PPEM Seminar Series: Luis Fernando Flores (Roman-Reyna Lab Ph.D. Student)

Abstract: Plant disease risk is increasingly shaped by the persistence, diversification, and mischaracterization of bacterial pathogens. Diagnostic and surveillance programs often rely on inconsistent methods, limited temporal resolution, and presence–absence frameworks that overlook ecological establishment and strain-level variation. These limitations obscure pathogen dynamics, leading to apparent emergence or reemergence without clear explanation and complicating regulatory decisions. Addressing these limitations requires integrating ecological, genomic, and functional data within a unified surveillance framework, an ecogenomic framework.

For Clavibacter nebraskensis, the causal agent of Goss’s wilt, Mexican isolates and historical U.S. strains collected over five decades were analyzed for genomic and phenotypic variation. The pangenome was largely closed, with accessory gene content structured by geography and isolation period. Differences in virulence, enzymatic activity, biofilm formation, and pigmentation suggest adaptive traits linked to the temporal and spatial patterns of disease observed in North America. For Ralstonia solanacearum, this framework was extended through international collaboration to address surveillance gaps constrained by regulation and infrastructure. Genomic and phenotypic data confirmed R. solanacearum Phylotype IIB, consistent with race 3 biovar 2 lineages causing bacterial wilt.

Integrating ecogenomic data and international partnerships provides a scalable model for improving pathogen surveillance. Such approaches enhance the resolution of biosecurity systems, inform regulatory policies, and strengthen preparedness against future disease outbreaks.

Bio: Luis Fernando Flores-López is a Ph.D. student in Plant Pathology with a dual title in Microbiome Sciences at The Pennsylvania State University, where he works under the guidance of Dr. Verónica Román-Reyna. His research focuses on the ecology and evolution of plant pathogenic bacteria, with an emphasis on Clavibacter nebraskensis, the causal agent of Goss’s wilt of maize. His work integrates comparative genomics, phylogenetic analysis, and microbiome approaches to study pathogen diversity, population structure, and host–microbe interactions in North American agricultural systems.

Fernando received his agronomist engineering degree from Chapingo Autonomous University in Mexico and his M.S. degree from Cinvestav Irapuato, where he studied Clavibacter nebraskensis and was externally advised by Dr. Anne Vidaver. He is interested in strengthening scientific collaboration between institutions in Latin America and the United States.