Plant Sciences & Plant Pathology

Permanent URI for this communityhttps://scholarworks.montana.edu/handle/1/12

The Department of Plant Sciences and Plant Pathology is part of the College of Agriculture at Montana State University in Bozeman. An exciting feature of this department is the diversity of programs in Plant Biology, Crop Science, Plant Pathology, Horticulture, Mycology, Plant Genetics and Entomology. The department offers BS, MS, and Ph.D. degree program

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Now showing 1 - 6 of 6
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    Novel alleles of MFT‐A and MFT‐B1 appear to impact wheat preharvest sprouting in Triticum aestivum and Triticum turgidum ssp. durum
    (Wiley, 2024-05) Tillet, Brandon J.; Vetch, Justin M.; Martin, John M.; Giroux, Michael J.
    Background and Objectives. Preharvest sprouting (PHS) is the premature germination of seeds, which is often caused by late-season rains after seeds reach physiological maturity. PHS negatively impacts grain yield and end-use quality. Previous studies in spring bread wheat (Triticum aestivum) and durum wheat (Triticum turgidum) have identified that some mutations in the mother of FT and TFL1 gene (MFT) coding sequence decrease seed dormancy and increase wheat PHS. Findings. Here, we report two novel alleles for the MFT-A and two novel alleles for the MFT-B1 homologs in spring bread wheat and durum wheat. Conclusions. A haplotype analysis suggests that TaMFT-3A1b (OQ729929), TaMFT-3B1b (OQ729932) and TdMFT-3B1b (OQ729937) increase PHS susceptibility. It is expected that functional copies of MFT promote seed dormancy. Variant analysis of the novel MFT-A and MFT-B1 alleles in both spring and durum wheat suggest impairment of protein function, therefore a negative impact on seed dormancy. Significance and Novelty: Previously unassessed durum wheat varieties were examined for PHS susceptibility. The information in this study can serve as a resource for spring and durum wheat breeders to make selections for alleles of MFT that impact susceptibility to PHS.
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    The Grain Number Increase 1 alleles GNI-A1-105Y and -105K increase grain number in spring wheat
    (Wiley, 2024-07) Hale, C. O.; Tillet, B. J.; Martin, J. M.; Hogg, A. C.; Giroux, M. J.
    Wheat (Triticum aestivum L.) has inflorescences made up of multiple spikelets arranged along a central rachis, with each spikelet producing between one and four grains. The Grain Number Increase 1 (GNI-A1) gene wheat directly influences grain number per spikelet and grain size. Three naturally occurring alleles have been described previously: GNI-A1-105N, 105Y, and 105K. This project's goal was to characterize the impact of these alleles within hard red spring wheat cultivars in Montana, where each of the alleles is common. The 105N allele and the 105K allele were compared through analysis of an F5 Vida by Spring-Yellowstone recombinant inbred line (RIL) population, and with near isogenic lines (NILs) derived from the same population. The 105N allele and the 105Y allele were compared with NILs derived from an F4 Lanning by Egan RIL population. We analyzed the impact of each of the three alleles and compared their effects on inflorescence architecture, grain size, grain yield, grain quality, and milling quality under Bozeman, MT, field conditions. Data show that either loss-of-function alleles (105Y and 105K) increased grain number per spikelet by 5% when compared to the more functional allele (105N) across all years and environments tested. Overall grain size was not significantly reduced and there was also not a significant increase in overall grain yield.
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    Molecular Mechanisms of the Co-Evolution of Wheat and Rust Pathogens
    (MDPI, 2023-04) Annan, Emmanuel N.; Huang, Li
    Wheat (Triticum spp.) is a cereal crop domesticated >8000 years ago and the second-most-consumed food crop nowadays. Ever since mankind has written records, cereal rust diseases have been a painful awareness in antiquity documented in the Old Testament (about 750 B.C.). The pathogen causing the wheat stem rust disease is among the first identified plant pathogens in the 1700s, suggesting that wheat and rust pathogens have co-existed for thousands of years. With advanced molecular technologies, wheat and rust genomes have been sequenced, and interactions between the host and the rust pathogens have been extensively studied at molecular levels. In this review, we summarized the research at the molecular level and organized the findings based on the pathogenesis steps of germination, penetration, haustorial formation, and colonization of the rusts to present the molecular mechanisms of the co-evolution of wheat and rust pathogens.
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    Historic trends and sources of year‐over‐year stability in Montana winter wheat yields
    (Wiley, 2023-04) Lachowiec, Jennifer; Berg, James E.; Liang, Meng; Correr, Fernando H.
