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Seminar: Population biology of Verticillium dahliae associated with potato agroecosystems

Laura del Sol Bautista Jalón, Graduate Student, Penn State
Laura del Sol Bautista Jalón

Laura del Sol Bautista Jalón

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December 2, 2019, 3:35 PM - 4:30 PM

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Verticillium dahliae is a worldwide distributed fungal plant pathogen and the causal agent of Verticillium wilt in over 300 different plant species including potatoes. Because of the limited availability of disease-resistant potato cultivars, Verticillium wilt of potatoes is primarily managed with soil disinfestation using soil fumigants and rotations with crop species considered to be non-hosts. Crop rotations are more sustainable and commonly employed management practices. However, they often render conflicting results regarding the reduction of incidence and severity of the disease in potato indicating that they do not perform as expected. Plants that do not show Verticillium wilt symptoms in the field have been considered non-hosts to V. dahliae and, consequently, incorporated into crop rotation programs. However, V. dahliae has been observed to infect asymptomatically weeds and rotational crops such as oat and barley. The aim of this research was to study the genetic diversity, evolution and ecology of V. dahliaepopulations associated with potato agroecosystems with the purpose of providing information that help improve the management of Verticillium wilt of potato using crop rotations. Analyses were conducted to investigate the diversity, evolution and pathogenicity of V. dahliae populations isolated from symptomatic and asymptomatic rotational crops and weeds in potato fields from Pennsylvania and Israel. Results showed that V. dahliae lineage 4B, a recognized pathogenic lineage of the fungus, was infecting some rotational crops and weeds as an endophyte. Population genetics and phylogenetic analyses were also conducted to explore the genetic diversity, structure and evolution of V. dahliae lineage 4A populations, a lineage mostly recovered infecting and causing disease on potatoes in North America. Results of these analyses indicated that V. dahliae lineage 4A populations from the northern US comprise mainly a clone that has been probably moved with contaminated potato seed tubers. Finally, PCR-based molecular markers were developed for the detection of V. dahliae lineage 4A and 4B isolates since these are the lineages frequently found associated with US potato agroecosystems.