Question

Substances that accumulate around a site of infection in plants is
A. Phytoalexins
B. Proteinome
C. Saponins
D. All the above

Answer 1

Hint: The plant initiates a two-pronged resistance when a plant cell recognizes particles from infected cells or particles from the pathogen: a general short-term response and a delayed long-term specific response.

Complete Answer:
Phytoalexins in plants that accumulate rapidly in areas of pathogen infection are antimicrobial and sometimes de novo-synthesized antioxidant substances. They are broad spectrum inhibitors and are chemically complex with various shapes of the properties of different plant species. Phytoalexins, including terpenoids, glyco steroids and alkaloids, appear to fall into several classes, but they may include some phytochemicals caused by microbial infection.

For the attacking organism, plant-produced phytoalexins act as toxins. They can puncture the cell wall, delay maturation, disrupt metabolism, or stop the reproduction of the pathogen in question. Their importance in plant defence is seen when phytoalexin biosynthesis is inhibited by an increase in plant tissue susceptibility to infection. Mutants incapable of phytoalexin production display more extensive pathogen colonization relative to the wild form.

Phytoalexin is therefore a plant-based substance that responds to an infectious agent and accumulates around the site of the infection. An infectious agent's production is inhibited.

Option A is therefore the right option.

Note: Allixin (3-hydroxy-5-methoxy-6-methyl-2-pentyl-4H-pyran-4-one), a non-sulfur-containing compound with a γ-pyrone skeleton structure, was the first compound isolated from garlic as phytoalexin, a compound induced in plants by continuous stress. This compound has been shown to have specific biological properties such as anti-oxidative, anti-microbial, anti-tumor-promoting, DNA binding inhibition of aflatoxin B2 and neurotrophic effects.