How to query NCBI (Nucleotide database) by a feature qualifier? I cannot seem to find a way to query nucleotide database (https://www.ncbi.nlm.nih.gov/nuccore) by a specific qualifier of the feature. For example, by /host under the feature "source".
For example, below is a part of one record, where the qualifier /host contains "Bemisia tabaci B".
How could I search for all sequences that contain the word "Bemisia" in the qualifier \host?

FEATURES             Location/Qualifiers
 source          1..351658
                 /organism="Candidatus Portiera aleyrodidarum BT-B-HRs"
                 /mol_type="genomic DNA"
                 /strain="BT-B"
                 /host="Bemisia tabaci B"
                 /db_xref="taxon:1206109"
 gene            1..1926
                 /gene="dnaK"
                 /locus_tag="C530_RS00005"
                 /old_locus_tag="C530_001"
 CDS             1..1926
                 /gene="dnaK"
                 /locus_tag="C530_RS00005"
                 /old_locus_tag="C530_001"
                 /inference="COORDINATES: similar to AA
                 sequence:RefSeq:WP_014894920.1"
                 /note="Derived by automated computational analysis using
                 gene prediction method: Protein Homology."
                 /codon_start=1
                 /transl_table=11
                 /product="molecular chaperone DnaK"
                 /protein_id="WP_014894920.1"
                 /translation="MIRIIGIDLGTTNSCVAVLENGKSRVIENSEGARTTPSIIAYTD
                 DNEILIGQTAKRQAVTNPSNTLYAIKRLIGRKFNDDIVQKDIKMVPYKIVSAENGDAW
                 VQVKNRKLAPPQISAEILKKMKKTAEDYLGEKITEAVITVPAYFNDSQRQATKDAGRI
                 AGLNVKRIINEPTAAALAYGMDKNRGDKKIAVYDLGGGTFDISIIEIADVDGETQFEV
                 MATNGDTFLGGEDFDLKLINYIVKQFKLESGVDLSGDSLAMQRLKEAAEKGKIELSSS
                 QQTDINLPYITADKTGPKHLTLKITRAKLESLVEDLIKRSLLPCKKAIDDAKLTTKEI
                 DDIILVGGQTRMPLVQKKVAEFFGKEARKDVNPDEAVAMGAAIQGGVLGGDVKDVLLL
                 DVTPLTLGIETMGGIMTPLIEKNTTIPTKKTQIFSTAEDNQTAVTIHALQGERKKALQ
                 NKSLGRFDLTDIPPAPRGTPQIEVAFDLDANGILNITAKDKATGKEQSIIIKSSGGLS
                 EEEINKMIQDAETNKEEDKKFEELVQTRNQADGMIHTIRKTLKEIKNEDEKNKLESLI
                 NNLEQTLKSDDIKTIKEDLNKLTEEYSTIYQKIYSEKKPQNHNSEPAQKNAEKSSSKK
                 EGDVVDAEYEEVNNKTK"
                 ...


Best,
Milan
For this particular query, try host=Bemisia tabaci B[WORD].  However, you may also be interested in related queries like host=Bemisia tabaci B biotype[WORD].
But, I am not sure a general solution exists, as I do not believe all qualifiers are indexed.

Also, you can see how your query is interpreted on the right side under &quot;Search details&quot;.  For the original attempt ([host]&quot;Bemisia tabaci B&quot;), it is interpreted as:
host[All Fields] AND &quot;Bemisia tabaci B&quot;[All Fields]

while the goal is to produce
host=Bemisia tabaci B biotype[WORD]