Micología Aplicada International ISSN: 1534-2581 [email protected] Colegio de Postgraduados México Esser, K. Genetics of fungi: retrospect and perspective Micología Aplicada International, vol. 13, núm. 1, january, 2001, pp. 1-8 Colegio de Postgraduados Puebla, México Available in: http://www.redalyc.org/articulo.oa?id=68513101 How to cite Complete issue Scientific Information System More information about this article Network of Scientific Journals from Latin America, the Caribbean, Spain and Portugal Journal's homepage in redalyc.org Non-profit academic project, developed under the open access initiative MICOLOGIA APLICADA INTERNATIONALGENETICS, 13(1),OF FUNGI 2001, pp. 1-81 © 2001, PRINTED IN BERKELEY, CA, U.S.A. www.micaplint.com GENETICS OF FUNGI: RETROSPECT AND PERSPECTIVE* K. ESSER Lehrstuhl für Allgmeine Botanik, Ruhr-Universität, D-44780 Bochum, Germany Tel.: +49-234-32-22211; Fax: +49-234-32-14211; E-mail: [email protected] http://homepage.ruhr-uni-bochum.de/Karl.Esser Accepted for publication August 30, 2000 ABSTRACT This short survey on fungal genetics in the 20th century reflects the course of development from classical to molecular genetics and its implication to biotechnology. Key words: Progressions in classical and molecular fungal genetics, implications to biotechnology. INTRODUCTION done in this domain, without a solid knowledge of Fundamental Mycology. This Applied Mycology comprises a broad again involves a wide array including spectrum ranging from agriculture via taxonomy, morphology, physiology and pharmacy to medicine. The foundation of a genetics of fungi. At present the latter is very new journal presents an occasion to reflect important, because it is the prerequisite for the state of art in the field which is covered improvement of fungal exploitation in by this journal. From the title MICOLOGIA biotechnology, an area in which the fungi APLICADA INTERNATIONAL, one may derive at have gained tremendous importance and a first sight, that the aim of this journal is to therewith a renaissance of mycology was publish mainly papers dealing with Applied initiated. Mycology. This is true to a certain extent Since in the time of computers and genetic only, because no serious research can be engineering there is a strong tendency, especially within the young generation, to wear blind folders: one knows all about * A circumstantial version of this paper was sequencing a gene or molecular MpublishedICOL. APL recently. INT., 1113(1),. 2001, PP. 1-8 transformation, but one is not anymore 2 K. ESSER aware where it all came about. Living in in which each step involved the general the presence and improving science requires interest of researchers being concentrated knowledge of the past. Otherwise on one with a circle of problems. Progress phenomena will be rediscovered, because was made in increments and, as soon as they slipped out of mind. elucidation on one given topic was In following this line of thoughts I shall exhausted, experimental studies led on to a try to show in a brief overview of fungal further new and more promising level. This genetics the close linkage, in the widest does not mean that the topics of earlier sense of the word, of Applied Mycology periods were abandoned or no longer of and Fungal Genetics. This will be not a interest. They also progressed, albeit with literature review in the classical sense. This less momentum; for example, even for paper is meant as an opening address for studies of molecular biology, mapping of this new journal, which hopefully will chromosomal genes is sometimes required. succeed and be the place where papers of all branches of Mycology will be found. Comprehensive literature covering the whole The mostly descriptive studies in area of fungal genetics may be found in the mycology at the beginning of the last century following books or reviews: Esser and Kuenen involved neither experimentation nor 1967; Burnett 1975; Fincham et al. 1978; inheritance studies with fungi. However, the Fincham 1983; Perkins 1992; Wessels and 1,5, first genetic experiments with fungi were Meinhardt 1994; Kück 1995; Bos 1996 12, 13, 14, 17, 18, 19. begun shortly after the rediscovery of Mendel’s work, with various unrelated species. RETROSPECT Crossing experiments were reported in the zygomycete Phycomyces blakesleeanus There is no question that in the different (Burgeff 1912, 1914, 1915); in the ascomyctes periods of fungal genetics, as summarized Glomerella cingulata (Edgerton 1912, 1914) in Fig. 1, the principal interest was and Ascobolus magnificus (Dodge 1920), and fundamental research. However, one in the basidiomycete Schizophyllum commune should not underestimate the significance (Kniep 1918, 1920) 2,3,4,6,7,8,15,16. of this field to underpin and supplement