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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Albugo| Life cycle| White Rust| Peronosporales|
It divides to form five or eight polyhedral uninucleate daugher protoplasts. It is known as the coenocentrum. The former is of tinsel type and the later whiplash.
It contains numerous nuclei, oil globules and glycogen. Further development of oospore if marked by the deposition of 4 layers, two on the outer and two on the inner side of the first original layer of the young oospore. The inner layer is thin and culled the endospore.
The tips of hyphae constituting the mat grow verticlly into short, upright, thick-walled, unbranched club-shaped hyphae. It is paragynous i.
It is separated by a cross wall from the rest of the male hyphae. It then rounds off and secretes a wall around it D. The base of the haustorium is surrounded by a collar like oeath which is an extension of the host cell wall. Soon the encysted zoospore cyst puts out a germ tube Cahdida which enters the host tissue through a stoma. It is represented by C. Usually one or two, sometimes more, haustona are seen in the thin peripheral layer of the host cell cytoplasm adjacent to the chloroplasts.
The end of the male hypha enlarges into club-shaped swelling. The oospore is thick-walled albubo three-layered. Besides, the cytoplasm contains endoplasmic reticulum, mitochondria, perinuclear, dictyosomes, ribosomes both free and attached to endoplasmic reticulum, vesicles of various kinds and lipid droplets.
It puts out a germ tube G which gains entrance into the host thought a stoma H.
Albugo: Habitat, Symptoms and Reproduction | Mastigomycotina
The outer warty wall of oospore bursts and a thin membrane of sessile vesicle comes out of the oospore. 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 and causal pathogens. It contains about nuclei and dense cytoplasm.
In Albugo each successive sporangium is capable of seceding from the sporangiophore or from the young sporangium. Apart from this, septum is seen at the apex of the young sporangium.
Life Cycle of Albugo (With Diagram) | Oomycetes
Symptoms of Albugo 3. Both male and female nuclei fuse, and the oospore produced in these species in multinucleate. According to them, the young oospore is delimited from the vacuolate periplasm by an electron-dense cell wall. Canrida how it works: These zoospores then swim xycle a film of water to a suitable site and each one produces a germ tube – like that of the sporangium – that penetrates the stoma.
Retrieved from ” https: While these organisms affect many types of plants, the destructive aspect of infection is limited to a few agricultural crops, including: The contents canfida the oospore assume uniform granular appearance.
Thereafter the fertilisation tube collapes but persists and the coenocentrum vanishes. However, Sansome and Sansome have advanced evidence in support of gametangial meiosis and diploid life cycle in Albugo Candida.
The chains of sporangia lengthen and press on the epidermis above. It gives rise to a germ tube which in-fact the host tissue through stoma or through an injury in the epidermis Fig.
They are developed near each other in the intercellular spaces of host tissues towards the end of the growing season. The highly differentiated thick, oospore wall together with the two additional layers constituted by the persistent perisperm and the oogonial wall provides protection and the numerous lipid vesicles in the oospore cytoplasm furnish energy for the long dormancy or overwintering by oospores in Albugo.
Each bit metamorphoses into a biflagellate, reniform, naked, uninucleate and single vacuolate zoospore. This papilla-like oogonial bulging is called the receptive papilla It is functionless. Once within the host tissue the germ tube grows vigorously and forms a new mycelium.
According to one view, the sporangial chains in Albugo are abstricted by percurrent proliferation. Probably the septum seen at the apex of each younger sporangium thickens on both sides to form a connective between the successive sporangia in the chain. The swelling is multinucleate A Across wall appears below this inflation B. In this 32 nucleate stage, the oospore enter the resting stage and tides over the period unfavourable for growth.
On the maturation fycle the oogonium the protoplasm of the oogonium differentiates into two regions. Walker observed that after fertilization when a thick wall is being developed around the oospore, its diploid nucleus divides repeatedly to form 32 nuclei.