Test: Albugo Or Cystopus - Class 11 MCQ

White Rust of Crucifers. White rust, also called white blisters, is a fungal disease caused by the fungus Albugo candida, which affects cruciferous plants that include vegetables such as kale, Brussels sprouts, cauliflower, broccoli and cabbage. Brassica weeds are also attacked.

Mycelium of Albugo: It is well developed and consists of branched, aseptate, coenocytic hyphae. The hyphae live and ramify in the intercellular spaces of the susceptible host tissue.

The infection is spread by Albugo is by oospore- infected seeds or by mechanical movement of sporangia. Oospores are light in weight and can be blown by wind.

This pollen tube carries a male gamete to meet a female gamete in an ovule. In a process called fertilisation, the two gametes join and their chromosomes combine, so that the fertilised cell contains a normal complement of chromosomes, with some from each parent flower.

Favorable conditions for the dispersal and consequent infection of white rust from diseased to healthy plants are most common in the autumn and spring seasons. This pathogen prefers cool, moist conditions for the spread and formation of new infections. Conversely, it rarely infects in warm, dry conditions.

Known on sweet potato and species of the Capparidaceae and Amaranthaceae. Some strains may attack a few closely related species of hosts in some species of Albugo. Disease Cycle. Most species overwinter by means of mycelium in perennial parts of overwintering hosts and oospores in debris of infected plant parts.

Stalking is unwanted or repeated surveillance by an individual or group towards another person. Stalking behaviors are interrelated to harassment and intimidation and may include following the victim in person or monitoring them.

Thereafter the fertilisation tube collapes but persists and the coenocentrum vanishes.

Haustoria are usually multinucleate, and the density of the protoplasm and the contents vary as much as the contents of the hyphae. In Albugo, where the haustoria are much smaller than those ofthe other members of the Peronosporales, they were said by Wager (1896) to be uninucleate, and this has been confirmed.

An obligate parasite or holoparasite is a parasitic organism that cannot complete its life-cycle without exploiting a suitable host. If an obligate parasite cannot obtain a host it will fail to reproduce. This is opposed to a facultative parasite, which can act as a parasite but does not rely on its host to continue its life-cycle. Obligate parasites have evolved a variety of parasitic strategies to exploit their hosts. Holoparasites and some hemiparasites are obligate.

The sporangia inside the pustules are spread by wind, rain, soil and insects. After landing on a susceptible plant, each sporangium gives rise to about six zoospores which, under suitable conditions of moisture and light, form germ tube which invade the plant’s tissues. Thick walled sexual spores, called oospores are produced which germinate, producing either vesicles inside the plant tissue, exist tubes with vesicles at the tip, or germ tubes. Further zoospores develops inside the vesicles. The infection is spread by either soil borne oospores or oospore- infected seed or by mechanical movement of sporangia.
 

Albugo is an obligate parasite which attacks mostly crucifers like turnip, mustard, radish, cabbage, cauliflower etc. The disease caused by Albugo is commonly known as white rust because it appears in the form of shiny, white, smooth irregular patches (pustules) or blisters on the leaves, stems and other aerial parts of the plant. Its thallus is eucarpic and mycelial. Hyphae are intercellular, coenocytic, aseptate and profusely branched.

Lactophenol Cotton Blue Solution is a mounting medium and staining agent used in the preparation of slides for microscopic examination of fungi. Fungal elements are stained intensely blue.

In Albugo, it has been observed that a species for e.g., A. Candida attacks only the members of family Brassicaceae (Cruciferae) but not others. It has also been observed that A. Candida infects only one host e.g., Brassica but it does not infect the other host i.e., radish. This means that the A. Candida obtained from different host are not the same and therefore, have to be named differently.

A secondary infection can occur when a different infection, known as the primary infection, makes a person more susceptible to disease. It is called a secondary infection because it occurs either after or because of another infection. In other words, it is secondary to that infection.

This book covers the discovery and development of the Bordeaux mixture by Pierre Marie Alexis Millardet. This discovery was significant in the history of plant pathogen control. The Bordeaux mixture was the first fungicide to be widely used throughout the world.

The terminal end of the sporangiophore becomes constricted and sporangium contains 5-8 nuclei and cytoplasm. Successively the sporangia develop by constriction method, in basigenous chains.

It pushes the newly-formed sporangium upward. Thus only one sporangium is formed at a time. As the second sporangium initial grows to the normal size, it is also delimited by the formation of a basal septum as the first. The repetition of the process results in the formation of a basipetal chain of sporangia.

Albugo candida commonly known as white rust, is a species of oomycete in the family Albuginaceae. It is on the leaves of a living plant sometimes called a fungus, but in fact forms part of a distinct lineage of fungus-like microorganisms, Oomycetes, commonly known as water moulds.

Root is not affected by albugo,because the disease caused by Albugo is commonly known as white rust which appears in the form of shiny, white, smooth irregular patches (pustules) or blisters on the leaves, stems and other aerial parts of the plant. 

1. Asexual reproduction: The asexual reproduction takes place by means of biflagellate zoospores formed inside the sporangia. In the very beginning the hyphae accumulate just beneath the epidermis of the infected leaf. 

2.  Sexual reproduction: The sexual reproduction is oogamous.

Asexual reproduction occurs in most Oomycetes by the formation of a structure called a sporangium (pl. In Albugo, an unbranched sporangiophore produces a chain of sporangia. Clusters of sporangia beneath the plant epidermis form blisters that rupture as sporangia are released.

Conidia usually develop either singly or in chains on a particular locus directly upon the vegetative hyphae or upon hyphal stalks or branches called conidiophores. Spores play an important role in the life cycle of fungi acting as dispersal or survival.

Zoospores of Albugo are uninucleated, reniform or bean-shaped and biflagellated. Flagella are located on the lateral side of zoospore which are unequal in length. Out of them small the hairy flagellum is called Tinsel or Pantonematic or Flimmergersa.

The root structure of the fungal haustorium which develop another structure to absorb water or nutrients. for example, in the broomrape family or mistletoe that enters the host's tissue and draws supplements from it  
Parasites in every single significant division structure haustoria.
On infiltration, the growth builds the surface region in contact with have plasma layer discharging chemicals that separate the cell divider, empowering more prominent potential development of natural carbon from host to organism.

Reserve food material is in the form of oil drops and glycogen bodies. Some mycelium is intracellular in the form of knob-like haustoria for the absorption of food material from the host cells.

Symptoms of white rust caused by Albugo typically include yellow lesions on the upper leaf surface and white pustules on the underside of the leaf. The pathogen is spread by wind, water, and insects.

The Albuginaceae reproduce by producing both sexual spores (called oospores) and asexual spores (called sporangia) in a many-stage (polycyclic) disease cycle.The liberated sporangia in turn can either germinate directly with a germ tube or begin to produce biflagellate motile zoospores.