Exo- and endophytic fungi enable rapid transfer of nutrients from ant waste to orchid tissue

Author(s)
Christian Gegenbauer, Anke Bellaire, Arno Schintlmeister, Markus C Schmid, Markus Kubicek, Hermann Voglmayr, Gerhard Zotz, Andreas Richter, Veronika Mayer
Abstract

The epiphytic orchid Caularthron bilamellatum sacrifices its water storage tissue for nutrients from the waste of ants lodging inside its hollow pseudobulb. Here, we investigate whether fungi are involved in the rapid translocation of nutrients. Uptake was analysed with a

15N labelling experiment, subsequent isotope ratio mass spectrometry (IRMS) and secondary ion mass spectrometry (ToF-SIMS and NanoSIMS). We encountered two hyphae types: a thick melanized type assigned to ‘black fungi’ (Chaetothyriales, Cladosporiales, and Mycosphaerellales) in ant waste, and a thin endophytic type belonging to Hypocreales. In few cell layers, both hyphae types co-occurred.

15N accumulation in both hyphae types was conspicuous, while for translocation to the vessels only Hypocreales were involved. There is evidence that the occurrence of the two hyphae types results in a synergism in terms of nutrient uptake. Our study provides the first evidence that a pseudobulb (=stem)-born endophytic network of Hypocreales is involved in the rapid translocation of nitrogen from insect-derived waste to the vegetative and reproductive tissue of the host orchid. For C. bilamellatum that has no contact with the soil, ant waste in the hollow pseudobulbs serves as equivalent to soil in terms of nutrient sources.

Organisation(s)
Functional and Evolutionary Ecology, Large-Instrument Facility for Environmental and Isotope Mass Spectrometry, Department of Microbiology and Ecosystem Science, Department of Botany and Biodiversity Research
External organisation(s)
Technische Universität Wien, Universität für Bodenkultur Wien, Carl von Ossietzky Universität Oldenburg, Smithsonian Tropical Research Institute
Journal
New Phytologist
Volume
238
Pages
2210-2223
No. of pages
14
ISSN
0028-646X
DOI
https://doi.org/10.1111/nph.18761
Publication date
2023
Peer reviewed
Yes
Austrian Fields of Science 2012
106008 Botany, 106024 Mycology, 106030 Plant ecology, 106054 Zoology
Keywords
ASJC Scopus subject areas
Physiology, Plant Science
Portal url
https://ucris.univie.ac.at/portal/en/publications/exo-and-endophytic-fungi-enable-rapid-transfer-of-nutrients-from-ant-waste-to-orchid-tissue(797375e1-e247-4a55-bd03-7ba788ad0d8d).html