B. Sc. (Ag). First Year, Second Semester Course Title: Fundamentals of Plant Pathology Topic: Important terms used in plant pathology & History of Plant Pathology Course Teacher: Dr. D. S. Tomar, Associate Professor, COA, Tikamgarh

Definition of pathology: Pathology: The term pathology etymologically means (Gr. Pathos = Suffering; logos = the study or to speak or discourse) the study of the suffering. Thus plant pathology is the study of the suffering plants.

Plant pathology: Plant pathology or Phytopathology (phyton – plant; pathos – ailments; logus – knowledge) is that branch of agricultural, botanical or biological science which deals with the cause; etiology, resulting losses and management of plant diseases. It is a science similar to that of medicine and veterinary which deal with diseases of man and animals, respectively.

Objectives of plant pathology: The science of plant pathology has four major objectives: 1. Etiology or aetiology: Study of living and nonliving entities. 2. Pathogenesis: Study of mechanism of disease development. 3. Epidemiology or Epiphytotic: Pathogen multiplies and spread. 4. Control: Development of suitable methods of controlling the disease.

Important terms used in plant pathology: Aggressiveness: The capacity of a parasite to invade and grow in its hosts plant and to reproduce on or in it (Term used by Gaumann). Antibiosis: One organism is harmed by another. Atrophy: When the organ or tissue does not develop at all. Biological control: In which one organism is used to eliminate or reduce the disease caused by an another organism. Biotype: A group of microorganisms that have the same genetic characteristic. Colonization: The pathogen advances through the tissues of host to varying extents. Compound interest disease: Some pathogens spread from plant to plant during the growing season. There are several generations of pathogen in life of crop. For example, Late blight of potato and black stem rust. Disease cycle: The chain of event involved in disease development including the stages of development of the pathogen and effect of the disease on the host. Disease: The disease is a pathological process caused by continuous irritation. (or reaction between the plant and the causal agent Disorder: When abnormal physiological changes due to non-parasitic agents. Endemic disease: When a disease is more or less constantly present from year to year in a moderate to severe form in particular country of part of the earth, it is classified as endemic to that area. Epidemic or Epiphytotic: A wide spread and destructive out break of a disease in plant population. Epidemiology: The study of factors affecting outbreak and spread of an infectious disease. Etiology or aetiology: Study of the cause of the plant disease and nature of the causal agent. Facultative parasite: They usually lives saprophytes but under favorable conditions lives as parasite (Ex. Rhizops and Botrytis). Facultative saprophyte: They usually live as parasites but can grow saprophytically (Ex. Phytophthora and Ventura). Hemi-biotroph: When it attacks living tissues in the same way as biotrophs but continuous to grow and reproduce after the tissue is dead. Host: A plant or animal that is invaded by a parasite and from which the parasite obtains its nutrients. Hyper sensitivity: The plants develop minute necrotic flecks or spots resulting from rapid death of the cells in the vicinity of invading pathogen (infection court) so that the progress of pathogen is halted. Hyperplasia: Increase in size of tissue (organs) due to increased cell division (increase in number of cell). Hypertrophy: Abnormal increase in the size of the cell. Hypha (Pl. Hyphae): A single thread of the fungus mycelium. Hypoplasia: Reduced development of the whole plant, parts of the plant, certain tissue, flowers, or fruits (sterility) or chlorophyll (chlorosis). Iatrogenic disease: This term first use by James G. Horsefall (1972). All crop protection chemicals which resulted in either the appearance of a new disease. Johnson (1946) was that first to report an iatrogenic disease due to pesticides. Immune: Exempt from disease, cannot be infected by a given pathogen. Infection court: The location where infection of the host parts take place. Infection: The establishment of parasitic relationship of a parasite with