Environmental Microbiology and Microbial Ecology Commons^™

Analysis Of Symptom Expressions And Transmission Rates Caused By The Plant Pathogen Phytophthora Ramorum On Native Chaparral Plants From The Genus Arctostaphylos, Bharati Gaonker

Natural Sciences and Mathematics | Biological Sciences Master's Theses

Phytophthora ramorum is the causal agent of Sudden Oak death (SOD), ramorum dieback and ramorum leaf blight which affect both forest environments and nurseries. This oomycete pathogen has had a huge economic impact on the nursery and lumber industry. Forests in California have experienced substantial mortality of oaks affecting the forest dynamics and diversity. Our research investigates four native species and two ornamental cultivars of plants, which belong to the genus Arctostaphylos (manzanita) and are considered to be new hosts for P. ramorum in the chaparral ecosystem of California. Symptom expression and transmission rates were analyzed on Arctostaphylos glauca, …

Efecto De La Adición De Biochar Como Enmienda De Un Suelo Degradado, Sobre Microorganismos Relacionados Con El Ciclo Del Carbono, Johan Alejandro Burbano Chinchajoy

Biología

Actualmente, la fuerte demanda agrícola y las malas prácticas han alterado el equilibrio natural del suelo, así como las interacciones físicas, químicas y biológicas, ocasionando su degradación del suelo; por tanto, los índices de calidad del suelo son considerados como herramientas para evaluar el estado de este sustrato en condiciones naturales o el utilizado para la producción agrícola.

Una de las prácticas utilizadas para mitigar su degradación es el uso de enmiendas orgánicas, como el biochar, a nivel mundial se ha evaluado su adición como medio para mejorar la fertilidad del suelo y mitigar el cambio climático, además, sus efectos …

Root Phosphomonoesterase As A Vital Component Of Increasing Phosphorus Availability In Tropical Forests, Kristine Grace Manno Cabugao

Doctoral Dissertations

Tropical forests, relative to other terrestrial ecosystems, exchange the largest amount of carbon with the atmosphere and also constitute a significant carbon sink. However, nutrient limitation, particularly of phosphorus (P), could limit growth of tropical forests and their function with the global carbon cycle. Thus, understanding root mechanisms to acquire P is necessary to representing the P cycle and corresponding interactions with plant growth. A large portion of total soil P in tropical forests occurs in organic forms, only accessible through root and microbial production of phosphatase enzymes. These phosphatase enzymes mineralize organic P into orthophosphate, the form of P …

A Comparative Taxonomic And Diversity Study Of Litter-Associated Fungi In Northwest Arkansas Forests, Rajaa Abdulrazzaq Abbas Al Aanbagi

Graduate Theses and Dissertations

Fungi are taxonomically the most species-rich group of organisms on the earth, ecologically occupy distinctive niches and interact with diverse other organisms throughout their biogeographic distributions and functionally play key roles through their various lifestyles. Plant litter, in particular, is a keystone component in ecosystems and provides heterogeneous microhabitats for the often overlooked litter-decomposing fungi and other organisms on the floor of temperate deciduous forests. Litter fungi involve indirect interactions with the plant, soil and whole food web network. However, the community structure and functions of litter-associated fungi as well as patterns of species richness distributed across various litter microhabitats …

Warming Up: Climate Change Related Shifts Of Mycorrhizal Fungal Communities In High Latitude Ecosystems, Megan Rae Devan

Biology ETDs

This dissertation examines how climate change affects mycorrhizal fungal communities in boreal and arctic ecosystems. In chapter one, I revealed that increases in fire severity and related increases in deciduous tree dominance result in greater Ascomycota relative abundance (RA) and subsequent declines in Basidiomycota RA. In chapter two I analyzed the effects of post-fire mycorrhizal fungal communites on host growth. There were trends at the fungal genus level that were largely reflected at the guild level across all hosts; however, there were some fungal genera that had the opposite effect on different host species. In chapter three, I found host …

Microbial Abundance And The Pattern Of Escherichia Coli Antibiotic Sensitivity And Resistance In Deer Creek And The Potential Impact Of A Veterinarian Hospital’S Input, Sarah Boxer, Tim Gsell

