Table 1. Assembly and sequencing statistics.

Sequenced reads (72 bp)	255 511 260 (18.2 Gb)
Reads after quality filtering	205 144 342 (12.5 Gb)
Contigs ⩾300 bp	269.385
Total assembly length	145 294 146
Reads useda	32 025 362
Average contig coveragea	14
N50b	522
Average contig lengthb	540
Maximum contig length	32 884
Predicted ORFs	338 863
Average ORF length (s.d.; bp)	363±262
Assigned putative function	209 413

Abbreviation: ORF, open reading frame.

N50 is the length of the smallest contig in the set that contains the fewest (largest) contigs whose combined length represents at least 50% of the assembly (Miller et al., 2010). The number of ORF-assigned putative functions was calculated on the basis of a BLASTP search against a subset of the NCBI nr database containing all bacterial, archaeal and viral proteins using an expect value (e-value) cutoff of 1e⁻⁵.

^aBased on a reference mapping of reads to contigs with the criteria of 95% identity over 90% of the read length.

^bCalculated on the basis of contigs ⩾300 bp.