    Producers desire cultivars that consistently perform with high yields and end-use qualities. Unlike easily recognized average yield improvements, yield stability over time is less examined, especially when considering the role of breeding relative to other factors like management and changing climatic conditions. Our study system was a 70-year historical dataset from which we estimated the year-over-year stability of winter wheat (Triticum aestivum L.) cultivars released by Montana's Agricultural Experimental Station. We examined yield stability within six locations representing diverse growing conditions across Montana and found no evidence that breeding has improved stability, that stability may be decreasing over time at one location, and that the year-over-year stability of a cultivar is sensitive to location. We examined the role of climatic conditions, including temperature, and rainfall to understand if increased climatic variability was masking improved patterns of stability. However, the lack of impact of breeding remained. These findings suggest that Montana's winter wheat may benefit from selective breeding for increased stability within locations.
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    Missense alleles of the HMW glutenin subunits Dx5 and Dy10 have small changes in function relative to missense changes in Puroindoline a and b
    (Wiley, 2022-12) Martin, John M.; Zhang, Jinrui; Hogg, Andrew C.; Giroux, Michael J.
    Background and Objectives. The high molecular weight glutenin subunit genes (HMW-GS) in wheat (Triticum aestivum L.) play a key role in determining dough functionality. More specifically allelic variation for the Glu-D1 subunit loci is consistently associated with bread making quality. Since much of the hard wheat germplasm is fixed for the more favorable 1Dx5 + 1Dy10 haplotype, our goal was to identify allelic variation in 1Dx5 and 1Dy10 HMW-GS genes using an ethyl methanesulfonate (EMS) mutagenized population in the soft white spring wheat cultivar “Alpowa.” The same source population was previously used in screening for creating novel alleles in Puroindoline a (Pina) and Puroindoline b (Pinb) which are responsible for grain hardness variation. Direct sequencing of 384 M3 families identified 135 point mutations equally dispersed across 1Dx5 and 1Dy10. The mutation discovery rate was 1/12.7 kb of DNA, equal to that found in the Pin loci. Mutation carrying plants were crossed to the nonmutagenized Alpowa parent to create F2 populations segregating for the induced EMS HMW Glutenin mutations. Swelling index of gluten (SIG) was measured from seed from field grown plants to assess the impact of each EMS mutation upon Glutenin function. Findings. Nonsense mutations in both 1Dx5 and 1Dy10 reduced SIG values, indicating both 1Dx5 and 1Dy10 are needed for gluten functionality. Missense mutations did not alter SIG values compared to their wild type counterparts. In contrast missense mutations within the tryptophan-rich region of both PINS increased grain hardness pointing to the importance of this protein region. No such region in 1Dx5 or 1Dy10 was found indicating these proteins are structurally stable and tolerant of amino acid substitution. Conclusions. Results from the Glu-D1 subunit and Pin loci show that useful phenotypic variation can be created using EMS mutagenesis for genes where naturally occurring mutations occur from amino substitutions as is the case for the Pin loci. Significance and Novelty. EMS induced mutations are useful for creating new alleles in storage proteins with much greater impacts in genes that have a defined active site as for the Pin loci than in genes such as the HMW Glu-1 genes which have a long repetitive region.
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    Relationships between roots, the stay‐green phenotype, and agronomic performance in barley and wheat grown in semi‐arid conditions
    (Wiley, 2022-01) Williams, Jessica L.; Sherman, Jamie D.; Lamb, Peggy F.; Cook, Jason; Lachowiec, Jennifer A.; Bourgault, Maryse
    Stay-green is a phenotype that crop breeders could use to improve drought adaptation. It increases the duration of grain fill in several species including barley (Hordeum vulgare L.) and wheat (Triticum aestivum L.), maintaining yield in semi-arid conditions. Evidence from controlled environment experiments suggests a connection between stay-green and root systems. These belowground structures are understudied and thus represent opportunity for crop improvement if relationships to agronomics can be understood. Minirhizotrons facilitate study of these relationships by allowing repeated nondestructive root measurements in field conditions. However, this is time-consuming, and proxies would be useful for increasing throughput capacity of root research. Here we present results from field trials with minirhizotrons in a semi-arid environment, as well as greenhouse seedling assays conducted on stay-green and non-stay-green barley and wheat lines. In barley, stay-green and greater yield were primarily associated with greater deep root length and delayed root senescence, whereas in wheat, yield was most strongly correlated with total root length, and root system differences for stay-green were not as apparent. We speculate that the physiology of stay-green is different between these two species, and that barley may use a more efficient root system to withstand drought whereas wheat relies on a larger one. Several seedling traits related consistently to field root traits, but correlation directions were often opposite between barley and wheat. The connections between traits presented here could be useful for breeders seeking to improve crop adaptation to drought, but more genotypes and environments will need to be tested.
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