The Rust Fungi

Rust fungi (Pucciniales, formerly Uredinales) belong to the subphylum Pucciniomycotina, which is considered the earliest diverging lineage in Basidiomycota. All rust fungi are obligate parasites of plants and they are found wherever their hosts grow, including high altitudes and deserts. The hosts of rust fungi range from ferns and conifers to dicotyledonous and monocotyledonous plants. In monocultural ecosystems rust fungi may cause considerable damage to their hosts and are therefore important pathogens in agricultural, horticultural and industrial forest habitats. 


Rust fungi have by far the most complex life cycles within the fungal kingdom and probably among eukaryotes. The general rust fungus life cycle requires five different spore stages and alternation between two taxonomically unrelated host plants for completion. Moreover, at ca. 8000 described species, they also represent the largest natural group of phytopathogens. 


The majority of the taxonomic studies on American rust fungi have historically been conducted at Purdue University, including classic studies demonstrating host ranges and alternation for numerous species. The application of molecular methods to rust fungal research has not been as widely applied as it has for other groups of Fungi. Primarily this is due to the fact that the rust fungi, as obligate pathogens, cannot be maintained in pure culture and are thus much more recalcitrant to work with. Fundamental work in our lab in this area includes applying molecular methodologies toward advancing our knowledge of rust fungal systematics and evolution.


Expert uredinologist Reinhard Berndt with the rust fungus Puccinia nivalis, found only in the Swiss Alps.

 Select Publications

  • Aime MC. 2006. Toward resolving family-level relationships in rust fungi (Uredinales). Mycoscience 47:112–122. doi: 10.1007/s10267-006-0281-0

  • Aime MC, Abbasi MA. 2018. Puccinia modiolae in North America: distribution and natural host range. MycoKeys 39:63–73. doi: 10.3897/mycokeys.39.27378

  • Aime MC, Bell C, Wilson AW. 2018. Deconstructing the evolutionary complexity of rust fungi (Pucciniales) and their hosts.  Studies in Mycology 89:143–152. doi: 10.1016/j.simyco.2018.02.002

  • Aime MC, Castlebury L, Abbasi M, Begerow D, Berndt R, Kirschner R, Maravanová L, Ono Y, Padamsee M, Scholler M, Thines M, Rossman AY. 2018. Recommendations of generic names competing for use: Pucciniomycotina and Ustilaginomycotina, Basidiomycota. IMA Fungus 9: 75–90. doi: 10.5598/imafungus.2018.09.01.06

  • Aime MC, McTaggart AR. 2020 [2021]. A higher-rank classification for rust fungi, with notes on genera. Fungal Systematics and Evolution 7:21-47. 10.3114/fuse.2021.07.02

  • Aime MC, McTaggart AR, Mondo SJ, Duplessis S. 2017. Phylogenetics and phylogenomics of rust fungi.  Advances in Genetics 100:267–307. doi: 10.1016/bs.adgen.2017.09.011.

  • Aime MC, Rossman AY, Ono Y, Castlebury LA. 2019. (2688) Proposal to conserve the name Phakopsora (Basidiomycota, Pucciniales) with a conserved type.  Taxon 68:592. doi: 10.1002/tax.12076

  • Aime MC, Rossman AY, Ono Y, Castlebury LA. 2019. (2689-2690) Proposals to conserve the names Phakopsora pachyrhizi against Uredo erythrinae and U. sojae (Malupa sojae) and Physopella meibomiae (Phakopsora meibomiae) against Aecidium crotalariicola, U. teramni, and U. vignae (M. vignae) (Basidiomycota, Pucciniales).  Taxon 68:593-594. doi: 10.1002/tax.12077

  • Bennett C, Aime MC, Newcombe G. 2011. Molecular and pathogenic variation within Melampsora on Salix in western North America reveals numerous cryptic species. Mycologia 103:1004–1018. doi: 10.3852/10-289

