New Claviceps Species from Warm-Season Grasses
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Fungal Diversity (2011) 49:145–165 DOI 10.1007/s13225-011-0102-4 New Claviceps species from warm-season grasses Sylvie Pažoutová & Gary N. Odvody & Debra E. Frederickson & Milada Chudíčková & Jana Olšovská & Miroslav Kolařík Received: 18 February 2011 /Accepted: 17 April 2011 /Published online: 24 May 2011 # Kevin D. Hyde 2011 Abstract Eight undescribed species of Claviceps were colonized Dichanthium spp. in the southern USA and recognized from the combinations of molecular and probably in Mexico. The occurrence of C. pusilla on pearl morphological characters. The teleomorph was observed millet in the USA (Texas) is reported and the record of C. only for Claviceps setariicola. Phylogenetic affinities of the sulcata on Urochloa brizantha in Brazil is confirmed by new species inside the genus were revealed by a 5.8S-ITS- nrDNA sequence comparison with an African herbarium 28S nrDNA analysis. Claviceps chloridicola, C. tenuis- specimen. No alkaloids were detected in sclerotia and/or pora, C. setariicola and C. setariiphila are related to C. sphacelia of the new species. maximensis; C. truncatispora is a sister species to C. pusilla. Claviceps clavispora and C. langdonii cluster with Keywords Ascomycota . Taxonomy. Phylogeny. species colonizing maize and sorghum. The position of C. Clavicipitales . Ergot loudetiae is unclear. Comparisons with herbarium speci- mens showed C. setariicola as a well-established species on Setaria spp. in the southern USA. C. tenuispora was Introduction recorded on Cenchrus and Pennisetum in Brazil, USA, and Zimbabwe. C. setariiphila was found on S. geniculata in In the tropics worldwide, native forest and savanna are Brazil. C. chloridicola, C. loudetiae and C. truncatispora converted to pastures using warm-season C-4 grasses occurred in African savannas on Chloris, Loudetia, and introduced from Africa (reviewed in Williams and Baruch Hyparrhenia spp., respectively. C. clavispora was found on 2000). Among the most ubiquitous introductions are the Paspalum sp. and Urochloa sp. in Mexico and C. langdonii panicoid grasses: Urochloa (Brachiaria) brizantha (pali- sade grass), Urochloa maxima (guinea grass), Panicum coloratum (Klein grass), Melinis (Rhynchelytrum) spp., Electronic supplementary material The online version of this article Setaria spp. and Cenchrus ciliaris (Buffel grass); the (doi:10.1007/s13225-011-0102-4) contains supplementary material, which is available to authorized users. andropogonoid grasses: Hyparrhenia rufa (thatching grass) and Dichanthium spp. (bluestem) and the chloridoid ž * : č : š : ř S. Pa outová ( ) M. Chudí ková J. Ol ovská M. Kola ík grasses: Cynodon dactylon (Bermuda grass) and Chloris Institute of Microbiology of the ASCR, v.v.i., Vídeňská 1083, gayana (Rhodes grass). These grasses are hosts to many 142 20 Prague 4, Czech Republic species of ergot (Loveless 1964a, b; Loveless and Herd e-mail: [email protected] 1964; Loveless 1967a; Loveless 1985; Frederickson et al. 1991;Pažoutová et al. 2008) and can also present a G. N. Odvody Texas AgriLife Research and Extension Center, problem as invasive species. 10345 State Hwy 44, With the exception of C. purpurea that, historically, has Corpus Christi, TX 78406–1412, USA been responsible for serious human and animal toxicoses, ergot epiphytotics have remained outside the interest of D. E. Frederickson Formerly INTSORMIL, c/o ICRISAT Bulawayo Centre, both phytopathology and medicine until relatively recently. Bulawayo, Zimbabwe The picture began to change with the large scale introduc- 146 Fungal Diversity (2011) 49:145–165 tions of African grasses and cereals to other semi-arid found (Pažoutová et al. 2002a;Pažoutová and Frederickson tropical areas worldwide and the production of F1 hybrid 2005;Pažoutová et al. 2008). seed. As a consequence of transfers with their hosts, During collections over the last decade in Mexico, African species of Claviceps were increasingly recorded Brazil, Texas, and Zimbabwe, various Claviceps spp. and from other regions. The spread of C. fusiformis to India their anamorphs were found. Some of the specimens started in 1955 and was enhanced by the introduction of the corresponded to species recorded previously in Africa first generation of pearl millet hybrids (Bhide and Hegde (Loveless and Herd 1964) and introduced to other locations 1957; Sundaram et al. 1969). Sorghum ergot C. africana (Pažoutová and Frederickson 2005;Pažoutová et al. 2005). was introduced to India (Bogo and Mantle 1999;Pažoutová In addition, parasites of Cenchrus, Pennisetum, Setaria, et al. 2000) and made a well-documented, dramatic sweep Urochloa, Paspalum, and Dichanthium, differing from any over the Americas and Australia starting in 1995–1996 of the known