March 28, 2025 | Plant Disease |
The genetic and phenotypic diversity of Neoscytalidium dimidiatum, a key fungal pathogen of dragon fruit (Hylocereus spp.), was the focus of a study conducted by researchers from National Chung Hsing University, the Taiwan Agricultural Research Institute, and the District Agricultural Research and Extension Station in Taiwan. This pathogen is known for its global distribution and broad host range, yet information on its population characteristics across time, space, and host types remains limited.
The study analyzed N. dimidiatum isolates collected from dragon fruit and other hosts in Taiwan between 2010 and 2021, comparing them to isolates from other countries. Multilocus sequence analysis showed that Taiwan’s isolates clustered primarily by host (dragon fruit and cattleya), regardless of their geographic or temporal origin. In contrast, isolates from other countries showed slightly higher phylogenetic diversity, suggesting greater genetic variation. The limited diversity in Taiwan implies that asexual reproduction is the main reproductive strategy in local populations.
Despite low genetic diversity, significant phenotypic variation was observed in colony color, mycelial growth, and spore germination under different temperatures. Notably, isolates from northwestern and eastern Taiwan exhibited better growth at 40 °C than those from the southwest. All tested isolates could infect dragon fruit cladodes, but those from dragon fruit caused larger lesions and had shorter latent periods.
These findings indicate that phenotypic plasticity and host specialization contribute to the pathogen’s adaptation and global spread.