the host. Infectious disease: A disease that is caused by a pathogen which can spread from the disease to a healthy plant. Infestation: Presence of disease or pathogen in a population of plants. Inoculate: To bring a pathogen into contact with a host. Inoculation: The arrival or transfer of a pathogen on to a host. Inoculum potential: The number of infective particles present in the environment of uninfected host, or combined energy of propagules to cause infection (The term coined by Horsfall, 1932). Inoculum: The portion of a pathogen which is transmitted to or contact a host and is capable of infecting the host. Integrated control: An approach to plant disease management that uses all available methods of control of a disease. Invasion: The spread of a pathogen in the host. Life cycle: The successive stages in the growth and development of an organism that occur between the appearance and reappearance of one stage (spore, eggs, etc). Mutualism: Mutually beneficial relationship between organisms. Mycelium: The mass of hyphae that make up body (thallus) of a fungus. Necrosis: A kind of symptom of pathogenic infection by a microorganism, including viruses, characterized by death and consequent disintegration of the infected plants (death of the infected tissue). Necro-troph or Pertho-troph or Perthophyts: When parasite is kill, host tissues in advance of penetration and then lives as a saprophytes. Obligate parasite or biotroph: A parasite that, in nature, can grow and multiply only on a living organism. They can not grow on artificial culture (Ex. Rust, Smut, Powdery mildew). Obligate saprophyte: An organism which feeds on dead organic matter. Pandemic disease: When a disease is prevalent throughout the country, continent or the world it is known as pandemic disease. Parasite: An organism that lives on or in any other living organism. Pathogen: An entity that can incite disease (living organism). Pathogenesis: The chain of events that occur from the time the pathogen enters the host until its effects become visible. Pathogenicity: The ability of a pathogen to cause disease. Pathotype: A subdivision of a species is distinguished by common characters of pathogenicity, particularly relationed to host range. Pathovar: A pathological variety of species of bacteria. Race: A species sub group of fungi, bacteria, nematodes or viruses that differs in virulence symptom expression to some extent in host range from other races (or stains) an the rate of the species. Resistant: Possessing qualities that hinder the development of a given pathogen little or no infection. Seasonal carryover: When susceptible host is absent from the field, the pathogens perennate in different ways. Simple interest disease: Many pathogens do not spread from plant to plant during the growing season of crop. There is only one generation of the pathogen in the life of crop. For example soil borne fungi attacking roots and seed borne smut infecting seedling. Sporadic disease: Diseases which occurs at very irregular intervals and locations na in relatively few instances. Spread: Spread means that pathogen reaches and shall infect plants. Susceptible: Lacking the inherent ability to resist disease or attack of a given pathogen, non-immune. Symbiosis: A mutually beneficial association of two or more organism of different kinds. Symptom-less carrier: The disease causing organism (usually a virus) is present but causes no symptoms. Symptoms: The external and internal reactions of the host to invasion of a pathogen, alteration in the plant due to infection, signs of infection. Syndrome: Thus diseased plants show a number of visible symptoms known as syndrome. Synergism: When the combined effect of two organism acting is greater than the some of two separate effects. Tolerance: The ability of a plant to sustain the effects of a disease without dying or suffering serious injury or crop loss. Transmission or Dissemination or Dispersal: The transport of inoculum from a diseased plant to healthy plant or from one place to another. Virulence: Relative ability to cause disease, the degree of pathogenicity of a pathogen. (Virulence is used as a measure or degree of pathogenicity in a qualitative sense). Virulent: Capable of causing a sever disease, strongly pathogenic, highly aggressive.

HISTORY OF PLANT PATHOLOGY:

