943 Mycologia, 95(5), 2003, pp. 943–954.  2003 by The Mycological Society of America, Lawrence, KS 66044-8897 Gibberella konza (Fusarium konzum) sp. nov. from prairie grasses, a new species in the Gibberella fujikuroi species complex Kurt A. Zeller Department of Plant Pathology, Throckmorton Plant Sciences Center, Kansas State University, Manhattan, Kansas 66506-5502 Brett A. Summerell Suzanne Bullock Royal Botanic Gardens, Mrs. Macquaries Road, Sydney, New South Wales 2000, Australia John F. Leslie 1 Department of Plant Pathology, Throckmorton Plant Sciences Center, Kansas State University, Manhattan, Kansas 66506-5502 Abstract: The Gibberella fujikuroi species complex (Fusarium section Liseola and allied taxa) is com- posed of an increasingly large number of morpho- logical, biological and phylogenetic species. Most of the known species in this group have been isolated from agricultural ecosystems or have been described from a small number of isolates. We sampled Fusar- ium communities from native prairie grasses in Kan- sas and recovered a large number of isolates that su- perficially resemble F. anthophilum. We used a com- bination of morphological, biological and molecular characters to describe a new species, Gibberella konza (Gibberella fujikuroi mating population I [MP-I]), from native prairie grasses in Kansas. Although fe- male fertility for field isolates of this species appears to be low, G. konza is heterothallic, and we developed reliably female fertile mating population tester strains for this species. The F. konzum anamorph is differentiated from F. anthophilum and from other Fusarium species in section Liseola by mating com- patibility, morphology, AFLP fingerprint profile and differences in -tubulin DNA sequence. Key words: AFLP, biological species, DNA se- quence, Fusarium anthophilum, mating population, -tubulin INTRODUCTION Before the early 1980s, morphological taxonomies of Fusarium section Liseola subdivided the group into a Accepted for publication March 3, 2003. 1 Corresponding author. E-mail: jfl@plantpath.ksu.edu relatively small set of species. Gerlach and Nirenberg (1982) recognized seven species within this section, while Nelson et al (1983) recognized only four. Since that time, cross-fertility data and data from molecular markers have been used to analyze section Liseola and have revealed an abundance of cryptic biological species and phylogenetic lineages. Within the Gibberella fujikuroi (Sawada) Wollenw. species complex (primarily Fusarium section Liseola), at least eight biological species have been defined with sexual cross-fertility criteria, reviewed in Samuels et al (2001). Additional Fusarium species with no known sexual stage, but whose morphology allies them with Fusarium section Liseola, also have been described (e.g., Marasas et al 1985, 1987, 2001; Nel- son et al 1987; Rheeder et al 1996). At least 25 ad- ditional phylogenetic lineages have been identified within the G. fujikuroi complex by using molecular characters (e.g., O’Donnell et al 1998, Steenkamp et al 1999, Marasas et al 2001). Together these findings indicate that the G. fujikuroi complex encompasses a large and incompletely documented set of species. In addition to morphology, several types of molec- ular and biochemical methods have been used to dif- ferentiate species within Fusarium section Liseola. Huss et al (1996) described an isozyme methodology that could be used to distinguish the (then seven) described biological species in G. fujikuroi. Voigt et al (1995) and Amoah et al (1996) used RAPD (ran- dom amplified polymorphic DNA) markers to distin- guish these same biological species, while Mo ¨ller et al (1999) developed PCR primers for species-specific RAPD fragments to differentiate them. DNA se- quence data also have been used to aid in distinguish- ing probable species and phylogenetic subgroupings within section Liseola (e.g., O’Donnell et al 1998, 2000, Steenkamp et al 1999, 2000), as has amplified fragment length polymorphism (AFLP, Vos et al 1995); e.g., Marasas et al (2001). We have been evaluating Fusarium communities as- sociated with prairie grasses in Kansas and have re- covered isolates that are superficially similar in mor- phology to Fusarium anthophilum (A Braun) Wollenw. (Nelson et al 1983) from greater than 50% of the sampled grasses. AFLP fingerprint data from the ma- jority of these isolates indicate that these isolates all are members of the same phylogenetic lineage but