Albugo is a genus of plant-parasitic oomycetes. Those are not true fungi Eumycota , although many discussions of this organism still treat it as a fungus. The taxonomy of this genus is incomplete, but several species are plant pathogens. Albugo is one of three genera currently described in the family Albuginaceae , the taxonomy of many species is still in flux. This organism causes white rust or white blister diseases in above-ground plant tissues.
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It includes only single genera Albugo. It is an obligate, inter cellular parasite. It cannot be grown on culture medium. It shows specificity towards the host. Characteristics of White-rust diesase :. Note :. The study of spread of disease is called Epidemiology.
Mycelium is branched, aseptate, coenocytic. The hyphal wall is made up of cellulose. Reserve food material is present in the form of glycogen and oil globules. Structure of Hypha. The shape of haustorium have taxonomic importance.
Reproduction methods. Asexual Reproduction. Conidia are dispersed by air. Two different types of germination takes place in favourable conditions. Free zoospores swim in water for few minute and finally they reaches on the surface of host, then after withdraw their flagella and round off and secretes a wall around itself. Deflagellated zoospores with wall germinates through the germ tube. This germ tube enter into the host tissue through stomata or through the teared epidermis and form mycelium.
Structure Of Zoospores. Out of them small the hairy flagellum is called Tinsel or Pantonematic or Flimmergersal. Sexual Reproduction.
Antheridium and oogonium develops very close in the mycelium. The wall of the antheridium and oogonium become thin at the region of their contact. This outgrowth stimulate the antheridium for fertilization.
Male nucleus fuses with the female nucleus and results in the formation of diploid nucleus. Now it is known as zygote. Prior to fertilization a mass of protoplast is found in ooplasm. It is called coenocentrum. Which is formed by granular cytoplasm. On returns of favourable conditions the 32 nuclei of oospore undergoes repeated divisions to form or more nuclei.
These zoospores are coming in contact with a suitable host seedling plants settle down on the host and infect them. The initial stage of the disease during the growth period is called primary infection and it takes place through the soil born oospores.
In Albugo meiosis not takes place in oospore. Control Of White Rust Disease. This is the best method to control the white — rust. By removal of infected plants from the field. Through this it can be eradicated. It is composed of. Life Cycle. Login New User. Sign Up. Forgot Password? New User? Continue with Google Continue with Facebook. Gender Male Female. Create Account. Already Have an Account? Full Screen. Structure Mycelium is branched, aseptate, coenocytic.
With the help of haustoria it absorbs nutrients from the host cells. It is a type of sporangium or zoosporangium. The mycelium gives rise to erect branching. They are usually formed towards lower epidermis. They are called Conidiophore. Their cell wall of the apical region is thin. The thin walled apical region forms the chains of conidia by constriction technique. Conidia are developed in basipetal sequence. It is called disjunctor. This disc helps, conidia to remain in a chain.
The chains of conidia grow and press the lower epidermis. Due to more pressure, the epidermis bursts. Albugo bliti Conidium absorbs some water which is present on the surface of the leaf. This tube enters inside host tissues through stomata and form intercellular mycelium. Conidium absorbs more water and swell up and forms zoospores. These zoospores are enveloped by vesicle. These enveloped zoospores are ooze out then the vesicle dissolves and zoospores become free.
Another long and smooth flagellum is called whiplash or Acronematic or peitgersal flagellum. Reproductive organs are endogenous. They develop in intercellular spaces, quite deep into the host tissues. A transverse septum is present in its basal region. It develop on male hypha which is placed very close to the oogonium.
There are many nuclei present in a young antheridium but mature antheridium has only one functional nucleus. The cytoplasm of oogonium differentiated into two distinct regions. It is called periplasm. It is known as ooplasm. However, some workers believe that all nuclei in the ooplasm except one disintegrate.
The oogonium of A. Oospore with 32 nuclei is the resting stage of Albugo. In this stage it lives on dry branches in the absence of host. Control Of White Rust Disease 1. This plant grows as weeds. Note : Albugo never infects the underground parts of the plants such as roots.
It infects only aerial parts of the plants. Content Details. Share with a friend. Share via Facebook. Share via Mail. Share via WhatsApp. It has gotten views and also has 4. Need something else?
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Aecidium candidum Pers. Gray Cystopus candidus Pers. Albugo candida commonly known as white rust , is a species of oomycete in the family Albuginaceae. It is sometimes called a fungus, but in fact forms part of a distinct lineage of fungus-like microorganisms, Oomycetes, commonly known as water moulds. It has not been recorded from northern Scandinavia, northern and central Siberia, northern China, western and central Africa, Alaska, northern and central Canada, and southern and western South America. This pathogen infects plants in the family Brassicaceae ; the growth stages involved include the seedling stage, the growing stage, the flowering stage, and the fruiting stage.
Albugo is an obligate parasite on a number of flowering plants. It is represented by 25 species. The vegetative pant body is composed of non-septate coenocytic hyphae that grow in the inter-cellular spaces of the host. They penetrate the cells of the host and absorb food material from it. The asexual reproduction takes place by means of biflagellate zoospores formed inside the sporangia.
It includes only single genera Albugo. It is an obligate, inter cellular parasite. It cannot be grown on culture medium. It shows specificity towards the host.