Chinese practicing crop rotation as early as 3000 BC and in the first century BC they were supposed to keep the field fallow for a year if the field gave poor yield in the second year. Fan Sheng-Chin: Seed health was mentioned in china in the first century BC. Theophrastus (384-322 BC): A Greek philosopher and writer, he was disciple of Plato and Aristotle, two of his books Historia Plantarum and Decausis Plantarum. In his writings, mentioned plant diseases (rusts, mildew, blight etc) but expressed the opinion that these diseases were due to bad nutrition and bad air. Varro (116-27 BC) and Maro (70-19 BC): Mention treatments of seed. Varro also believed in worship of the rust god Robigus. In his Rerum Rustcarum the best treatise on agriculture of that time. Varro included 12 councillor gods including Robigus and Flora. Koutilya (3700 BC and later): Kautilya also known as Chanakya and vishnugupt had written Arthashastra and composed the four Vedas. Rigveda and Yajurveda are hymns and rituals. Samveda and Atharveda (3000 BC and later): Which contained charms and spells for warding off evils and diseases. This composition specifically mentioned blight as a disease and its control. During the Vedic period agriculture in India was fairly developed. Other diseases as powdery mildew, rust and tumors on trees, fungi (mushroom) and algae are also mentioned in Veda. Susruta (400 BC): The great Indian pioneer in medicine and surgery who wrote Susruta- Samhita. Charak; He was also a man of medicine, aware of diseased conditions in plants and often compared them to diseases in man. Parashar: The oldest text on Indian agriculture Krishi Prashar was written by Parashar. Tholkappier (200 BC): Tamil poet considered plants as living beings mentioned monocoat and dicoat plants and wrote about benefits of rice-legume rotation. Varahamihir (505-587 AD): In his Brihat-Samhita included a chapter on science of plant life. He writing about fungi (mushroom) and algae, he also advocated the importance of good seed and seed treatment for good and healthy seedlings. He is also suggests value of green manuring and organic amendment. Surapal (1000 AD): He writes the text, Vriksharyurveda. It covers such topics as importance of trees, their location, soil types, method of propagation, tree nutrition, diseases and their treatment. Surapal divided plant diseases in to two categories internal and external. He prescribed treatment of pests for platting trees, treatment of seed and treatment of standing trees. Kautilya (3321-296 BC): In his Arthashastra listed treatments of seed in addition to recommendations for punishment against sale of spurious seed. He also recommended treatment of cut ends of sugarcane cuttings before planting.

DISCOVERY OF THE ROLE OF FUNGI:

Dutchman Loeuwenhoek (1675): Develop the first microscope and in 1683 described bacteria seen this microscope. Micheli (1729): Italian botanist studied fungi and saw their spores under the microscope. Tillet (1775): French botanist published a paper on bunt or stinking smut of wheat and proved that such wheat seeds that contained a black powder on their surface. Persoon (1801) and Fries (1821): Give the classification and nomenclature of fungi. Provest (1807): French scientist proved that diseases are caused by microorganism. Discovering the life cycle of the bunt fungus. He also mentioned the fungicidal and fungi static properties of chemical treatments. R. L. Tulasne and C. Tulasne (Tulasne brothers): France scientist, he had produced illustrated description of rust and smut fungi. Berekely (1846), Morren (1845) and Von Martius (1842): These few scientists who believed that late blight of potato was caused by the fungus found associated with it. Wow ever, they had no experimental evidence to prove it. Anton de Bary (1831-1888): German scientist, he known as father of plant pathology, the foundation of modern experimental plant pathology. In 1853 he confirmed the findings of Provest. In 1861 he experimentally proved that the fungus Phytophthora infestans was the cause late blight. He studied other diseases like rusts, smuts, downy mildews and rots. The discovery of heteroecious nature of rust fungi was made by him. In 1886 he reported the role of enzymes and toxins in tissue degradation caused by Sclerotina sclerotiorum. Brefeld (1875-1912): A colleague of de Bary, developed method of artificial culture of microorganism. Jones (1905): Reported the role of cytolytic enzymes in soft rots caused by bacteria. Brown (1915): Recognized the role of pectic enzymes which was followed by discovery of the role of celluloses. Tanaka (1933): The first time role of toxin experimental proof was obtained in black spots of pear caused by Alternaria. Orton (1900-1909) and Biffen (1905-1912): Both are mentioned as pioneer in the field of resistance breeding. Biffen (1905): Described inheritance of resistance to yellow rust in two varieties of wheat and their progenies. Orton (1909): Working with wilt diseases of cotton watermelon and cow pea developed varieties resistant to the disease.

