Primers utilized in this study.

Forkhead transcription factors regulate several important biological processes in many eukaryotic species including fungi. Bioinformatic analysis of the Aspergillus flavus genome revealed four putative forkhead transcription factor genes. Genetic disruption of (AFLA_005634), a homolog of the Aspergillus nidulans fhpA/fkhA gene (AN4521), revealed that the fhpA gene is a negative regulator of both asexual spore production and aflatoxin B1 production in A. flavus. Furthermore, disruption of the fhpA gene caused a complete loss of sclerotial formation. Overexpression of the fhpA gene caused A. flavus to become more sensitive to sodium chloride whereas disruption of the fhpA gene did not change the ability of A. flavus to respond to any osmotic stress agent tested. Interestingly, both disruption and overexpression of the fhpA gene led to increases in sensitivity to the oxidative stress agent menadione. Overall, these results suggest that fhpA is an important regulator of morphological and chemical development in addition to stress response in A. flavus.叉头框转录因子（Forkhead transcription factors）可调控包括真菌在内的诸多真核生物的多项关键生物学过程。对黄曲霉（Aspergillus flavus）基因组开展生物信息学分析后，共鉴定出4个候选叉头框转录因子基因。对构巢曲霉（Aspergillus nidulans）fhpA/fkhA基因（AN4521）的同源基因AFLA_005634进行遗传敲除实验，结果显示fhpA基因在黄曲霉中同时作为无性孢子生成与黄曲霉毒素B1（aflatoxin B1）合成的负调控因子。此外，敲除fhpA基因会导致黄曲霉完全丧失菌核形成能力。过表达fhpA基因会使黄曲霉对氯化钠的敏感性显著升高，而敲除fhpA基因则未改变黄曲霉对所测试的各类渗透胁迫试剂的响应能力。值得注意的是，无论是敲除还是过表达fhpA基因，均会提升黄曲霉对氧化胁迫试剂甲萘醌（menadione）的敏感性。综合上述实验结果，fhpA基因是黄曲霉形态发育与化学合成代谢的重要调控因子，同时亦参与其胁迫响应过程。