Effector gene variation in Polish and Norwegian Phytophthora infestans strains

Poster presented at 2023 IS-MPMI Congress, Molecular Plant-Microbe Interactions, Providence, USA The research leading to these results has received funding from the Norwegian Financial Mechanism 2014-2021, project DivGene: UMO2019/34/H/NZ9/0055

Differences in Avr-vnt1 alleles and aggressiveness in four European Phytophthora infestans lineages

Poster presented at 12TH INTERNATIONAL CONGRESS OF PLANT PATHOLOGY ICPP2023, Lyon, France The research leading to these results has received funding from the Norwegian Financial Mechanism 2014-2021, project DivGene: UMO2019/34/H/NZ9/0055

Aggressiveness test of Phytophthora infestans isolates with different effector alleles

Poster presented at EAPR Pathology & Pests Section Meeting, Arras, France The research leading to these results has received funding from the Norwegian Financial Mechanism 2014-2021, project DivGene: UMO2019/34/H/NZ9/0055

Isolation, Identification and Preservation of Fusarium SPP. Causing Dry Rot of Potato Tubers

Fungi of the genus Fusarium cause dry rot, a potato disease which develops during long-term storage of tubers. The disease-inducing capabilities differ among Fusarium spp., but may also vary within species uni-versally considered main dry rot agents. Identification of Fusarium spp. present on diseased tubers in a surveyed area can help minimize crop losses and mycotoxin contamination by, for example, applying proper fungicides or planning crop rotation. Here, we present a procedure of obtaining single spore colonies of Fusarium spp. from potato tubers infected by dry rot, their identification using molecular methods and ways of preservation

Phytophthora Infestans: Isolation of Pure Cultures, Storage and Inoculum Preparation

Phytophthora infestans causes potato and tomato late blight, economically the most important disease of these plant species. The Oomycete pathogen is frequently sampled, isolated to pure cultures, stored, and char-acterized. The knowledge of its diversity, migrations and evolution is essential for breeding resistant plants and for designing appropriate control strategies. The article presents methods for collection, storage and prep-aration of P. infestans isolates for inoculation of plant tissues, based on the publication by Zarzycka (2001), later updated and modified

Effect of deep freezing of Phytophtora infestans on their survival and pathogenicity

The maintenance of Phytophthora infestans cultures isolates from blighted potato, frozen in liquid nitrogen, was studied in two experiments. The effects of deep freezing and acclimatization pre-treatment at different temperatures on culture survival and stability of virulence and aggressiveness were evaluated. The best survival of cultures maintained for three months in liquid nitrogen was expressed, when cultures were acclimatized before freezing at 7˚C. The survival of frozen cultures was significantly worse in comparison with control combinations stored on rye-agar and rye-agar under paraffin oil for short time (in experiment I – 40 days, in experiment II – three months). The virulence spectrum of frozen cultures after thawing was more narrow than that one observed before culture freezing. However this virulence spectrum did not differ significantly from virulence range of control cultures. The level of aggressiveness of culture stored in liquid nitrogen did not differ significantly from control cultures as well. The virulence spectrum and aggressiveness level of cultures frozen in liquid nitrogen were significantly higher after two passages of thawed cultures on potato tissues than after single passage

Quantitative Trait Loci for Resistance to Potato Dry Rot Caused by Fusarium sambucinum

Tuber dry rot is an important disease of potato caused by soil and seed-borne pathogens of the Fusarium genus leading to losses that may reach 60% of the yield. The goal of this work was to study the inheritance of the dry rot resistance in two diploid potato hybrid populations (11–36 and 12–3) with complex pedigrees, including several wild Solanum spp. We used an aggressive isolate of F. sambucinum for phenotyping both progenies, parents, and standard potato cultivars in laboratory tuber tests, in three subsequent years. The QTL for dry rot resistance were mapped by interval mapping on existing genetic maps of both mapping populations. The most important and reproducible QTL for this trait was mapped on chromosome I and additional year- and population-specific QTL were mapped on chromosomes II, VII, IX, XI, and XII, confirming polygenic control of this resistance. This is the first study mapping the loci affecting tuber dry rot resistance in potato genome that can contribute to better understanding of potato-F. sambucinum interaction and to more efficient breeding of resistant potato cultivars