Erickson (1894): Swedish scientist, the variability among fungi was first discovered. He reported the existence of physiologic races in the rust fungi. Ward (1903) and salmon (1904): Discovered physiologic specialization in fungi causing rust and powdery mildew of cereals. E. C. Stakman (second decade): University of Minnesota, USA. After prolonged studies he came to conclusion that due to continuous evolution of races and biotypes in botanical species of the rust fungi their pathogenic capability goes on changing in their favor and as a result the resistance capability of the host also shows changes. Flor (1946): Working with linseed rust advanced the gene for gene concept of disease resistance and susceptibility. Vanderplank (1963): Suggested that there are two kinds of resistance; one, controlled by few “major” genes is strong but race specific (vertical resistance) and the other determined by many “minor” genes is weaker but effective against all races of a pathogen species (horizontal resistance). Gaumann (1946), Muller (1961) and Cruick Shank (1963): The phenomenon of resistance through hypersensitivity. Confirmed accumulation of antimicrobial plant metabolites called phytoalexins during pathological processes and their role in resistance.

DISCOVERY OF THE ROLE OF BACTERIA:

Robert Koch (1876): Give the prove of the bacterial etiology of anthrax disease. He gave the famous Koch’s postulates for proving that a particular disease. T. J. Burill (1882): USA scientist, first time reported that a plant disease fire blight of pear caused by a bacterium Ervinia amylovora. E. F. Smith (1895): USA scientist, Father of phyto bacteriology. Discovery of most of these bacterial plant diseases. He introduced for study of bacterial plant diseases during 1905-1920. Smith was also among the first to notice and study the crown gall disease (1893-1894). Later (19877): It was demostered by Chilton and his team that the crown gall bacterium trans forms normal plant cells into tumor cells by introducing into them a plasimid part of which becomes inserted in the DNA of chromosomes of the plant cells. Alfred Fischer (Germany): He had claimed to have seen bacteria in plant cell.

DISCOVERY OF THE ROLE OF VIRUSES:

The year 1882 may be considered as the beginning of the era of plant virology. Adolf Eduard Mayer (1882-1886): German scientist reported the tobacco mosaic disease was neither due to a microorganism nor due to nutritional imbalance. Describe the nature of causal agent by artificial inoculation and also showed that boiling of the sap of infected leaves destroyed infectivity of the causal agent. Dimitrii Ivanowski (1892): Russian botanist. He had confirmed the finding of Mayer regarding transmission of tobacco mosaic agent and found that the causal agent could pass through filters with pores. The filtered sap is infective for month. Martinus Wilhem Beijerink (1898): Dutch scientist confirmed the finding of Mayer and Ivanowski. He concluded that the causal agent of tobacco mosaic was some thing other than a microbe. He was convinced that the agent was not a bacterium but a Contagium Vivum Fluidum a contagious living fluid. W. M. Stanley (1935): USA, he was able to obtain a crystalline protein by treating juice of TMV infected leaves with ammonium sulphate. This crystalline substance remained infective. The virus and autocatalytic protein is can multiply with in living cells.

F. C. Bawden and N. W. Pirie (1936): Britain scientist showed that TMV was a nucleo- protein and contained phosphorus. The specific nucleic acid in TMV was identified as ribonucleic acid (RNA). H. O. Holmes (1929): Provided a method by which the quantity of the virus in tissues could be estimated. He showed that the amount of virus present in a plant sap preparation is proportionate to the number of local lesions produced on an appropriate host plant leaf rubbed with that sap. Gieerer and Schramm (Germany) and Fraenkel Conrat (1956): U. S. A. showed that TMV nucleicacid freem from its protein coat, could alone cause infection provided it was protected from inactivation. Electron Microscope Developed (193.9): Kausche and colleagues for the first time saw the virus particles with the help of this microscope. T. O. Diener (1971): Reported that potato spindle tuber disease was caused by a small naked single stranded circular molecule of infectious RNA which he called viroid. D. Herelle (1971): Give the name of phase his means bacteriophase.

