Comparative Transcriptome Analysis of the Cosmopolitan Marine Fungus Corollospora maritima Under Two Physiological Conditions

Abstract

Marine sandy beaches represent dynamic environments often subject to harsh conditions and climate fluctuations, where natural and anthropogenic inputs of freshwater from fluvial and pluvial sources alter salinity, which has been recognized as a key variable affecting the distribution of aquatic organisms and influencing critical physiological processes. The marine arenicolous fungus Corollospora maritima is a worldwide-distributed saprobe that has been reported to present tolerance to freshwater. Here, we present a transcriptome analysis that will provide the first insight of the genomic content for this fungus and a gene expression comparison between two different salinity conditions. We also identified genes that are candidates for being differentially expressed in response to environmental variations on salinity during the fungal growth. The de novo reconstruction of C. maritima transcriptome Illumina sequencing provided a total of 14,530 transcripts (16 megabases). The comparison between the two growth conditions rendered 103 genes specifically overexpressed in seawater, and 132 genes specifically up-regulated under freshwater. Using fungal isolates collected from different beaches, the specific environmental regulation of particular transcript differential expression was confirmed by RT-qPCR. To our knowledge, this is the first analysis that explores the marine fungus C. maritima molecular responses to overcome freshwater stress, and these data could shed light to understand the fungal adaptation and plasticity mechanisms to the marine habitat.

Growth study under combined effects of temperature, pH and salinity and transcriptome analysis revealed adaptations of Aspergillus terreus NTOU4989 to the extreme conditions at Kueishan Island Hydrothermal Vent Field, Taiwan

“…Arginine was suggested to have a positive effect on acidic pH during propionic acid fermentation in Propionibacterium acidipropionici [44]. In a comparative transcriptome analysis of the marine fungus Corollospora maritima when grown in a freshwater and a seawater media, transcripts of aspartic-type peptidase activities and a choline sulfatase were up-regulated and concluded to be related to osmotic regulation [45]; these genes were also found to be up-regulated in this study. However, no expression of the endoplasmic reticulum transmembrane protein (MPS), predicted to be involved in osmotic homeostasis, was found in A. terreus, in contrast to 4-to 25-fold up-regulation in the seawater condition in C. maritima [45].…”

Fungi in the Marine Environment: Open Questions and Unsolved Problems

“…Tempting as it may be to interpret these data as evidence that a large proportion of marine fungi are metabolically inactive flotsam (as spores or relictual DNA), evidence suggests otherwise. Strong correlations with abiotic environmental conditions (8, 21) and gene expression data (22) suggest that at least some fungi display a truly amphibious ability (23). Furthermore, phylogenetic studies suggest that many obligately marine lineages recently transitioned from terrestrial ancestors (e.g., 24) and that such transitions to marine habitats have occurred multiple times.…”

“…Considerable work has been done developing the cosmopolitan, arenicolous marine fungus Corollospora maritima in the class Sordariomycetes (Ascomycota). In addition to a publicly available genome (https://genome.jgi.doe.gov/Corma2/Corma2.home.html), there has been transcriptome analysis under freshwater versus saltwater conditions (23), as well as population genetics and structure studies of this species (113). Moreover, C.…”

RNA Sequencing Reveals Differential Gene Expression of Cerrena Unicolor in Response to Variable Lighting Conditions

“…Since the first published transcriptome study [8], an increasing number of transcriptomes of wood decay basidiomycetes have been reported [9,10,11,12,13,14]. In contrast to the static genome, the transcriptome reflects the differential gene expression in response to developmental or environmental factors, which constitute a dynamic link between an organism’s genome and its physical characteristics [15,16,17]. Transcriptome analysis performed recently for Cerrena unicolor , a wood-degrading basidiomycete with great importance in biotechnology and medicine [18,19,20], revealed differential expression of genes coding for proteins engaged in degradation of various kinds of wood [14].…”