Fungal colonization of the roots of selected halophytes from Sečovlje salterns

Abstract

To reveal their mycotrophic status, we have here analysed the fungal colonisation of the roots, and the identity of these fungi, of the most abundant halophytic plant species from Sečovlje salterns (Slovenia): Aster tripolium, Limonium angustifolium and Salicornia europaea. The highest frequency of fungal colonisation was seen for the roots of A. tripolium, followed by those of L. angustifolium and S. europaea. Hyphae and occasional microsclerotia, the assumed structures of dark septate endophytes, were seen in the roots of all three species, whereas arbuscules, as typical structures of arbuscular mycorrhiza, were seen in the roots of A. tripolium and in one specimen of L. angustifolium. Fungal partial small subunit ribosomal DNA (SSU-rDNA) fragments were amplifi ed from total root DNA extracts for further restriction fragment length polymorphism (RFLP) analyses of the structures of the fungal root communities. Fifteen different RFLP profi les were obtained that grouped into two major clusters. Two RFLP profi les strongly dominated in samples of all three of the plant species. Sequencing revealed that one of these profiles corresponds to the species Cylindrobasidium laeve (Basidiomycota), and the second to Capnobotryella sp. / Phaeotheca fi ssurella, putative dark septate endophytes from the class Dothideomycetes (Ascomycota). Intraspecific RFLP polymorphisms were demonstrated for both species. To our knowledge, this is the first report on dark septate endophyte fungi occurrence in roots of A. tripolium, L. angustifolium and S. europaea.