Research Days

The gram-negative bacteria, E. coli, is an indicator of fecal input for both point and non-point source origin. The veterinarian hospital located on Deer Creek may contribute to high antibiotic levels, which are known to select for resistant strains of bacteria living in impacted waters. The water running north of the veterinarian hospital was considered potentially antibiotic influenced as it was downstream of the site. The origin of the stream and sites upstream from the hospital were considered influent water. Sediments were also collected from these sites to determine if more long term resident E. coli were present with elevated …

Tracking A Tree-Killer: Improving Detection And Characterizing Species Distribution Of Phytophthora Cinnamomi In Appalachian Forests, Kenton L. Sena

Theses and Dissertations--Plant and Soil Sciences

Phytophthora cinnamomi is a soil-borne oomycete pathogen causing root rot in susceptible host species. P. cinnamomi is thought to have originated in Southeast Asia, but has since been introduced to many regions around the world, where it causes dramatic declines in many forest tree species. In the eastern US, the primary susceptible tree species of concern are American chestnut (Castanea dentata), white oak (Quercus alba), and shortleaf pine (Pinus echinata). American chestnut, functionally eliminated in the early 1900s by the rapidly acting chestnut blight (Cryphonectria parasitica), has been the subject of decades-long …

Fungi Of Forests: Examining The Diversity Of Root-Associated Fungi And Their Responses To Acid Deposition, Donald Jay Nelsen

Graduate Theses and Dissertations

Global importance of forests is difficult to overestimate, given their role in oxygen production, ecological roles in nutrient cycling and supporting numerous living species, and economic value for industry and as recreational zones. Fitness of the forest-forming trees strongly depends on microbial communities associated with tree roots. In particular, fungi impact tree fitness: mycorrhizal species provide water and nutrients for the trees in exchange for C, endophytic fungi play key roles in host defense against pathogenic organisms, and saprotrophic fungi decompose dead organic matter and facilitate nutrient cycling. In addition, pathogenic fungal species strongly affect forest fitness. Despite their importance, …

Range-Wide Prevalence And Impacts Of Pseudocercosporella Inconspicua On Lilium Grayi And An Assessment Of L. Superbum And L. Michauxii As Reservoirs, Cindy L. Barrett

Electronic Theses and Dissertations

Lilium grayi (Gray’s Lily), a southern Appalachian endemic species, is threatened by a Lilium-specific fungal pathogen, Pseudocercosporella inconspicua. The disease is characterized by tan lesions that can cause early senescence, while also lowering seed production and viability. This project tested for P. inconspicua conidia and accessed health at nine locations. The disease was present and ubiquitous across the range of L. grayi. Through identification of P. inconspicua conidia in the field, L. superbum (Turk’s Cap Lily) was identified as an additional host, while L. michauxii (Michaux’s Lily) was disease-free. However, infection was inducible in both species. With …

Molecular Diversity Of Foliar Fungal Endophytes In Relation To Defense Strategies And Disease In Whitebark Pine, Lorinda Bullington

Graduate Student Theses, Dissertations, & Professional Papers

An invasive fungal pathogen, Cronartium ribicola (the causative agent of white pine blister rust) infects and kills whitebark pine (Pinus albicaulis) throughout the western US. Blister rust has decreased whitebark pine populations by over 90% in some areas. Whitebark pine, a keystone species, has been proposed for listing under the Endangered Species Act in the U.S., and the loss of this conifer is predicted to have severe impacts on forest composition and function in high elevations. Hundreds of asymptomatic fungal species live inside whitebark pine tissue, and recent studies suggest that these fungi can influence the frequency and …

The Influence Of The Invasive Chinese Tallow (Triadica Sebifera) Leaf Litter On Aquatic Chemistry And Microbial Community Composition, Raymond D. Montez

Electronic Theses and Dissertations

Global climate change and anthropogenic activity have facilitated the movement and invasive potential of nonnative plants in native environments. These invasions can have negative effects on ecosystem diversity and function. The nonnative and invasive plant, Chinese Tallow (Triadica sebifera), has already invaded much of the south eastern US where it is outcompeting native tree species and changing ecosystem diversity in a variety of habitats. Leaf litter from the Chinese tallow has been shown cause changes in dissolved oxygen and pH in the aquatic environment. Turbidity is also affected when Chinese tallow litter is present in water. A series of …

Do Novel Weapons That Degrade Mycorrhizal Mutualisms Explain Invasive Species Success?, Philip L. Pinzone Mr.

