Virus Infection Impairs Fungal Response to Stress: Effect of Salt.

Infection with Aspergillus fumigatus polymycovirus 1 (AfuPmV-1) weakens the resistance of biofilms of common A. fumigatus reference strain Af293 in intermicrobial competition with Pseudomonas aeruginosa, and sensitizes A. fumigatus for antifungal effects of nikkomycin Z. We compared the sensitivity of two virus-infected (VI) and one virus-free (VF) Af293 strains to hypertonic salt. Salt stress impairs the growth of VI and VF at all times; VF control growth always exceeds VI, and VF growth in salt always exceeds VI. Since VF growth exceeds VI in the presence and absence of salt, we also examined growth in salt as a percentage of control growth. Initially, as a percentage of control, VI exceeded VF, but at 120 h VF began to exceed VI consistently even by this measure; thus, at that time the growth of VF in salt surges in relation to control growth, or, alternatively, its growth in salt persists compared to the relative inhibition of VI. In summary, virus infection impairs the response of A. fumigatus to several different stresses, including hypertonic salt.