AUTHOR=Fischer Gregory J. , Bacon William , Yang Jun , Palmer Jonathan M. , Dagenais Taylor , Hammock Bruce D. , Keller Nancy P. 

TITLE=Lipoxygenase Activity Accelerates Programmed Spore Germination in Aspergillus fumigatus

JOURNAL=Frontiers in Microbiology

VOLUME=Volume 8 - 2017

YEAR=2017

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2017.00831

DOI=10.3389/fmicb.2017.00831

ISSN=1664-302X

ABSTRACT=The opportunistic human pathogen Aspergillus fumigatus initiates invasive growth through a programmed germination process that progresses from dormant spore to swollen spore to germling and ultimately invasive hyphal growth. We find a lipoxygenase with considerable homology to human Alox5 and Alox15, LoxB, that impacts the transitions of programmed spore germination. Overexpression of loxB (OE::loxB) increases germination with rapid advance to the germling stage. However, deletion of loxB (∆loxB) or its signal peptide only delays progression to the swollen spore stage in the presence of arachidonic acid (AA); no delay is observed in minimal media. This delay is remediated by the addition of the oxygenated AA oxylipin 5-hydroxyeicosatetraenoic acid (5-HETE) that is a product of human Alox5. We propose that A. fumigatus acquisition of LoxB (found in few fungi) enhances germination rates in polyunsaturated fatty acid-rich environments.