DISCOVERY OF THE ROLE OF MLO & RLBs:

E. N. Nocard and E. r. Roux (1898): Succeeded in growing the organism in artificial medium and the organism are now known as mycoplasma mycoides. Doi (1967): Doi and his colleagues in Japan observed that mycoplasma like bodies were constantly present in the phloem of plants suffering from leafhopper transmitted yellows diseases till then considered as virus diseases although virus particals had not been seen. Ishiie and colleagues (1967): Reported that the mycoplasma like bodies temporarily dis appeared when the plants were treated with tetracycline antibiotics. Davis and Colleagues (1972): Observed a motile helical wall-less micro organism associated with corn stunt disease. They called it spiroplasma. (1973): Prokaryotes was discovered in citrus plants attacked by greening disease. (1974): Gram negative character of the organism was confirmed.

DISCOVERY OF THE ROLE OF PROTOZOA (IN PLANT PATHOLOGY):

(1909): Flagelate protoza had been found in latex bearing cells of plants in family Euphorbiaceae. Stahel (1931): Found flagelates infecting the phloem of coffee trees and causing abnormal phloem formation and wilting of trees. Vermeulen (1963): Confirmed the findings of Stahel. (1976): Flagellates were reported to be associated with several diseases of coconut and oil palm trees in South America and Africa. HISTORY OF NEMATOLOGY:

Borellus (1656): First time discovered the vinegar eelworm (sirik sutrakrmi). Needham (1743): He discovered the first plant parasitic nematode as seed gall or cockles (Anguina tritici) from England. Roffredi (1755): Give the proof of Needham discovery. Barkely (1855): Reported the cucumber root not nematode. Kuhn (1857): Stem nematode Ditylenchus dipsaci reprted by him. Shacht (1859): Cyst nematode found in sugar beet as Heterodera schachtii. Goeldi (1887): Gall formation in coffee root by Meloidogyne exigua. Bastian (1837-1915): He known as father of Nematology and he write a monograph of Anguittulidae in 1866. Otto Butschli(1873): Reported the soil nematode. Stekhoven (1941): He writes a manual of agricultural Helminthalogy. T. Gouday (1933): First book on plant parasitic nematode and disease they cause written by him. T. Gude (1951): Second book on Soil and Fresh Water Nematode written by him. Josephleidy (1851): First work on Nematology in USA. Cobb (1859-1932): Known as father of American Nematology. He writes laboratory manual in 1918. B. G. Chitwod and M. B. Chitwod (1950): He writes a book An Introduction to Nematology. J. R. Christie (1959): Plant Nematodes their bionomics and Control written by him as a best book of Nematology.

History of Nematology in India: Barber (1901): First plant parasitic nematode in India reported from south India tea root knot nematode. Butler (1906-1919): Described Ufra disease of rice caused by Ditylenchus angustus and black pepper root knot nematode. Ayyar (1934): Studies on the root knot Nematode of vegetables and other crops. Dastur (1936): Described the White Tip of Rice caused by nematode Aphelenchoides sp. Jones (1961): Reported potato cyst Nematode caused by Heterodera rostochiensis. Siddiki (1959) & Das (1960): Study on the plant parasitic nematode in soil.

PLANT PATHOLOGY IN INDIA:

The study of fungi in India was initiated by Europeans in the nineteenth century. They used to collect fungi in India and send them for identification to laboratories in Europe. D. D. Cunningham and A. Barclay (1850-1875): Both are started identification of fungi in this country. K. R. Kirtikar: He was the first Indian scientist who collected and identified fungi in this country. E. J. Butler: Initiated an exhaustive study of fungi and diseases caused by them. The diseases a detailed account of which was given for the first time by the butler, inoculated wilt of cotton and pigeon pea, different diseases of rice, toddy palm, sugarcane, potato and rust of cereals. He writes a monograph on Pythiaceous and allied fungi. Best contribution of butler to plant pathology in India still exists in the form of the classic “Fungi and Diseases in Plants” written by him and published from Calcutta in 1918. Butler was known as father of Indian plant pathology. He was left India in 1920 to join as first director of the imperial Mycological Institute (now CMI) In England. J. F. Dastur (1886-1971): Detailed study of fungi and plant diseases. Special field of study was the genus Phytophthora and diseases of castor and potato caused bi its species. Duster was internationally known for establishment of the species Phytophthora parasitica from castor. G. S. Kulkarni: Published exhaustive information on downy mildew and smut of sorghum and pear millet. S. L. Ajrekae: Studied wilt of cotton smut of sugarcane and ergot of sorghum. B. B. Mundkur: Started work on control of cotton wilt through varietals resistance. He was also responsible for identification and classification of a large number of Indian smut fungi. A classic book “Fungi and Plant Diseases” written by him. The Indian Phytopathological Society started in 1948 with its Journal Indian Phytopathology in. K. C. Mehta: From Agra College, described the disease cycle of cereals rust. J. C. Luthra and associates, develop the solar heat treatment of wheat seeds for the control of loose smut. Before the advent of systemic fungicides this was the only sure method of control of this disease. Davis and Colleagues (1972): Observed a motile, helical wall less microorganism associated with corn stunt disease. They called it spiroplasma. Dye et al. (1980): Give the pathover name for bacteria.