  • Bruckart WL, Eskandari FM, Berner DK, Aime MC. 2010. Life cycle of Puccinia acroptili on Rhaponticum (=Acroptilonrepens. Mycologia 102:62–68. doi: 10.3852/08-215

  • Bruckart WL, Thomas JL, Abbasi M, Aime MC, Frederick RD, Tancos MA. 2020. Uromyces rebeccae sp. nov., a newly described rust on the federally endangered plant, California sea-blite (Suaeda califonrinica). Mycologia: doi: 10.1080/00275514.2020.17.1739602

  • Dixon LJ, Castlebury LA, Aime MC, Glynn NC, Comstock JC. 2010. Phylogenetic relationships of sugarcane rust fungi. Mycological Progress 9:459–468. doi: 10.1007/s11557-009-0649-6

  • Duplessis S, Lorrain C, Petre B, Figueroa M,  Dodds PN, Aime MC. 2021. Host adaptation and virulence in heteroecious rust fungi. Annual Review of Phytopathology 59: 403-422. doi: 10.1146/annurev-phyto-020620-121149

  • Kenaley SC, Quan M, Aime MC, Bergstrom GC. 2018. New insight into the species diversity and life cycles of rust fungi (Pucciniales) affecting bioenergy switchgrass (Panicum virgatum) in the Eastern and Central United States. Mycological Progress 17:1251-1267. doi: 10.1007/s11557-018-1434-1

  • McTaggart AR, Aime MC. 2018. The species of Coleosporium (Pucciniales) on Solidago in North America. Fungal Biology122: 800–809. doi: 10.1016/j.funbio.2018.04.007

  • McTaggart AR, Doungsa-ard C, Geering ADW, Aime MC, Shivas RG. 2015. A co-evolutionary relationship exists between Endoraecium (Pucciniales) and its Acacia hosts in Australia. Peersoonia 35: 50-62. doi:

  • Minnis AM, McTaggart A, Rossman A, Aime MC. 2012. Taxonomy of mayapple rust: the genus Allodus resurrected. Mycologia 104:942–950. doi: 10.3852/11-350

  • Okane I, Ono Y, Ohmachi K, Aime MC, Yamaoka Y. 2021. Phylogenetic relationships among fern rust fungi and Desmella lygodii comb. nov. Mycoscience 62: 364-372. doi: 10.47371/mycosci.2021.06.006

  • Scholler M, Aime MC. 2006. On some rust fungi (Uredinales) collected in an Acacia koa-Metrosideros polymorpha woodland, Mauna Loa Road, Big Island, Hawaii. Mycoscience 47:159–165. doi: 10.1007/s10267-006-0286-8

  • Scholler M, Lutz M, Aime MC. 2018. Repeated formation of correlated species in Tranzschelia (Pucciniales).  Mycological Progress 18: 295–303. doi: 10.1007/s11557-018-1417-2

  • Song J, Aime MC, Xu B. 2020. Puccinia xinyuanensis sp. nov., the causal agent of rust on wild tulip (Tulipa iliensis) in China. Phytotaxon 459: 87–92. doi: 10.11646/phytotaxa.459.1.10

  • Souza ESC, Aime MC, Elias SG, Pinho DB, Miller RNG, Dianese JC. 2018. Crossopsorella, a new tropical genus of rust fungi. Phytotaxa 375: 189–202. doi: 10.11646/phytotaxa.375.3.1

  • Tabe A, Aime MC, Yorou NS, Piepenbring M. 2022.New records and data on rust fungi (Pucciniales, Basidiomycota) in Benin.  Phytotaxon 548: 127-145. doi: 10.11646/phytotaxa.548.2.1

  • Toome M, Aime MC. 2015. Reassessment of rust fungi on weeping willows in the Americas and description of Melampsora ferrinii sp. nov. Plant Pathology 64:216–224. doi: 10.1111/ppa.12237

  • Yun HY, Minnis AM, Kim YH, Castlebury L, Aime MC. 2011. The rust genus Frommeëlla revisited: a later synonym of Phragmidium after all. Mycologia 103:1451–1463. doi: 10.3852/11-120