Stephen B. Goodwin was born in Bethlehem, PA, but grew up mostly in Williamsburg, VA. He received his B.S. degree in botany from Duke University in 1981 and his Ph.D. degree in genetics from the University of California, Davis in 1988. He completed a postdoctoral appointment at Cornell University before accepting his current positions as research plant pathologist with the USDA ARS and as an adjunct faculty member at Purdue University. He is an internationally recognized authority in the fields of fungal population genetics and evolution and of resistance to Septoria tritici blotch in wheat. The techniques he developed and the discoveries he made contributed significantly to our understanding of host–pathogen interactions and to the improvement of disease resistance in cereals.
Goodwin’s research is focused on pathogen genetics, genomics, and population biology and on molecular and classical analyses of genes for resistance to fungal pathogens. During his Ph.D. work, he significantly increased our understanding of the barley scald pathogen, Rhynchosporium secalis. Goodwin concluded that parasexual recombination was not important in R. secalis, contrary to earlier reports, and stimulated research into the relevance of sexual reproduction. He developed a comprehensive, standardized nomenclature for pathotypes of R. secalis that is now widely used. He used this nomenclature to analyze pathogenicity variation within and among populations of R. secalis and to infer the probable resistance genes in barley cultivars. Resistance breeding programs in the Pacific Northwest and Canada changed to emphasize quantitative resistance after his work showed that classical approaches probably would not be successful. More recently, Goodwin used phylogenetic analyses to show that R. secalis is closely related to fungi in the sexual genera Tapesia and Pyrenopeziza. This work predicted what the sexual stage of this organism should look like, suggested where it might be found, and guided scientists in other laboratories to clone its mating-type genes.
Goodwin’s postdoctoral work in William Fry’s lab on the potato late blight pathogen Phytophthora infestans stands in a class by itself. He developed the DNA fingerprint and isozyme identification systems that have been used worldwide to characterize local populations of this devastating pathogen. Goodwin’s work showed that the global pandemic of potato late blight was due to a single clone that escaped from Mexico, and he played the leading role in shaping our understanding of the population biology of this pathogen. He showed that sexual populations of P. infestans are now emerging as a result of the “escape” of new strains of P. infestans from Mexico. Many groups around the world continue to build on his findings. Goodwin took the P. infestans work a step further by assessing the genetic relationships among P. infestans and its close relatives, determining the likely ancestors that gave rise to the potato-infecting population. This work was very significant as it offered new insights into the origins of plant pathogens, illustrating that host jumps following the movement of crops into new areas of cultivation may be a common mechanism for the emergence of new pathogens.
After joining USDA ARS, Goodwin turned his attention to the wheat pathogen Mycosphaerella graminicola (anamorph Septoria tritici). In collaboration with Gert Kema (Plant Research International, Wageningen, Netherlands), he developed the first genetic map for M. graminicola. He developed molecular markers that could be used easily in other laboratories and discovered the first transposon in this fungus. He recently identified 50 polymorphic microsatellite loci and added 23 of these to the existing genetic map. Other labs are using these microsatellites for phylogeographical studies of M. graminicola.
Goodwin recently showed that a barley pathogen, Septoria passerinii, is closely related to S. tritici. The evolutionary relationships between these fungi were not known previously, but he showed that they had a common ancestor in their recent evolutionary history. He cloned both mating-type genes from S. passerinii and showed that this pathogen reproduced sexually, rather than exclusively asexually as believed previously, which changed our understanding of its epidemiology. This work stimulated a search for the sexual stage of S. passerinii, leading to its rapid identification as another Mycosphaerella species. An expanded phylogenetic analysis of the genus Mycosphaerella, including other fungi associated with this genus, showed that toxin-producing members of the asexual genus Cercospora evolved only once and that all Cercospora are related to the sexual genus Mycosphaerella. These phylogenetic analyses added significantly to our understanding of the origins and evolution of several important cereal pathogens and cleared up several long-standing questions in fungal taxonomy and systematics. Most recently, Goodwin and others procured the resources to sequence the genomes of M. graminicola and M. fijiensis, causal agent of black Sigatoka on banana. Comparative analyses of these genomes will likely lead to new insights regarding the genetic basis of host specialization.
Goodwin also made significant contributions in his analysis of resistance to Septoria tritici blotch in wheat. His lab mapped four previously identified sources plus a new gene for resistance to M. graminicola. He discovered one or more molecular markers linked to each of the genes for resistance that now can be used by plant breeders to increase the level of resistance in future wheat cultivars. The markers and corresponding genetic materials have been requested by several laboratories internationally, including the United Kingdom, Czech Republic, Germany, Denmark, Kazakhstan, Russia, and Australia, in addition to the United States. Goodwin’s research on gene expression during the resistance response identified early and late peaks of induction in response to M. graminicola. The late genes had not been implicated in plant defense responses previously and are the subjects of current research. Recent work with a barley microarray showed for the first time that nonhost responses of barley to S. tritici were different compared with R-gene responses to S. passerinii. This research shows considerable promise to offer new insights into the nature of nonhost resistance.
Goodwin’s research impact is documented by 50 peer-reviewed publications, nine of which have been cited more than 100 times each. Citations over all his publications collectively total more than 2,500.
