The Ti plasmid from Agrobacterium tumefaciens has genes for auxin, cytokinin, and opine synthesis, while genes for opine catabolism and Vir genes lie outside the T-DNA region. Which one of the following genes is involved in providing carbon source to Agrobacterium in their ecological niche?​

Correct option is C

Agrobacterium tumefaciens is able to use opines, which are produced by the plant cells it infects, as a carbon source. The Ti plasmid contains genes for opine synthesis, and the bacterium also has genes for opine catabolism (the breakdown of opines), allowing it to utilize these compounds for growth and energy. Opines are typically produced in plant cells after infection and are specific to the strains of Agrobacterium. This characteristic allows Agrobacterium to thrive in its ecological niche, where it exploits the opine-rich environment created by plant infection.

Information Booster:

1. The Ti plasmid of Agrobacterium tumefaciens contains genes involved in the synthesis of plant hormones like auxins and cytokinins, which are important for plant cell division and growth, but these are not directly involved in providing a carbon source.
2. Opines are compounds produced by plant cells in response to infection by Agrobacterium, and they serve as the main carbon and nitrogen sources for the bacterium.
3. Agrobacterium also possesses genes for opine catabolism, allowing it to break down the opines into simpler compounds that can be utilized for growth.
4. The production and catabolism of opines allow Agrobacterium to be a successful pathogen, as it exploits the plant's resources without competing with the plant for nutrients.
5. Auxins and cytokinins, although important for the bacterial infection process, do not directly serve as a carbon source for Agrobacterium in its ecological niche.

Additional Information:

• Option (a) - Genes for auxin synthesis only: This is incorrect because auxins are plant hormones that help Agrobacterium induce tumor formation in plants, but they are not involved in providing a carbon source.

• Option (b) - Genes for auxin as well as cytokinin synthesis: This is incorrect because, while auxins and cytokinins are involved in the infection process and help in the formation of tumors, they are not the carbon sources for Agrobacterium.

• Option (d) - Genes for auxin synthesis as well as opine synthesis: This is partially correct, as opine synthesis is important for carbon acquisition. However, the question specifically asks about genes involved in providing a carbon source, and opine catabolism (breaking down opines) is also crucial in utilizing the carbon.