B. Sc. (Ag). First Year, Second Semester Course Title: Fundamentals of Plant Pathology Topic: General character of fungi and their classification Course Teacher: Dr. D. S. Tomar, Associate Professor, COA, Tikamgarh

The Fungi

In this part of the course, we will be studying the organisms that are referred to as fungi (sing.=fungus). Although you have now studied various groups of plants and algae, as well as other eukaryotic organisms, in other courses, you will find that the fungi are probably the least understood among the eukaryotes. Looking back at my undergraduate career, prior to taking my first mycology class, I had a very negative concept of the fungi. My impression of fungi was that they were disease-causing organisms that were found in unsanitary conditions. Although this impression was not entirely wrong, fungi are so much more than that. They are also very beneficial organisms. We have derived a number of useful antibiotics from them, including the "wonder drug" penicillin. Without fungi, we would not have leavened bread, Roquefort and Camembert cheeses, beer, wine and other alcoholic beverages and some mushrooms, morels and truffles are considered to be delicacies among gourmands.

Characteristics of "fungi" in the broad sense

1. Achlorophyllous: Fungi cannot make their own food like plants. They are heterotrophs and depend upon other organism for their carbon source. Heterotrophs can further be divided into the following categories: a. Parasites: Organisms that derives their nutrition from the protoplasm of another organism (=host). b. Saprobes: Organisms that obtains their carbon source (=food) from the by-products of organisms or dead organisms. However, if the opportunity arises, some saprobes may become parasitic. Such organisms are said to be facultative parasites. c. Symbiosis: In the strict sense, this term refers to the habitual "living together" of different species. As such, there are a number of different categories of relationships that may fit under this term. However, we will define it in its most common usage: "The intimate association of two dissimilar organisms in a mutually beneficial relationship, e.g. lichens and mycorrhizae." This type of symbiosis is specifically referred to as a mutualistic symbiosis. 2. Eukaryotic: Fungi have membrane bound organelles, i.e. nucleus, mitochondrion, E.R., etc. Once upon a time filamentous bacteria called Actinomycetes were classified with fungi, but this is no longer the case. 3. The body or assimilative part of the fungus (=thallus) usually takes the following forms: a. Yeast: Unicellular fungi that reproduce, asexually, by budding or fission (terms to be defined later). b. Mycelium: The collective, filamentous strands that make up the fungal thallus. Strands of mycelium is referred to as hyphae (sing.=hypha). Mycelium may be of two types: i. Septate: Mycelium that is divided into discreet cells by cell walls that are laid down at regular intervals along the length of the mycelium. These cell walls are called septa (sing.= septum). ii. Coenocytic: Mycelium that is not divided up by septa and forms a continuous tubular network. Septa, however, are present occasionally, especially where reproductive structures occur and where the cell wall of the mycelium has been compromised. c. Some species may have have thalli that are mycelium and yeast. Such fungi are said to be dimorphic (=two forms). 4. The assimilative stage of the fungal body, i.e. mycelium or yeast, has a cell wall. In the strict sense organisms classified as fungi have cell walls composed primarily of chitin. 5. Fungi have a common nutritional mode: Absorption: The transport of food from their substrate into their cell walls. The following events occur in this mode of nutrition: a. If the available food that the fungus is using is soluble, i.e. a simple organic compound, such as simple sugars and amino acids, the mycelium or yeast cells can transport the food directly through their cell wall. b. If the available food is insoluble, i.e. a large, complex, organic compound, such as lignin, cellulose and pectin, then production the food must first be digested. Digestion is carried out by the production of various enzymes that are substrate specific and will break down insoluble food material to soluble compounds that can be transported through the cell wall. 6. Either sexual or asexual reproduction or both may occur by spores. Spores and/or gametes can be motile or not. However, in the strict sense as fungi are currently defined, only those organisms that produce nonmotile spores and gametes are classified as fungi. Nevertheless, we will be going over organisms that have motile spores, called zoospores, and motile gametes.

