Kenji Suetsugu, Ryuta Yagi, Hidehito Okada, Jun Matsubayashi
{"title":"The tiny-leaved orchid Disperis neilgherrensis primarily obtains carbon from decaying litter via saprotrophic Ceratobasidium.","authors":"Kenji Suetsugu, Ryuta Yagi, Hidehito Okada, Jun Matsubayashi","doi":"10.1007/s00572-025-01183-x","DOIUrl":null,"url":null,"abstract":"<p><p>While most green orchids establish associations with non-ectomycorrhizal rhizoctonias belonging to Ceratobasidiaceae, Tulasnellaceae, and Serendipitaceae, fully mycoheterotrophic orchids-excluding albino mutants-primarily depend on either ectomycorrhizal fungi or saprotrophic non-rhizoctonia fungi. This suggests that non-ectomycorrhizal rhizoctonias may be unable to meet the carbon demands of adult orchids that exhibit a high degree of mycoheterotrophy. To understand the physiological ecology of Disperis neilgherrensis, an orchid species with reduced leaves growing in decaying litter from non-ectomycorrhizal trees, we employed molecular and stable isotope analyses to identify its mycorrhizal partners and ultimate nutritional sources at two populations on Ishigaki Island, Japan. Molecular barcoding techniques revealed that D. neilgherrensis forms exclusive associations with non-ectomycorrhizal Ceratobasidiaceae fungi. The Disperis specimens exhibited δ<sup>13</sup>C and δ<sup>15</sup>N isotopic values similar to those found in fully mycoheterotrophic orchids that exploit litter-decaying fungi. Furthermore, the pelotons of D. neilgherrensis showed significantly elevated δ<sup>13</sup>C values similar to saprotrophic non-rhizoctonia fungi. Our findings indicate that D. neilgherrensis primarily obtains its carbon from decaying litter through a specialized relationship with non-ECM Ceratobasidiaceae. Given that saprotrophic Ceratobasidiaceae facilitate nearly fully mycoheterotrophic growth in D. neilgherrensis, at least under warm and humid conditions, it is plausible that other (nearly) fully mycoheterotrophic tropical orchids also meet their carbon requirements through associations with saprotrophic rhizoctonias.</p>","PeriodicalId":18965,"journal":{"name":"Mycorrhiza","volume":"35 1","pages":"9"},"PeriodicalIF":3.3000,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11821799/pdf/","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Mycorrhiza","FirstCategoryId":"99","ListUrlMain":"https://doi.org/10.1007/s00572-025-01183-x","RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MYCOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
While most green orchids establish associations with non-ectomycorrhizal rhizoctonias belonging to Ceratobasidiaceae, Tulasnellaceae, and Serendipitaceae, fully mycoheterotrophic orchids-excluding albino mutants-primarily depend on either ectomycorrhizal fungi or saprotrophic non-rhizoctonia fungi. This suggests that non-ectomycorrhizal rhizoctonias may be unable to meet the carbon demands of adult orchids that exhibit a high degree of mycoheterotrophy. To understand the physiological ecology of Disperis neilgherrensis, an orchid species with reduced leaves growing in decaying litter from non-ectomycorrhizal trees, we employed molecular and stable isotope analyses to identify its mycorrhizal partners and ultimate nutritional sources at two populations on Ishigaki Island, Japan. Molecular barcoding techniques revealed that D. neilgherrensis forms exclusive associations with non-ectomycorrhizal Ceratobasidiaceae fungi. The Disperis specimens exhibited δ13C and δ15N isotopic values similar to those found in fully mycoheterotrophic orchids that exploit litter-decaying fungi. Furthermore, the pelotons of D. neilgherrensis showed significantly elevated δ13C values similar to saprotrophic non-rhizoctonia fungi. Our findings indicate that D. neilgherrensis primarily obtains its carbon from decaying litter through a specialized relationship with non-ECM Ceratobasidiaceae. Given that saprotrophic Ceratobasidiaceae facilitate nearly fully mycoheterotrophic growth in D. neilgherrensis, at least under warm and humid conditions, it is plausible that other (nearly) fully mycoheterotrophic tropical orchids also meet their carbon requirements through associations with saprotrophic rhizoctonias.
期刊介绍:
Mycorrhiza is an international journal devoted to research into mycorrhizas - the widest symbioses in nature, involving plants and a range of soil fungi world-wide. The scope of Mycorrhiza covers all aspects of research into mycorrhizas, including molecular biology of the plants and fungi, fungal systematics, development and structure of mycorrhizas, and effects on plant physiology, productivity, reproduction and disease resistance. The scope also includes interactions between mycorrhizal fungi and other soil organisms and effects of mycorrhizas on plant biodiversity and ecosystem structure.
Mycorrhiza contains original papers, short notes and review articles, along with commentaries and news items. It forms a platform for new concepts and discussions, and is a basis for a truly international forum of mycorrhizologists from all over the world.