Theses and Dissertations at Montana State University (MSU)
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Item Biochemical, physiological, and genetic investigations of multiple herbicide resistant Avena fatua L.(Montana State University - Bozeman, College of Agriculture, 2023) Wright, Lucas Arlin; Chairperson, Graduate Committee: William Dyer; Barbara K. Keith (co-chair)Intense herbicide usage has led to the evolution of herbicide resistant weeds, which threaten food production and security. The multiple herbicide resistant (MHR) Avena fatua (wild oat) lines investigated here are resistant to all members of selective herbicide families available for A. fatua control. The research in this thesis is designed to help understand some of the ecological, biochemical, and genetic aspects of MHR. First, MHR lines with elevated volatile organic compound (VOC) levels and herbicide susceptible lines were used to compare the feeding behavior of Spodoptera exigua (beet armyworm), and potential role of VOCs to mitigate herbicide injury. Results for feeding behavior were mixed, possibly being influenced by environmental and genetic changes more than VOCs. Exposing VOCs to A. fatua lines found that linalool reduced flucarbazone injury of HS plants, while a combined VOC treatment generally increased herbicide injury. MHR responded differently than HS plants to some treatments, suggesting that MHR has fundamental VOC perception alterations. Other studies compared plant pigments and energy management capabilities and showed that MHR lines had higher beta-carotene and chlorophyll b concentrations, as well as enhanced photosynthetic and excess energy management capabilities in MHR lines. Finally, two populations of recombinant inbred lines (RILs) were phenotyped for herbicide resistance and used to discover several quantitative trait loci (QTL) associated with resistance. Overall, this work contributes to our understanding of MHR and will lay the groundwork for future studies.Item Management of Kochia (Bassia scoparia) in a time of herbicide resistance(Montana State University - Bozeman, College of Agriculture, 2020) Lim, Charlemagne Ajoc; Chairperson, Graduate Committee: Alan T. Dyer; Alan Dyer and Prashant Jha were co-authors of the article, 'Kochia (Bassia scoparia) growth and fecundity under different crops and weed densities' submitted to the journal 'Weed science journal' which is contained within this dissertation.; Alan Dyer and Prashant Jha were co-authors of the article, 'Survival and reproductive fitness of glyphosate-resistant kochia (Bassia scoparia) in the presence of glyphosate' submitted to the journal 'Weed technology journal' which is contained within this dissertation.; Alan Dyer and Prashant Jha were co-authors of the article, 'Survival, growth and fecundity of Dicamba-resistant kochia (Bassia scoparia) in the absence and presence of Dicamba' submitted to the journal 'Weed technology journal' which is contained within this dissertation.Kochia [Bassia scoparia (L.) A. J. Scott] is one of the most troublesome weeds in the US Great Plains. This is exacerbated by the development of herbicide-resistant kochia populations which necessitates more ecologically driven approaches for its control. This research examined the competitive effects of four crops (sugar beet, soybean, barley and corn) in combination with kochia densities (3, 13, 24, 47, 94 and 188 plants m-2) on kochia development and kochia seed production. Corn had greatest effect in reducing kochia biomass and seed production. Barley had greatest effect in delaying kochia flowering which happened after barley senesced at 113 days after kochia emergence. Soybean and sugar beet had the least effect in reducing kochia biomass and seed production, respectively, relative to fallow. This research also reports the fitness of glyphosate-resistant kochia and dicamba-resistant kochia in the presence and absence of glyphosate and dicamba selection, respectively, under field conditions. Glyphosate-resistant kochia showed limited fitness cost (less seed weight and seed radicle length relative to the susceptible) in the absence of glyphosate selection and reduced reproductive fitness (seed production) in the presence of increasing glyphosate selection. In the absence of dicamba selection, dicamba-resistant kochia showed a fitness cost (reduced growth and seed production relative to the susceptible) associated with dicamba resistance with greater fitness cost observed with increased level of resistance. Dicamba-resistant kochia also showed reduced reproductive fitness (seed production) in the presence of increasing dicamba selection. Overall, this research provides information on the growth and reproductive fitness of glyphosate-resistant kochia and dicamba-resistant kochia in the presence and absence of glyphosate and dicamba selection, respectively. Furthermore, this research provides insights on the competitive abilities of different but financially viable rotational crops for kochia management in Montana.Item Genetic and physiological characterization and ecological management of non-target site resistance in multiple herbicide resistant Avena fatua L.