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Item Mycofumigation with Muscodor albus : effects on Verticillium wilt and black dot root rot of potato, effects on Glomus intraradices and ectomycorrhizal fungi, and M. albus proliferation in soil(Montana State University - Bozeman, College of Agriculture, 2008) Grimme, Eva; Chairperson, Graduate Committee: Barry J. Jacobsen.Muscodor albus Worapong, Strobel & Hess, isolate CZ-620 (MA) is an endophytic fungus that produces volatile organic compounds (VOCs) and non-volatile antimicrobial compounds. The use of these VOCs to inhibit or kill a wide range of microorganisms is termed mycofumigation. This dissertation focuses on parameters of MA mycofumigation including: production and bioactivity of previously un-described water-soluble antimicrobial compounds produced by MA; distribution of antimicrobial compounds from a MA point source in three soil types as measured by effects on Verticillium dahliae and Colletotrichum coccodes; control of V. dahliae and C. coccodes on potato; the ability of MA to colonize soil; and the effects of mycofumigation on ectomycorrhizal fungi (EMF) in vitro and on the colonization of onion roots by the arbuscular mycorrhizal (AM) fungus Glomus intraradices. The bioactivity of water-soluble compounds produced in potato dextrose broth was significantly increased as measured in growth reduction of C. coccodes, V. dahliae, and Rhizoctonia solani. No reduction was observed for Aphanomyces cochlioides and Pythium ultimum. Antimicrobial compounds from a MA colonized barley point source reduced V. dahliae and C. coccodes populations in soils by 60-100% at distances up to 9 cm from the inoculation source depending on soil type. Mortality rate ranging from 70-100% was observed within a 3 cm radius from the inoculation source. In both field and greenhouse trials, MA colonized barley formulation reduced Verticillium wilt and black dot root rot severity and reduced populations of both pathogens in potato tissue as measured by real-time quantitative PCR and serial dilution. Planting directly into mycofumigated soil previously infested with V. dahliae or C. coccodes resulted in equal control of the pathogens when compared to a one-week mycofumigation period prior to planting. After six weeks of incubation MA did not colonize sterile soil further than 0.5 cm away from a MA inoculation point. In vitro experiments showed that most of the tested EMF were inhibited in the presence of MA VOCs, but were able to resume growth when removed from VOCs. Incorporating MA into soil had no negative but supportive effect on onion root colonization by the AM fungus G. intraradices.Item Disease control and plant defense pathways induced by Bacillus mojavensis isolate 203-7 and Bacillus mycoides isolate BmJ(Montana State University - Bozeman, College of Agriculture, 2008) Neher, Oliver Thomas; Chairperson, Graduate Committee: Barry J. Jacobsen.The objective of this study was to investigate the plant defense pathways induced by Bacillus mojavensis isolate 203-7 (203-7) and B. mycoides isolate BmJ (BmJ) and to test their ability to control fungal pathogens on tomato and cucumber by means of systemic acquired resistance (SAR). An Arabidopsis thaliana mutant - Botrytis cinerea pathosystem was used to investigate plant defense pathways activated by 203-7 and BmJ. A. thaliana wild type (Col-0), ein2-1, jar1-1, NahG, ndr1-1/npr1-2, and npr1-1 mutants were induced by application of bacilli, distilled water, or chemical inducers. Both bacilli reduced disease severity on wild type and NahG mutants, but provided no reduction on jar1-1, indicating that induction was salicylic acid (SA) independent but jasmonic acid (JA) dependent. 203-7 induced plants had lower disease severity on npr1-1 and ein1-2 mutants but were equivalent to buffer controls on jar1-1 mutants. BmJ did not decrease disease severity on npr1-1, jar1 or ein2-1 mutants. Enzyme assays confirmed the induction of chitinase, beta-1,3-glucanase, and superoxide dismutase by 203-7 and BmJ. These results demonstrate that induction by 203-7 is JA dependent and NPR1 independent. BmJ is SA independent but NPR1 and JA/ethylene dependent. Bacilli were tested for their ability to control B. cinerea grey mold on hydroponically grown greenhouse tomatoes and Glomerella cingulata var. orbiculare on cucumber by means of SAR. Weekly foliar applications of bacilli were able to significantly (a=0.05) reduce the severity of grey mold leaf lesions and to reduce the area under the disease progress curve (AUDPC) calculated for seven Botrytis stem canker ratings. Chitinase, beta-1,3-glucanase, and SOD activity of apoplastic fluids were not significantly (a=0.05) increased by the treatments. Bacilli reduced total and live spore production of G. orbiculare per mm 2 of lesion and increased beta-1,3-glucanase activity of cucumber apoplastic fluids. Applications of BmJ compared to fungicides for the control of anthracnose in cucumber (var. 'General Lee') and cantaloupe (var. 'Athena') were evaluated in 2004 and 2005 field experiments. BmJ applied seven days before inoculation provided disease reduction in cucumber and cantaloupe statistically equal to the fungicide treatments.Item Risk assessment of plant-based pharmaceuticals and biologics(Montana State University - Bozeman, College of Agriculture, 2006) Shama, Leslie Marie; Chairperson, Graduate Committee: Robert K. D. Peterson.Biotechnology is evolving to produce pharmaceutical proteins in plants. Plantbased pharmaceutical production creates concerns of exposure in an open environment and contamination of the food supply. Consequently, quantitative human health and ecological risk assessments were conducted for aprotinin, gastric lipase, and LT-B expressed in maize. A comparative, qualitative risk assessment was conducted for conventionally derived and plant-cell derived Newcastle disease virus vaccine. Effect and exposure scenarios were modeled for each quantitative risk assessment and each scenario was based on a tiered approach in which inadvertent exposure through ingestion were examined to determine a risk characterization of the plant-based pharmaceuticals. The qualitative Newcastle disease virus vaccine risk assessment characterized risks based on the potential exposures to the poultry being vaccinated, to humans administering the vaccine, and to non-target birds. For the human-health risk assessment, the dietary exposure evaluation model (DEEM) was used to estimate the inadvertent dietary intake of the pharmaceutical proteins in food. The ecological risk assessment used Monte Carlo simulations to evaluate the exposure of each protein in maize for four receptor species.