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Root Endophytes (root + endophyte)

Distribution by Scientific Domains

Life Sciences	100%

Selected Abstracts

Ascomycetes associated with ectomycorrhizas: molecular diversity and ecology with particular reference to the Helotiales

ENVIRONMENTAL MICROBIOLOGY, Issue 12 2009
Leho Tedersoo
Summary Mycorrhizosphere microbes enhance functioning of the plant,soil interface, but little is known of their ecology. This study aims to characterize the ascomycete communities associated with ectomycorrhizas in two Tasmanian wet sclerophyll forests. We hypothesize that both the phyto- and mycobiont, mantle type, soil microbiotope and geographical distance affect the diversity and occurrence of the associated ascomycetes. Using the culture-independent rDNA sequence analysis, we demonstrate a high diversity of these fungi on different hosts and habitats. Plant host has the strongest effect on the occurrence of the dominant species and community composition of ectomycorrhiza-associated fungi. Root endophytes, soil saprobes, myco-, phyto- and entomopathogens contribute to the ectomycorrhiza-associated ascomycete community. Taxonomically these Ascomycota mostly belong to the orders Helotiales, Hypocreales, Chaetothyriales and Sordariales. Members of Helotiales from both Tasmania and the Northern Hemisphere are phylogenetically closely related to root endophytes and ericoid mycorrhizal fungi, suggesting their strong ecological and evolutionary links. Ectomycorrhizal mycobionts from Australia and the Northern Hemisphere are taxonomically unrelated to each other and phylogenetically distant to other helotialean root-associated fungi, indicating independent evolution. The ubiquity and diversity of the secondary root-associated fungi should be considered in studies of mycorrhizal communities to avoid overestimating the richness of true symbionts. [source]

Patterns of Interaction between Populus Esch5 and Piriformospora indica: A Transition from Mutualism to Antagonism

PLANT BIOLOGY, Issue 2 2005
M. Kaldorf
Abstract: Piriformospora indica (Sebacinaceae, Basidiomycota) is an axenically cultivable, plant growth promoting root endophyte with a wide host range, including Populus. Rooting of Populus Esch5 explants started within 6 days after transfer to WPM medium. If such plantlets with roots were inoculated with P. indica, there was an increase in root biomass, and the number of 2nd order roots was increased significantly. A totally different observation was recorded when the explants were placed into WPM with pre-grown P. indica. The interaction led to complete blocking of root production and severely inhibited plant growth. Additionally, branched aerial roots appeared which did not penetrate the medium. On contact with the fungal colony or the medium, the ends of the aerial roots became inflated. Prolonged incubation stimulated the fungus to colonize aerial parts of the plant (stem and leaves). Mycelium not only spread on the surface of the aerial parts, but also invaded the cortical tissues inter- and intracellularly. Detached Populus leaves remained vital for 4 - 5 weeks on sterile agar media or on AspM medium with pre-grown P. indica. When the fungus was pre-grown on culture media such as WPM, containing ammonium as the main source of nitrogen, leaves in contact with the cultures turned brownish within 4 - 12 h. Thereafter, the leaves bleached, and about one day later had become whitish. Thus, cultural conditions could alter the behaviour of the fungus drastically: the outcome of the interaction between plant and fungus can be directed from mutualistic to antagonistic, characterized by fungal toxin formation and extension of the colonization to Populus shoots. [source]

High specificity generally characterizes mycorrhizal association in rare lady's slipper orchids, genus Cypripedium

MOLECULAR ECOLOGY, Issue 2 2005
RICHARD P. SHEFFERSON
Abstract Lady's slipper orchids (Cypripedium spp.) are rare terrestrial plants that grow throughout the temperate Northern Hemisphere. Like all orchids, they require mycorrhizal fungi for germination and seedling nutrition. The nutritional relationships of adult Cypripedium mycorrhizae are unclear; however, Cypripedium distribution may be limited by mycorrhizal specificity, whether this specificity occurs only during the seedling stage or carries on into adulthood. We attempted to identify the primary mycorrhizal symbionts for 100 Cypripedium plants, and successfully did so with two Cypripedium calceolus, 10 Cypripedium californicum, six Cypripedium candidum, 16 Cypripedium fasciculatum, two Cypripedium guttatum, 12 Cypripedium montanum, and 11 Cypripedium parviflorum plants from a total of 44 populations in Europe and North America, yielding fungal nuclear large subunit and mitochondrial large subunit sequence and RFLP (restriction fragment length polymorphism) data for 59 plants. Because orchid mycorrhizal fungi are typically observed without fruiting structures, we assessed fungal identity through direct PCR (polymerase chain reaction) amplification of fungal genes from mycorrhizally colonized root tissue. Phylogenetic analysis revealed that the great majority of Cypripedium mycorrhizal fungi are members of narrow clades within the fungal family Tulasnellaceae. Rarely occurring root endophytes include members of the Sebacinaceae, Ceratobasidiaceae, and the ascomycetous genus, Phialophora. C. californicum was the only orchid species with apparently low specificity, as it associated with tulasnelloid, ceratobasidioid, and sebacinoid fungi in roughly equal proportion. Our results add support to the growing literature showing that high specificity is not limited to nonphotosynthetic plants, but also occurs in photosynthetic ones. [source]

Colonisation of barley roots by endophytic Fusarium equiseti and Pochonia chlamydosporia: Effects on plant growth and disease

ANNALS OF APPLIED BIOLOGY, Issue 3 2009
J.G. Maciá-Vicente
Abstract Colonisation of plant roots by endophytic fungi may confer benefits to the host such as protection against abiotic or biotic stresses or plant growth promotion. The exploitation of these properties is of great relevance at an applied level, either to increase yields of agricultural crops or in reforestation activities. Fusarium equiseti is a naturally occurring endophyte in vegetation under stress in Mediterranean ecosystems. Pochonia chlamydosporia is a nematode egg-parasitic fungus with a worldwide distribution. Both fungi have the capacity to colonise roots of non-host plants endophytically and to protect them against phytopathogenic fungi under laboratory conditions. The aim of this study was to evaluate the root population dynamics of these fungi under non-axenic practical conditions. Both fungal species were inoculated into barley roots. Their presence in roots and effects on plant growth and incidence of disease caused by the pathogen Gaeumannomyces graminis var. tritici were monitored periodically. Both fungi colonised barley roots endophytically over the duration of the experiment and competed with other existing fungal root colonisers. Furthermore, colonisation of roots by P. chlamydosporia promoted plant growth. Although a clear suppressive effect on disease could not be detected, F. equiseti isolates reduced the mean root lesion length caused by the pathogen. Results of this work suggest that both F. equiseti and P. chlamydosporia are long-term root endophytes that confer beneficial effects to the host plant. [source]