Biodiversity of pollen in indoor air samples as revealed by DNA metabarcoding

Abstract

We conducted DNA metabarcoding (based on the nuclear ITS2 region) to characterize indoor pollen samples (possibly accompanied by other plant fragments) and to discover whether there are seasonal changes in their taxonomic diversity. It was shown that DNA metabarcoding has potential to allow a good discovery of taxonomic diversity. The number of spermatophyte families and genera varied greatly among sampling sites (pooled results per building) and times, between 9–40 and 10–66, respectively. Comparable Shannon's diversity indices equaled 0.33–2.76 and 0.94–3.16. The total number of spermatophyte genera found during the study was 187, of which 43.9, 39.6, 7.5 and 9.1% represented wild, garden/crop and indoor house plants, and non‐domestic fruit or other plant material, respectively. Comparable proportions of individual sequences equaled 77.4, 18.8, 2.7 and 1.1%, respectively. When comparing plant diversities and taxonomic composition among buildings or between seasons, no obvious pattern was detected, except for the second summer, when pollen coming from outdoors was highly dominant and the proportions of likely allergens, birch, grass, alder and mugwort pollen, were very high. The average pairwise values of SørensenChao indices that were used to compare similarities for taxon composition between samples among the samples from the two university buildings, two nurseries and farmhouse equaled 0.514, 0.109, 0.564, 0.865 and 0.867, respectively, while the mean similarity index for all samples was 0.524. Cleaning frequency may strongly contribute to the observed diversity. The discovery of considerable diversities, including pollen coming from outside, in both winter and summer shows that substantial amounts of pollen produced in summer enter buildings and stay there throughout the year.

Analyzing airborne environmental DNA: A comparison of extraction methods, primer type, and trap type on the ability to detect airborne eDNA from terrestrial plant communities

“…Typically, airborne eDNA research has mainly discussed findings in relation to human allergens and other aspects of human health Craine et al, 2016;Folloni et al, 2012;Korpelainen & Pietilainen, 2017;Kraaijeveld et al, 2015). Building upon these studies, Johnson, Cox, and Barnes () found that airborne eDNA could detect both wind-pollinated Bouteloua genus and insect pollinated honey mesquite (Prosopis glandulosa Torr.…”

The detection of a non-anemophilous plant species using airborne eDNA

“…Furthermore, Nuñez et al [17] utilized next-generation sequencing to confirm it was possible to genetically identify bacterial, fungi, and pollen samples captured from a Hirst-type spore trap with the goal of understanding more about urban allergens and health hazards in the air. Lastly, in addition to outdoor samples, Korpelainen and Pietilainen [18] successfully characterized indoor pollen samples with a metabarcoding approach to understand the effects of pollen and indoor airborne particles on humans. While this brief review of airborne genetic sampling shows how various methods and questions can be addressed within these studies, it also highlights how these studies focus primarily on pollen detection.…”

Beyond Biodiversity: Can Environmental DNA (eDNA) Cut It as a Population Genetics Tool?

“…Potentially, statistical models can be built for total variation detection at a specific locus [114]. This has already been done for taxon biodiversity [114,175,176]. Additionally, estimates of relatedness between populations could be based on genetic similarities [42,68,69].…”