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Contrasting diversity and host association of ectomycorrhizal basidiomycetes versus root-associated ascomycetes in a dipterocarp rainforest.

Sato H, Tanabe AS, Toju H - PLoS ONE (2015)

Bottom Line: The putative ectomycorrhizal Basidiomycota were likely to be associated with closely related dipterocarp taxa to greater or lesser extents, whereas host association patterns of the root-associated Ascomycota were much less distinct.The community structure of the putative ectomycorrhizal Basidiomycota was possibly more influenced by host genetic distances than was that of the root-associated Ascomycota.This study also indicated that in dipterocarp rainforests, root-associated Ascomycota were characterized by high biodiversity and indistinct host association patterns, whereas ectomycorrhizal Basidiomycota showed less biodiversity and a strong host phylogenetic preference for dipterocarp trees.

View Article: PubMed Central - PubMed

Affiliation: Center for Ecological Research, Kyoto University 509-3, 2-chome, Hirano, Otsu, Shiga, 520-2113 Japan.

ABSTRACT
Root-associated fungi, including ectomycorrhizal and root-endophytic fungi, are among the most diverse and important belowground plant symbionts in dipterocarp rainforests. Our study aimed to reveal the biodiversity, host association, and community structure of ectomycorrhizal Basidiomycota and root-associated Ascomycota (including root-endophytic Ascomycota) in a lowland dipterocarp rainforest in Southeast Asia. The host plant chloroplast ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit (rbcL) region and fungal internal transcribed spacer 2 (ITS2) region were sequenced using tag-encoded, massively parallel 454 pyrosequencing to identify host plant and root-associated fungal taxa in root samples. In total, 1245 ascomycetous and 127 putative ectomycorrhizal basidiomycetous taxa were detected from 442 root samples. The putative ectomycorrhizal Basidiomycota were likely to be associated with closely related dipterocarp taxa to greater or lesser extents, whereas host association patterns of the root-associated Ascomycota were much less distinct. The community structure of the putative ectomycorrhizal Basidiomycota was possibly more influenced by host genetic distances than was that of the root-associated Ascomycota. This study also indicated that in dipterocarp rainforests, root-associated Ascomycota were characterized by high biodiversity and indistinct host association patterns, whereas ectomycorrhizal Basidiomycota showed less biodiversity and a strong host phylogenetic preference for dipterocarp trees. Our findings lead to the working hypothesis that root-associated Ascomycota, which might be mainly represented by root-endophytic fungi, have biodiversity hotspots in the tropics, whereas biodiversity of ectomycorrhizal Basidiomycota increases with host genetic diversity.

No MeSH data available.


Related in: MedlinePlus

values (index of degrees of apparent host preference at the particular taxonomic rank of host plants) within the respective OTUs of (a) Ascomycota and (b) putative ectomycorrhizal Basidiomycota. These values were calculated separately for the datasets based on the different cut-off similarities of host plant sequences (97%, 98%, 99%, and 99.8%). The values of  correspond to those of Fig 2 and Fig 3, respectively. Different letters indicate a statistically significant difference between cut-off levels of host plant sequences (α = 0.05, using a Holm correction).
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pone.0125550.g003: values (index of degrees of apparent host preference at the particular taxonomic rank of host plants) within the respective OTUs of (a) Ascomycota and (b) putative ectomycorrhizal Basidiomycota. These values were calculated separately for the datasets based on the different cut-off similarities of host plant sequences (97%, 98%, 99%, and 99.8%). The values of correspond to those of Fig 2 and Fig 3, respectively. Different letters indicate a statistically significant difference between cut-off levels of host plant sequences (α = 0.05, using a Holm correction).

Mentions: The genetic similarity levels of host plants at which the ECM basidiomycetous OTUs exhibited the most distinct host association pattern were much more evident than those for the ascomycetous OTUs. values observed in ascomycetous OTUs were not significantly different between the datasets based on different cut-off similarities of host rbcL sequences. However, values observed in basidiomycetous OTUs were significantly lower in the dataset based on a 99.8% cut-off rbcL sequence similarity than for other cut-off similarity levels (Fig 3). In addition, values were much lower for ascomycetous OTUs (average values were 0.241, 0.286, 0.295 and 0.325 for 99.8%, 99%, 98% and 97% cut-off levels, respectively) than for the ECM basidiomycetous OTUs (average values were 0.327, 0.520, 0.518, and 0.577 for 99.8%, 99%, 98%, and 97% cut-off levels, respectively).


