The Anamorphic Fungi.pptx
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Deuteromycotina is a polyphyletic group of fungi that reproduce asexually by the generation of conidia (asexual spores). Because these fungi lack a sexual reproductive cycle, they do not have a known sexual stage in their life cycle. The categorization of Deuteromycotina has been debated, as the lack of a documented sexual stage has made determining their evolutionary links with other fungal taxa problematic. With the introduction of molecular biology tools in recent years, several Deuteromycotina species have been reassigned into other fungal phyla based on genetic similarities. Aspergillus, Penicillium, and Trichoderma are examples of Deuteromycotina that are commonly used in the biotechnology and pharmaceutical industries for the synthesis of antibiotics and other chemicals. However, genetic analysis has led to the reclassification of many of these fungi into different phyla.
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The Anamorphic Fungi.pptx
- 1. The Anamorphic Fungi Deutromycetes, MitosporicFungi, Imperfect Fungi, Asexual Fungi By V.AjayDesouza M.Sc.(Agri) Plant Pathology Annamalai university ajaydesouza0003@gmail.com
- 2. Anamorphic Fungi Anamorphic fungi are known as septate fungus, which are unable to reproduce sexually and only reproduce asexually. These are referred to as "imperfect fungi" because they lack the sexual stage or the "perfect stage." Since these fungi only produce mitospores, or conidia, and do not produce meiospores, they are referred to as mitosporic fungi.
- 3. Since the conidia that these fungi produce resemble those of Ascomycota, it is believed that these organisms are Ascomycetes that abandoned their sexual stage. The sexual stages are often identified, and depending on the type of meiospore—ascospore or basidiodpore—they have been moved to Ascomycota and occasionally Basidiomycota.
- 4. Reproduction Conidia can form either directly on the hyphae or on the conidiophore. The latter can grow on the hyphae or in cavities known as Acervuli and Pycnidia. It is comparable to the creation of conidia in Ascomycota.
- 5. Acervuli Pycnidia (Sing. Pycnidium) are flask- to globose in shape, with a little papilla or long neck with an apical opening termed an ostiole. The pycnidia are embedded in the host tissue beneath the epidermis and have their own wall that is bordered by conidiophores. Conidia can be hyaline or pigmented, as well as septate or non-septate. (Sing-Acervulus) are flat, disk- shaped cavities that occur beneath the plant's cuticle or epidermis. Short conidiophore grow from hyphae-formed immersed pseudoparenchyma. Conidia cause the overlying epidermis and cuticle to tear. The acervulus does not have its own wall. Reproduction Asexual fruiting body
- 6. Classification Anamorphic fungi are not the same as other fungus and hence cannot be categorized into phylum, class, order, and so on. Their only designations are genus and species. Previously, these were classified as sub-divisions (Deuteromycotina, Deutromycetes), but their lower status was known. (Deutero means "secondary"). However, this division into classes or orders is no longer valid, and these fungi are now arranged alphabetically by genera (Hawksworth et al., 1995; Krik et al., 2001; Dictionary of Fungi).
- 7. Genus ALTERNARIA There are various saprobic and parasitic species in the genus. The mycelium, which is branching and septate, is hyaline (transparent) at first but darkens over time. The conidiophore is short and has obclavate conidia with pointy distal ends and transverse and longitudinal septa. Scars are left on the conidiophore after separation. A. solani and A. tenuis are the most prevalent species that cause major disease condition
- 9. ● Conidia or mycelia lei in the soil or on plant debris and perennate the fungus in absences of the crop ● When the potato crop is sown and the leaves formed (3 weeks) the conidia reach the leaves through wind and germinate ● The germ tube enter the leaves through stomata or by direct penetration of the epidermis, form inter or intra cellular mycelium. ● The mycelium secretes enzymes and toxins which kills the cells. The fungus derives nutrition from these dead cells. Life cycle of the Alternaria solani
- 10. ● When the cells dies leaf spots appears ● Clavate conidia having both transverse and longitudinal septa are formed on the hyphae ● The conidiophore show ‘knee’- like swellings which indicates the position of the detached conidia. The conidia are wind- disseminated and in this way disease spread to more plants throughout the season. In the absence of the host plant., the hyphae or conidia remain in the fallen leaf tissues or in the soil Life cycle of the Alternaria solani
- 12. ● Aspergillus species that develop sex organs are now classified as Ascomycota genera Eurotium, Emericella, or Neosartorya, and are no longer referred to as Aspergillus. Those, like A. niger, that have not yet been linked to a sexually reproducing organism are classified as Aspergillus. Genus ASPERGILLUS
- 14. ● Colletotrichum is known as anthracnose fungus because it produces anthracnose (coal-like) leaf spot disease in several crops.Gloeosporium, a previous genus, has been combined with Colletotrichum. Acervuli can be subcuticular or subepidermal, with a distinctive ring of black setae around the circumference. Genus COLLETOTRICHUM (anthracnose fungus)
- 16. Anthracnose fungus- Colletotrichum • The conidia are hyaline elongated, with rounded ends and a slightly narrower centre. Colletotrichum is responsible for several significant diseases, including red root of sugarcane caused by C. falcatum, bean anthracnose caused by C. lindemuthianum, and jute anthracnose caused by C. corchorum.
