DOI: 10.5061/dryad.nr51124
title: Data from: Are traded forest tree seeds a potential source of non-native pests?

description: The international seed trade is considered relatively safe from a
 phytosanitary point of view and is therefore less regulated than trade in
 other plants for planting. However, the pests carried by traded seeds are
 not well known. We assessed insects and fungi in 58 traded seed lots of
 eleven gymnosperm and angiosperm tree species from North America, Europe
 and Asia. Insects were detected by x-raying and molecular methods. The
 fungal community was characterised using high-throughput sequencing (HTS)
 and by growing fungi on non-selective agar. About 30% of the seed lots
 contained insect larvae. Gymnosperms contained mostly hymenopteran
 (Megastigmus spp.) and dipteran (Cecidomyiidae) larvae, while angiosperms
 contained lepidopteran (Cydia latiferreana) and coleopteran (Curculio
 spp.) larvae. HTS indicated the presence of fungi in all seed lots and
 fungi grew on non-selective agar from 96% of the seed lots. Fungal
 abundance and diversity were much higher than insect diversity and
 abundance, especially in angiosperm seeds. Almost 50% of all fungal Exact
 Sequence Variants (ESVs) found in angiosperms were potential pathogens, in
 comparison with around 30% of potentially pathogenic ESVs found in
 gymnosperms. The results of this study indicate that seeds may pose a
 greater risk of pest introduction than previously believed or accounted
 for. A rapid risk assessment suggests that only a small number of species
 identified in this study is of phytosanitary concern. However, more
 research is needed to enable better risk assessment, especially to
 increase knowledge about the potential for transmission of fungi to
 seedlings and the host range and impact of identified species.
description: 1. Taxonomy and origin
 of study seed lotsColumn “Seed lot ID”
 represents the unique identifier of each seed lot included in the study.
 Taxonomy of tree species to which each seed lot belongs is specified in
 columns “Species”, “Family” and “Group”. Origin of each seed lot is
 indicated in columns “Continent” and “Location”. Column “Range” specifies
 if seeds were collected in their native or non-native
 range.2. Seed size of selected
 seed lots and corresponding fungal infestation and
 richnessThe average size of the
 seeds in a seed lot is calculated as a mean surface of the intersection
 area of 100 measured seeds per seed lot (column “Ø Area [mm2]”). Columns
 “Species”, “Group” and “Continent” indicate taxonomy of tree species to
 which seed lots belong and continent of origin of each seed lot. Fungal
 infestation of each seed lot is indicated by the column “Number of
 isolates” and fungal richness of each seed lot is indicated by columns
 “Number of morphotypes” and “Number of ESVs”.3. Morphotype
 assignments of fungal cultures obtained in the studyEach row corresponds to
 one out of the 4202 fungal cultures obtained in the study. Column “Seed
 lot ID” specifies the unique identifier of a seed lot, and column “Seed
 number” specifies from which of 100 assessed seed from a seed lot the
 culture was obtained. Columns “Species”, “Group” and “Continent” indicate
 taxonomy of tree species to which seed lots from which the culture was
 obtained belong and continent of origin of these seed lots. Grouping of
 obtained cultures was done on a tree species level and each letter-number
 combination indicates different morphotype. No cultures were obtained from
 seed lots SL 22 and SL 24 so they are not listed here.4. Sequenced fungal
 cultures and corresponding ESVs.Each row in the table
 corresponds to one out of 473 representative fungal cultures that were
 sequenced. Seed lot and seed number from which the culture was obtained
 are indicated in the first two columns, and the assigned morphotype in the
 third column. Column “ESV” indicates the ESV sequence with which the ITS2
 region of sequenced fungal culture mapped and the column “Identity (%)”
 indicates the percentage of the overlap between two sequences. Last six
 columns indicate the taxonomical assignment ("Division",
 "Phylum", "Class", "Order",
 "Family", "Genus", "Species") of each
 sequenced culture.5. Sample x ESV
 matrixThe matrix represents
 number of reads of each fungal ESV (columns) in each seed lot (rows). The
 information about the taxonomy and origin of each seed lot is provided in
 last three columns ("Species", "Group" and
 "Continent").6. ESV taxonomy and
 guildsThe table provides
 information about the taxonomy (division; phylum; class; order; family;
 genus; species) of each of 1905 obtained fungal ESVs in the study and
 assigned guilds.7. Infestation of seeds
 with insectsThe table contains the
 information about presence ("Exit holes PA" and "Larvae
 PA") and number of exit holes and insect larvae ("Exit
 holes" and "Larvae") in each of 100 assessed seeds per seed
 lot. Column "Infestation" indicates combined presence of exit
 holes and/or larvae in a seed. Columns "Group" and
 "Species" indicate the taxonomy and column "Continent"
 the origin of a seed lot.8. Insect
 taxonomyEach row corresponds to
 one of 79 insects revealed from seeds in this study. For each insect the
 seed lot in which it was found ("Seed lot ID"), tree taxonomy
 (columns "Species" and "Group) and origin of a seed lot
 (column "Continent") are indicated in first four columns. The
 information about the insect order as a result of morphological
 identification (column “Insect order”) and the results of molecular
 identification (column “Insect taxonomy”) and the percentage of identity
 match with the reference sequence are provided.