English
Characterization of a bZIP Transcription Factor ZipD in Aspergillus flavus
Da-Eun Jeong1, He-Jin Cho1, and Hee-Soo Park1,2,3*
1 School of Food Science and Biotechnology, Kyungpook National University, Daegu 41566, South Korea
2 Department of Integrative Biology, Kyungpook National University, Daegu 41566, South Korea
3Department of Advanced Bioconvergence, Kyungpook National University, Daegu 41566, South Korea
*E-mail: phsoo97@knu.ac.kr
Aspergillus flavus produces aflatoxin B1, a Group 1 carcinogen, that causes severe economic and agricultural losses and invasive aspergillosis in humans. Transcription factors are considered as regulator of development and pathogenicity, and major transcription factor families include Zinc Finger (C2H2), basic helix-loop-helix (bHLH), and basic leucine zipper (bZIP). Among these families, bZIP proteins have been shown to be associated with growth, metabolism, and stress tolerance. In particular, hyphal growth is closely associated with host colonization and toxin production, and transcription factors regulating this process are of significant interest. Based on previous screening, ZipD was identified as a hyphae-associated bZIP transcription factor. In A. fumigatus, the bZIP transcription factor ZipD is known to regulate calcium signaling pathways and cell wall integrity. However, the ortholog of ZipD in A. flavus has not been characterized. To investigate this, we generated a deletion mutant and a complemented strain. First, zipD deletion mutant showed reduced colony growth and conidia production. Second, zipD deletion mutant exhibited increased sclerotia formation, suggesting a role in sexual development. Finally, zipD deletion mutant displayed reduced conidial colonization in pathogenicity assays using corn, bean, and meju. All these phenotypes were restored in the complemented strain. These results suggest that ZipD functions as a regulator of both growth developmental processes and pathogenic traits in A. flavus.