(Montana State University - Bozeman, College of Agriculture, 2017) Burns, Erin Elizabeth; Chairperson, Graduate Committee: William Dyer; Barbara K. Keith, Luther E. Talbert and William E. Dyer were co-authors of the article, 'Non-target site herbicide resistance is controlled by a single gene in Avena fatua L.' submitted to the journal 'Weed Research' which is contained within this thesis.; Barbara K. Keith, Mohammed Y. Refai, Brian Bothner, and William E. Dyer were co-authors of the article, 'Proteomic and biochemical assays of glutathione-related proteins in suseptible and multiple herbicide resistant Avena fatua L.' submitted to the journal 'Pesticide Biochemistry and Physiology' which is contained within this thesis.; Barbara K. Keith, Mohammed Y. Refai, Brian Bothner, and William E. Dyer were co-authors of the article, 'Constitutive redox and phosphoproteome changes in multiple herbicide resistant Avena fatua L. are similar to those of systemic acquired resistance and systemic acquired acclimation' submitted to the journal 'Journal of Plant Physiology' which is contained within this thesis.; Erik A. Lehnhoff, Sean C. McKenzie, Bruce D. Maxwell, William E. Dyer and Fabian D. Menalled were co-authors of the article, 'You can't fight fire with fire: model suggests alternate approaches to manage multiple herbicide resistant Avena fatua L.' submitted to the journal 'Journal of Applied Ecology' which is contained within this thesis.Extensive herbicide usage has led to the evolution of resistant weed populations that cause substantial crop yield losses and increase production costs. The multiple herbicide resistant (MHR) Avena fatua populations utilized in this study are resistant to members of all selective herbicide families, across five modes of action, available for A. fatua control in small grain production, and thus pose significant agronomic and economic threats. Resistance to ALS and ACCase inhibitors is not conferred by target site mutations, indicating that non-target site resistance (NTSR) mechanisms are involved. The objectives of this dissertation were to investigate the following features of NTS MHR in comparison to herbicide susceptible (HS) A. fatua: 1) inheritance and genetic control, 2) the involvement of glutathione-related enzymes, 3) differentially expressed stress-related proteins in HS and MHR redox and phosphoproteomes, and 4) the influence of abiotic and biotic stress on A. fatua demography. First, NTSR in MHR A. fatua is controlled by three separate, closely-linked nuclear genes for flucarbazone-sodium, imazamethabenz-methyl, and pinoxaden. Second, a combination of proteomic, biochemical, and immunological approaches showed that constitutive glutathione-S-transferase (GST) activities and other glutathione-related enzymes are not directly involved in enhanced rates of fenoxaprop-P-ethyl and imazamethabenz-methyl metabolism in MHR A. fatua. Instead, we hypothesize that constitutively elevated GST enzyme rates and amounts are representative of a global suite of abiotic stress-related changes in MHR plants. Third, post-translation modifications including protein phosphorylation and oxidation were compared in two-dimensional gels, showing that MHR plants contain constitutive changes very similar to systemic acquired resistance and systemic acquired acclimation to biotic and abiotic stressors, respectively. And fourth, we investigated the influence of nitrogen fertilizer rate and spring Triticum aestivum seeding density on the demography of MHR and HS A. fatua under two cropping systems (continuous cropping and crop-fallow rotation). In both systems, MHR seedbank densities were negatively impacted by increasing nitrogen fertilization rate and T. aestivum density, and density-dependent seed production was the most influential parameter impacting population growth rate. Overall, this work provides significant insights into the genetic and physiological mechanisms that confer NTS MHR in A. fatua, and presents realistic ecologically-based approaches for management.Item Confirmation and