Mycologia, 00(3), 2008, pp. 417-430. 2008 by The Mycological Society of America. Lawrence, KS 66044-8897 Molecular phylogeny of Laetiporus and other brown rot polypore genera in North America Daniel L. Lindner Key words: evolution, Fungi, Macro hyporia Mark T. Banik Polyporaceae, loria, root rot, sulfur shelf, Woijiporia (LS.l).A. Forest Service, A!ailisoo lie/il 0/f/ce of ihC exienca Noel/tern Research Station, Center for loreci iVJcoiogi Research, One Cifford Pine/wt Drive, Madison, Wisconsin 53726 INTRODUCTION The genera Laetiporus Murrill, Leptoporus Quél., Pliacolus (Pat.) Pat., P1 cn oporellus Murrill and Woiji- Abstract: Phylogenetic relationships were investigat- poe/a Rvvarden & Gilb. contain species that possess ed among North American species of Laeii/ont.s, simple septate hvphae, cause brown rots and produce Lepto1borus, Phaeolus, Pçcnoporellus and Wol/tpona annual, polvporoid I nii ti iig bodies with hyaline using ITS, nuclear large subunit anti iiiitochondrial spores. These shared morphological and physiologi- small subunit rDNA sequences. Members of these cal characters have been considered important in genera have poroid hymenophores, simple septate traditional polypore taxonomy (e.g. Gilbertson and hyphae and cause brown rots in a variety of substrates. Rvvardcn 1986, Gilbertson and Rvvarden 1987, Analyses indicate that Laeti/wrus and Wol/ipona are Rvvar(ien 1991) . However recent molecular work I.aeilporhs not monophvletic. All North American indicates that I.ac/iporus, Phaeolus anti Pcnopore11its species formed a well supported monophyletic group kill within the "Ajitrodia dade" of true pOlvpores with (the "core Laeti/orus dade" or Laetiporu.s s.s.) identified by Hibhett anti Donoghue (2001) while the exception of L. persicinus, which showed little I.cptoporus antI Woijiporia fall respectively within the affinity for any genus for which sequence data are phlehioid" and core polyporoicl" clades of true available. Based on data from GenBank, the southern polypores (Binder et al 200) also fell well hemisphere species L. portentosus Recent molecular and mating studies also have led dade. Woijiporia dilato/cy- outside the core Laetiporus to a revision of genus Laetiporus in North America pha was found to represent a sister group to the core (Banik et al 1998, Banik and Burdsall 1999, Banik and Phaeolus, Prcnopore1lui Laetiporus dade. Isolates of Buidsall 2000) , which formerly contained only Laetiporus dade all fell L. and members of the core sniphureus (Bull.) Murrill and L. Persicinus (Berk & within the Antrodia dade of polypores, while M.A. Curtis) Gilbertson. Burdsall and Banik (2001) fell within Lepioorus Fnoilis and Laetiporus portentosus concluded that genus Lacliporus cocos contains at least six the phlebioid dade of polypores. Wol,tiporia morphologically anti ecologically distinct species. isolates also fell in the Antroclia dade, in contrast to Despite this recent work relationships remain unre- W cocos in the core previous studies that placed solved among North American Lcteliporns species and polyporoid dade. ITS analyses resolved eight clades among other brown rot polyporoid species lacking three of which might represent within Lactiporus s.s., clamps. This study had two goals: (i) to determine undescribed species. A combined analysis using the relationships among North American species of three DNA regions resolved five major clades within Laetiporus and (ii) to determine whether any North a dade containing conifer-inhabiting Laetiporus s.s.: America polyporoid species that cause brown rots and species ("Conifericola dade"), a dade containing L. lack clamps are closely related to Laetiporus. To ("Cincinnatus dade"), a dade contain- cincinnatus accomplish these goals species of Laetiporus, Lepto- L. suiphureus s.s. isolates with yellow pores ing porus, Phaeolus, Pycnoporellus and Woijiporia were ("Sulphureus dade I"), a dade containing L. sequenced in three regions of rDNA: the intergenic suiphureus s.s. isolates with white pores ( Sulphureus L. gilbertsonii and transcribed spacer (ITS), the nuclear large subunit dade II") and a dade containing (nLSU) and the mitochondrial small subunit unidentified isolates from the Caribbean ("Gilhertso- (mtSSU). nii dade). Although there is strong support for Of the genera included in this study the most groups within the core Laetiporus dade, relationships widely known is Laetiporus. As it is currently defined among these groups remain poorly resolved. Laetiporus includes annual polypore species that produce a brown rot, have dimitic binding hyphae Accepted for publication 26 February 2008. Corresponding author. E-mail: [email protected] and lack cystidia and clamp connections (Gilbertson 417 418 MYCOLOGIA and Ryvarden 1986, Ryvarden 1991). With