John developed an interest in the use of electron microscopy to define the structural framework within which pathogens and plant cells interact, and began experiments on gene-for- gene interactions and the hypersensitive response (HR). Moving to Wye College in 1981 allowed interests in the HR to be expanded, using lettuce downy mildew and bean halo-blight diseases as model interactions. The emerging power of molecular genetics was harnessed to clone avirulence (avr) genes from pathovars of Pseudomonas syringae that controlled both varietal and non-host resistance. A successful and ongoing collaboration with colleagues at UWE, Bristol and HRI, Wellesbourne led to the identification of several avr genes, and more significantly the first cloning of an effector through its virulence function (virPphA). Two landmark papers demonstrating the suppression of the HR by effector proteins VirPphA and AvrPphF have provided the framework for much of the current research on effector functions. Working with colleagues from Helsinki, ably assisted by the technical expertise of the electron microscopist Ian Brown, John was also able to visualize the delivery of effectors through the Hrp pilus, a component of the type III secretion system. He has also used microscopy to demonstrate the importance of localized cell wall interactions in the basal defences of plants against non-pathogenic bacteria. The two strands of research, cloning effectors and analysis of basal defences have come together in his group’s demonstration of the suppression of wall alterations by effector proteins, notably AvrPtoB which is now known to target plant receptor-like kinases. During 28 years at Wye, John supervised a succession of postgraduate students from the UK and overseas, working on plant –pathogen interactions and more applied projects ranging from cashew powdery mildew in Tanzania to cauliflower diseases in Nepal. He was promoted to Reader in 1986 and offered a Research Professorship in Plant Pathology from the University of London in 1991. John’s academic career came full circle when he returned to Imperial College London after the closure of the Wye campus. He has acted as head of the group of plant scientists transferred to South Kensington. He is currently on a part-time appointment in the Division of Biology at Imperial. John continues to be active in the laboratory, with ongoing projects on the mobility of effector genes, the metabolomics of disease and plant-aphid interactions. As a founder member of the BSPP he has had significant roles within the Society, the highpoint being his Presidency of BSPP in 2000. The presidential meeting held at Wye focused on how research on disease has impacted on our fundamental understanding of microbial and plant biology. His tenure of the Presidency coincided with the launch of Molecular Plant Pathology and he has been on the editorial board of both MPP and Plant Pathology. An enthusiastic conference delegate, John has often acted as a member of organizing committees, notably for the successful ICPP1998 and ICPPB 2006 meetings, both held in Edinburgh. He is currently helping to organize the 8th Symposium on Pseudomonas syringae and related pathogens, to be held in Oxford 2010. It is with great pleasure that the Society confers Honorary Membership on John Mansfield.