An Overview of the Alternaria Genus: Ecology, Pathogenicity and Importance for Agriculture and Human Health

<i>Alternaria</i> is a widespread genus and a diverse taxonomic group of fungi, whose members exhibit a wide range of ecological roles, from endophytes and saprophytes to potent plant pathogens, and in some cases, to opportunistic pathogens or allergens affecting humans. Their high adaptability to various environmental conditions determines their widespread distribution and resilience. A key feature of the genus <i>Alternaria</i> is its substantial species diversity. According to the Species Fungorum database, it currently comprises 792 registered species, which are grouped into 29 sections. It should be noted that this number reflects the current state of taxonomic classification and is subject to ongoing revision. The ecological role of representatives of this genus is particularly relevant in the context of agriculture, as many species are pathogens and causative agents of <i>Alternaria</i> leaf spot in important agricultural plants such as tomatoes, potatoes, apples, wheat, and others. This disease causes significant economic losses. At the same time, some strains demonstrate potential for use in biotechnology due to their ability to produce biologically active metabolites. This review examines the taxonomy, morphological characteristics, ecological role, pathogenicity, and control methods of fungi of the genus <i>Alternaria</i>, as well as their biotechnological potential.