Organisms Commons^™

How Megadrought Causes Extensive Mortality In A Deep-Rooted Shrub Species Normally Resistant To Drought-Induced Dieback: The Role Of A Biotic Mortality Agent, Natalie M. Aguirre, Marissa E. Ochoa, Helen I. Holmlund, Gabriella N. Palmeri, Emily R. Lancaster, Gina S. Gilderman, Shaquetta R. Taylor, Kaitlyn E. Sauer, Adriana J. Borges, Avery N.D. Lamb, Sarah B. Jacques, Frank W. Ewers, Stephen D. Davis

School of Medicine Faculty Publications

Southern California experienced unprecedented megadrought between 2012 and 2018. During this time, Malosma laurina, a chaparral species normally resilient to single-year intense drought, developed extensive mortality exceeding 60% throughout low-elevation coastal populations of the Santa Monica Mountains. We assessed the physiological mechanisms by which the advent of megadrought predisposed M. laurina to extensive shoot dieback and whole-plant death. We found that hydraulic conductance of stem xylem (Ks, native) was reduced seven to 11-fold in dieback adult and resprout branches, respectively. Staining of stem xylem vessels revealed that dieback plants experienced 68% solid-blockage, explaining the reduction in water transport. Following Koch's …

Characterizing The Cutaneous Microbiome Of Eurycea Lucifuga As A Potential Defense Against Chytridiomycosis, Madeline Key

Senior Honors Theses

Chytridiomycosis is an emerging infectious disease that is significantly reducing global amphibian populations. The disease is caused by Batrachochytrium dendrobatidis (Bd), a fungus that lethally modifies amphibian skin. Recent research has suggested that the cutaneous microbiome of individual amphibians may play a role in susceptibility to the pathogen. In this study, twelve cave salamanders (Eurycea lucifuga) were collected. Cutaneous bacteria from each salamander were isolated and identified using Sanger Sequencing. Additionally, a Bd-challenge assay was performed to determine each isolate’s antifungal activity. Results indicated many microbial isolates possessed inhibitory capabilities against Bd, which may …

Reporting Charcoal Rot In Chia And Developing A Susceptibility Assay, Reis M. Misaka, Hagop S. Atamian Dr., Julien Besnard Dr.

Student Scholar Symposium Abstracts and Posters

Chia (Salvia Hispanica) cross breeds were planted in the summer of 2018 with the intent of selective breeding for agricultural benefit. Preexisting pathogens in the soil caused 40-50% fatality of adult plants. This was surprising due to the precursory knowledge that chia has antibiotic and antifungal oils (Elshafie et. al. 2018); chia was only recently documented to be susceptible to Fusarium wilt (Fusarium oxysporum). The primary pathogen responsible was identified as Macrophomina phaseolina (aka charcoal rot); a widespread soilborne pathogen which has multiple commercial hosts (Su et. al. 2001).

M. phaesolina on wheat seed vector where used as …

Repeat Elements Organise 3d Genome Structure And Mediate Transcription In The Filamentous Fungus Epichloë Festucae, David J. Winter, Austen R. D. Ganley, Carolyn A. Young, Ivan Liachko, Christopher L. Schardl, Pierre-Yves Dupont, Daniel Berry, Arvina Ram, Barry Scott, Murray P. Cox

Plant Pathology Faculty Publications

Structural features of genomes, including the three-dimensional arrangement of DNA in the nucleus, are increasingly seen as key contributors to the regulation of gene expression. However, studies on how genome structure and nuclear organisation influence transcription have so far been limited to a handful of model species. This narrow focus limits our ability to draw general conclusions about the ways in which three-dimensional structures are encoded, and to integrate information from three-dimensional data to address a broader gamut of biological questions. Here, we generate a complete and gapless genome sequence for the filamentous fungus, Epichloë festucae. We use Hi-C …

Draft Genome Sequence Of Cercospora Sojina Isolate S9, A Fungus Causing Frogeye Leaf Spot (Fls) Disease Of Soybean, Fanchang Zeng, Chaofan Wang, Guirong Zhang, Junmei Wei, Carl A. Bradley, Ray Ming

Plant Pathology Faculty Publications

Fungi are the causal agents of many of the world's most serious plant diseases causing disastrous consequences for large-scale agricultural production. Pathogenicity genomic basis is complex in fungi as multicellular eukaryotic pathogens. The fungus Cercospora sojina is a plant pathogen that threatens global soybean supplies. Here, we report the genome sequence of C. sojina strain S9 and detect genome features and predicted genomic elements. The genome sequence of C. sojina is a valuable resource with potential in studying the fungal pathogenicity and soybean host resistance to frogeye leaf spot (FLS), which is caused by C. sojina. …

Metacaspase Gene Function In The Mushroom Fungus Schizophyllum Commune, Matthew P. Hanley

Honors Theses

The overall goal of this project was to investigate the biological role of a putative metacaspase gene present in the mushroom fungus Schizophyllum commune. For this study, we have utilized a strain of S. commune that is unable to integrate DNA via the non-homologous end joining pathway. This forces transforming DNA to integrate homologously, as is required for the purposes of gene knockout. The gene Scp1 encodes a likely member of the metacaspase protein family, which are suspected to have activity similar to caspases, the latter crucial to programmed cell death. A knockout construct containing a non-functional version of Scp1 …

A Study Of Puccinia Graminis And Cronartium Ribicola, Duane W. Hughes

Graduate Student Research Papers

It was the purpose of this study (1) to review the literary history of rusts in the United States and in the Northwest in particular, ( 2) to learn where rusts generally are found geographically, (3) to gain further information regarding the etiology of wheat rust (Puccinia graminis tritici), of white pine blister rust (Cronartium ribicola) and to become enlightened on other rusts, (4) to learn ways of controlling the two rusts, black stem rust of wheat and white pine blister rust, and to gain an appreciation of the economic importance of rust prevention.