Transcript Fungi
I Nyoman P. Aryantha SITH-ITB mykes = mushroom (cendawan) logos = ilmu Leeuwenhoek (mikroskop) Pier’ Antonio Micheli (Itali) : Nova Plantarum (1729) FUNGI ~ JAMUR MOLD (MOULD) ~ LAPUK RUSTS SMUTS MILDEWS YEAST ~ RAGI, KAMIR KAPANG MUSHROOM ~ CENDAWAN TOADSTOOL A eukaryotic, heterotrophic organism devoid of chlorophyll that obtains its nutrients by absorption, and reproduces by spores. Carl Linnaeus (1707-1778) the “Father of Taxonomy” Plants without obvious sexual organs were classified in Class Cryptogamia (lichens, fungi, mosses, ferns) Fungi are primitive plants under this classification of organisms. At least 7 kingdoms are now recognized: Eubacteria, Archaebacteria, Animalia, Plantae, Eumycota, Stramenopila (Chromista), Protoctista (Protozoa, Protista) NUMBER OF GENUS AND SPECIES NUMBER OF GENUS AND SPECIES NUMBER OF GENUS AND SPECIES “fungus” is used inclusively for a heterogenous group of organisms that have traditionally been studied by mycologists “Fungi” refers to the organisms in the Kingdom Fungi, the true fungi, also called the “Eumycota” Hierarchical Classification Kingdom Fungi Phylum Basidiomycota Class Basidiomycetes Order Agaricales Family Agaricaceae Genus Agaricus Species: Agaricus campestris L. Agaricus is the genus campestris is the specific epithet The genus + species is the Latin binomial; note that the genus and species are in italics (or underlined), the genus is capitalized and the species epithet is in lower case L. stands for Linnaeus, the authority Agaricus campestris is the type species of the genus Lange first described this fungus as Coprinus bisporus Imbach later transferred the species to Agaricus Nomenclature: the “allocation of scientific names to the units a systematist considers to merit formal recognition.” (Hawksworth et al., 1995. The Dictionary of the Fungi). The nomenclature of fungi is governed by the International Code for Botanical Nomenclature, as adopted by the International Botanical Congress. To determine the correct name for a taxon, certain steps must be followed, including: Effective publication Valid publication Description or diagnosis in Latin Clear indication of rank 80,000 -100,000 species of fungi described 1,700 new species described each year Most fungi are morphospecies, delimited on the basis of phenotype, most commonly by morphological characters, and represented by a type specimen. A biological species is “a population, or a group of populations, among which there is interbreeding. Two individuals might not be able to interbreed, but they are still members of the same species (conspecific) if they are part of the same gene pool.” ( Futuyma, D.J. 1998. Evolutionary Biology). A phylogenetic species is “irreducible (basal) cluster of organisms diagnosably different from other such clusters, and within which there is a parental pattern of ancestry and descent” (Cracraft, J. 1989. Speciation and Its Consequences). Miller & Huhndorf. 2004. Mycologia 96:1106-1127 Fungi=absorptive heterotrophs Animals=phagotrophic heterotroph Heterotroph (chemo-organotrophs): an organism incapable of synthesizing carbohydrates from inorganic sources; requires preformed organic compounds produced by other organisms Plants=autotrophs Cylindrical, branching filaments composed of a tubular cell wall filled with cytoplasm and organelles Most fungal hyphae are 2-10 m diameter Fungal hyphae form a network called a mycelium (pl. mycelia) Septa—regular cross-walls formed in hyphae. Hyphae with septa are septate, those lacking septa except to delimit reproductive structures and aging hyphae are called aseptate or coenocytic. primary septa are formed as a process of hyphal extension and generally have a septal pore, which allows for cytoplasmic and organelle movement. Secondary or adventitious septa are imperforate, formed to wall off ageing parts of the mycelium. Structural components: chitin microfibrils [ß(1-4)-linked polymer of Nacetylglucosamine] chitosan in Zygomycota [ß(1-4)-linked polymer of glucosamine] ß-linked glucans Gel-like components: Mannoproteins (form matrix throughout wall) Antigenic glycoproteins, agglutinans, adhesions—on cell wall surface Melanins—dark brown to black pigments (confer resistance to enzyme lysis, confer mechanical strength and protect cells from UV light, solar radiation and desiccation) Plasma membrane—semi-permeable 1--3 m diam 3--40 chromosomes Up to 13--40 Mb (million base pairs) DNA coding for 6,000 to 13,000 genes Organism Escherichia coli Saccharomyces cerevisiae # bp # genes 4,600,000 4288 13,000,000 5885 Arabidopsis thaliana ~120,000,000 ~10,000 Drosophila melanogaster ~170,000,000 ~12,000 ~3,400,000,000 ~80,000 humans Using the common bread mold Neurospora crassa, in 1941 developed the classic concept of “one gene, one enzyme” Awarded Nobel Prize in 1945 Many fungi have the ability to reproduce by asexual and sexual means Anamorph= asexual stage Mitospore=spore formed via asexual reproduction (mitosis), commonly called a conidium or sporangiospore Teleomorph= sexual stage Meiospore=spore formed via sexual reproduction (e.g., resulting from meiosis), type of spore varies by phylum Asexual and sexual reproduction may be separated in time and space The holomorph is the entire fungus—including asexual and sexual stages if both are formed The vegetative thallus predominates in the life cycle of a fungus The thallus may be haploid (1n), dikaryotic (n+n) or diploid (2n) in different groups of fungi Ploidy of thallus is determined by the timing of these events in the life cycle: Plasmogamy (cell fusion) Karyogamy (nuclear fusion) Meiosis (reduction division)