Interspecific variation in bamboo decay capacity of bambusicolous <i>Apiospora</i> species

Abstract Bambusicolous fungi play crucial roles in bamboo growth, health, disease, and lignocellulose decomposition. Among them, Apiospora species occupy diverse ecological niches as endophytes, pathogens, and saprotrophs. Fungal decay ability is an important functional trait for understanding ecological roles and substrate utilization strategies. Therefore, this study aimed to evaluate the decay activities of nine bambusicolous Apiospora species on Phyllostachys bambusoides and Phyllostachys nigra var. henonis and to determine whether decay ability is associated with ecological lifestyle. Chemical composition analyses and transmission electron microscopy (TEM) were conducted to characterize substrate-specific degradation patterns and cell wall decay. All tested Apiospora species exhibited measurable decay activity with substantial interspecific and substrate-dependent variation. Apiospora rasikravindrae demonstrated the highest decay activity on both bamboo species, whereas Apiospora hysterina and Apiospora sargassi consistently showed low decay performance, suggesting functional differentiation associated with distinct ecological strategies. Several species exhibited moderate decay activity on P. bambusoides ; however, their decay efficiency was markedly reduced on P. nigra var. henonis , while Apiospora saccharicola displayed the opposite pattern. Chemical analyses and TEM observations confirmed degradation patterns consistent with soft-rot decay. These results demonstrate substantial functional diversity among bambusicolous Apiospora species and provide new insights into their ecological roles in bamboo decay.