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Phylogenetic analysis of algal symbionts associated with four North American amphibian egg masses.

Kim E, Lin Y, Kerney R, Blumenberg L, Bishop C - PLoS ONE (2014)

Bottom Line: We designate this group as the 'Oophila' clade, within which the symbiotic algae are further divided into four distinct subclades.Phylogenies of the host amphibians and their algal symbionts are only partially congruent, suggesting that host-switching and co-speciation both play roles in their associations.We also established conditions for isolating and rearing algal symbionts from amphibian egg capsules, which should facilitate further study of these egg mass specialist algae.

View Article: PubMed Central - PubMed

Affiliation: Division of Invertebrate Zoology and Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, New York, United States of America.

ABSTRACT
Egg masses of the yellow-spotted salamander Ambystoma maculatum form an association with the green alga "Oophila amblystomatis" (Lambert ex Wille), which, in addition to growing within individual egg capsules, has recently been reported to invade embryonic tissues and cells. The binomial O. amblystomatis refers to the algae that occur in A. maculatum egg capsules, but it is unknown whether this population of symbionts constitutes one or several different algal taxa. Moreover, it is unknown whether egg masses across the geographic range of A. maculatum, or other amphibians, associate with one or multiple algal taxa. To address these questions, we conducted a phylogeographic study of algae sampled from egg capsules of A. maculatum, its allopatric congener A. gracile, and two frogs: Lithobates sylvatica and L. aurora. All of these North American amphibians form associations with algae in their egg capsules. We sampled algae from egg capsules of these four amphibians from localities across North America, established representative algal cultures, and amplified and sequenced a region of 18S rDNA for phylogenetic analysis. Our combined analysis shows that symbiotic algae found in egg masses of four North American amphibians are closely related to each other, and form a well-supported clade that also contains three strains of free-living chlamydomonads. We designate this group as the 'Oophila' clade, within which the symbiotic algae are further divided into four distinct subclades. Phylogenies of the host amphibians and their algal symbionts are only partially congruent, suggesting that host-switching and co-speciation both play roles in their associations. We also established conditions for isolating and rearing algal symbionts from amphibian egg capsules, which should facilitate further study of these egg mass specialist algae.

No MeSH data available.


Related in: MedlinePlus

Map of the geographic range and collection sites for egg masses of four amphibian hosts.Species range maps are plotted on a map of North America (see the Materials and Methods). The dark green color represents a range overlap between L. sylvatica and A. maculatum, and the pink color represents a range overlap between L. aurora and A. gracile. Numbered locations correspond to higher detail panels below. The maps of collection sites for algae corresponding to egg masses from A. maculatum and L. sylvatica in Nova Scotia, Canada (1), A. gracile in California, USA (2), L. aurora and A. gracile in Vancouver Island, British Columbia, Canada, and A. maculatum in New Jersey and Tennessee of USA (4/5).
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pone-0108915-g001: Map of the geographic range and collection sites for egg masses of four amphibian hosts.Species range maps are plotted on a map of North America (see the Materials and Methods). The dark green color represents a range overlap between L. sylvatica and A. maculatum, and the pink color represents a range overlap between L. aurora and A. gracile. Numbered locations correspond to higher detail panels below. The maps of collection sites for algae corresponding to egg masses from A. maculatum and L. sylvatica in Nova Scotia, Canada (1), A. gracile in California, USA (2), L. aurora and A. gracile in Vancouver Island, British Columbia, Canada, and A. maculatum in New Jersey and Tennessee of USA (4/5).

Mentions: Egg clutches of amphibians were collected from vernal ponds or other types of temporary or permanent freshwater bodies between 2009 and 2013. Collection sites included multiple locations from New Jersey (USA), Tennessee (USA), California (USA), British Columbia (Canada), and Nova Scotia (Canada) (Figure 1, Table 1). None of the amphibian species from whose egg masses algae were collected are endangered or protected. Collections were approved as part of Animal Care Protocols to RK (IACUC#2013F17; Gettysburg College Animal Care Committee) and CB (CCAC#12-007-N; St. Francis-Xavier Animal Care Committee). Most samples were from locations for which no specific permission was required. Samples from the Greenbrook Sanctuary (private land) were collected with permission (Sandra Bonardi, Director) and samples from the University of the South (private land) were collected by Professor David G. Haskell. Nova Scotia and British Columbia Ministry of Natural Resources granted permission for collections. For NS collections, a letter from the relevant authorities, but no permit number is issued. For BC collections, permits #NA11-68662 was issued to RK for A. gracile; #NA12-76509 to CB for L. aurora). Sampling locations, including GPS co-ordinates are listed in Table 1. Typically, clutches were collected when the algal bloom inside each egg was visible, which occurs after Harrison stage 17 [17], [21]. Algal cells were collected by piercing an egg and withdrawing the capsular fluid using an insulin syringe, or by dissecting out the capsular part of the egg with fine forceps. These collection methods constitute environmental samples, since no selection of cells was performed prior to DNA extraction. C. gloeophila strains were obtained from the Experimental Phycology and Culture Collection of Algae at the University of Göttingen (strains SAG 12–4, 12–5) and the Culture Collection of Algae and Protozoa, maintained by the Scottish Association of Marine Science (strain 11/127).


