Question

Which one among the following is a symbiotic bacterium?
(a) Erwinia amylovora
(b) Rhizobium leguminosarum
(c) Xanthomonas campestris
(d) Agrobacterium tumefaciens

Answer 1

Hint: Symbiotic bacteria are bacteria that live in symbiosis with or between another organism. They profit mutually. The common microaerophilic root nodule bacteria, which form nodules in legume plant roots, are examples. This relationship is symbiotic. The bacteria receive reduced coenzymes from plants and bacteria, in exchange, the plant obtains nitrogen-rich compounds.

Complete answer:
The plants do not get atmospheric nitrogen. Nitrogen-fixing bacteria convert and make available to the plant's atmospheric nitrogen into ammonium compounds. There are two groups of bacteria, they are free-living and symbiotic bacteria. Examples of free-living bacteria that fix nitrogen include the Azotobacter. The example of bacteria that fix symbiotic nitrogen includes Rhizobium. Rhizobium leguminosarum is a symbiotic bacterium that lives in symbiotic association with plants in the legumes and fixes atmospheric nitrogen.
Some plants form a symbiotic relationship with bacteria, allowing them to develop nodules that promote the conversion of atmospheric nitrogen into ammonia. Cytokinins have been found to play a role in the formation of nodules for root fixation in this regard. Not only does the plant seem to need nitrogen-fixing bacteria, but it also needs to be able to synthesize cytokinins that encourage the development of root nodules required for nitrogen fixation.
So, the correct answer is, 'Rhizobium leguminosarum.'

Note: The symbiotic bacteria may live in or on the tissue of plants or animals. Symbiotic bacteria help break down foods containing fiber in digestive systems. They also assist in the production of vitamins. Symbiotic bacteria likely live near hydrothermal vents. Their interaction with other bacteria is typically reciprocal. Some are living in tube worms. Zoamastogopera, located in the stomach of termites, is an example for a symbiotic organism that helps them to digest cellulose.