the gilbertsonzi occurs in the southern and western regions exception of L. perszcinus, all North American of North America and occurs on a wide range of Laetzporus species produce brightly colored, conspic- hardwoods including Eucalyptus. The upper pileus uous fruiting bodies that have been regarded tradi- surface of L. gilbertsonii is generally more salmon to tionally as part of the L. suiphureus s.l. species pink than other Laeliporus species while the pore complex. Species in the L. suiphureus si. complex layer is either yellow or white, which differentiates the are popular edibles that frequently are collected two color forms, L. gilbertsonii with a yellow pore layer under the common name Sulfur Shelf" or "Chicken and L. gilbertsonii var. pallidus with a white pore layer. of the Woods" (Arora 1986). Luetiporus suiphureus s.l. Laeliporus persicinus is the one North American also has been investigated for novel antimicrobial and Laetiporus species not considered part of the L. medicinal compounds (Turkoglu et a! 2007) and its suipliureus s.l. complex. This is due to striking bright pigments have been examined for potential as macroscopic differences, including a brown to pink- food colorants (Davoli et al 2005). Various authors ish-brown pileus surface, it pinkish-cream pole layer from the late 19th and early 20th centuries described and flesh and tubes that bruise blackish-brown. additional varieties and species within the L. sulphur- Laetiporus persicinus originally was described by ens s.l. complex to account fr the wide range of Berkeley and Curtis in 1872 as Poiyporus persicinus morphological and ecological variation exhibited by but was transferred to Laeliporus in 1981 by R. this species, although few of these names were used Gilbertson(Gilbertson 1981). Laetiporus jiercicin us is widely or consistently. Biirdsall and Banik (2001) found in the southeastern United States occurring recognize five species and all variety within primarily oil although it is found occasionally the L. suiphureus si. complex: L. (incinnatus (Mor- on conifers. Burdsall and Banik (2001) hypothesized gan) Burds., Banik & T.J. Volk, L. eon[erieoia Burds. that L. persicinus might not be closely related to & Banik, L. giIbeitsonii Buns., L. gilbertsonii var. species in the L. sulphnreus si. complex based on the pallidus Burds., L. huroniensis Btirds. & Banik inid L. dark pigmentations in the fruiting bodies, the su Iphu reus s.s. appearance of the binding hvphae and preliminary With the exception of Laetiporus rinciii nalus, all RFLP data. species in the L. suiphureus si. complex typically Work by Hibbett and Donoghue (1995) with produce sessile to laterally substipitate pilei with mtSSU nI)NA sequences indicated that genus Phaeo- bright orange upper surfaces and yellow or white Ins is closely related to Laetiporus snlphureus si. This pore layers (Burdsall and Banik 2001). Laetiporus result has been observed in man y analyses (Hihbett cincinnatus produces centrally stipitate, rosette- and Donoghue 2001, Hihhett and Binder 2002, shaped fruiting bodies with a white pore layer; these Binder ci al 2005), which confirmed that Phaeoius is fruiting bodies arise near the base of large diameter not aligned with the Hymenochaetales despite super- hardwood trees, usually Quercus species, iii the ficial similarities (Wagner and Fischer 2001). The eastern and midwestern United States. In North single North American species of Phaeolus treated by America LaeIporus suiphureus s.s. (as defined by Gilbertson and Rvvarden (1987), P. schweinitzii (Fr.) Burdsall and Banik 2001 and the present study) is Pat., is all root rot pathogen in conifer found in the eastern and midwestern United States ecosystems. Like L. cincinnatus and L. persicinus, P. and often occurs on Quercus species although schweinitzii has a centrally stipitate fruiting body specimens occasionally are found on other hard- found at the base of trees. Unlike Laetiporus species, woods. Preliminary evidence based on a limited it possesses a monomitic hyphal system and produces number of ITS sequences suggests that North hymenial cystidia. Young Phaeolus fruiting bodies are American and European populations of L. suiphureus yellow to orange but become predominantly brown s.s. are conspecific (unpubl data), however further with age (Gilbertson and Ryvarden 1987). comparative work is needed. If species barriers exist Genus Pcnoporellus also contains species with between North American and European populations monomitic, yellow to orange fruiting bodies, leading of L. sulphureus s.s., nomenclatural revision of the Gilbertson and Ryvarden (1987) to suggest a close North American species would be required given that relationship between Phaeolus and Pycnoporellus. L. sulphureus s.s. is typified