Package: roprokka
Report On PROKKAProkkais a commonly used tool to annotate bacterial genomes. Roprokka (Row-pro-ka) is an add-on tool that gathers information from and computes metrics on Prokka output. Further, Roprokka will align common species identifier genes against the NCBI database and return the most similar species. The information is consolidated into one convenient results file to quickly assess the status of a bacterial genome assembly. Note that this tool does not run Prokka or comment on the significance of results.About this toolProkka is a bioinformatics tool for annotating bacterial, archaeal, and vial genome assemblies. Output files are generated that contain a lot of information, including the annotation list, annotation sequences (nucleic acid and amino acid), and assembly statistics (Seemann, 2014). The information can be time consuming to gather when there are many samples, but the standard output format of the Prokka software makes it a good candidate for an automated mining system.Getting StartedRequirementsProkka output. Before applying this tool, runProkka.pysamblastn 2.10.1+python 3.7+InstallationRoprokka is available onPyPIand can be installed using pip.pip install roprokkaUsageAs input, this script takes a path to the directory of Prokka output.Example:roprokka -b path/to/blastn -i input_directory -o ouput_directoryTL;DRBasic Assembly StatsDisplays the statistics presented in the Prokka.tsvfile. Note, the statistics reported in this section are entirely dependendent upon the Prokka run parameters. For example, non-coding RNAs (ncRNAs) will only be reported if Prokka was run with the--rfamparameter.StatisticDescriptioncontigsNumber of contigs or segments in the assemblybasesLength of assembly, including all contigsgeneNumber of open reading frames identifiedCDSNumber of coding sequences identifiedrRNANumber of ribosomal RNAs identifiedtRNANumber of transfer RNAs identifiedmisc_RNANumber of miscellaneous RNAs identifiedtmRNANumber of transfer-messenger RNAs identifiedNote that the CDS and RNA classes are subsets of the genes class.Annotatios by functionThe percent hypothetical is an important statistic for determining assembly quality. Due to limitations in current knowlege, there are many bacterial CDS that have not been annotated. Thus, an assembly where 40-60% of CDS are hypothetical proteins may still be a high quality assembly. However, if the percent hypothetical exceeds 90%, the quality/usability should be considered.StatisticDescriptionCDSNumber of coding sequences identifiedhypothetical proteinNumber of CDS classified as hypotheticalputative proteinNumber of CDS classified as putativeperc_hypothetical% of CDS classified as hypotheticalperc_putative% of CDS classfied as putativetRNA BreakdownThe number of tRNAs in an assembly can be indicative of assembly completeness and quality. A high quality assembly will have at least one (1 to many) tRNA for each of the 20 AAs (amino acids) (Land, 2014). A quick check of assembly completeness can be done (by looking at the 'tRNA AA range' line) to make sure that each AA is represented by at least one tRNA; however, note that it is not uncommon for an assembly to contain multiple tRNAs for some AAs. If all AAs have 2 or more corresponding tRNAs, consider checking your sample for multiple genomes. See supplementary.md for additional information.A table of tRNAs by codon is also provided in the report file. It is common the number of tNRAs to be unevenly distributed across the codons. This could be due to reasons that are biological (codon usage bias) or computational (limited resolution for tRNA detection).Example Codon TableAla:3Arg:4Asn:2Asp: 1Cys: 2Gln:2Glu:2Gly:3His:1Ile:1Leu:5Lys:2Met:3Phe:1Pro:3Ser:4Thr:3Trp:1Tyr:1Val:3Most importantly, Roprokka displays the range of AA that are representedtRNA AA range: 1-5Number of Identifier GenesThe 16S rRNA and rpoB genes are commonly used for bacterial species identification because these genes are ubiquitous in bacteria and are somewhat species specific. An isolate may contain multiple copies of the 16S gene but bacteria typically only contain one copy of the rpoB gene. Multiple copies of the rpoB gene could indicate sequence duplications or multiple genomes.BLAST AlignmentsManually finding and extracting these sequences from the.ffnfile then running a BLAST alignment for each sequence can be labor and time intensive. Thus, Roprokka extracts the sequence of each identifier gene and aligns the sequence to the BLASTn database using blastn. Returned are the top 5 BLAST hits that have at least 90% sequence identity and at least 95% coverage of the query sequence. Each hit will have the following field information:FieldDescriptionqseqidquery sequence IDstitlesubject titlepident% identityqcovs% query coverage per subjectqcovhsp% query coverage per hsplengthlength of alignmentevaluee valueThe entirety of the BLAST results are returned to the user. This is because a single query might have multiple close matches to related species in the BLAST database. Sometimes distinguishing between these relults are better left to human the human eye.The sequences for each identifier gene are retained in the output directory in case additional alignments are needed.References (APA)Land, M. L., Hyatt, D., Jun, S. R., Kora, G. H., Hauser, L. J., Lukjancenko, O., & Ussery, D. W. (2014). Quality scores for 32,000 genomes. Standards in genomic sciences, 9(1), 1-10.Seemann, T. (2014). Prokka: rapid prokaryotic genome annotation. Bioinformatics, 30(14), 2068-2069.AcknowledgementsCody Glickman