Whole-Genome sequencing and phylogenomic analyses of Alternaria japonica and A. telliensis (Section Japonicae)

Abstract

Species of Alternaria are necrotrophic fungi responsible for leaf spot diseases on a wide range of cultivated and wild plants. Species delimitation within this genus, however, often relies on morphological features and a limited set of molecular markers, which can constrain phylogenetic resolution at finer taxonomic scales. This is the case for Alternaria telliensis, a species recently described from Algeria and subsequently reported in Iran, whose relationships within section Japonicae require clarification. To provide a higher resolution framework for this species, we performed whole-genome sequencing, assembly, and BUSCO completeness assessment for type strains of A. telliensis (CBS 145643) and A. japonica (CBS 118390), using Oxford Nanopore Technologies MinION sequencing. The genome assembly of A. telliensis spans 34.4 Mbp across 132 contigs, with an N50 of 2.2 Mbp and a GC content of 50.94%. The A. japonica assembly comprises 33.5 Mbp in 196 contigs, with an N50 of 1.6 Mbp and a GC content of 51.47%. Phylogenomic analysis places A. telliensis alongside A. japonica within section Japonicae. These genomic data support the classification of A. telliensis and contribute to clarifying taxonomic relationships within the genus Alternaria.