Lack of host specialization in Aspergillus flavus

Aspergillus spp. cause disease in a broad range of organisms, but it is unk nown if strains are specialized for particular hosts. We evaluated isolates of Aspergillus flavus, Aspergillus fumigatus, and Aspergillus nidulans for their ability to infect bean leaves, corn kernels, and insects (Galleria m ellonella). Strains of A. flavus did not affect nonwounded bean leaves, cor n kernels, or insects at 22 degrees C, but they killed insects following he mocoelic challenge and caused symptoms ranging from moderate to severe in e arn kernels and bean leaves injured during inoculation. The pectinase P2c, implicated in aggressive colonization of cotton bells, is produced by most A. flavus isolates, but its absence did not prevent colonization of bean le aves. Proteases have been implicated in colonization of animal hosts, All A . flavus strains produced very similar patterns of protease isozymes when c ultured on horse lung polymers. Quantitative differences in protease levels did not correlate with the ability to colonize insects. In contrast to A. flavus, strains of A. nidulans and A. fumigatus could not invade living ins ect or plant tissues or resist digestion by insect hemocytes. Our results i ndicate that A. flavus has parasitic attributes that are lacking in A. fumi gatus and A. nidulans but that individual strains of A. flavus are not spec ialized to particular hosts.