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=8

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=<p>The opportunistic human pathogen <italic>Aspergillus fumigatus</italic> initiates invasive growth through a programmed germination process that progresses from dormant spore to swollen spore (SS) to germling (GL) 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 <italic>loxB</italic> (<italic>OE::loxB</italic>) increases germination with rapid advance to the GL stage. However, deletion of <italic>loxB</italic> (<italic>ΔloxB</italic>) or its signal peptide only delays progression to the SS 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 <italic>A. fumigatus</italic> acquisition of LoxB (found in few fungi) enhances germination rates in polyunsaturated fatty acid-rich environments.</p>