Program Book - 27th Fungal Genetics Conference

FULL POSTER SESSION ABSTRACTSrapid development of novel effector genes. Likely, chromosomal reshuffling is a general mechanism for adaptation in asexually propagating organisms.252. Genomic census of transmembrane proteins of the marine fungus, Corollospora maritima. Derek Johnson, Joseph Spatafora. Botany and PlantPathology, Oregon State University, Corvallis, OR.The class Sordariomycetes (Ascomycota) presents a model phylogenetic system to study the genomic evolution of marine fungi, as there have been atleast four major independent transitions from terrestrial to marine environments. These marine fungi have adapted to an environment which requiresincreased control of the movement of water between the cell and the environment due to osmosis. Given this, the greatest adaptive pressure may befound working at the interface of the fungal cell with the environment in the form of transmembrane proteins and in biochemical pathways dealing inosmoregulation. We have initiated a comparative, phylogenomic study of the independent lineages of marine Sordariomycetes with the goal ofdetermining what pathways have been modified in the transition to the marine environment. Here we present preliminary data of the draft genome of themarine fungus Corollospora maritima, which is a member of the largest family of marine fungi, Halospheriaceae (Microascales). The draft genome of C.maritima is similar to other Sordariomycetes (37 MB, 10269 predicted gene models) but is characterized by an increased number of transmembraneproteins; both in raw number (2017), and as a percentage of protein coding genes (19.64%), than non-marine members of the Sordariomycetes. Thus, it ishypothesized that C. maritima has expanded osmoregulatory protein families and adapted novel transmembrane proteins as a consequence of thetransition to the marine environment. Transmembrane proteins belonging to C. maritima along with select species of fungi and Eukaryotes were predictedvia hidden markov modeling using the program TMHMM and clustered into orthologous groups using Ortho-MCL. Putative protein identities (e.g.,aquaporins, aquaglyceroporins, osmosensors and the sodium efflux ENA ATPases) were assigned to each cluster using the BLAST tool comparingorthologous protein cluster identities to proteins of the model organisms Neurospora crassa and Saccharomyces cerevisiae. Expansions and contractionsof transmembrane proteins will be presented in a phylogenetic context, and more complex patterns of evolution, such as more ancient lineage sorting vs.lineage specific expansions, will be tested for each orthologous group of proteins using gene tree/species tree reconciliation analyses.253. Fungal Calcium Signaling Database (FCSD). Venkatesh Moktali, Bongsoo Park, Seogchan Kang. Penn State University, University Park, PA 16802, USA.Calcium probably is one of the most versatile elements in biological systems. It serves as a pivotal signal in controlling diverse cellular and developmentalprocesses to ensure the healthy functioning of every organism ranging from microbes to humans. The mechanism of translating external stimuli to specificcellular and developmental responses via changes in calcium ions plays an essential role in the plant-microbe and microbe-environmental interactions.Accordingly, many genes of the calcium-signaling pathway have been found to be virulence factors of fungal pathogens. How this simple and ubiquitousion has evolved to control so many processes is one of the central questions in biology with many practical implications. Rapid advances in genomesequencing of many fungal and oomycete species have uncovered conserved core calcium signaling genes, as well as lineage-specific features. To supportsystematic studies on this evolutionary variability in fungi and oomycetes and the functional roles of individual genes, we built the Fungal Calcium SignalingDatabase (FCSD; http://fcsd.ifungi.org/), an online platform that categorizes and annotates key calcium signaling proteins from more than 120 publishedfungal and oomycete genomes. The database also archives experimental results from studies on mutants of calcium signaling genes and resulting calciumsignatures in both video and picture formats. The calcium signaling genes in FCSD are divided into five major groups namely, calcium-permeable channels,calcium pumps, calcium exchanger/antiporter, calcium signaling regulators, and calcium-binding proteins. Comparison of calcium signaling machineriesbetween fungi and oomycetes has been conducted to identify evolutionary changes that have shaped up this signaling pathway in these kingdoms. TheFCSD will greatly support the fungal community in studying and understanding calcium signaling.254. Evolutionary genomic analysis of cytochrome P450 proteins in the subphyla Pezizomycotina. Venkatesh Moktali, Seogchan Kang. The PennsylvaniaState University, University Park, PA 16802.The subphylum Pezizomycotina presents a vast diversity of ecological niches and biochemical processes observed in fungal subphyla. Changes inmembers of the cytochrome P450 (CYP) superfamily appear to have played key roles in fungal niche adaption and evolution. Availability of genomic datafrom many species in this subphylum has enabled comprehensive phylogenomic studies to understand the taxon-specific genetic changes that potentiallyunderpin the observed functional and ecological diversity. CYPs from 53 Pezizomycotina species were analyzed to study the gene birth and death patternsat the genus level. This analysis revealed niche- and class-specific CYP family expansions and contractions. Putative metabolic functions were assigned toindividual CYPs in each species based on sequence similarity to functionally characterized CYP proteins. Also, pathogenic Pezizomycotina fungi weredivided into three classes (hemibiotrophs, obligate biotrophs and necrotrophs) to identify CYP family expansions and innovations potentially associatedwith these classes. Large losses in CYP families were observed among obligate biotrophs whereas hemibiotrophs and necrotrophs showed gene gains aswell as functional innovation in the form of species-specific CYP families. Examination of the classes/divisions within Pezizomycotina suggested a numberof independent losses and gains in CYP families. These findings shall be presented in the poster.255. Uncovering the evolutionary pressures shaping the Glomeromycota-Glomeribacter endosymbiosis. Stephen J. Mondo, Teresa E. Pawlowska. PlantPathology, Cornell University, Ithaca, NY.Many eukaryotes interact with heritable endobacteria to satisfy diverse metabolic needs. Of the characterized fungal-bacterial endosymbioses, theassociation between Gigasporaceae (Glomeromycota) and Ca. Glomeribacter is one of the best described. Glomeribacter is a member of the Burkholderialineage of b-proteobacteria, and was shown previously to represent one of the few cases of an ancient, long-term non-essential endosymbiont. In order tofurther explore what adaptations have taken place to shape this unique bacterial lifestyle, we have sequenced three Glomeribacter genomes anddeveloped a computational pipeline to compare across bacteria engaging in different lifestyles using genome wide patterns of mutation accumulation. Weused PAML to identify gene orthologs that exhibited both over-accumulation and under-accumulation of amino acid substitutions and then used thesedata to compare across taxa at the level of functional gene categories. We found that bacteria can be grouped by lifestyle using this approach.Glomeribacter, as expected, appears most similar to other potentially long-term non-essential endosymbionts. Therefore, we were able to exploit thedifferences in mutation accumulation patterns between these taxa to identify processes, which may be relevant within the particular interaction betweenGlomeribacter and its host. While several of these processes, including vitamin synthesis and amino acid transport, have been identified previously, weadditionally discovered features related to lipid biosynthesis and energy metabolism to be of potential importance for this symbiosis. Interestingly, genesexhibiting an under-accumulation of nonsynonymous substitutions (indicative of purifying selection) in Glomeribacter tend to be involved inrecombination, cell division, and ribosome maintenance. While these processes are typically fast evolving in endosymbiotic organisms, they may representfeatures that increase the stability of Glomeribacter in their fungal host population and increase their resilience to genetic drift. We speculate that theseprocesses are unique to the Glomeribacter-Glomeromycota symbiosis and could partially explain why Glomeribacter has been successful as a nonessentialendosymbiont for over 400 million years.27th Fungal Genetics Conference | 183