A Systematic Overview of Descolea (Agaricales) in the Nothofagaceae Forests of Patagonia

Accepted Manuscript A systematic overview of Descolea (Agaricales) in the Nothofagaceae forests of Patagonia Francisco Kuhar, Matthew E. Smith, Alija Mujic, Camille Truong, Eduardo Nouhra PII: S1878-6146(17)30086-7 DOI: 10.1016/j.funbio.2017.06.006 Reference: FUNBIO 828 To appear in: Fungal Biology Received Date: 1 March 2017 Revised Date: 16 June 2017 Accepted Date: 26 June 2017 Please cite this article as: Kuhar, F., Smith, M.E, Mujic, A., Truong, C., Nouhra, E., A systematic overview of Descolea (Agaricales) in the Nothofagaceae forests of Patagonia, Fungal Biology (2017), doi: 10.1016/j.funbio.2017.06.006. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. ACCEPTED MANUSCRIPT 1 A systematic overview of Descolea (Agaricales ) in the Nothofagaceae forests of Patagonia 2 3 Kuhar, Francisco 1*; Smith, Matthew E. 2; Mujic, Alija 2; Truong, Camille 2; Nouhra, 4 Eduardo 3. 5 6 1 7 Centro de Investigación y Extensión Forestal Andino Patagónico (CONICET), Ruta 259 Km 8 16,24 CC 14 Esquel (9200), Chubut, Argentina. 9 Universidad Nacional de la Patagonia S.J. Bosco, Chubut, Argentina. 2 10 Department of Plant Pathology, University of Florida, Gainesville, Florida 32611. 3 11 Instituto Multidisciplinario de Biología Vegetal (CONICET), FCEFyN, Universidad Nacional 12 de Córdoba, Argentina. 13 14 *Corresponding author: [email protected], phone +54 (11) 49702360, fax +54 (2945) 453948 15 16 Research highlights MANUSCRIPT 17 18 The genus Descolea is emended in light of new and historical Patagonian collections. 19 20 A new sequestrate Descolea species is described from Patagonia. 21 22 Two sequestrate species of Cortinarius (Thaxterogaster ) are transferred to the genus Descolea . 23 24 Morphological variation within Descolea and key characters for delimiting this genus are 25 discussed. 26 ACCEPTED 27 28 29 30 ACCEPTED MANUSCRIPT 31 Abstract 32 The descolea clade includes species of ectomycorrhizal basidiomycetes in the genera Descolea , 33 Setchelliogaster, Descomyces, and Timgrovea that are known primarily from the Southern 34 Hemisphere. Taxa in this group produce basidiomes that range in morphology from typical 35 epigeous mushrooms ( Descolea ) and secotioid taxa ( Setchelliogaster ) to fully gasteroid species 36 (Descomyces and Timgrovea ). High intraspecific morphological variation has been reported in 37 several species within this clade, suggesting that careful morphological and molecular studies are 38 needed to refine species concepts. Molecular analyses of fresh Patagonian collections in 39 conjunction with taxonomic studies have confirmed high variability in key morphological 40 features, including overall sporocarp form, spore shape and dimensions, universal veil remnants 41 and cuticle configuration. Based on our synthesis, we emend the genus Descolea to include 42 sequestrate species. We describe the new sequestrate taxon Descolea inferna sp. nov. from 43 Nothofagaceae forests in Patagonia and we propose Thaxterogaster squamatus as a synonym of 44 our new combination Descolea brunnea . We also formalize the identity of Descolea pallida as a 45 synonym of D. antarctica and provide new specimens of Thaxterogaster archeuretus, a species 46 that has not been encountered since the original discovery during the expeditions of Roland 47 Thaxter in 1905-1906. Here we re-describe andMANUSCRIPT transfer this species to Descolea as D. 48 archeureta . We also discuss diagnostic features that can be used to delimitate the four known 49 South American taxa in the descolea clade. 50 51 Keywords: Setchelliogaster , Descomyces , Timgrovea , secotioid, hypogeous, South America. 52 531. Introduction 54 Close affinities between the genus Descolea and the sequestrate taxa Setchelliogaster , 55 Descomyces , and Timgrovea have been previously inferred based on morphology (Lago et al. 56 2001) and also via molecular data (Peintner et al. 2001, Tedersoo and Smith 2013). This group of 57 fungi has been referred to as the ‘descolea clade’ by Peintner et al (2001) or the /descolea lineage 58 by Tedersoo andACCEPTED Smith (2013). Multilocus phylogenetic studies suggest that this lineage belongs 59 to the family Bolbitiaceae and is distantly related to other macroscopically similar, brown-spored 60 lineages of ectomycorrhizal fungi (e.g. Cortinarius , Hebeloma , Hymenogaster ) (Matheny et al. 61 2006). Taxa within the descolea clade produce basidiomes that range in morphology from typical ACCEPTED MANUSCRIPT 62 agaricoid mushrooms ( Descolea ) or secotioid taxa ( Setchelliogaster ) to fully gasteroid forms 63 (Descomyces