Abstract
Flower-sourced assembly of seed microbiota remains an understudied ecological process. Here, we investigated the floral transmission pathway for bacterial acquisition by developing seeds of watermelon ( Citrullus lanatus). Comparison of stigma- and seed-associated bacterial communities from field-grown C. lanatus revealed significant overlap: up to 40% of the bacterial diversity that was detected in seed was also found on stigmas. In a field pollinator exclusion experiment, honeybee visitation to flower stigmas had no significant effect on bacterial community composition in seeds. Among a collection of bacterial isolates from stigmas and seeds collected in the field, more than half (57%) were able to transmit to seeds after inoculation onto stigmas under laboratory conditions. Interestingly, for most bacterial strains, fruit set rates increased after floral inoculation, and in some cases even in the absence of transmission to the seed. We also found that bacterial isolates from watermelon stigmas and seeds had variable (i.e., positive or negative) effects on seed germination and seedling emergence. Our findings highlight the contribution of floral transmission to seed microbiota assembly and its consequences for seedling fitness. [Formula: see text] Copyright © 2026 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 5
Claim · model-written summary
Seed bacterial communities of field-grown watermelon overlapped with stigma communities, with up to 40% of seed bacterial diversity also found on stigmas.
- Taxon
- watermelon
Citrullus lanatuse0 - Outcome
- bacterial diversitye1
- Value
- 40%e1
- Setting
- field-growne1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“developing seeds of watermelon”
e1“Comparison of stigma- and seed-associated bacterial communities from field-grown C. lanatus revealed significant overlap: up to 40% of the bacterial diversity that was detected in seed was also found on stigmas”
Claim · model-written summary
Honeybee visitation to watermelon stigmas had no significant effect on seed bacterial community composition in a field pollinator exclusion experiment.
- Taxon
- watermelonCitrullus lanatuse0
- Treatment
- honeybee visitation to flower stigmase2
- Interactor
- honeybee
_Apis_mellifera_(female)_-_on_viburnum_tinus_flowers.jpg?width=60)
Apis melliferae2pollinator - Outcome
- bacterial community compositione2
- Direction
- no significant effecte2
- Comparator
- pollinator exclusione2
- Setting
- fielde2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
_Apis_mellifera_(female)_-_on_viburnum_tinus_flowers.jpg?width=500)
Verbatim
e0“developing seeds of watermelon”
e2“In a field pollinator exclusion experiment, honeybee visitation to flower stigmas had no significant effect on bacterial community composition in seeds”
Claim · model-written summary
More than half (57%) of watermelon stigma and seed bacterial isolates were able to transmit to seeds after inoculation onto stigmas under laboratory conditions.
- Taxon
- watermelonCitrullus lanatuse0
- Treatment
- inoculation onto stigmase3
- Interactor
- bacterial isolatese4symbiont
- Outcome
- transmit to seedse3
- Value
- 57%e3
- Setting
- laboratory conditionse3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“developing seeds of watermelon”
e3“more than half (57%) were able to transmit to seeds after inoculation onto stigmas under laboratory conditions”
e4“Among a collection of bacterial isolates from stigmas and seeds collected in the field”
Claim · model-written summary
For most bacterial strains, watermelon fruit set rates increased after floral inoculation, in some cases even without transmission to the seed.
- Taxon
- watermelonCitrullus lanatuse0
- Treatment
- floral inoculatione5
- Interactor
- bacterial strainse5symbiont
- Outcome
- fruit set ratese5
- Direction
- increasede5
- Qualifier
- in some cases even in the absence of transmission to the seede5
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“developing seeds of watermelon”
e5“for most bacterial strains, fruit set rates increased after floral inoculation, and in some cases even in the absence of transmission to the seed”
Claim · model-written summary
Bacterial isolates from watermelon stigmas and seeds had variable positive or negative effects on seed germination and seedling emergence.
- Taxon
- watermelonCitrullus lanatuse6
- Treatment
- bacterial isolates from watermelon stigmas and seedse6
- Interactor
- bacterial isolatese6symbiont
- Outcome
- seed germination and seedling emergencee6
- Direction
- variablee6
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e6“bacterial isolates from watermelon stigmas and seeds had variable (i.e., positive or negative) effects on seed germination and seedling emergence”
The same questions in other papers
inoculation · yield · Citrullus lanatus (watermelon)Results agree
8 papers in the same direction as this paper
- positive
- positive
- positive
5 papers more in this group
See all 9 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.