15 Genetic and Metabolic Aspects of Primary and Secondary Metabolism of the Zygomycetes

Abstract

Mycology, the study of fungi, originated as a sub discipline of botany and was a descriptive discipline, largely neglected as an experimental science until the early years of this century. A seminal paper by Blakeslee in 1904 provided evidence for self-incompatibility, termed "heterothallism," and stimulated interest in studies related to the control of sexual reproduction in fungi by mating-type specificities. Soon to follow was the demonstration that sexually reproducing fungi exhibit Mendelian inheritance and that it was possible to conduct formal genetic analysis with fungi. The names Burgeff, Kniep and Lindegren are all associated with this early period of fungal genetics research.These studies and the discovery of penicillin by Fleming, who shared a Nobel Prize in 1945, provided further impetus for experimental research with fungi. Thus, began a period of interest in mutation induction and analysis of mutants for biochemical traits. Such fundamental research, conducted largely with Neurospora crassa, led to the one gene:one enzyme hypothesis and to a second Nobel Prize for fungal research awarded to Beadle and Tatum in 1958. Fundamental research in biochemical genetics was extended to other fungi, especially to Saccharomyces cerevisiae, and by the mid-1960s fungal systems were much favored for studies in eukaryotic molecular biology and were soon able to compete with bacterial systems in the molecular arena.The experimental achievements in research on the genetics and molecular biology of fungi have benefited more generally studies in the related fields of fungal biochemistry, plant pathology, medical mycology, and systematics. Today, there is much interest in the genetic manipulation of fungi for applied research. This current interest in biotechnical genetics has been augmented by the development of DNA-mediated transformation systems in fungi and by an understanding of gene expression and regulation at the molecular level. Applied research initiatives involving fungi extend broadly to areas of interest not only to industry but to agricultural and environmental sciences as well.It is this burgeoning interest in fungi as experimental systems for applied as well as basic research that has prompted publication of this series of books under the title The Mycota. This title knowingly relegates fungi into a separate realm, distinct from that of either plants, animals, or protozoa. For consistency throughout this series of volumes, the names adopted for major groups of fungi (representative genera in parentheses) are as follows:

Comparative genomics applied to Mucor species with different lifestyles

“…All Mucor genomes investigated in this study included a NRPS gene which role has still to be determined as well as different genes encoding for enzymes associated with terpene biosynthesis. As noticed by Voigt et al who analysed different Mucor genomes, no PKS genes but genes with a typical structure and domain order of Type I fatty acid synthases (FAS) were detected in the different Mucor genomes investigated in the present study [3]. These Mucor FAS have their domains allocated within a single gene as in Basidiomycota and not over two genes as in Ascomycota (Fig.…”

“…Whether or not this additional FAS might be involved in secondary metabolisms like specialized secondary metabolism FAS [57] has to be determined. Among the secondary metabolites, terpenes play a role in natural pigment synthesis such as the carotenoid biosynthesis [3]. Carotenoid synthesis has been described in M. circinelloides and in particular in overproducing isolates [3,58,59].…”

“…Among the secondary metabolites, terpenes play a role in natural pigment synthesis such as the carotenoid biosynthesis [3]. Carotenoid synthesis has been described in M. circinelloides and in particular in overproducing isolates [3,58,59]. Although the different species within the Mucoromycotina subphylum are expected to produce and accumulate large amount of carotenoids, differences might exist among species [60].…”

“…From the first microscopic observation of a Mucor specimen in 1665 up until now, several hundreds of potential Mucor species have been reported [2]. Mucor species are common and predominantly saprotrophs [3]. These ubiquitous microorganisms may colonize multiple and contrasted environments from dungs or dead plant materials to plant and animal tissues.…”

Molecular mechanisms of mucormycosis—The bitter and the sweet

“…circinelloides to be the cause of food poisoning illness [34]. Genomic evidence also supports the notion that Mucorales possess pathways for secondary metabolites including polyketide synthases (PKSs), nonribosomal peptide synthetases (NRPs), and L-tryptophan dimethylallyl transferases (DMATs) [35]. …”