Identification and Characterization of Peptaibols as the Causing Agents of Pseudodiploöspora longispora Infecting the Edible Mushroom Morchella

Pseudodiploöspora longispora (previously known as Diploöspora longispora ) is a pathogenic fungus of Morchella mushrooms. The molecular mechanism underlying the infection of P. longispora in fruiting bodies remains unknown. In this study, three known peptaibols, alamethicin F-50, polysporin B, and septocylindrin B ( 1 – 3 ), and a new analogue, longisporin A ( 4 ), were detected and identified in the culture of P. longispora and the fruiting bodies of M. sextelata infected by P. longispora . The primary amino sequence of longisporin A is defined as Ac-Aib 1 -Pro 2 -Aib 3 -Ala 4 -Aib 5 -Aib 6 -Gln 7 -Aib 8 -Val 9 -Aib 10 -Glu 11 -Leu 12 -Aib 13 -Pro 14 -Val 15 -Aib 16 -Aib 17 -Gln 18 -Gln 19 -Phaol 20 . The peptaibols 1 – 4 greatly suppressed the mycelial growth of M. sextelata . In addition, treatment with alamethicin F-50 produced damage on the cell wall and membrane of M. sextelata . Compounds 1 – 4 also exhibited inhibitory activities against human pathogens including Aspergillus fumigatus, Candida albicans, methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus, and plant pathogen Verticillium dahlia . Herein, peptaibols are confirmed as virulence factors involved in the invasion of P. longispora on Morchella, providing insights into the interaction between pathogenic P. longispora and mushrooms.