Mycosphere Essays 14: Assessing the aggressiveness of plant pathogenic Botryosphaeriaceae

Species of Botryosphaeriaceae (Dothideomycetes, Ascomycota) have been reported as endophytes, pathogens and saprobes on a wide range of plants. Their roles in different life forms are not well-defined and should be studied in more detail. It is of interest to understand how these fungi become pathogenic on living tissues. Previous studies have proposed that the pathogenicity of botryosphaeriaceous species is triggered by the changes in environmental conditions. It is assumed that, external stimuli caused by above ground and below ground factors, extensive physical damage due to management practices or from pests, impose stress on the host plant. Due to these stresses, these botryosphaeriaceous taxa activate their biochemical mechanisms and become plant pathogens, causing disease. These diseases may ultimately result in plant death and thus cause economic losses. Since the aggressiveness of Botryosphaeriaceae species depends on changes in their surrounding environmental factors, species in this group are regarded as opportunistic pathogens. Nevertheless, it is still debatable, whether it is the changing environment that triggers pathogenicity of Botryosphaeriaceae, or disease development is a result of weakening of the host defences. Therefore, it is important to design experiments to understand the factors involved in pathogenesis.