Evolutionary transitions between beneficial and phytopathogenic challenge disease management.

Understanding how bacteria affect plant health is crucial for developing sustainable crop production systems. We coupled ecological sampling and genome sequencing to characterize the population genetic history of and the distribution patterns of virulence plasmids in isolates from nurseries. Analysis of chromosome sequences shows that plants host multiple lineages of , and suggested that these bacteria are transmitted due to independent introductions, reservoir populations, and point source outbreaks.

Bacterial Canker of Sweet Cherry in Oregon-Infection of Horticultural and Natural Wounds, and Resistance of Cultivar and Rootstock Combinations.

This study was done to (i) compare seven types of natural or horticultural injuries and wounds for incidence, severity, and mortality of infection of sweet cherry (Prunus avium) by Pseudomonas syringae pv. syringae; (ii) determine the relative resistance to bacterial canker of 14 cultivar-rootstock combinations; (iii) determine if P. syringae pv.

Description of Cryptosporiopsis kienholzii and species profiles of Neofabraea in major pome fruit growing districts in the Pacific Northwest USA.

The objectives of this study were i) to give a taxonomic description of a fungus phylogenetically related to Neofabraea and assign the name Cryptosporiopsis kienholzii to this fungus, ii) to expand previous Neofabraea species profiles from infected apple and pear fruit collected from major pome fruit production districts in Oregon and Washington, and iii) to determine the sensitivity of Neofabraea alba, Neofabraea malicorticis, Neofabraea perennans, and C. kienholzii to a range of fungicides. A name is given herein to the anamorph of the fungus previously called 'Neofabraea sp.

Methodology for Determining Relationships Between Inoculum Concentration of Botrytis cinerea and Penicillium expansum and Stem End Decay of Pear Fruit.

The objective of this research was to determine quantitative relationships between incidence of stem end decay of pear fruit and inoculum concentration of Botrytis cinerea and Penicillium expansum using dry conidia applied to pear fruit in a settling tower. Five concentrations of conidia were applied to pear fruit, fruit were stored at -1°C for 8 months, and stem end decay was evaluated. In addition, conidia were washed from the surface of inoculated fruit, and DNA was extracted and quantified with real-time polymerase chain reaction (PCR).

A five-gene phylogeny of Pezizomycotina.

Pezizomycotina is the largest subphylum of Ascomycota and includes the vast majority of filamentous, ascoma-producing species. Here we report the results from weighted parsimony, maximum likelihood and Bayesian phylogenetic analyses of five nuclear loci (SSU rDNA, LSU rDNA, RPB1, RPB2 and EF-lalpha) from 191 taxa. Nine of the 10 Pezizomycotina classes currently recognized were represented in the sampling.

Reconstructing the early evolution of Fungi using a six-gene phylogeny.

The ancestors of fungi are believed to be simple aquatic forms with flagellated spores, similar to members of the extant phylum Chytridiomycota (chytrids). Current classifications assume that chytrids form an early-diverging clade within the kingdom Fungi and imply a single loss of the spore flagellum, leading to the diversification of terrestrial fungi. Here we develop phylogenetic hypotheses for Fungi using data from six gene regions and nearly 200 species.

Inoculum Sources of Botrytis cinerea Important to Pear Orchards in Oregon.

Botrytis cinerea was capable of colonizing and persisting in tissue pieces of six common weed species found in pear orchards in Oregon from midsummer until pear harvest in early September. Sporulation occurred on blackberry mummies in orchard perimeters and ranged from 5,700 to 55,000 conidia per mummy at pear harvest. Conidia of B.