Endophytic fungi in European aspen (Populus tremula) leaves—diversity, detection, and a suggested correlation with herbivory resistance

Abstract

Fungal endophytes are found in most seed plants, but their ecological function mainly remains elusive, except in pooid (or clavicipitalean) systems. The diversity and dynamics of endophytes in non clavicipitalean plants make studies of their ecological function challenging. This paper describes the advantage of using molecular techniques to survey the ecological function of endophytes in Populus tremula clones. About 1,000 endophyte isolates were distinguished using traditional methods; these isolates represented approximately 100 morphologically distinct groups. We generated 73 DNA-sequences (18S and ITS rDNA) from these groups and determined 33 distinct taxa. They represented the Basidiomycota and Ascomycota, including diverse Sordariomycetes and Dothideomycetes, and three sequences that were identified, by their ITS sequences, as a species of Epicoccum (a genus of supposedly unknown relation within the Ascomycota) were placed within the Pleosporales, in the 18S phylogeny. Primer pairs were designed for eleven of the fungi. Of these, three primers produced bands for a subset of Aspen samples. The primer pairs allowed endophytes in field samples to be readily identified, with a detection limit of 0.15 percent fungal DNA. The presence of fungi in Aspen clones was related to field damage by herbivores and the pathogen Venturia tremula. A negative association was found in two separate surveys between Aureobasidium sp. and herbivore damage, but we found no evidence that endophyte presence was related to a history of Venturia symptoms. This approach promises to enhance greatly the scope for qualitative and quantitative detection of endophyte communities, and to improve our ability to elucidate the ecological function of non clavicipitalean endophytes.

Diversity of endophytic fungal community associated with Piper hispidum (Piperaceae) leaves

“…hispidum endophytes may be divided into two main groups: the first one comprises 18 ascomycetous isolates (85.71%) whereas the second group comprises three basidiomycetes (14.29%). A predominance of ascomycetes was reported in other studies (Sánchez Márquez et al, 2007;Albrectsen et al, 2010;Gazis and Chaverri, 2010;Sakayaroj et al, 2010;González and Tello, 2011;Rocha et al, 2011). Sieber (2007) pointed out that representatives of both the bitunicate ascomycetes (orders Dothideales, Pleosporales and Mycosphaerellales) and the Xylariales order can be dominant in endophytical communities from angiosperms and gymnosperms.…”

“…However, Albrectsen et al (2010) considered that where ITS information is available in the database a correct taxonomical match is more likely. In the analyses of these authors the BLAST results for the 18S sequences were, in most cases, sufficiently strong to suggest affinity even to the genus.…”

Effect of Endophyte Association with Brachiaria Species on Shoot and Root Morpho-physiological Responses under Drought Stress

“…Apart from their well-known role in plant protection against invertebrate herbivores and pathogens, fungal endophytes that form symbiotic associations with grass species have been shown to enhance growth and persistence under drought conditions [2][3][4][5]. Beneficial effects of endophytes on shoot traits such as tiller number leaf expansion, and shoot biomass have been reported [6][7][8].…”

Isolation and Characterization of Endophytic Fungi from Bauhinia sp., Delonix regia and Crotalaria sp.

“…In the case of symbiotic association there is an increase in biomass as well as better development of aerial parts (Das et al, 2012). They are important components of the plant micro-ecosystem (Rodriguez et al, 2009;Zhang et al, 2006;Tan and Zhou, 2001) and are ubiquitous, colonize all plants and have been isolated from mosses (Davey and Currah, 2006), lichens (Li et al, 2007 a,b;Suryanarayanan et al, 2005) shrubs (Petrini et al, 1982), ferns (Swatzell et al, 1996), grasses (Muller and Krauss, 2005;Su et al, 2010), coniferous trees (Sun et al, 2011;Albrectsen et al, 2010;Mohamed et al, 2010). In the long co-evolution of the endophytes and their host plant, the endophytes have adapted themselves to the microenvironment by genetic variation including uptake of some plant DNA into their own genome.…”