Seedling mycorrhiza: a discussion of origin and evolution in Orchidaceae

• DOI: 10.1111/boj.12170
• Publication Date: 2014-06-19T16:01:39Z
• Authors: Hanne N. Rasmussen; Finn N. Rasmussen
• Keywords: Orchidaceae; Monophyly

Recent phylogenetic analyses confirm the monophyly of Orchidaceae as sister group to remainder Asparagales, and identify sequence early branching lineages in Orchidaceae. Orchid seedling mycorrhiza (OSM) involving rhizoctonious fungi is distributed widely all subfamilies, including first ones, its status a founding event thus supported. OSM recognized one element character syndrome that distinguishes orchid biology, we argue was evolve. We also discuss possible evolutionary origins Asparagales. The prevalent mycobionts suggest derivation from pathogenic relationship, comparison offers little support for other mycorrhizal relationships. A combination situ sowings molecular identification has established broad range besides mycelia are presently involved OSM, presumably evolving secondarily often parallel different clades. Structural features internal patterns mycobiont behaviour appear have remained largely same, implying needs only minor physiological adjustment accommodate new mycobionts. Such modifications will checkpoints recognition/rejection formation/breakdown pelotons. These mechanisms so far unknown. trophic versatility apparently easy shifts could be main factor ecological adaptability orchids proliferation family.