Multi-locus phylogeny and morphology of Curvularia isolates associated with leaf spots of corn in northern Algeria unveiled two new species, C. algeriensis sp. nov. and C. boudouaouensis sp. nov., with a new record for C. spicifera

In this study, we investigated fungi associated with leaf spots of corn in northern Algeria. Fungal isolates were recovered from sampled leaves and were subjected to morphological and molecular identification. Morphology and multi-locus phylogeny, including the internal transcribed spacers 1 and 2 with 5.8S (ITS) along with partial glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and translation elongation factor 1-alpha (TEF1) genes, supported the proposal of two new species, Curvularia algeriensis and Curvularia boudouaouensis, as well as a new record for Curvularia spicifera. These two new species are closely related and clustered sisters to Curvularia sporobolicola in the phylogenetic analysis. Morphologically, they can be distinguished by the shape and size of their conidia and conidiophores. The conidia of C. algeriensis are asymmetrically ellipsoidal, with the basal side larger than the apical side. In contrast, those of C. boudouaouensis are ellipsoidal to subcylindrical, and in C. sporobolicola, they are hemi-ellipsoidal. Additionally, the conidia of C. algeriensis are distinctly longer and larger than those of C. boudouaouensis and tend to be slightly longer and narrower than those of C. sporobolicola. C. algeriensis can also be distinguished by its longer conidiophores compared to its closest relatives. Inoculation of corn seedlings supported the pathogenicity of the two new species, as well as the new record.