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Colburn B.C.,Oregon State University | Mehlenbacher S.A.,Oregon State University | Mehlenbacher S.A.,Hermiston Agricultural Research and Extension Center | Sathuvalli V.R.,Oregon State University | And 2 more authors.
Journal of the American Society for Horticultural Science | Year: 2015

European hazelnut (Corylus avellana L.) is a significant crop in Oregon, where 99% of United States hazelnuts are produced. Eastern filbert blight (EFB) caused by Anisogramma anomala (Peck) E. Mu¨ ller is an important disease that infects the trees, reduces yield, and causes premature death. Managing the disease through cultural methods and fungicide applications is laborious and expensive, and genetic host resistance is considered the most viable option for control. Genetic resistance from ‘Gasaway’ has been used to develop resistant cultivars including Yamhill and Jefferson, but concern about the durability of this single resistance gene stimulated a search for additional sources of resistance. This study used three recently identified sources of EFB resistance: ‘Culpl_a’ from Spain, ‘Crvenje’ from Serbia, and OSU 495.072 from southern Russia. RAPD markers linked to resistance from ‘Gasaway’ were absent in all three accessions. Disease response was noted in segregating progenies following greenhouse or structure inoculation, and the resistance loci were mapped using microsatellite markers. In only four of the nine progenies did segregation for disease response fit the ratio of 1 resistant:1 susceptible expected for a single locus, a heterozygous resistant parent, and a dominant allele for resistance. Three progenies showed an excess of resistant seedlings while two showed a deficiency of resistant seedlings. The reciprocal translocations reported in several leading hazelnut cultivars may be present in the parents of the studied progenies, and affecting the segregation ratios. Microsatellite marker A614, previously mapped to linkage group (LG) 6, was closely linked to resistance from all three sources. Maps were constructed for LG6 for each resistant parent using microsatellite markers. The three resistance loci mapped to the same region on LG6 where resistance from ‘Gasaway’ and OSU 408.040 are located. The resistance alleles in all five accessions may be the same, or more likely are a cluster of different resistance genes in the same region. Markers LG628, LG610, and LG696 will be useful to breed new hazelnut cultivars with resistance from Culpl_a, Crvenje, and OSU 495.072. © 2015, American Society for Horticultural Science. All rights reserved. Source


Kaiser C.,Oregon State University | Hamm P.B.,Hermiston Agricultural Research and Extension Center | Gieck S.,Hermiston Agricultural Research and Extension Center | David N.,Hermiston Agricultural Research and Extension Center | And 3 more authors.
HortScience | Year: 2011

In vitro dose responses of several calcium and potassium salts were determined on some commercially significant plant pathogens, including: Helminthosporium solani, Fusarium oxysporum f. sp. pisi race 2, Colletotricum coccodes, Phytophthora cactorum, Phytophthora cinnamomi, Phytophthora erythroseptica, Phytophthora infestans, Phytophthora megasperma, Pythium ultimum, and Venturia inaequalis. Mycelial growth inhibition was both salt-specific and dose-related. Pythium ultimum was completely inhibited by 75 mg·L-1or greater calcium propionate, but needed 300 mg·L-1or greater of calcium acetate and 40 mL· L-1or greater of potassium silicate for complete inhibition. Phytophthora infestans was completely inhibited by 150 mg·L-1or greater calcium acetate, 150 mg·L-1or greater calcium propionate, or 5 mL· L-1or greater potassium silicate. Phytophthora cactorum was completely inhibited by 300 mg·L-1or greater calcium propionate, but required 600 mg·L-1or greater calcium acetate and 10 mL· L-1or greater potassium silicate for complete inhibition. Phytophthora cinnamomi was completely inhibited by calcium propionate at 600 mg·L-1or greater or by 10 mL· L-1or greater potassium silicate. Only potassium silicate inhibited Phytophthora megasperma, Phytophthora erthroseptica, V. inequalis, and H. solani at concentrations of 5 mL· L-1or greater, 20 mL· L-1or greater, 40 mL· L-1or greater, or 80 mL· L-1or greater, respectively. Potassium acetate did not completely inhibit any of the pathogens in this study when tested at concentrations 1200 mg·L-1or less. Source


Goyer A.,Oregon State University | Goyer A.,Hermiston Agricultural Research and Extension Center | Hamlin L.,U.S. Department of Agriculture | Crosslin J.M.,U.S. Department of Agriculture | And 2 more authors.
BMC Genomics | Year: 2015

Background: Potato virus Y (PVY) is one of the most important plant viruses affecting potato production. The interactions between potato and PVY are complex and the outcome of the interactions depends on the potato genotype, the PVY strain, and the environmental conditions. A potato cultivar can induce resistance to a specific PVY strain, yet be susceptible to another. How a single potato cultivar responds to PVY in both compatible and incompatible interactions is not clear. Results: In this study, we used RNA-sequencing (RNA-Seq) to investigate and compare the transcriptional changes in leaves of potato upon inoculation with PVY. We used two potato varieties: Premier Russet, which is resistant to the PVY strain O (PVYO) but susceptible to the strain NTN (PVYNTN), and Russet Burbank, which is susceptible to all PVY strains that have been tested. Leaves were inoculated with PVYO or PVYNTN, and samples were collected 4 and 10 h post inoculation (hpi). A larger number of differentially expressed (DE) genes were found in the compatible reactions compared to the incompatible reaction. For all treatments, the majority of DE genes were down-regulated at 4 hpi and up-regulated at 10 hpi. Gene Ontology enrichment analysis showed enrichment of the biological process GO term "Photosynthesis, light harvesting" specifically in PVYO-inoculated Premier Russet leaves, while the GO term "nucleosome assembly" was largely overrepresented in PVYNTN-inoculated Premier Russet leaves and PVYO-inoculated Russet Burbank leaves but not in PVYO-inoculated Premier Russet leaves. Fewer genes were DE over 4-fold in the incompatible reaction compared to the compatible reactions. Amongst these, five genes were DE only in PVYO-inoculated Premier Russet leaves, and all five were down-regulated. These genes are predicted to encode for a putative ABC transporter, a MYC2 transcription factor, a VQ-motif containing protein, a non-specific lipid-transfer protein, and a xyloglucan endotransglucosylase-hydroxylase. Conclusions: Our results show that the incompatible and compatible reactions in Premier Russet shared more similarities, in particular during the initial response, than the compatible reactions in the two different hosts. Our results identify potential key processes and genes that determine the fate of the reaction, compatible or incompatible, between PVY and its host. © 2015 Goyer et al. Source

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