Biology Theses

Invasive plants often dominate novel habitats where they did not co-evolve with local species. Several hypotheses suggest mechanisms that explain increased exotic plant success, including 'novel weapons' and 'degraded mutualisms'. Japanese knotweed (Fallopia japonica) and European buckthorn (Rhamnus cathartica) are widespread plant invaders in North America that can dominate ecosystems. The goal of this study is to test whether these impacts are more consistent with novel weapons or degraded mutualism hypotheses. I examine tree seedling recruitment, (germination and initial survival) growth, (biomass) and mycorrhizal invasion (AMF content) as a function of F. japonica and R. cathartica …

Spatial Variation In Carbon And Nitrogen In Cultivated Soils In Henan Province, China: Potential Effect On Crop Yield, Xuelin Zhang, Qun Wang, Frank S. Gilliam, Yilun Wang, Feina Cha, Chaohai Li

Frank S. Gilliam

Improved management of soil carbon (C) and nitrogen (N) storage in agro-ecosystems represents an important strategy for ensuring food security and sustainable agricultural development in China. Accurate estimates of the distribution of soil C and N stores and their relationship to crop yield are crucial to developing appropriate cropland management policies. The current study examined the spatial variation of soil organic C (SOC), total soil N (TSN), and associated variables in the surface layer (0–40 cm) of soils from intensive agricultural systems in 19 counties within Henan Province, China, and compared these patterns with crop yield. Mean soil C and …

Nutrient Limitation In Three Lowland Tropical Forests In Southern China Receiving High Nitrogen Deposition: Insights From Fine Root Responses To Nutrient Additions, Feifei Zhu, Muneoki Yoh, Frank S. Gilliam, Xiankai Lu, Jiangming Mo

Frank S. Gilliam

Elevated nitrogen (N) deposition to tropical forests may accelerate ecosystem phosphorus (P) limitation. This study examined responses of fine root biomass, nutrient concentrations, and acid phosphatase activity (APA) of bulk soil to five years of N and P additions in one old-growth and two younger lowland tropical forests in southern China. The old-growth forest had higher N capital than the two younger forests from long-term N accumulation. From February 2007 to July 2012, four experimental treatments were established at the following levels: Control, N-addition (150 kg N ha–1 yr–1), P-addition (150 kg P ha–1 yr–1) and N+P-addition (150 kg N …

Spatial Variation In Carbon And Nitrogen In Cultivated Soils In Henan Province, China: Potential Effect On Crop Yield, Xuelin Zhang, Qun Wang, Frank S. Gilliam, Yilun Wang, Feina Cha, Chaohai Li

Frank S. Gilliam

Improved management of soil carbon (C) and nitrogen (N) storage in agro-ecosystems represents an important strategy for ensuring food security and sustainable agricultural development in China. Accurate estimates of the distribution of soil C and N stores and their relationship to crop yield are crucial to developing appropriate cropland management policies. The current study examined the spatial variation of soil organic C (SOC), total soil N (TSN), and associated variables in the surface layer (0–40 cm) of soils from intensive agricultural systems in 19 counties within Henan Province, China, and compared these patterns with crop yield. Mean soil C and …

Nutrient Limitation In Three Lowland Tropical Forests In Southern China Receiving High Nitrogen Deposition: Insights From Fine Root Responses To Nutrient Additions, Feifei Zhu, Muneoki Yoh, Frank S. Gilliam, Xiankai Lu, Jiangming Mo

Frank S. Gilliam

Elevated nitrogen (N) deposition to tropical forests may accelerate ecosystem phosphorus (P) limitation. This study examined responses of fine root biomass, nutrient concentrations, and acid phosphatase activity (APA) of bulk soil to five years of N and P additions in one old-growth and two younger lowland tropical forests in southern China. The old-growth forest had higher N capital than the two younger forests from long-term N accumulation. From February 2007 to July 2012, four experimental treatments were established at the following levels: Control, N-addition (150 kg N ha–1 yr–1), P-addition (150 kg P ha–1 yr–1) and N+P-addition (150 kg N …

Arbuscular Mycorrhizal Fungi Of Northern White Cedar (Thuja Occidentalis L.): Habitat Effects On Fungal Communities And Inoculum Effects On Plant Growth On Acid Peat Soils, Guswarni Anwar

