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Shifts in Symbiotic Endophyte Communities of a Foundational Salt Marsh Grass following Oil Exposure from the Deepwater Horizon Oil Spill.

Kandalepas D, Blum MJ, Van Bael SA - PLoS ONE (2015)

Bottom Line: We compared bacterial and fungal endophytes isolated from plants in reference areas to isolates from plants collected in areas with residual oil that has persisted for more than three years after the DWH spill.Plants from oiled areas exhibited near total loss of leaf fungal endophytes.Root fungal endophytes exhibited a more modest decline and little change was observed in endophytic bacterial diversity or abundance, though a shift towards hydrocarbon metabolizers was found in plants from oiled sites.

View Article: PubMed Central - PubMed

Affiliation: Department of Ecology and Evolutionary Biology, Tulane University, New Orleans, Louisiana, United States of America; Tulane-Xavier Center for Bioenvironmental Research, Tulane University, New Orleans, Louisiana, United States of America.

ABSTRACT
Symbiotic associations can be disrupted by disturbance or by changing environmental conditions. Endophytes are fungal and bacterial symbionts of plants that can affect performance. As in more widely known symbioses, acute or chronic stressor exposure might trigger disassociation of endophytes from host plants. We tested this hypothesis by examining the effects of oil exposure following the Deepwater Horizon (DWH) oil spill on endophyte diversity and abundance in Spartina alterniflora - the foundational plant in northern Gulf coast salt marshes affected by the spill. We compared bacterial and fungal endophytes isolated from plants in reference areas to isolates from plants collected in areas with residual oil that has persisted for more than three years after the DWH spill. DNA sequence-based estimates showed that oil exposure shifted endophyte diversity and community structure. Plants from oiled areas exhibited near total loss of leaf fungal endophytes. Root fungal endophytes exhibited a more modest decline and little change was observed in endophytic bacterial diversity or abundance, though a shift towards hydrocarbon metabolizers was found in plants from oiled sites. These results show that plant-endophyte symbioses can be disrupted by stressor exposure, and indicate that symbiont community disassembly in marsh plants is an enduring outcome of the DWH spill.

No MeSH data available.


Related in: MedlinePlus

Rarefaction curves for the number of operational taxonomic units (OTUs) by group.The dotted line corresponds to samples from oiled areas, the solid line represents samples from unoiled reference areas, and the dashed line corresponds to all samples combined.
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pone.0122378.g002: Rarefaction curves for the number of operational taxonomic units (OTUs) by group.The dotted line corresponds to samples from oiled areas, the solid line represents samples from unoiled reference areas, and the dashed line corresponds to all samples combined.

Mentions: We obtained 507 bacterial and fungal endophyte isolates from leaves and roots of S. alterniflora plants from oiled and unoiled reference sites in Louisiana (Fig 1). We acquired DNA sequences from a subset of 271 isolates, which represented 60 OTUs (Fig 2), for which we could assign to 41 genera, 32 families, 23 orders, 13 classes, 8 phyla, and three kingdoms. A Distance-Based Linear Model (DistLM) revealed that the genera that contributed significantly (>5% of the solution and p<0.05) to our solution were: Bacillus (Eubacteria; 34.6%; F7,33 = 2.91, p = 0.001), Phaeosphaeria (Fungi; 21.92%; F11,29 = 3.66, p = 0.001), Lulworthia (Fungi; 13.91%; F13,27 = 6.36, p = 0.001), and Vibrio (Eubacteria; 8.09%; F16,24 = 3.02, p = 0.006). Approximately 83% of the variation in our data set is attributable to these genera.


Shifts in Symbiotic Endophyte Communities of a Foundational Salt Marsh Grass following Oil Exposure from the Deepwater Horizon Oil Spill.

Kandalepas D, Blum MJ, Van Bael SA - PLoS ONE (2015)

Rarefaction curves for the number of operational taxonomic units (OTUs) by group.The dotted line corresponds to samples from oiled areas, the solid line represents samples from unoiled reference areas, and the dashed line corresponds to all samples combined.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4414556&req=5

pone.0122378.g002: Rarefaction curves for the number of operational taxonomic units (OTUs) by group.The dotted line corresponds to samples from oiled areas, the solid line represents samples from unoiled reference areas, and the dashed line corresponds to all samples combined.
Mentions: We obtained 507 bacterial and fungal endophyte isolates from leaves and roots of S. alterniflora plants from oiled and unoiled reference sites in Louisiana (Fig 1). We acquired DNA sequences from a subset of 271 isolates, which represented 60 OTUs (Fig 2), for which we could assign to 41 genera, 32 families, 23 orders, 13 classes, 8 phyla, and three kingdoms. A Distance-Based Linear Model (DistLM) revealed that the genera that contributed significantly (>5% of the solution and p<0.05) to our solution were: Bacillus (Eubacteria; 34.6%; F7,33 = 2.91, p = 0.001), Phaeosphaeria (Fungi; 21.92%; F11,29 = 3.66, p = 0.001), Lulworthia (Fungi; 13.91%; F13,27 = 6.36, p = 0.001), and Vibrio (Eubacteria; 8.09%; F16,24 = 3.02, p = 0.006). Approximately 83% of the variation in our data set is attributable to these genera.

Bottom Line: We compared bacterial and fungal endophytes isolated from plants in reference areas to isolates from plants collected in areas with residual oil that has persisted for more than three years after the DWH spill.Plants from oiled areas exhibited near total loss of leaf fungal endophytes.Root fungal endophytes exhibited a more modest decline and little change was observed in endophytic bacterial diversity or abundance, though a shift towards hydrocarbon metabolizers was found in plants from oiled sites.

View Article: PubMed Central - PubMed

Affiliation: Department of Ecology and Evolutionary Biology, Tulane University, New Orleans, Louisiana, United States of America; Tulane-Xavier Center for Bioenvironmental Research, Tulane University, New Orleans, Louisiana, United States of America.

ABSTRACT
Symbiotic associations can be disrupted by disturbance or by changing environmental conditions. Endophytes are fungal and bacterial symbionts of plants that can affect performance. As in more widely known symbioses, acute or chronic stressor exposure might trigger disassociation of endophytes from host plants. We tested this hypothesis by examining the effects of oil exposure following the Deepwater Horizon (DWH) oil spill on endophyte diversity and abundance in Spartina alterniflora - the foundational plant in northern Gulf coast salt marshes affected by the spill. We compared bacterial and fungal endophytes isolated from plants in reference areas to isolates from plants collected in areas with residual oil that has persisted for more than three years after the DWH spill. DNA sequence-based estimates showed that oil exposure shifted endophyte diversity and community structure. Plants from oiled areas exhibited near total loss of leaf fungal endophytes. Root fungal endophytes exhibited a more modest decline and little change was observed in endophytic bacterial diversity or abundance, though a shift towards hydrocarbon metabolizers was found in plants from oiled sites. These results show that plant-endophyte symbioses can be disrupted by stressor exposure, and indicate that symbiont community disassembly in marsh plants is an enduring outcome of the DWH spill.

No MeSH data available.


Related in: MedlinePlus