Díaz-Valderrama, Jorge R. , Aime, M. Catherine .
Conidiogenesis in the cacao pathogen Moniliophthora roreri (Marasmiaceae).
Moniliophthora roreri, the causal agent of the emergent disease frosty pod rot of cacao, is a member of the mushroom-forming family Marasmiaceae (Agaricales, Basidiomycota). Yet, M. roreri has never been observed to produce a mushroom fruiting body, but rather produces billions of spores on the surface of infected pods. The question of whether these spores are produced via meiosis or mitosis has been the subject of some speculation. However, numerous molecular-based studies have been unable to support a hypothesis of sexual recombination for this fungus. We re-examined sporogenesis and nuclear condition of hyphae and spores in M. roreri via nuclear staining and spore germination studies. Conidia are produced asexually in a thallic and rhexolytic way as is true for other marasmioid species such as M. perniciosa and Flammulina velutipes. We also found that hyphal cells as well as spores harbor mostly either one or two nuclei (as is typical of monokaryons), that conidium size is influenced by number of nuclei within, and that individual isolates produced consistently and significantly different proportions of binucleate and mononucleate spores regardless of varietal group. Therefore, future phenotypic and morphological characterizations of the fungus must consider nuclear condition.
1 - Purdue University, 915 West State St., Department of Botany and Plant Pathology, West Lafayette, Indiana, 47907, Estados Unidos
2 - Purdue University, Botany & Plant Pathology, 915 W. State Street, Botany & Plant Pathology, West Lafayette, IN, 47907, USA
tropical plant diseases
Presentation Type: Oral Paper:Papers for Sections
Candidate for Awards:MSA Best Oral Presentation Award by a Graduate Student