Since Agostino Bassi first isolated the fungal pathogenic agent of the white muscardine in insects (later named Beauveria bassiana in his honor), and Ilya Mechnikov cultivated Metarhizium anisopliae as a first approach to use fungi as pest control agents, many other entomopathogenic fungi have been studied over the last two centuries [1,2].
There is evidence of a several-million-year coevolutionary history between invertebrate-pathogenic fungi and their hosts. Fungus–insect interactions are known to drive pathogenic cycles that usually culminate in killing the hosts; however, these fungi are also facultative saprophytes in the soil and/or the rhizosphere [3,4]. They can also develop endophytic relationships with plants, conferring protection to the host plant from the insects that feed on them [5]. In addition to invertebrate pathology, B. bassiana also has diverse applications in a range of other disciplines, including as an important whole-cell eukaryotic biocatalyst, and together with other entomopathogenic fungi, remains a reservoir for the discovery of numerous secondary metabolites with bioactive functions [6].
These topics were addressed in two Special Issues, which have captured a diversity of studies that focus on biological, molecular, and biotechnological aspects of the interaction between insect-related fungi and their wide range of hosts, including arthropods and plants, as well as on the expression of secondary metabolites, and other aspects regarding their catalyst role in biotransformation and bioremediation. A total of 11 original articles and one review article were published in the Special Issues “Multifaceted Beauveria bassiana and Other Insect-Related Fungi 1.0” (9 articles) and “Multifaceted Beauveria bassiana and Other Insect-Related Fungi 2.0” (3 articles). We briefly summarize them in the following paragraphs and encourage readers to explore them fully.