Parses an SILVA FASTA file that can be found at https://www.arb-silva.de/no_cache/download/archive/release_128/Exports/.
parse_silva_fasta(file = NULL, input = NULL, include_seqs = TRUE)The path to a FASTA file containing sequences to use. Either "input" or "file" must be supplied but not both.
(character) One of the following:
See the example below for what this
  looks like. The parser read_fasta produces output like this.
Each vector should have one base per element.
This is the result of parsers like
  read.FASTA.
This is the result of parsers like
  read.fasta.
(logical of length 1) If TRUE, include
sequences in the output object.
The input file has a format like:
>GCVF01000431.1.2369 Bacteria;Proteobacteria;Gammaproteobacteria;Oceanospiril... CGUGCACGGUGGAUGCCUUGGCAGCCAGAGGCGAUGAAGGACGUUGUAGCCUGCGAUAAGCUCCGGUUAGGUGGCAAACA ACCGUUUGACCCGGAGAUCUCCGAAUGGGGCAACCCACCCGUUGUAAGGCGGGUAUCACCGACUGAAUCCAUAGGUCGGU ...
Other parsers: 
parse_dada2(),
parse_edge_list(),
parse_greengenes(),
parse_mothur_tax_summary(),
parse_mothur_taxonomy(),
parse_newick(),
parse_phyloseq(),
parse_phylo(),
parse_qiime_biom(),
parse_rdp(),
parse_ubiome(),
parse_unite_general()