{"title":"单型异养菌属Relictithismia (Thismiaceae)的高菌根特异性。","authors":"Kenji Suetsugu, Hidehito Okada","doi":"10.1007/s00572-025-01202-x","DOIUrl":null,"url":null,"abstract":"<p><p>Mycoheterotrophic plants, which depend entirely on mycorrhizal fungi for carbon acquisition, often exhibit high specificity toward their fungal partners. Members of Thismiaceae are generally recognized for their extreme mycorrhizal specialization and rarity. In this study, we examined the mycorrhizal associations of Relictithismia, a recently discovered monotypic genus within Thismiaceae, and Thismia abei, a Thismia species with a similar distribution in southern Japan, by employing high-throughput DNA sequencing of the 18S rRNA gene. Our analyses revealed that both R. kimotsukiensis and T. abei are predominantly associated with two specific virtual taxa (VTX00295 and VTX00106) of the genus Rhizophagus (Glomeraceae). These shared associations may reflect either phylogenetic niche conservatism, in which the common ancestor of R. kimotsukiensis and T. abei retained the same AM fungal partners, or convergent evolution, in which the AM fungal phylotypes were independently recruited due to their potential benefits for these mycoheterotrophic plants. Furthermore, BLAST searches demonstrated that VTX00295 and VTX00106 are widely distributed globally, suggesting that highly specialized mycorrhizal interactions are unlikely to be the primary drivers of the limited distribution and rarity of R. kimotsukiensis and T. abei. Overall, our findings enhance our understanding of high mycorrhizal specificity in Thismiaceae. However, broader investigations, combining extensive sampling of Thismiaceae species with ancestral state reconstruction, are needed to determine whether the shared associations detected here reflect phylogenetic niche conservatism or convergent evolution.</p>","PeriodicalId":18965,"journal":{"name":"Mycorrhiza","volume":"35 2","pages":"29"},"PeriodicalIF":3.8000,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"High mycorrhizal specificity in the monotypic mycoheterotrophic genus Relictithismia (Thismiaceae).\",\"authors\":\"Kenji Suetsugu, Hidehito Okada\",\"doi\":\"10.1007/s00572-025-01202-x\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p><p>Mycoheterotrophic plants, which depend entirely on mycorrhizal fungi for carbon acquisition, often exhibit high specificity toward their fungal partners. Members of Thismiaceae are generally recognized for their extreme mycorrhizal specialization and rarity. In this study, we examined the mycorrhizal associations of Relictithismia, a recently discovered monotypic genus within Thismiaceae, and Thismia abei, a Thismia species with a similar distribution in southern Japan, by employing high-throughput DNA sequencing of the 18S rRNA gene. Our analyses revealed that both R. kimotsukiensis and T. abei are predominantly associated with two specific virtual taxa (VTX00295 and VTX00106) of the genus Rhizophagus (Glomeraceae). These shared associations may reflect either phylogenetic niche conservatism, in which the common ancestor of R. kimotsukiensis and T. abei retained the same AM fungal partners, or convergent evolution, in which the AM fungal phylotypes were independently recruited due to their potential benefits for these mycoheterotrophic plants. Furthermore, BLAST searches demonstrated that VTX00295 and VTX00106 are widely distributed globally, suggesting that highly specialized mycorrhizal interactions are unlikely to be the primary drivers of the limited distribution and rarity of R. kimotsukiensis and T. abei. Overall, our findings enhance our understanding of high mycorrhizal specificity in Thismiaceae. However, broader investigations, combining extensive sampling of Thismiaceae species with ancestral state reconstruction, are needed to determine whether the shared associations detected here reflect phylogenetic niche conservatism or convergent evolution.</p>\",\"PeriodicalId\":18965,\"journal\":{\"name\":\"Mycorrhiza\",\"volume\":\"35 2\",\"pages\":\"29\"},\"PeriodicalIF\":3.8000,\"publicationDate\":\"2025-04-10\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Mycorrhiza\",\"FirstCategoryId\":\"99\",\"ListUrlMain\":\"https://doi.org/10.1007/s00572-025-01202-x\",\"RegionNum\":2,\"RegionCategory\":\"生物学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"MYCOLOGY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Mycorrhiza","FirstCategoryId":"99","ListUrlMain":"https://doi.org/10.1007/s00572-025-01202-x","RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MYCOLOGY","Score":null,"Total":0}
High mycorrhizal specificity in the monotypic mycoheterotrophic genus Relictithismia (Thismiaceae).
Mycoheterotrophic plants, which depend entirely on mycorrhizal fungi for carbon acquisition, often exhibit high specificity toward their fungal partners. Members of Thismiaceae are generally recognized for their extreme mycorrhizal specialization and rarity. In this study, we examined the mycorrhizal associations of Relictithismia, a recently discovered monotypic genus within Thismiaceae, and Thismia abei, a Thismia species with a similar distribution in southern Japan, by employing high-throughput DNA sequencing of the 18S rRNA gene. Our analyses revealed that both R. kimotsukiensis and T. abei are predominantly associated with two specific virtual taxa (VTX00295 and VTX00106) of the genus Rhizophagus (Glomeraceae). These shared associations may reflect either phylogenetic niche conservatism, in which the common ancestor of R. kimotsukiensis and T. abei retained the same AM fungal partners, or convergent evolution, in which the AM fungal phylotypes were independently recruited due to their potential benefits for these mycoheterotrophic plants. Furthermore, BLAST searches demonstrated that VTX00295 and VTX00106 are widely distributed globally, suggesting that highly specialized mycorrhizal interactions are unlikely to be the primary drivers of the limited distribution and rarity of R. kimotsukiensis and T. abei. Overall, our findings enhance our understanding of high mycorrhizal specificity in Thismiaceae. However, broader investigations, combining extensive sampling of Thismiaceae species with ancestral state reconstruction, are needed to determine whether the shared associations detected here reflect phylogenetic niche conservatism or convergent evolution.
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.