Plant Pathology Masters Papers

Permanent URI for this collectionhdl:10365/32452

Browse

Recent Submissions

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Prevalence of Pathogenicity Groups of the Blackleg Species Complex on Canola in North Dakota
    (North Dakota State University, 2011) Mazurek, Shanna Andrea
    North Dakota is the leading producer of canola (Brassica napus) in the United States. Blackleg, caused by two species of Leptosphaeria, L. maculans (Desm.) Ces & De Not and L. biglobosa, is an economically important disease wherever canola is grown. The virulence profile of these species has been classified in six pathogenicity groups (PG) based on inoculations on three differential cultivars, 'Westar', 'Glacier', and 'Quinta'. A PG-1 reaction is caused only by L. biglobosa isolates. By 2001, PG-2 was the predominant profile in North Dakota, although PG-1 isolates were also present. Between 2007 and 2008 canola leaves with characteristic blackleg lesions were collected from 54 fields located in the major canola growing regions of North Dakota. The virulence profile of 280 isolates retrieved from these leaves was characterized on the above mentioned set of differentials. The predominant species was L. maculans with approximately 74% of all isolates retrieved. Virulence profiles typical of PG-2, PG-3, PG-T, PG-4, and PG-5, which were previously described, were observed among the isolates evaluated. The virulence profile of almost 32% of all isolates did not fit within the previously described PGs and were assigned to new groups. The most prevalent PG among L. ma cu/ans isolates were PG-6 and PG-T. PG-6 causes a resistant reaction on differential 'Quinta'. PG-2, previously regarded as the most prevalent, was identified in only 13% of isolates. These results suggest a shift in the population of the blackleg species complex in North Dakota.
  • No Thumbnail Available
    Item
    Effectors and Effector Delivery in Magnaporthe Oryzae
    (North Dakota State University, 2016) Thevathasan, Thakshayni
    Rice blast, caused by the fungus Magnaporthe oryzae, is one of the most destructive rice diseases. All plant parts can be affected including leaves, leaf collars, necks, panicles, pedicels, and seeds. The disease symptoms are caused in part by the effectors produced by Magnaporthe oryzae. Magnaporthe oryzae apoplastic effectors are secreted from invasive hyphae into the extracellular compartment through the conventional secretory pathway, Golgi complex to the plasma membrane, and are released into the apoplastic space. The biotrophic interfacial complex (BIC) appears to be the site of transfer of some of the cytoplasmic effectors into the host. Experimental results suggest that effector secretion to the BIC is associated with a unique secretion system involving exocyst components and the Sso1 t-SNARE complex. This manuscript reviews the most recent advances in our understanding of the rice-Magnaporthe oryzae interactions based on effectors.