Genetic diversity patterns of arbuscular mycorrhizal fungi associated with the mycoheterotroph Arachnitis uniflora Phil. (Corsiaceae)

RENNY, M. E.; ACOSTA, M. C.; COFRÉ, N.; DOMÍNGUEZ, L. S.; BIDARTONDO, M. I.; SÉRSIC, A. N.

ANNALS OF BOTANY

OXFORD UNIV PRESS

Lugar: Oxford; Año: 2017 vol. 119 p. 1279 - 1294

0305-7364

Background and Aims: Arachnitis uniflora is a mycoheterotrophic plant that exploits arbuscular mycorrhizalfungi of neighbouring plants. We tested A. uniflora?s specificity towards fungi across its large latitudinal range, aswell as the role of historical events and current environmental, geographical and altitudinal variables on fungal geneticdiversity. Methods: Arachnitis uniflora mycorrhizas were sampled at 25 sites. Fungal phylogenetic relationships were reconstructed,genetic diversity was calculated and the main divergent lineages were dated. Phylogeographical analysis wasperformed with the main fungal clade. Fungal diversity correlations with environmental factors were investigated. Key: Results Glomeraceae fungi dominated, with a main clade that likely originated in the Upper Cretaceous anddiversified in the Miocene. Two other arbuscular mycorrhizal fungal families not previously known to be targetedby A. uniflora were detected rarely and appear to be facultative associations. High genetic diversity, found inBolivia and both northern and southern Patagonia, was correlated with temperature, rainfall and soil features. Conclusions: Fungal genetic diversity and its distribution can be explained by the ancient evolutionary history ofthe target fungi and by micro-scale environmental conditions with a geographical mosaic pattern.