Fungi in the Xylariaceae are able to decompose lignin in dead leaves to cause bleaching (white-lot), but little is known about their ecology and life cycle. Xylariaceae are frequently isolated from healthy-looking living leaves as endophytes, suggesting these fungi are already present on living leaves before litter fall and become saprobic after the leaf death. To test this hypothesis, we investigated the identity of Xylariaceous fungi isolated from bleached portion of dead leaves with those from living leaves in a subtropical evergreen broad-leaved forest in southern Japan where the bleaching of leaf litter is obvious.

Dead and living leaves of 13 and 64 plant species were collected in April and July 2008 and in April 2010, respectively. A total of 75 and 343 isolates of Xylariaceous fungi were isolated from bleached portions of dead leaves and living leaves, respectively. Molecular phylogenetic analysis revealed that these isolates were classified into 24 and 45 operational taxonomic units (OTUs) (98% ITS similarity), respectively, with 18 OTUs being common. The 18 OUTs accounted for 85% of isolates from bleached portions. These results supported the hypothesis that Xylariacesou fungi with potential ability to decompose lignin can also live as endophytes of living leaves and become saprobes after leaf death.