anamorphs and teleomorphs, were collected. (Reis et al. 1996; Ryley et al. 1996; Bandyopadhyay et al. The present study aims to describe these new species and, 1998). Most recently, C. cynodontis was recorded on where appropriate, to clarify descriptions of known Clav- Bermuda grass in the USA and Mexico (Pažoutová et al. iceps species through fresh collections and cultures, thus 2005; Marek et al. 2006). An outbreak of sphacelial facilitating their routine recognition and assignment to epiphytotics on Urochloa brizantha occurred in Brazil, species and lineages inside the genus. probably caused by Claviceps sulcata (Fernandes et al. 1995), a known pathogen of U. brizantha in Africa (Langdon 1954; Loveless and Herd 1964). Since then, this Material and methods ergot disease has caused economic losses to Brazil, a world leader in the production of U. brizantha seed (Verzignassi Herbarium specimens and Fernandes 2001). Even in Africa, native Claviceps species described as endemic many decades previously may Specimens of ergotized grasses were obtained from the U. cause sudden epiphytotics. An outbreak of Claviceps cyperi S. National Fungus Collections Specimen Database (BPI), (Loveless 1967b) on yellow nutsedge, followed by toxico- Kew Herbarium (IMI) and Herbarium Hamburgense (HBG) ses in grazing cattle, was recently observed in South Africa (Tab. 1). Specimens of the new species were deposited in (Naudè et al. 2005). the herbarium of the National Museum in Prague (PRM). Numerous anamorphs and sclerotia related to Claviceps have been found and deposited in herbaria, but few were Isolates and their cultivation formally described as the essential teleomorph was lacking. Induction of formation of perithecial heads is quite difficult Pure cultures of Claviceps spp. were isolated by plating in most Claviceps species, as they require various dorman- honeydew drops found on florets of infected grasses on cy treatments. Loveless (1964b) pointed out that some sucrose-asparagine medium, T2, agar plates and by subse- Claviceps species may be identified using their character- quent transfer of agar pieces containing germinating macro- istic conidial shape and size. However, conidial dimensions conidia (Pažoutová et al. 2002b). Isolates were maintained vary considerably in different collections of the same on T2 agar slants and transferred each two months. For species (Muthusubramanian et al. 2005;Pažoutová and alkaloid production, seed cultures in sucrose-asparagine Frederickson 2005). Despite this variability, conidial shape medium, TI, were inoculated with 3 ml of conidial or and length/width ratio are often the only useful markers for mycelial suspension from a slant culture and incubated the identification of recently found anamorphs by compar- 10 days. Five ml of the seed culture were transferred to ison with herbarium specimens of described Claviceps fermentation cultures T2 and incubated for 20 days species. (Pažoutová et al. 1981). Cultivations proceeded on a rotary Crous and Groenewald (2005) stated that taxonomic shaker at 24°C in 250 ml Erlenmeyer flasks with 60 ml of names based solely on fungal phenotype often represent the respective medium. complexes of cryptic species, and not single operational units and this is especially remarkable in the phytopathogenic Alkaloid analysis fungi. In the genus Claviceps, three closely related groups of species have been found to cluster around C. purpurea, C. Alkaloid content of in planta sphacelia was assayed fusiformis,andC. maximensis, each suggesting past adaptive colorimetrically; three to five ergotized florets were radiations from a common ancestor (Pažoutová 2001; squashed in 2 ml of distilled water and left to macerate Pažoutová et al. 2004). The speciation process continues until the honeydew dissolved. The suspension was centri- inside extant species: in C. purpurea, C. africana and C. fuged and 2 ml of Van Urk’s reagent was added to the fusiformis specialized populations/cryptic species have been supernatant (Pažoutová et al. 1981).Thebluecolor Fungal Diversity (2011) 49:145–165 147 intensity was read at wawelength 540 nm with elymocla- were parsimony-informative. Sequences were aligned vine (30 μg.mL−1) solution in 2% tartaric acid as a using MAFFT (Katoh and Toh 2008)undertheQ-INS-i standard. From shaken cultures, samples of cultivation option considering secondary structure of RNA and were liquid were taken in 3–day intervals and colorimetry manually corrected in BioEdit (Hall 1999). Where the performed as above. Alkaloids from powdered sclerotia sequences of different isolates of the same species were were extracted with aqueous methanol (80%) containing identical, only one of them was used in the dataset. Two 0.1% of NH4OH (24% aqueous solution) for 2 h at methods were used for phylogeny construction, one based