Comparison of Next-Generation Sequencing and Traditional
Melissopalynological Methods for Geographically Labeled Anzer Honey
Abstract
This study utilized next-generation sequencing (NGS) of nrDNA ITS
regions (ITS1 and ITS2) for the first time to analyze three honey
samples from Anzer (Ballıköy), Rize province, Türkiye. The NGS results
were evaluated alongside melissopalynological data. Pollen grains were
first isolated and identified microscopically, and DNA was extracted
from the honey samples for NGS analysis. ITS1 and ITS2 regions were
sequenced using Illumina MiSeq, and results were compared with a custom
reference library. NGS produced 310,745 paired-end reads for ITS1 and
39,835 reads for ITS2. Of these, 75.2% of ITS1 reads and 68.4% of ITS2
reads were identified to at least the family level. NGS analysis
detected 27 plant families and 54 taxa, a 37% increase in taxa
detection compared to melissopalynology, which identified 19 families
and 34 taxa. Both approaches consistently identified dominant floral
components, with NGS providing greater species-level resolution.
Spearman’s correlation revealed a moderate linear relation between the
two methodologies for two of the three samples. However, the
Shannon-Wiener and Pielou indices were lower in metabarcoding than in
melissopalynology due to the uneven distribution of read counts for some
species. The R-coefficient results of all the families for the three
samples showed over or underrepresentation except for Caryophyllaceae
(honey sample ZT2 = 0.85) and Asteraceae (honey sample ZT3 = 0.93).
While to date, melissopalynolgy has been the prime identification method
for determining the geographical origin of honey, this study, for the
first time, presents a comprehensive and reliable metabarcoding data for
Anzer honey identification.