Endoglucanase H from <i>Aspergillus westerdijkiae</i> Plays an Important Role in the Virulence on Pear Fruits

Abstract

<i>Aspergillus westerdijkiae</i> can infect many agricultural products including cereals, grapes, and pear. Pathogenic fungi secrete diverse effectors as invasive weapons for successful invasion the host plant. During the pathogen-host interaction, 4486 differentially expressed genes were observed in <i>A. westerdijkiae</i> with 2773 up-regulated and 1713 down-regulated, whereas 8456 differentially expressed genes were detected in pear fruits with 4777 up-regulated and 3679 down-regulated. A total of 309 effector candidate genes were identified from the up-regulated genes in <i>A. westerdijkiae</i>. Endoglucanase H (<i>AwEGH</i>) was significantly induced during the pathogen-host interaction. Deletion of <i>AwEGH</i> resulted in altered fungal growth and morphology and reduced conidia production and germination compared to the wild-type. Further experiments demonstrated that <i>AwEGH</i> plays a role in cell wall integrity. Importantly, disruption of <i>AwEGH</i> significantly reduced the fungal virulence on pear fruits, and this defect can be partly explained by the impaired ability of <i>A. westerdijkiae</i> to penetrate host plants.