management of glyphosate-resistant Kochia (Kochia scoparia) in Montana(Montana State University - Bozeman, College of Agriculture, 2015) Kumar, Vipan; Chairperson, Graduate Committee: Prashant Jha; Prashant Jha and Nicholas Reichard were co-authors of the article, 'Occurrence and characterization of Kochia (Kochia scoparia) accessions with resistance to glyphosate in Montana' in the journal 'Weed technology journal' which is contained within this thesis.; Prashant Jha, Darci Giacomini, Eric Westra and Philip Westra were co-authors of the article, 'Molecular basis of evolved resistance to glyphosate and acetolactate synthase-inhibitor herbicides in Kochia (Kochia scoparia) accessions from Montana' submitted to the journal 'Weed science journal' which is contained within this thesis.; Prashant Jha was a co-author of the article, 'Impact of EPSPS gene amplification and intraspecific competition on fitness of glyphosate-resistan Kochia scoparia inbreds' submitted to the journal 'PLoS one journal' which is contained within this thesis.; Prashant Jha was a co-author of the article, 'Effective preemergence and postemergence herbicide programs for Kochia control' in the journal 'Weed technology journal' which is contained within this thesis.; Prashant Jha was a co-author of the article, 'Influence of herbicides applied postharvest in wheat stubble on control, fecundity, and progeny fitness of Kochia scoparia in the US Great Plains' in the journal 'Crop protection journal' which is contained within this thesis.; Prashant Jha was a co-author of the article, 'Influence of glyphosate timing on Kochia (Kochia scoparia) demographics in glyphosate-resistant sugar beet' submitted to the journal 'Weed technology journal' which is contained within this thesis.; Prashant Jha was a co-author of the article, 'Control of volunteer glyphosate-resistant canola in glyphosate-resistant sugar beet' in the journal 'Weed technology journal' which is contained within this thesis.Kochia (Kochia scoparia L.) is one of the most problematic weeds in cropland and non-cropland areas of the US Great Plains. This research confirms the first report on glyphosate-resistant (GR) K. scoparia in Montana, and elucidates the mechanisms of glyphosate and ALS-inhibitor resistance, growth and reproductive fitness of GR K. scoparia, and its management. This research also reports the response of K. scoparia demographics to glyphosate timings in GR sugar beet and evaluate herbicide options for managing volunteer GR canola in GR sugar beet. Based on whole-plant dose-response experiments, four GR K. scoparia accessions (JOP01, GIL01, CHES01, CHES02) had 4.6 to 11-fold levels of resistance to glyphosate compared to a glyphosate-susceptible (GS) accession. Confirmed GR K. scoparia accessions (GIL01, JOP01, and CHES01) also exhibited 9.3- to 30-fold resistance to sulfonylurea herbicide (ALS inhibitors). Results from PCR, quantitative PCR, and immunoblotting assays indicated that EPSPS gene amplification (~ 4 to 10 copies) and single point mutation at Pro197 in ALS gene conferred resistance to glyphosate and ALS-inhibitors, respectively. Inbred lines of GR K. scoparia (CHES01 and JOP01) with 2- to 14-fold amplification of the EPSPS gene did not confer any growth- or fecundity-related fitness cost. From a management standpoint, acetochlor + atrazine, S-metolachlor + atrazine + mesotrione, and sulfentrazone applied PRE and paraquat + atrazine, paraquat + linuron, and paraquat + metribuzin applied POST or in postharvest wheat stubble provided effective (> or = 91%) control of K. scoparia. In GR sugar beet, sequential applications of glyphosate (6-leaf fb 10-leaf stage of sugar beet) reduced survival, biomass and seed production of K. scoparia plants in cohort 1 and 2; however, an additional application of glyphosate at the canopy closure stage of sugar beet was needed to prevent seed production from the late-emerging K. scoparia (cohort 3). Ethofumesate (4,200 g ha -1) PRE followed by sequential POST triflusulfuron methyl (17.5 g ha -1) was the most effective treatment for managing volunteer GR canola in GR sugar beet. Overall, this research demonstrates the adaptability of K. scoparia evolving resistance to glyphosate and ALS inhibitors, and suggest the need for adoption of integrated weed management practices.Item Temporal and spatial dynamics of herbicide resistant weeds(Montana State University - Bozeman, College of Agriculture, 1997) Davidson, Robert MayfieldItem Molecular studies of dicamba-resistant Kochia scoparia L.(Montana State University - Bozeman, College of Agriculture, 2002) Kern, Anthony John