the results of molecular genetics, not only at Thus, fungal genetics was born. present but also in the future. Unfortunately, the interest of geneticists in Following the spirit of the time, the aim this domain of genetics was slight at that of the fungal geneticists was at first to use time, partially due to the tremendous the fungi as experimental model organisms progress having been made in genetics using to support and enlarge the knowledge of diploid organisms, such as higher plants and inheritance as predicted by the Mendelian the fruit fly Drosophila as model organisms. laws. This mainly concerned the location of Nevertheless, fungal genetics developed genes on the chromosomes and their mode concomitantly with increasing knowledge of transmission (chromosomal or formal in other areas of biology as well as in genetics). Only decades later did the fungi chemistry and physics. In retrospect, a become accessible to extrachromosomal or stepwise progression becomes apparent, molecular genetics. MICOL. APL. INT., 13(1), 2001, PP. 1-8 GENETICS OF FUNGI 3 Genetic engineering Extra chromosomal Plasmids genetics Mitochondria Gene expression Chromosomal Recombination genetics Breeding systems 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 Fig. 1. Scheme showing the stepwise progression of fungal genetics during the 20th century. The beginning of the main research areas is indicated in each particular step, followed by its specific topic 5. As may be further seen from Fig. 1, in together with studies on the mechanism of the early 1920th the interest of geneticists mutation. was directed toward the elucidation of the In the mid of the 1940th, a third platform breeding systems. At the end of the 1920th was attained and therewith an essential it became evident, that mating in most fungi breakthrough, namely the inclusion of is not controlled by sexual differences based physiology into fungal genetics. A direct on sexual chromosomes, but by sexual correlation between chromosomal genes and incompatibility expressed as mating types. enzymes became evident. This area of gene The next platform was attained, when expression or biochemical genetics was first initiated by the work of Lindegren with established in Neurospora crassa and is Neurospora crassa, it became possible to connected with the names of Beadle and exploit the possibility of tetrad analysis Tatum. (especially in Ascomycetes) in order to Almost concomitantly with the understand the phenomenon of understanding of gene expression another recombination. Crossing over platform was reached at the beginning of chromosomal and chromatid interference the 1950th, when Ephrussi identified in and the establishment of chromosomal Saccharomyces cerevisiae mitochondria as maps, corrected by mapping functions were genetic traits responsible for the brought up to date by the late 1950th extrachromosomal inheritance, a MICOL. APL. INT., 13(1), 2001, PP. 1-8 4 K. ESSER phenomenon recognized already along with fungal genetics and biotechnology had the rediscovery of the mendelian laws. developed for a long time quite There is another step, not shown in Fig. independently without a direct connection. 1. During the late 1950th, the genetic studies In the 1950th, when fungi were used for the of morphogenesis gained interest in several conversion of biochemical compounds laboratories. In my laboratory the (biological conversion), and later in the differentiation of fruiting bodies in the 1960s, when also perfect fungi were Ascomycetes and later in the included in biotechnology, it became Basidiomycetes, was shown to be controlled obvious that breeding techniques needed by a chain of nuclear genes steering the steps improvement. The time was ready to of differentiation. perform strain improvement by making use The largest platform was attained in the of the knowledge meanwhile accumulated mid of the 1970th, when fungal genetics in fundamental research by chromosomal became integrated into the domain of genetics. molecular genetics. This was achieved not This was achieved by recognizing the only by the discovery of genetic value of recombination, now using three information in mitochondrial DNA, but parameters: mutation, recombination, and also by the detection of mitochondrial selection under controlled conditions plasmids either integrated in the (concerted breeding 9, 10). The general mitochondrial genome or in the cytosol. The procedure is to bring together in one latter involved my laboratory as well as other organism, by means of recombination, groups in the US and France. favorable properties found either in wild Due to the cumulative data concerning the strains or obtained following mutagenic structure of extrachromosomal DNA, treatment, and then select for favorable