Phylogenetic analysis of algal symbionts associated with four North American amphibian egg masses.

Kim E, Lin Y, Kerney R, Blumenberg L, Bishop C - PLoS ONE (2014)

Map of the geographic range and collection sites for egg masses of four amphibian hosts.Species range maps are plotted on a map of North America (see the Materials and Methods). The dark green color represents a range overlap between L. sylvatica and A. maculatum, and the pink color represents a range overlap between L. aurora and A. gracile. Numbered locations correspond to higher detail panels below. The maps of collection sites for algae corresponding to egg masses from A. maculatum and L. sylvatica in Nova Scotia, Canada (1), A. gracile in California, USA (2), L. aurora and A. gracile in Vancouver Island, British Columbia, Canada, and A. maculatum in New Jersey and Tennessee of USA (4/5).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4230919&req=5

pone-0108915-g001: Map of the geographic range and collection sites for egg masses of four amphibian hosts.Species range maps are plotted on a map of North America (see the Materials and Methods). The dark green color represents a range overlap between L. sylvatica and A. maculatum, and the pink color represents a range overlap between L. aurora and A. gracile. Numbered locations correspond to higher detail panels below. The maps of collection sites for algae corresponding to egg masses from A. maculatum and L. sylvatica in Nova Scotia, Canada (1), A. gracile in California, USA (2), L. aurora and A. gracile in Vancouver Island, British Columbia, Canada, and A. maculatum in New Jersey and Tennessee of USA (4/5).
Mentions: Egg clutches of amphibians were collected from vernal ponds or other types of temporary or permanent freshwater bodies between 2009 and 2013. Collection sites included multiple locations from New Jersey (USA), Tennessee (USA), California (USA), British Columbia (Canada), and Nova Scotia (Canada) (Figure 1, Table 1). None of the amphibian species from whose egg masses algae were collected are endangered or protected. Collections were approved as part of Animal Care Protocols to RK (IACUC#2013F17; Gettysburg College Animal Care Committee) and CB (CCAC#12-007-N; St. Francis-Xavier Animal Care Committee). Most samples were from locations for which no specific permission was required. Samples from the Greenbrook Sanctuary (private land) were collected with permission (Sandra Bonardi, Director) and samples from the University of the South (private land) were collected by Professor David G. Haskell. Nova Scotia and British Columbia Ministry of Natural Resources granted permission for collections. For NS collections, a letter from the relevant authorities, but no permit number is issued. For BC collections, permits #NA11-68662 was issued to RK for A. gracile; #NA12-76509 to CB for L. aurora). Sampling locations, including GPS co-ordinates are listed in Table 1. Typically, clutches were collected when the algal bloom inside each egg was visible, which occurs after Harrison stage 17 [17], [21]. Algal cells were collected by piercing an egg and withdrawing the capsular fluid using an insulin syringe, or by dissecting out the capsular part of the egg with fine forceps. These collection methods constitute environmental samples, since no selection of cells was performed prior to DNA extraction. C. gloeophila strains were obtained from the Experimental Phycology and Culture Collection of Algae at the University of Göttingen (strains SAG 12–4, 12–5) and the Culture Collection of Algae and Protozoa, maintained by the Scottish Association of Marine Science (strain 11/127).

Bottom Line: We designate this group as the 'Oophila' clade, within which the symbiotic algae are further divided into four distinct subclades.Phylogenies of the host amphibians and their algal symbionts are only partially congruent, suggesting that host-switching and co-speciation both play roles in their associations.We also established conditions for isolating and rearing algal symbionts from amphibian egg capsules, which should facilitate further study of these egg mass specialist algae.

View Article: PubMed Central - PubMed

Affiliation: Division of Invertebrate Zoology and Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, New York, United States of America.

ABSTRACT
Egg masses of the yellow-spotted salamander Ambystoma maculatum form an association with the green alga "Oophila amblystomatis" (Lambert ex Wille), which, in addition to growing within individual egg capsules, has recently been reported to invade embryonic tissues and cells. The binomial O. amblystomatis refers to the algae that occur in A. maculatum egg capsules, but it is unknown whether this population of symbionts constitutes one or several different algal taxa. Moreover, it is unknown whether egg masses across the geographic range of A. maculatum, or other amphibians, associate with one or multiple algal taxa. To address these questions, we conducted a phylogeographic study of algae sampled from egg capsules of A. maculatum, its allopatric congener A. gracile, and two frogs: Lithobates sylvatica and L. aurora. All of these North American amphibians form associations with algae in their egg capsules. We sampled algae from egg capsules of these four amphibians from localities across North America, established representative algal cultures, and amplified and sequenced a region of 18S rDNA for phylogenetic analysis. Our combined analysis shows that symbiotic algae found in egg masses of four North American amphibians are closely related to each other, and form a well-supported clade that also contains three strains of free-living chlamydomonads. We designate this group as the 'Oophila' clade, within which the symbiotic algae are further divided into four distinct subclades. Phylogenies of the host amphibians and their algal symbionts are only partially congruent, suggesting that host-switching and co-speciation both play roles in their associations. We also established conditions for isolating and rearing algal symbionts from amphibian egg capsules, which should facilitate further study of these egg mass specialist algae.

No MeSH data available.


Related in: MedlinePlus