Genome analysis of Phytophthora cactorum strains associated with crown- and leather-rot in strawberry

Phytophthora cactorum has two distinct pathotypes that cause crown rot and leather rot in strawberry (Fragaria × ananassa). Strains of the crown rot pathotype can infect both the rhizome (crown) and fruit tissues, while strains of the leather rot pathotype can only infect the fruits of strawberry. The genome of a highly virulent crown rot strain, a low virulent crown rot strain, and three leather rot strains were sequenced using PacBio high fidelity (HiFi) long read sequencing. The reads were de novo assembled to 66.4–67.6 megabases genomes in 178–204 contigs, with N50 values ranging from 892 to 1,036 kilobases. The total number of predicted complete genes in the five P. cactorum genomes ranged from 17,286 to 17,398. Orthology analysis identified a core secretome of 8,238 genes. Comparative genomic analysis revealed differences in the composition of potential virulence effectors, such as putative RxLR and Crinklers, between the crown rot and the leather rot pathotypes. Insertions, deletions, and amino acid substitutions were detected in genes encoding putative elicitors such as beta elicitin and cellulose-binding domain proteins from the leather rot strains compared to the highly virulent crown rot strain, suggesting a potential mechanism for the crown rot strain to escape host recognition during compatible interaction with strawberry. The results presented here highlight several effectors that may facilitate the tissue-specific colonization of P. cactorum in strawberry.publishedVersio

PacBio amplicon sequencing of Rysto homologues in wild potato species

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

Amplicon sequencing of NBS LRR genes conferring resistance to Phytophthora infestans in potato

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

Genetic transformation of Fusarium avenaceum by Agrobacterium tumefaciens mediated transformation and the development of a USER-Brick vector construction system

BACKGROUND: The plant pathogenic and saprophytic fungus Fusarium avenaceum causes considerable in-field and post-field losses worldwide due to its infections of a wide range of different crops. Despite its significant impact on the profitability of agriculture production and a desire to characterize the infection process at the molecular biological level, no genetic transformation protocol has yet been established for F. avenaceum. In the current study, it is shown that F. avenaceum can be efficiently transformed by Agrobacterium tumefaciens mediated transformation. In addition, an efficient and versatile single step vector construction strategy relying on Uracil Specific Excision Reagent (USER) Fusion cloning, is developed. RESULTS: The new vector construction system, termed USER-Brick, is based on a limited number of PCR amplified vector fragments (core USER-Bricks) which are combined with PCR generated fragments from the gene of interest. The system was found to have an assembly efficiency of 97% with up to six DNA fragments, based on the construction of 55 vectors targeting different polyketide synthase (PKS) and PKS associated transcription factor encoding genes in F. avenaceum. Subsequently, the ΔFaPKS3 vector was used for optimizing A. tumefaciens mediated transformation (ATMT) of F. avenaceum with respect to six variables. Acetosyringone concentration, co-culturing time, co-culturing temperature and fungal inoculum were found to significantly impact the transformation frequency. Following optimization, an average of 140 transformants per 10(6) macroconidia was obtained in experiments aimed at introducing targeted genome modifications. Targeted deletion of FaPKS6 (FA08709.2) in F. avenaceum showed that this gene is essential for biosynthesis of the polyketide/nonribosomal compound fusaristatin A. CONCLUSION: The new USER-Brick system is highly versatile by allowing for the reuse of a common set of building blocks to accommodate seven different types of genome modifications. New USER-Bricks with additional functionality can easily be added to the system by future users. The optimized protocol for ATMT of F. avenaceum represents the first reported targeted genome modification by double homologous recombination of this plant pathogen and will allow for future characterization of this fungus. Functional linkage of FaPKS6 to the production of the mycotoxin fusaristatin A serves as a first testimony to this

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

Diversity analysis of Rpi-ber1 and Rpi-vnt1 genes determining broad spectrum resistance to Phytophthora infestans

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

High throughput analysis of Rpi genes in potato cultivars, breeding lines and wild Solanum species

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

Presence of homologues of the PVY resistance gene Rysto in wild relatives of potato

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

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