Phylogeny and assemblage composition of Frankia in Alnus tenuifolia nodules across a primary successional sere in interior Alaska. Issue 14 (4th June 2013)

• Record Type: Journal Article
• Authors: Anderson, M. D.; Taylor, D. L.; Ruess, R. W.
• Is Part Of: Molecular ecology. Volume 22:Issue 14(2013)
• Page Start: 3864
• Page End: 3877
• Publication Date: 2013-06-04
• Subjects: Molecular ecology -- Periodicals; Molecular population biology -- Periodicals; 576
• DOI: 10.1111/mec.12339
• Languages: English
• ISSNs: 0962-1083

Abstract

<abstract abstract-type="main" id="mec12339-abs-0001"> <title>Abstract</title> <p>In nitrogen (N) fixing symbioses, host‐symbiont specificity, genetic variation in bacterial symbionts and environmental variation represent fundamental constraints on the ecology, evolution and practical uses of these interactions, but detailed information is lacking for many naturally occurring N‐fixers. This study examined phylogenetic host specificity of <italic>Frankia</italic> in field‐collected nodules of two <italic>Alnus</italic> species (<italic>A. tenuifolia</italic> and <italic>A. viridis</italic>) in interior Alaska and, for <italic>A. tenuifolia</italic>, distribution, diversity, spatial autocorrelation and correlation with specific soil factors of <italic>Frankia</italic> genotypes in nodules collected from replicated habitats representing endpoints of a primary sere. <italic>Frankia</italic> genotypes most commonly associated with each host belonged to different clades within the <italic>Alnus</italic>‐infective <italic>Frankia</italic> clade, and for <italic>A. tenuifolia</italic>, were divergent from previously described <italic>Frankia</italic>. <italic>A. tenuifolia</italic> nodules from early and late succession habitats harboured distinct <italic>Frankia</italic> assemblages. In early succession, a single genotype inhabited 71% of nodules with no discernable autocorrelation at any scale, while late succession <italic>Frankia</italic> were more diverse, differed widely among plants within a site and were significantly autocorrelated within and among plants. Early succession <italic>Frankia</italic> genotype occurrence was strongly correlated with carbon/nitrogen ratio in the mineral soil fraction, while in late succession, the most common genotypes were correlated with different soil variables. Our results suggest that phylogenetic specificity is a significant factor in the <italic>A. tenuifolia</italic>‐<italic>Frankia</italic> interaction and that significant habitat‐based differentiation may exist among <italic>A. tenuifolia</italic>‐infective genotypes. This is consistent with our hypothesis that <italic>A. tenuifolia</italic> selects specific <italic>Frankia</italic> genotypes from early succession soils and that this choice is attenuated in late succession.</p> </abstract>