ABSTRACT
Globisporangium polare is an oomycete species associated with mosses. Here, we report the draft genome sequence of G. polare strain 14-1, isolated from Sanionia uncinata (sickle-leaved hook-moss) on Adelaide Island, Antarctica.
KEYWORDS: Globisporangium polare
ANNOUNCEMENT
Globisporangium is a genus of oomycetes belonging to the phylum Oomycota within the kingdom Straminipila. The genus was formerly classified within Pythium, but molecular phylogenetic analyses have demonstrated that it forms an independent monophyletic clade, leading to its reclassification as Globisporangium (1, 2). Species of this genus are widely distributed in soils and freshwater environments, and several species are known to infect a broad range of host plants (3, 4). G. polare is a psychrophilic oomycete isolated from mosses and freshwater in the Arctic and Antarctic, which has been reported to infect and persist in living plant tissues at low temperatures (5, 6). Here, we report the draft genome sequence of G. polare strain 14-1, which was isolated from the moss Sanionia uncinata (Hedw.) Loeske—a species adapted to cold and moist environments (7)—collected at Rothera Point, Adelaide Island, Antarctica (67°34′0″ S, 68°5′60″ W) in November 2007 (Fig. 1A). Shoots of S. uncinata were washed with water, placed on NARM medium (8), and incubated in darkness at 4°C. Emerging mycelia were grown on 1.5% water agar at 4°C, and each agar plug containing a single hyphal tip was transferred onto a 10% V8 juice agar plate at 4°C. The cultures were maintained in darkness at 2°C–10°C at Osaka Metropolitan University, Japan. Globose to subglobose sporangia were observed in and around moss tissues (Fig. 1B). For the genomic analyses, the strain was grown on potato dextrose agar at 23°C for 7 days and subcultured in potato dextrose broth at 23°C at 120 rpm for 4 days before fixation in 100% ethanol. DNA was extracted using a NucleoSpin Plant II kit (Takara Bio). Whole-genome sequencing libraries were prepared with a MGIEasy FS DNA Library Prep Set (MGI) and sequenced on a DNBSEQ-G400RS platform (2 × 150 bp). Unless otherwise noted, default parameters were used for all software. Reads were processed with fastp v0.24.0 (9) and assembled de novo using SPAdes v3.15.3 (10). Assembly quality was assessed with QUAST v5.0.2 (11). The summary of genome assemblies is shown in Table 1. Protein-coding genes were predicted with BRAKER3 v3.0.8 (12) using the oomycota_odb12 BUSCO data set for protein hints (13). Genome completeness was assessed with BUSCO v6.0.0 using oomycota_odb12 (13), yielding 99.1% complete BUSCOs. The ITS1 and mitochondrial cox2 sequences were identified in the assembly by BLASTn using reference Globisporangium sequences were extracted as single contiguous sequences. The best BLASTn matches supported the assignment of strain 14-1 as G. polare (ITS1: 99.9% identity, 89.7% query coverage; cox2: 99.6% identity, 100% query coverage; best-hit accessions: ITS1, KJ716859; cox2, KJ595417 from G. polare CBS118203).
Fig 1.
(A) Map of the Antarctic Peninsula showing the location from which Globisporangium polare strain 14-1, associated with Sanionia uncinata, was sampled (red arrowhead). The map was obtained from Google Maps. (B) Images of globose (gs) to subglobose (sgs) sporangia of G. polare developed in and around moss tissues.
TABLE 1.
Summary of Globisporangium polare genome assemblies and annotations
| Strain | Host plant | No. of read pairs (spots) | N50 | GC contents (%) | No. of total bases (bp) | No. of contigs | Sequencing coverage | No. of genes | Results from BUSCO analysis with data set oomycota_odb12 | |||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Complete BUSCOs (%) | No. of BUSCOs | No. of missing BUSCOs | No. of fragmented BUSCOs | |||||||||
| 14-1 | Sanionia uncinata | 11,527,521 | 44,986 | 57.9 | 39,404,733 | 3,348 | 174 | 15,063 | 99.1 | 3,431 | 11 | 21 |
ACKNOWLEDGMENTS
This work was supported by a Grant-in-Aid for Challenging Exploratory Research (22K19176) to D.T. and a Grant-in-Aid for Scientific Research (C) (23K11504) to M.T. from the Japan Society for the Promotion of Science, by a research grant (G-2022-2-075) from the Institute for Fermentation, Osaka, to D.T., by the National Institute of Polar Research through Special Collaboration Project no. B24-03 to M.T. and M.U., and by the Arctic Challenge for Sustainability Project (ArCS III, grant no. JPMXD1720251001) for M.T. and M.U. British Antarctic Survey staff assisted with sample collection.
Contributor Information
Daigo Takemoto, Email: dtakemo@agr.nagoya-u.ac.jp.
Leighton Pritchard, University of Strathclyde, Glasgow, United Kingdom.
DATA AVAILABILITY
The draft genome assembly of Globisporangium polare strain 14-1 has been deposited in DDBJ/EMBL/GenBank under the whole-genome shotgun project BAAJAQ01 and is available as a genome assembly under accession number GCA_054786475.1 (assembly name: Gp_assembly_01). The raw sequencing reads are available in the DDBJ Sequence Read Archive under accession number DRR794741 and BioProject accession number PRJDB38039.
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Data Availability Statement
The draft genome assembly of Globisporangium polare strain 14-1 has been deposited in DDBJ/EMBL/GenBank under the whole-genome shotgun project BAAJAQ01 and is available as a genome assembly under accession number GCA_054786475.1 (assembly name: Gp_assembly_01). The raw sequencing reads are available in the DDBJ Sequence Read Archive under accession number DRR794741 and BioProject accession number PRJDB38039.