Work

The infection-inducible chitin deacetylase AwCDA1 drives virulence in postharvest fungus Aspergillus westerdijkiae

Year: 2026

Type: article

Abstract: • AwCDA1 is a postharvest infection-inducible chitin deacetylase. • Deleting AwCDA1 reduces virulence and slows fruit lesion development. • AwCDA1 partially deacetylates chitin oligomers, thereby weakening host immune recognition. • AwCDA2–4 have distinct roles, showing functional diversification in AwCDA family. • Benzohydroxamic acid inhibits AwCDA1, reducing fungal growth and infection. Aspergillus westerdijkiae is a significant postharvest fungal pathogen causing decay and ochratoxin A (OTA) contamination in fruits. The molecular mechanisms underlying its postharvest infection remain poorly understood. This study investigated the roles of chitin deacetylase genes ( AwCDAs ), particularly AwCDA1 , in A. westerdijkiae pathogenicity, OTA biosynthesis, and host immune recognition, and assessed AwCDA1 as a potential antifungal target. Transcriptomic analyses of postharvest fruits identified four AwCDA genes, and their roles in pathogenicity on pear and grape fruits were evaluated using gene knockout and phenotypic assays. Their transcriptional responses were examined under simulated host conditions. Recombinant AwCDA1 deacetylation activity toward chitin oligomers was measured using MALDI-TOF-MS, and Zn 2+ dependence was assessed. Molecular docking of the broad-spectrum CDA inhibitor benzohydroxamic acid (BHA) was performed using a Chai-1-based homology model to examine interactions with the conserved Asp–His–His catalytic triad, with inhibition validated in vitro . AwCDA1 was specifically and strongly induced during pear infection, whereas AwCDA2–4 showed minimal responses. The Δ AwCDA1 mutant exhibited severe virulence defects, including smaller lesions, delayed colonization, and markedly reduced OTA production. In contrast, deletion of AwCDA2 or AwCDA4 enhanced OTA synthesis, indicating functional differentiation within the AwCDA family. AwCDA1 was induced by chitin-related signals and catalyzed partial deacetylation via a conserved Zn 2+ -dependent Asp–His–His triad. This modification reduced host immune recognition, facilitating fungal colonization. Inhibition assays revealed that BHA bound the AwCDA1 catalytic pocket, significantly suppressing enzymatic activity and reducing fungal growth and lesion formation in pears. AwCDA1 is a postharvest infection-inducible virulence factor in A. westerdijkiae that weakens host immune recognition and regulates OTA biosynthesis. Its responsiveness to chitin-related signals and Zn 2+ -dependent activity supports postharvest fruit colonization. BHA inhibition validates AwCDA1 as a promising antifungal target, offering insights for sustainable OTA control.

Source: Journal of Advanced Research

DOI: 10.1016/j.jare.2026.02.024

Authors: Yibing Liu, Fei Pan, Xinglu Zhang, Yanhua Fan, Gang Wang, Fuguo Xing

Institutions: Southwest University, Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Institute of Apiculture Research

Language: English

Topic: Plant Pathogens and Fungal Diseases

Subfield: Cell Biology

Field: Biochemistry, Genetics and Molecular Biology

Domain: Life Sciences

SDGs: Zero hunger, Good health and well-being

Open Access status: gold

Estimated APC paid: $4,000