Classification of Fungi

Once upon a time biologist only recognized two kingdoms: Plant and Animal (this was how organisms were classified when I was an undergraduate). Fungi, as well as bacteria and algae were classified in the plant kingdom under this system and that is the reason that these organisms are traditionally studied in botany. In the case of fungi, MYCOLOGY is that part of botany that studies fungi. Although fungi are no longer classified as plants, there is still good reason to study them in botany. Fungi are most often associated with plants, commonly as decomposers, and pathogens, and as their benefactors, e.g. mycorrhiza, but "What is a fungus?" Based on what your studies on plants, in this course, you know that plants are known to be derived from a single algal ancestor from the algal division: Chlorophyta, i.e. they are monophyletic. Once upon a time, the fungi were also believed to be monophyletic and to be derived from an algal ancestor that lost its ability to photosynthesize. However, over time, with the discovery of new techniques in determining relationships between organisms, it was discovered that the fungi are made up of a polyphyletic group of organisms that, in some cases, are very distantly related to one another. Thus, organisms that we call fungi are not grouped together because they are closely related, but rather because they share a combination of characteristics that we will now go over:

Fungi, as well as bacteria and algae were classified in the plant kingdom, based mainly on the presence of a cell wall and the lack of ingestion of food material. However, *Whittaker (1969) erected the five-kingdom system, which is currently still the accepted system of classification of organisms. As a result, the fungi, algae and bacteria were placed in different kingdoms. While, the concepts of the five kingdoms have changed since Whittaker (1969), the classification of organisms into five kingdoms have persisted.

Although, our definition of a fungus has changed a great deal, by tradition, mycology classes have continued to study the same organisms that have been studied since the 1960’s and earlier. While mycologists have learned a great deal about the fungi in these last 30-35 years, there is still not agreement as to how best to classify the fungi, nor will there likely be any agreement at a later time. Some examples of the more popular classification schemes are reproduced below:

Over the last ten years, there have a great deal of changes in the concepts of the relationships of the various groups of fungi. The classification below represents one of the more recent systems and is based, in part, on molecular research that has been carried out in recent years. Because of time constraints, not all of the different taxa of "fungi" will be listed below :

Kingdom: Protista

Division: Myxomycota (Currently classified with protozoans)

Flagellated Fungi

 Division: Hyphochytridiomycota  Division: Oomycota

The above two divisions have also been placed in a recently erected Kingdom: Stramenopila. This kingdom includes the divisions Phaeophyta and Chrysophyta.

Kingdom: Myceteae (=Fungi)

Division: Chytridiomycota

Division: Zygomycota Division: Ascomycota

 Class: Ascomycetes o Order: Saccharomycetales and Schizosaccharomycetales (Yeast)  Filamentous Ascomycetes o Order: Eurotiales (Fruiting body a cleistothecium) o Order: Sordariales and Xylariales (Fruiting body a perithecium) o Order: Pezizales (Fruiting body an apothecium) o Order: Dothideales (Fruiting body an ascostroma)

Division: Basidiomycota

 Class: Basidiomycetes o Order: Agaricales (Mushrooms) o Order: Lycoperdales, Phallales and Nidulariales (Puffballs) o Order: Aphyllophorales (Polypores) o Order: Tremellales, Dacrymycetales and Auriculariales (Jelly Fungi)  Class: Teliomycetes (Rust)  Class: Ustomycetes (Smuts)

Division: "Deuteromycota" (Asexual Fungi)