Dissertations, Master's Theses and Master's Reports

The relationship of arbuscular mycorrhizal (AM) fungi with northern white cedar (NWC) was examined from the perspective of both fundamental questions about habitat specificity in the root fungal community, as well as applied questions regarding AM fungal efficacy in NWC restoration in peat soils. I performed two experiments testing the effects of AM fungi on survival, growth, and nutrition of NWC seedlings; and one molecular study to determine the habitat effects on community composition of NWC root-associated fungi. First, a greenhouse AM inoculation experiment was conducted in factorial combination with fertilization and liming to examine conditional effectiveness of AM fungal …

Spatial Variation In Carbon And Nitrogen In Cultivated Soils In Henan Province, China: Potential Effect On Crop Yield, Xuelin Zhang, Qun Wang, Frank S. Gilliam, Yilun Wang, Feina Cha, Chaohai Li

Biological Sciences Faculty Research

Improved management of soil carbon (C) and nitrogen (N) storage in agro-ecosystems represents an important strategy for ensuring food security and sustainable agricultural development in China. Accurate estimates of the distribution of soil C and N stores and their relationship to crop yield are crucial to developing appropriate cropland management policies. The current study examined the spatial variation of soil organic C (SOC), total soil N (TSN), and associated variables in the surface layer (0–40 cm) of soils from intensive agricultural systems in 19 counties within Henan Province, China, and compared these patterns with crop yield. Mean soil C and …

Diversity Of Bacteria Carried By Pinewood Nematode In Usa And Phylogenetic Comparison With Isolates From Other Countries, Diogo Neves Proença, Luís Fonseca, Thomas Powers, Isabel M.O. Abrantes, Paula V. Morais

Department of Plant Pathology: Faculty Publications

Pine wilt disease (PWD) is native to North America and has spread to Asia and Europe. Lately, mutualistic relationship has been suggested between the pinewood nematode (PWN), Bursaphelenchus xylophilus the causal nematode agent of PWD, and bacteria. In countries where PWN occurs, nematodes from diseased trees were reported to carry bacteria from several genera. However no data exists for the United States. The objective of this study was to evaluate the diversity of the bacterial community carried by B. xylophilus, isolated from different Pinus spp. with PWD in Nebraska, United States. The bacteria carried by PWN belonged to Gammaproteobacteria …

National Park Service Cave Ecology Inventory And Monitoring Framework, Gretchen M. Baker, Steven J. Taylor, Shawn Thomas, Rick Olson, Kathy Lavoie, Marie Denn, Steven Thomas, Hazel Barton, Kurt Helf, Rene Ohms, Joel Despain, Jim Kennedy, David Larson

Hazel Barton

A team developed the Cave Ecology Inventory and Monitoring Framework for National Park Service (NPS) units. It contains information for NPS cave managers across the United States to determine how to inventory and monitor cave ecology. Due to the wide geographical scope of NPS caves and their many different types, the document does not prescribe exact protocols. Instead, it provides guidance for what types of inventory and monitoring are possible, a framework for deciding how to prioritize inventory and monitoring activities, and references to specific protocols that are already in place at NPS cave parks. Keywords: cave ecology, cave microbiology, …

Nutrient Limitation In Three Lowland Tropical Forests In Southern China Receiving High Nitrogen Deposition: Insights From Fine Root Responses To Nutrient Additions, Feifei Zhu, Muneoki Yoh, Frank S. Gilliam, Xiankai Lu, Jiangming Mo

Biological Sciences Faculty Research

Elevated nitrogen (N) deposition to tropical forests may accelerate ecosystem phosphorus (P) limitation. This study examined responses of fine root biomass, nutrient concentrations, and acid phosphatase activity (APA) of bulk soil to five years of N and P additions in one old-growth and two younger lowland tropical forests in southern China. The old-growth forest had higher N capital than the two younger forests from long-term N accumulation. From February 2007 to July 2012, four experimental treatments were established at the following levels: Control, N-addition (150 kg N ha^–1 yr^–1), P-addition (150 kg P ha^–1 yr^{–1 …}

