Submitted to: Fungal Genetics Conference/Asilomar
Publication Type: Abstract Only
Publication Acceptance Date: March 15, 2011
Publication Date: March 15, 2011
Citation: Breakspear, A., Pasquali, M., Broz, K.L., Dong, Y., Kistler, H.C. 2011. Npc1 is involved in sterol trafficking in the filamentous fungus Fusarium graminearum. Fungal Genetics Conference/Asilomar. 58(Supplement):186. Technical Abstract: The ortholog of the human gene NPC1 was identified in the plant pathogenic, filamentous fungus Fusarium graminearum by shared amino acid sequence, protein domain structure and cellular localization of the mature fungal protein. The Fusarium Npc1 gene shares 34% amino acid sequence identity and 51% similarity to the human gene, has similar domain structure and is constitutively expressed, although up-regulated in ungerminated macroconidia and ascospores. GFP-tagged Npc1p localizes to the fungal vacuolar membrane. Cultures derived from a 'npc1 mutant strain contain significantly more ergosterol than cultures of the wild type. Staining with the fluorescent, sterol binding dye filipin, shows that ergosterol accumulates in vacuoles of the 'npc1 mutant but not the wild type strain. The 'npc1 mutant has a temperature dependent reduction in growth and greater sensitivity to the ergosterol synthesis inhibiting fungicide tebuconazole compared with the wildtype strain or the mutant complemented with wild type Npc1. The mutant also is significantly reduced in pathogenicity to wheat. Our results are consistent with the interpretation that Npc1p is important for normal transport of ergosterol from the vacuole and is essential for proper membrane function under particular environmental conditions.