Pathogenicity of Alternaria spp. Affecting Crops Plants : A Review

Wheat (Triticum aestivum L.) is one of the most important cereal crops, which feeds more than 37% of the world population. It is grown worldwide, in more than 1/3 of total cereal output, with a production of over 550 million metric tons. Foliar pathogens of wheat include leaf blight caused by Alternaria triticina, Helminthosporium spp., Curvularia spp., and some other pathogens. Alternaria, a genus of ascomycetes, comprises major plant pathogens, saprobes, and is a common allergen to humans. Leaf blight caused by Alternaria triticina Prasada and Prabhu is an important disease of wheat and is responsible for considerable yield loss (Prabhu and Prasada 1970; 1974). There are more than 360 accepted species in the genus, which are currently divided into 29 sections. The two major features of Alternaria species are the production of melanin, especially in the spores, and the production of host-specific toxins in the case of pathogenic species (Hýsek et al. 2017; Hýsek et al. 2017; Meena et al. 2017; Meena and Samal 2019). This review will focus on leaf blight of wheat and its pathogenicity, while the second review will focus on host-specific toxins.