- 17. ● Fusarium species are significant because they cause root rot and wilt disease in a variety of plants. The water received by the roots is not transmitted to the leaves due to hyphae blockage of the xylem arteries in wilt diseases, as it is in undesired plants. All Fusarium wilt-causing species are known as Fusarium oxysporum because their leaves droop, dry, and die because of a lack of water. The septate and branching hyphae. Conidiophores are short and made up of spore- producing cells known as phialides. Genus FUSARIUM
- 18. ● These each produce curved, sickle-shaped macroconidia and globular microconidia. Because the spores are held together by slime, they are known as slime spores. They are not spread by wind. Genus FUSARIUM
- 19. Genus FUSARIUM
- 20. ● Conidia are brown, cylindrical, and transversely septate, resulting in numerous cells. There are 20 Helminthosporium species that cause major plant diseases such as brown leaf spot of rice (H. oryzae), maize leaf spot (H.maydis), and Victoria blight of oats (H.victoriae). ● Much research has been conducted on the toxins secreted by H. victoriae and H. maydis. It has been demonstrated that the pathogenicity of these species is due to their toxins. These toxins have greatly helped to our understanding of parasitism's mechanism. Genus HELMINTHOSPORIUM
- 22. ● The species of penicillium that reproduce purely asexually are still classified as penicillium, whereas the sexually reproducing species have been classified as Eupenicillium or Talaromyces of the Ascomycetes class. Genus PENICILLIUM
- 23. ● Conidia are spindle-shaped or clavate, five celled, with three coloured centre cells and hyaline terminal cells. The higher terminal cell, known as the apical hyaline cell, has 2- 3 setae. The lower hyaline cell is the posterior hyaline cell. It has a short pedicel from which the conidia of the Acervulus are attached. Pestalotiopsis causes a variety of serious diseases, including grey blight of tea (P.theae), leaf spot of litchi (P. paucista), and mango leaf spot (P. mangiferae). Genus PESTALOTIOPSIS
- 24. Genus PESTALOTIOPSIS Upper hyaline cell Setulae Middle dark cells Lower hyaline cell pedicel
- 26. ● Hyaline, septate, branching hyphae grow inter and intracellularly within the host. ● Acervuli are generated beneath the epidermis and have a unique basal wall from which conidiophores and conidia emerge. ● Later, the epidermis breaks and the conidia fall to the leaves' surface. ● The conidia are spindle-shaped and 5-celled, with three dark center cells and three hyaline terminal cells. ● The apical hyaline cells contain 2-3 setae, while the lower hyaline cells have a pedicel. ● Conidia germinate mostly through the center cells and infect additional leaves. Mycelium remains in dead host tissues in the absence of the host. Life cycle of Pestalotiopsis theae
- 27. Life cycle of Pestalotiopsis theae
- 28. ● Phyllostica is a widespread fungus that causes leaf spots. The pycnidia have thin walls and are dark brown in colour, resembling black dots on the leaf spot. ● When the leaf spots are probed with a needle and studied under a microscope, an endless stream of minute conidia begins to flow out of the pycnidia. ● The conidia are hyaline, 1celled, globose to oval, and guttaulate, meaning they contain one or more oil drops. ● The conidia are distinguished by a minute apical mucilaginous appendage. Genus PHYLLOSTICA
- 30. ● Conidia are pyriform, bi-septate, with a tiny hilum at the base. These are carried apically on conidiophores that emerge through the stomata P.oryzae causes "the blast of Rice" Genus PYRICULARIA
- 32. ● Conidia can be found in plant debris, soil, or collateral hosts. Wind-blown conidia land on the leaves when the rice crop is accessible. ● Germ tubes enter the leaves during germination to form an intracellular mycelium. ● The fungus develops within the host tissue, producing conidiophores that emerge from the stomata and bear conidia. ● Throughout the season, the conidia spread the infection. When the crop is harvested, the residue is left in the fields as debris. ● Alternatively, until the next rice crop is available, the conidia may infect and live on other collateral hosts. Life cycle of Pyricularia oryzae
- 33. Life cycle of Pyricularia oryzae
- 34. Spore dissemination Alternaria, Pyricularia and helminthosporium, the spores are dry spores and are easily blown by winds
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