A new species complex including Claviceps fusiformis and Claviceps hirtella uri icon

abstract

  • Isolates of Claviceps species with lunate to fusiform macroconidia were collected from panicoid grasses in Texas andZimbabwe and described as new species based on anamorphs since no teleomorphs were available. Characterizationwas based upon morphology and partial sequences of rDNA and ?-tubulin. The isolates grouped into two stronglysupportedclades. The first clade contained ancestral C. hirtella and C. fusiformis from pearl millet (Pennisetumglaucum) in clade terminal position with Texas isolates from native cup grass (Eriochloa sericea) and pearl milletgrouped between them. The second clade consisted of African isolates from Urochloa and Eragrostis. The isolates fromTexas from pearl millet and buffel grass (Cenchrus ciliaris) and isolates from E. sericea were described as new species,Sphacelia texensis and Sphacelia eriochloae, respectively. Both species had morphology, DNA markers, and alkaloidproduction that was intermediate between those features exhibited in C. fusiformis and C. hirtella. The African isolatesfrom Urochloa and Eragrostis were also described as a new species, Sphacelia lovelessii. In shaken cultures, C. hirtellareadily produced a whole range of clavines with agroclavine and festuclavine predominating, but ergometrine was alsodetected. Claviceps fusiformis produced mainly agroclavine and elymoclavine, S. eriochloae produced mainlyagroclavine, elymoclavin and festuclavine and the cultures of S. texensis contained small amounts of agroclavine andfestuclavine. Only traces of clavines were found in cultures of S. lovelessii of the second clade. The alkaloid content ofinfected florets in the sphacelial (honeydew) developmental stage was also measured. Only C. fusiformis and S.eriochloae produced alkaloids in planta at this early stage

publication date

  • 2008