<i>Alternaria</i>: update on species limits, evolution, multi-locus phylogeny, and classification

Alternaria, a genus of ascomycetes, comprises major plant pathogens, saprobes and are common allergens to humans. There are more than 360 accepted species in the genus, which are currently divided into 29 sections. This paper aims to elaborate the taxonomy of Alternaria with multi-locus phylogenetic trees derived by analyses of a concatenated DNA sequence dataset consisting of ITS, LSU, TEF1-α, RPB2, GAPDH and Alt-a1 loci. Eighteen new species viz. Alternaria arctoseptata, A. arundinis,A. baoshanensis, A. breviconidiophora,A. brevirostra,A. ellipsoidialis,A. eupatoriicola,A. falcata,A. lathyri, A. macilenta,A. macroconidia,A. minimispora,A. nodulariconidiophora, A. oblongoellipsoidea, A. orobanches, A. phragmiticola,A. phytolaccae and A. salicicola are introduced and classified in sect. Alternaria, sect. Infectoriae, sect. Porri and sect. Radicina. Alternaria alternata andA. doliconidium are also described herein with new host and geographical records, in China, Italy, and Thailand. This study further explores the utility of divergent time estimates to gain additional insights into the evolutionary relationships of Alternaria in Pleosporales.