Lasiodiplodia spp. associated with Aquilaria crassna in Laos

Aquilaria (Thymelaeaceae) is a genus of evergreen trees, which is well-known in producing resinous heartwood (known as agarwood). Infection by Lasiodiplodia spp. has been reported effectively inducing the agarwood formation in members of Aquilaria. In this study, 12 taxa of Lasiodiplodia were retrieved from trunks of healthy, brown, and ligaloes tissue of Aquilaria crassna in Laos, of which eight species are new to science. Fungal identification was conducted using a combination of morphology and multi-locus phylogenetic analyses based on combined translation elongation factor 1-a sequence (tef1-a), internal transcribed spacer (ITS), beta-tubulin (TUB), and RNA polymerase II beta subunit (RPB2) nuDNA sequences. Cashew nut-shaped conidia and the baculate ornamentation on the conidia of Lasiodiplodia spp. are first reported in this study. Aquilaria crassna proved a good host for Lasiodiplodia, and the function of Lasiodiplodia spp. in inducing agarwood formation needs further study.