and Timgrovea ). These are ectomycorrhizal fungi that are mostly restricted to 64 forests of Australasia and southern South America. They are usually associated with 65 Nothofagaceae and Myrtaceae host plants but at least two epigeous species have been reported 66 from Asia with other hosts (e.g. D. flavoannulata in Japan and Siberia, D. pretiosa in India) 67 (Horak 1971, Bougher and Castellano 1993, Tedersoo et al. 2010). Taxa in the descolea clade 68 have brown limoniform spores that lack a germ pore but always have a more or less hyaline, 69 ornamented utricle that covers the spores. The ornamented utricle is present in epigeous 70 Descolea species (Singer 1949) but is much more developed and obvious in many of the 71 sequestrate taxa in this group (Bougher and Castellano 1993, Danks et al. 2010). A fully 72 developed universal veil that may remain until maturity is also frequent in some taxa within this 73 group but it is not obvious in all collections or species (Horak 1971). 74 Pouzar (1958) erected the genus Setchelliogaster to accommodate species of the descolea 75 clade that produce secotioid basidiomes with Setchelliogaster tenuipes (Setch.) Pouzar 76 (= Secotium tenuipes Setch.) as the type species.The genera Descomyces and Timgrovea were 77 originally described by Bougher and Castellano (1993) to accommodate hypogeous sequestrate 78 taxa originally placed in the genus HymenogasterMANUSCRIPT (which is phylogenetically aligned with 79 epigeous species of Alnicola and Hebeloma – Matheny et al. 2006). Bougher and Castellano 80 (1993) recognized that Descomyces and Timgrovea shared some morphological similarities with 81 the agaricoid species of Descolea as well as the secotioid species of Setchelliogaster but they 82 reasoned that these fully sequestrate lineages were morphologically and ecologically unique and 83 therefore required separate genus-level recognition. However, molecular analyses of Peintner et 84 al. (2001) and the morphological analysis by Lago et al (2001) have confirmed the close and 85 complex relations between Descolea , Descomyces , Timgrovea and Setchelliogaster and suggest 86 that further taxonomic and phylogenetic studies are needed (Lago et al. 2001, Peintner et al. 87 2001). Although Peintner et al. (2001) confirmed the close evolutionary relationships among 88 these lineages, theirACCEPTED phylogenetic analyses suggested that gasteroid and secotioid taxa (e.g. 89 Descomyces , Timgrovea and Setchelliogaster ) likely arose multiple times due to convergent 90 evolution. 91 High morphological variation was reported for some species within the descolea clade by 92 Lago et al. (2001), who found high variability in the spore dimensions and also in the presence ACCEPTED MANUSCRIPT 93 and morphology of cystidia. They concluded that broader species concepts are needed within this 94 lineage to accommodate variable intraspecific morphological features. They also determined that 95 generic boundaries are not always clear. For example, the generic boundary between Descolea 96 (epigeous, agaricoid basidiomes) and Setchelliogaster (secotioid basidiomes) is transgressed by 97 some taxa (e.g. Descolea maculata , D. gunni ) that can produce basidiomes of both types (Lago 98 et al. 2001). This exceptional intraspecific variability was previously described by Cribb (1956), 99 when she studied the spore morphology and development of Descomyces albus (Berk.) Bougher 100 and Castellano (as Hymenogaster albus ). 101 There are currently 15 accepted species and five varieties of Descolea (according to 102 Index Fungorum http: //www.indexfungorum.org/) but only two described species are known 103 from Patagonia. Descolea antarctica was described from the forests of Tierra del Fuego by 104 Singer (1951) as the type species, whereas Descolea pallida was later described by Horak (1971) 105 from Valdivian forests of coastal Chile. Descolea pallida was separated from D. antarctica 106 based on the geographic distribution as well as the spore size and color differences of the cap and 107 veil remnants. However, both Singer (1954) and Horak (1971) discussed the difficulty in 108 differentiating these two species by their morphological characteristics. 109 In addition, the sequestrate taxa within the MANUSCRIPTclade are taxonomically confused for several 110 reasons. First, the original species descriptions for some of the sequestrate taxa are based on 111 specimens preserved in liquid rather than fresh collections and this made it challenging to 112 accurately describe these taxa (Halling 1981). Second, there are longstanding

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