Cell wall protein involved in development of asexual structures such as phialide and conidium development, and thus required for spore formation (PubMed:14599891). Plays a role as a general stress protectant produced by the fungus in competition with antagonistic bacteria (By similarity). Mainly present in phialides and conidia. Expression is highly induced by the V-ATPase inhibitor bafilomycin B1 and by oncanamycin A (PubMed:10376827, PubMed:12207217). The promoter contains two abaA ATTS DNA binding motifs (PubMed:14599891). Leads to reduced sporulation and division of phialides instead of forming a single flask-shaped cell. Belongs to the phiA family.