Contrasting diversity and host association of ectomycorrhizal basidiomycetes versus root-associated ascomycetes in a dipterocarp rainforest.

Sato H, Tanabe AS, Toju H - PLoS ONE (2015)

values (index of degrees of apparent host preference at the particular taxonomic rank of host plants) within the respective OTUs of (a) Ascomycota and (b) putative ectomycorrhizal Basidiomycota. These values were calculated separately for the datasets based on the different cut-off similarities of host plant sequences (97%, 98%, 99%, and 99.8%). The values of  correspond to those of Fig 2 and Fig 3, respectively. Different letters indicate a statistically significant difference between cut-off levels of host plant sequences (α = 0.05, using a Holm correction).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4401655&req=5

pone.0125550.g003: values (index of degrees of apparent host preference at the particular taxonomic rank of host plants) within the respective OTUs of (a) Ascomycota and (b) putative ectomycorrhizal Basidiomycota. These values were calculated separately for the datasets based on the different cut-off similarities of host plant sequences (97%, 98%, 99%, and 99.8%). The values of correspond to those of Fig 2 and Fig 3, respectively. Different letters indicate a statistically significant difference between cut-off levels of host plant sequences (α = 0.05, using a Holm correction).
Mentions: The genetic similarity levels of host plants at which the ECM basidiomycetous OTUs exhibited the most distinct host association pattern were much more evident than those for the ascomycetous OTUs. values observed in ascomycetous OTUs were not significantly different between the datasets based on different cut-off similarities of host rbcL sequences. However, values observed in basidiomycetous OTUs were significantly lower in the dataset based on a 99.8% cut-off rbcL sequence similarity than for other cut-off similarity levels (Fig 3). In addition, values were much lower for ascomycetous OTUs (average values were 0.241, 0.286, 0.295 and 0.325 for 99.8%, 99%, 98% and 97% cut-off levels, respectively) than for the ECM basidiomycetous OTUs (average values were 0.327, 0.520, 0.518, and 0.577 for 99.8%, 99%, 98%, and 97% cut-off levels, respectively).

Bottom Line: The putative ectomycorrhizal Basidiomycota were likely to be associated with closely related dipterocarp taxa to greater or lesser extents, whereas host association patterns of the root-associated Ascomycota were much less distinct.The community structure of the putative ectomycorrhizal Basidiomycota was possibly more influenced by host genetic distances than was that of the root-associated Ascomycota.This study also indicated that in dipterocarp rainforests, root-associated Ascomycota were characterized by high biodiversity and indistinct host association patterns, whereas ectomycorrhizal Basidiomycota showed less biodiversity and a strong host phylogenetic preference for dipterocarp trees.

View Article: PubMed Central - PubMed

Affiliation: Center for Ecological Research, Kyoto University 509-3, 2-chome, Hirano, Otsu, Shiga, 520-2113 Japan.

ABSTRACT
Root-associated fungi, including ectomycorrhizal and root-endophytic fungi, are among the most diverse and important belowground plant symbionts in dipterocarp rainforests. Our study aimed to reveal the biodiversity, host association, and community structure of ectomycorrhizal Basidiomycota and root-associated Ascomycota (including root-endophytic Ascomycota) in a lowland dipterocarp rainforest in Southeast Asia. The host plant chloroplast ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit (rbcL) region and fungal internal transcribed spacer 2 (ITS2) region were sequenced using tag-encoded, massively parallel 454 pyrosequencing to identify host plant and root-associated fungal taxa in root samples. In total, 1245 ascomycetous and 127 putative ectomycorrhizal basidiomycetous taxa were detected from 442 root samples. The putative ectomycorrhizal Basidiomycota were likely to be associated with closely related dipterocarp taxa to greater or lesser extents, whereas host association patterns of the root-associated Ascomycota were much less distinct. The community structure of the putative ectomycorrhizal Basidiomycota was possibly more influenced by host genetic distances than was that of the root-associated Ascomycota. This study also indicated that in dipterocarp rainforests, root-associated Ascomycota were characterized by high biodiversity and indistinct host association patterns, whereas ectomycorrhizal Basidiomycota showed less biodiversity and a strong host phylogenetic preference for dipterocarp trees. Our findings lead to the working hypothesis that root-associated Ascomycota, which might be mainly represented by root-endophytic fungi, have biodiversity hotspots in the tropics, whereas biodiversity of ectomycorrhizal Basidiomycota increases with host genetic diversity.

No MeSH data available.


Related in: MedlinePlus