The pciniaresentation describe the life cycle of Pythium, Albugo, Erysiphae, Claviceps, Ustilago, Puccinia. Albugo is a genus of plant-parasitic oomycetes. Those are not true fungi ( Eumycota), although Albugo candida, on Capsella bursa-pastoris oospores) and asexual spores (called sporangia) in a many-stage (polycyclic) disease cycle . Albugo candida commonly known as white rust, is a species of oomycete in the family 1 Distribution; 2 Hosts; 3 Symptoms; 4 Life-cycle; 5 References; 6 Further This pathogen infects plants in the family Brassicaceae; the growth stages.
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The zoospores after swimming for sometime encyst and germinate by a germ tube which reinfects the host plant Fig. The former is of tinsel type and the later whiplash.
This organism causes white rust or white blister diseases in above-ground plant tissues. The paragynous antheridium comes in direct contact with the oogonium at the side C. This is a question and answer forum for students, teachers and general visitors for exchanging articles, answers and notes.
The fertilisation tube passes through the thin spot in the oogonial wall and enters the multinucleate periplasm. It is described as the penetration site Fig. When the sporangia are formed in abundance on innumerable sporangiophores, the pressure is caused; the host epidermis ruptures and hundreds of sporangia are seen on the surface of the host in the form of white creamy powder forming pustules.
They hold that the first two divisions of nuclei which occur in the gametangia constitute meiosis. Successively the sporangia develop by constriction method, in basigenous chains. The contents then emerge in the form of one or two simple or branched germ tubes. It is rich in lipid vesicles and reserve vesicles containing electron dense inclusions reserve globules.
The vesicle soon bursts to liberate the zoospores.
Albugo candida – Wikipedia
The outer region is called the periplasm containing thin cytoplasm, many nuclei and many vacuoles. The lower two-third portion of sporangiophore is narrow, thick-walled, with a undulating surface whereas the upper one-third is broader, thin-walled with a smoother surface. Each oospore produces forty to sixty zoospores. They are then blown away in the air by wind or washed away by rain water.
The sporangial wall increased 3-fold the thickness. The mature sporangiophores are thus longer, more thick-walled and show annellations. Such oospore is called a compound oospore. At the point of contact of antheridium with the oogonium, the walls become very thin.
According to them, the young oospore is delimited from the vacuolate periplasm by an electron-dense cell wall. Albugo Albugo candidaon Capsella bursa-pastoris Scientific classification Phylum: On root crops, infected leaf removal either by mowing or plowing prior to harvest will limit the spread of the pathogen during harvest. The central protoplasm with denser consistency surrounded by periplasm is called the oosphere or the egg. The oogonium develops a papilla like out growth at the point of contact with the antheridium.
Soon the encysted zoospore cyst puts out a germ tube E which enters the host tissue through a stoma. It is represented by 25 species.
Albugo: Habitat, Symptoms and Reproduction | Mastigomycotina
The antheridium and oogonium develops deeper in the host tissue in close association within the intercellular spaces. The process is repeated resulting in a chain of sporangia. The thick oospore wall then cracks.
National Center for Biotechnology Information. The inner layer is thin and culled the endospore. The oospore is thick-walled and three-layered.
White rust plant diseases caused by Albugo fungal-like pathogens should not be confused with White Pine Blister RustChrysanthemum white rust or any fungal rustsall of which are also plant diseases but have completely different symptoms cydle causal pathogens. The two soon establish contact.
The tips of hyphae constituting the mat alvugo verticlly into short, upright, thick-walled, unbranched club-shaped hyphae. Of the two flagella one is of whiplash type and the other tinsel type Fig. In the course of time a mycelial base is established inside the host tissue cotyledons. Biological Specialization or Physiological Specialization 6. The encysted zoospore cyst then germinates.
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Stevens suggested that Albugo lifee diploid somatic nuclei which undergo meiosis in the gametangia antheridia and oogonia.
The outer layer of the oospore wall is comparatively thicker. Biology, Ecology and Management. Before fertilization a deeply staining mass of cytoplasm, Fig. The cytoplasmic membrane which is closely appressed to the hyphal wall forms lomasomes. Retrieved from ” https: The septum is formed by the centripetal growth of the inner layer of the sporangiophore wall C.
A germ tube emerges through the split. Zygotic canddia divides only mitotically and not meiotically.