Redefining the Genus Corollospora Based on Morphological and Phylogenetic Approaches

The present study, initially to resolve the cryptic species within Corollospora maritima, is to determine how to attain taxonomic discrimination at species and generic levels. Multiple sequence alignments (MSAs) of the ITS, 28S, and 18S regions of the nuclear ribosomal cistron were separately subjected to pairwise distance assessments, Bayesian, and Maximum likelihood phylogenetic analyses. Morphological descriptions of 15 type strains of Corollospora species, along with MSAs involving representatives of the whole genus Corollospora (268 isolates, many from C. maritima sensu lato) totaling 355 published sequences, allowed phylogenetic assessments conducted to the following p-distance thresholds in the ITS/28S regions: ≥3%/1% for species segregation and ≥8%/2% for generic segregation. This resulted in the introduction of 10 new genera encompassing 13 new combinations of current Corollospora species: Ajigaurospora pseudopulchella, Corollosporella anglusa, Corollosporella ramulosa, Corollosporopsis portsaidica, Garethelia parvula, Honshuriella fusca, Keraliethelia pulcehlla, Nakagariella filiformis, Paracorollospora angusta, Paracorollospora luteola, Paracorollospora marina, Shirahamella gracilis, and Tokuratelia colossa. Furthermore, seven undefined genera considered putative new genera (pNGenus A to G), and 16 undefined putative new species (seven spp. come from the resolution of the C. maritima complex), await re-assessment of their morphology and additional molecular data, which may result in the recognition of new taxa.

Diversity of marine fungi associated with wood baits in the estuary Ria de Aveiro, with descriptions of Paralulworthia halima, comb. nov., Remispora submersa, sp. nov., and Zalerion pseudomaritima, sp. nov

Lignicolous marine fungi are a particular group of microorganisms that are typically found in mangroves, salt marshes, and estuaries, normally associated with driftwood or submerged wood. During investigations of lignicolous fungi occurring in the estuary Ria de Aveiro, Portugal, wood baits were submerged in a marina for 1 year. Seventeen distinct marine fungal species were identified, with the most abundant taxa belonging to the family Lulworthiaceae. Through single- and multilocus phylogenies based on sequences of the internal transcribed spacer (ITS) region and large subunit (28S) and small subunit (18S) of the ribosomal RNA gene cluster in combination with morphological and physiological data, we describe Remispora submersa, sp. nov., and Zalerion pseudomaritima, sp. nov., as novel species. Additionally, we propose that Papulaspora halima, a species whose taxonomic placement has been somehow confusing, be transferred to the genus Paralulworthia as Paralulworthia halima.

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

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.