Question

Plant growth promoting- rhizobacteria, Pseudomonas produce which chelates iron and makes it unavailable to harmful fungi for potato, sugar beet and radish.
A. Nutrilite
B. NPK with Anabaena
C. Biopesticide rich in Nostoc
D. Siderophore

Answer 1

Rhizobacteria usually colonize on the roots of the monocots and dicot and thus enhance plant growth by direct and indirect mechanism. It modifies the root functioning, improves the plant nutrient and thus works on the physiology of the whole plant.

Complete answer: Plant growth promoting rhizobacteria are the soil bacteria inhabiting around the root surface and are directly or indirectly taking part in the plant growth and development via production of many chemicals in the vicinity of the rhizosphere. It usually assists and facilitates plant growth directly assisting in resource acquisition.
Several substances are produced by the antagonists that control the pathogen and indirectly promote the growth in many plants , such as siderophores and antibiotics. They render resistance in plants through salicylic acid which is a dependent SAR pathway. Rhizobacteria belonging to genera pseudomonas and bacillus are known for their antagonistic effects and their ability for triggering the SAR.
One of the most important elements that is required for the growth in living things is iron which is found abundant in earth's crust.How ever, it is not taken directly due to difficulty in solubility. Ferric ion is the available and accessible form of iron to the organism. The uptake of ferric ions is done usually via siderophores which can be pathogenic and non- pathogenic microorganisms from the soil, humans or from the environment. Siderophore is closely related to iron which is needed for biological processes.
These organisms colonize around the roots surface of potato, sugar beets and radish. The siderophores usually bind to ferric ions and make it unavailable to the harmful fungi for potato, sugar beets and radish.

So, the correct answer is option D, Siderophore.

Note: Siderophores can be defined as a small peptide molecule that contains the side chain and functional groups with high - affinity ligands to coordinate with ferric ions. In soil, production of siderophores plays a central role in determining the ability of different microorganisms to improve the plant development.