training a classifier using HOMD database

Hello
I would like to use HOMD database as reference database http://www.homd.org/ I download the Taxon Table and 16s rRNA gene reference sequences. my code is

qiime tools import
–type ‘FeatureData[Sequence]’
–input-path HOMD_16S_rRNA_RefSeq_V15.2.p9.fasta
–output-path homd-ref.qza

qiime tools import
–type ‘FeatureData[Taxonomy]’
–input-format HeaderlessTSVTaxonomyFormat
–input-path homd_taxonomy.txt
–output-path homd-ref-taxonomy.qza

qiime feature-classifier extract-reads
–i-sequences homd-ref.qza
–p-f-primer CCTACGGGNGGCWGCAG
–p-r-primer GACTACHVGGGTATCTAATCC
–p-trunc-len 200
–p-min-length 100
–p-max-length 400
–o-reads homd-ref-seqs.qza

qiime feature-classifier fit-classifier-naive-bayes
–i-reference-reads homd-ref-seqs.qza
–i-reference-taxonomy homd-ref-taxonomy.qza
–o-classifier classifier.qza

But got an error : Plugin error from feature-classifier:

not enough values to unpack (expected 2, got 0)

Debug info has been saved to /vol/tmp/qiime2-q2cli-err-ur9njsb0.log
Thank you in advance!

This indicates that the taxonomy file is not formatted correctly. The classifier is expecting that all taxonomies contain the same number of ranks; you probably either have one or more seqs that are missing in the taxonomy, or have incomplete taxonomic info.

See here for an example of this error:

Please let us know what you find! This will be useful for others who are trying to use the HOMD database.

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