Abstract
Acidovorax citrulli, the causal agent of bacterial fruit blotch (BFB) of cucurbits has been observed to survive for >34 years in stored melon and watermelon seeds. To better understand this remarkable longevity, we investigated the bacterium's tolerance to desiccation and the effect of bacterial localization in different watermelon seed tissues on its survival. We compared the ability of A. citrulli to tolerate desiccation on filter paper discs and on host (watermelon) and nonhost (cabbage, corn and tomato) seeds to two seedborne (Xanthomonas campestris pv. campestris and Pantoea stewartii subsp. stewartii) and one soilborne (Ralstonia solanacearum) plant-pathogenic bacteria. A. citrulli survival on dry filter paper (>12 weeks) was similar to that of X. campestris pv. campestris but longer than P. stewartii subsp. stewartii. Ralstonia solanacearum survived longer than all other bacteria tested. On all seeds tested, A. citrulli and X. campestris pv. campestris populations declined by 5 orders of magnitude after 12 weeks of incubation at 4°C and 50% relative humidity, while R. solanacearum populations declined by 3 orders. P. stewartii subsp. stewartii was not recovered after 12 weeks of incubation. To determine the effect of tissue localization on bacterial survival, watermelon seeds infested with A. citrulli by flower stigma inoculation (resulting in bacterial localization in the embryo/endosperm) or by ovary pericarp inoculations (resulting in bacterial localization under the testa) were treated with peroxyacetic acid or chlorine (Cl2) gas. Following these treatments, a significantly higher reduction in BFB seed-to-seedling transmission was observed for seeds generated by ovary pericarp inoculation (≥89.5%) than for those generated by stigma inoculation (≤76.5%) (P<0.05). Additionally, higher populations of A. citrulli survived when the bacteria were localized to the embryo/endosperm versus the seed coat, suggesting that tissue localization is important for bacterial survival in seed. This observation was confirmed when P. stewartii subsp. stewartii survived significantly longer in stigma-inoculated (embryo/endosperm-localized) watermelon seeds than in vacuum-infiltrated (testa-localized) seeds. Based on these results we conclude that A. citrulli cells are not intrinsically tolerant to desiccation and that localization of the bacterium to testa tissues does not enhance A. citrulli survival. In contrast, it is likely that embryo/endosperm localization enhances the survival of A. citrulli and other bacteria in seeds.
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Claims 10
Claim · model-written summary
On dry filter paper, A. citrulli survived over 12 weeks, similarly to X. campestris but less long than R. solanacearum.
- Taxon
- Watermelon
Citrullus lanatust0 - Interactor
- A. citrulliParacidovorax citrullie0pathogen
- Outcome
- A. citrulli survival on dry filter papere0
- Value
- >12 weekse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A. citrulli survival on dry filter paper (>12 weeks) was similar to that of X. campestris pv. campestris but longer than P. stewartii subsp. stewartii. Ralstonia solanacearum survived longer than all other bacteria tested.”
t0“Watermelon”
Claim · model-written summary
A. citrulli outlasted P. stewartii on dry filter paper.
- Taxon
- WatermelonCitrullus lanatust0
- Interactor
- A. citrulliParacidovorax citrullie0pathogen
- Second interactor
- P. stewartii subsp. stewartiiPantoea stewartii subsp. stewartiie0pathogen
- Outcome
- A. citrulli survival on dry filter papere0
- Direction
- longere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A. citrulli survival on dry filter paper (>12 weeks) was similar to that of X. campestris pv. campestris but longer than P. stewartii subsp. stewartii.”
t0“Watermelon”
Claim · model-written summary
R. solanacearum outlasted all other bacteria on dry filter paper.
- Taxon
- WatermelonCitrullus lanatust0
- Interactor
- Ralstonia solanacearum
Ralstonia solanacearume0pathogen - Outcome
- Ralstonia solanacearum survivede0
- Direction
- longere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Ralstonia solanacearum survived longer than all other bacteria tested.”
