Abstract

In the continuation of studies on Alternaria species from wheat plants with black head mold symptoms, 10 isolates with typical characteristics of the section Pseudoalternaria were isolated and studied by a combined approach based on morphological characteristics and phylogenetic analyses using sequence data sets of the internal transcribed spacer of ribosomal DNA (ITS-rDNA), glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and plasma membrane adenosine triphosphatase (ATPase) genes. These isolates represented a new and previously undescribed species in this section which is illustrated and described here as Alternaria ershadii sp. nov. Also based on our phylogenetic analyses, it was revealed that Alternaria brassicifolii, which was recently described from Brassica rapa subsp. pekinensis in Korea and placed in this section, formed a well separated monotypic lineage distinct from the other members in the section Pseudoalternaria. Comparisons of three-dimensional sporulation patterns and conidial characteristics supported the molecular results. So, at present, Alternaria section Pseudoalternaria contains only seven species viz. Alternaria altcampina, A. arrhenatheri, A. ershadii, A. inflata, A. kordkuyana, A. parvicaespitosa and A. rosae. Morphological comparisons of Alternaria ershadii with other species in the section Pseudoalternaria and with Alternaria brassicifolii is also provided.