Effects of Host Taxonomic Relatedness on Colonisation Rates and Community Patterns of Foliar Endophytic Fungi in...

Leaves, due to their high exposure, are particularly susceptible to environmental influences. Foliar endophytic fungi play important roles in plant resilience and adaptation yet remain poorly documented in the Zingiberaceae. This study investigated the colonisation and diversity patterns of culturable foliar endophytic fungi associated with nine host species, representing four genera of Zingiberaceae, collected from urban environments in Bogor, Indonesia. Endophytic fungi were isolated using a standardised surface sterilisation method. Colonisation rates, isolation frequencies, and diversity indices of endophytic fungi were calculated. Molecular identification was conducted via Sanger sequencing of the internal transcribed spacer (ITS) region. Host taxonomic relatedness was represented by a categorical taxonomic distance matrix derived from nomenclatural classification and used to assess its relationship with fungal colonisation and community patterns using Mantel tests. Colonisation rates differed significantly among host species and were positively correlated with host taxonomic distance, indicating that closely related hosts tended to harbour similar levels of endophytic colonisation. In contrast, fungal diversity indices and species-level distribution patterns showed no significant relationship with host taxonomy. At the genus level, endophytic communities were consistently dominated by Colletotrichum, followed by Phyllosticta and Diaporthe, whereas species-level assemblages showed no clear clustering by host. These results demonstrate that host taxonomic relatedness influences colonisation rates but does not structure species-level distribution patterns of foliar endophytic fungi in the Zingiberaceae. By focusing on culturable endophytes, this study provides new insights into host-endophyte associations and establishes a baseline for future ecological and functional studies in tropical plant systems.