National Park Service Cave Ecology Inventory And Monitoring Framework, Gretchen M. Baker, Steven J. Taylor, Shawn Thomas, Rick Olson, Kathy Lavoie, Marie Denn, Steven Thomas, Hazel Barton, Kurt Helf, Rene Ohms, Joel Despain, Jim Kennedy, David Larson

National Cave and Karst Management Symposium 2013

A team developed the Cave Ecology Inventory and Monitoring Framework for National Park Service (NPS) units. It contains information for NPS cave managers across the United States to determine how to inventory and monitor cave ecology. Due to the wide geographical scope of NPS caves and their many different types, the document does not prescribe exact protocols. Instead, it provides guidance for what types of inventory and monitoring are possible, a framework for deciding how to prioritize inventory and monitoring activities, and references to specific protocols that are already in place at NPS cave parks.

Keywords: cave ecology, cave microbiology, …

Bacterial Community Structure Of Contrasting Soils Underlying Bornean Rain Forests: Inferences From Microarray And Next-Generation Sequencing Methods, Sabrina E. Russo, Ryan Legge, Karrie A. Weber, Eoin L. Brodie, Katherine C. Goldfarb, Andrew K. Benson, Sylvester Tan

School of Biological Sciences: Faculty Publications

Soil microbial diversity is vast, and we lack even basic understanding of how this diversity is distributed ecologically. Using pyrosequencing and microarray methods, we quantified the structure of bacterial communities in two contrasting soils underlying Bornean rain forest (clay and sandy loam) that differ markedly in soil properties, aboveground tree flora, and leaf litter decomposition rates. We found significant soil-related taxonomic and phylogenetic differences between communities that, due to their proximity, are independent of climate. Bacterial communities showed distinct compositional and taxon-abundance distributions that were significantly correlated with the structure of the overlying tree community. Richness of bacteria was greater …

Genome Sequence Of The Model Mushroom Schizophyllum Commune, Robin A. Ohm, Jan F. De Jong, Luis G. Lugones, Andrea Aerts, Erika Kothe, Jason E. Stajich, Ronald P. De Vries, Eric Record, Anthony Levasseur, Scott E. Baker, Kirk A. Bartholomew, Pedro M. Coutinho, Susann Erdmann, Thomas J. Fowler, Allen C. Gathmen, Vincent Lombard, Bernard Henrissat, Nicole Knabe, Ursula Kues, Walt W. Lily

Biology Faculty Publications

Much remains to be learned about the biology of mushroom-forming fungi, which are an important source of food, secondary metabolites and industrial enzymes. The wood-degrading fungus Schizophyllum commune is both a genetically tractable model for studying mushroom development and a likely source of enzymes capable of efficient degradation of lignocellulosic biomass. Comparative analyses of its 38.5-megabase genome, which encodes 13,210 predicted genes, reveal the species's unique wood-degrading machinery. One-third of the 471 genes predicted to encode transcription factors are differentially expressed during sexual development of S. commune. Whereas inactivation of one of these, fst4, prevented mushroom formation, inactivation of another, …

Letter From The Dean, Lalit Verma

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

No abstract provided.

An Investigation Of The Acarine Fauna Of Rehabilitated Bauxite Mines In The Northern Jarrah Forest, Alex Cuccovia

Theses : Honours

The northern jarrah forest relies on efficient nutrient cycling for its growth and long term sustainability. The decomposition of organic matter and the recycling of nutrients in such ecosystems are facilitated through the interaction of microflora with a myriad of invertebrates. The recolonisation of invertebrate fauna to rehabilitated bauxite mines is thus of critical importance to the long-term success of rehabilitation. This study investigated the soil and litter mite fauna, important components of the invertebrate community well known for their numerical dominance and high biodiversity. A spring sampling of the mite fauna was undertaken, employing standard soil and litter sampling …

Occurrence And Characteristics Of Nonfruiting Myxobacteria Isolated From Pine Forest Soils, Paul M. Kulvi

All Master's Theses

A study was conducted to contribute to the taxonomy of the nonfruiting myxobacteria and to determine the effects of fire on the occurrence and characteristics of nonfruiting myxobacteria isolated from pine forest soil Three years after a prescribed burn, the population of nonfruiting myxobacteria was decreased in the burn site. The organisms isolated were distinct from any of the known species of nonfruiting myxobacteria, and apparently are new species.