t0“Watermelon”
Claim · model-written summary
A. citrulli populations fell five orders of magnitude on seeds after 12 weeks.
- Taxon
- WatermelonCitrullus lanatust0
- Interactor
- A. citrulliParacidovorax citrullie0pathogen
- Outcome
- populationse0
- Direction
- declinede0
- Value
- 5 orders of magnitudee0
- Qualifier
- after 12 weeks of incubation at 4°C and 50% relative humiditye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“On all seeds tested, A. citrulli and X. campestris pv. campestris populations declined by 5 orders of magnitude after 12 weeks of incubation at 4°C and 50% relative humidity, while R. solanacearum populations declined by 3 orders.”
t0“Watermelon”
Claim · model-written summary
X. campestris populations fell five orders of magnitude on seeds after 12 weeks.
- Taxon
- WatermelonCitrullus lanatust0
- Interactor
- X. campestris pv. campestris
Xanthomonas campestris pv. campestrise0pathogen - Outcome
- X. campestris pv. campestris populationse0
- Direction
- declinede0
- Value
- 5 orders of magnitudee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“On all seeds tested, A. citrulli and X. campestris pv. campestris populations declined by 5 orders of magnitude after 12 weeks of incubation at 4°C and 50% relative humidity, while R. solanacearum populations declined by 3 orders.”
t0“Watermelon”
Claim · model-written summary
R. solanacearum populations fell three orders of magnitude on seeds.
- Taxon
- WatermelonCitrullus lanatust0
- Interactor
- R. solanacearumRalstonia solanacearume0pathogen
- Outcome
- R. solanacearum populationse0
- Direction
- declinede0
- Value
- 3 orderse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“R. solanacearum populations declined by 3 orders.”
t0“Watermelon”
Claim · model-written summary
P. stewartii could not be recovered after 12 weeks on seeds.
- Taxon
- WatermelonCitrullus lanatust0
- Interactor
- P. stewartii subsp. stewartiiPantoea stewartii subsp. stewartiie0pathogen
- Outcome
- P. stewartii subsp. stewartii was not recoverede0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“P. stewartii subsp. stewartii was not recovered after 12 weeks of incubation.”
t0“Watermelon”
Claim · model-written summary
After disinfection, pericarp inoculated seeds had at least 89.5% reduction in disease transmission, exceeding stigma inoculated seeds.
- Taxon
- WatermelonCitrullus lanatust0
- Treatment
- ovary pericarp inoculatione0
- Interactor
- Acidovorax citrulliParacidovorax citrullit0pathogen
- Outcome
- BFB seed-to-seedling transmissione0
- Direction
- higher reductione0
- Value
- ≥89.5%e0
- Qualifier
- ≤76.5%e0
- Comparator
- stigma inoculatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a significantly higher reduction in BFB seed-to-seedling transmission was observed for seeds generated by ovary pericarp inoculation (≥89.5%) than for those generated by stigma inoculation (≤76.5%) (P<0.05).”
t0“Acidovorax citrulli in Watermelon Seeds”
Claim · model-written summary
A. citrulli populations survived better inside the embryo or endosperm than at the seed coat.
- Taxon
- WatermelonCitrullus lanatust0
- Organ / stage
- embryo/endosperme0
- Interactor
- A. citrulliParacidovorax citrullie0pathogen
- Outcome
- populations of A. citrulli survivede0
- Direction
- highere0
- Comparator
- seed coate0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“higher populations of A. citrulli survived when the bacteria were localized to the embryo/endosperm versus the seed coat”
t0“Watermelon”
Claim · model-written summary
P. stewartii survived longer in stigma inoculated than testa localized watermelon seeds.
- Taxon
- watermelonCitrullus lanatuse0
- Interactor
- P. stewartii subsp. stewartiiPantoea stewartii subsp. stewartiie0pathogen
- Outcome
- P. stewartii subsp. stewartii survivede0
- Direction
- longere0
- Comparator
- vacuum-infiltrated (testa-localized) seedse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“P. stewartii subsp. stewartii survived significantly longer in stigma-inoculated (embryo/endosperm-localized) watermelon seeds than in vacuum-infiltrated (testa-localized) seeds.”
The same questions in other papers
inoculation · Paracidovorax citrulli · Citrullus lanatus (watermelon)Positive and negative results
1 paper in the same direction as this paper · 5 in the opposite direction
- negative
- negative
- negative
3 papers more in this group
See all 7 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.