Question

Xylem or phloem limited bacteria need insect vector for their transmission.
A. They need insects because they have lost their ability to translocate
B. They do possess cell wall
C. They are pleiotropic in nature
D. They can be cultured in media
E. They cause a symptom termed as 'yellows'
Choose the correct answer from the options given below:

• A. A, B, E only
• B. B, D, E only
• C. A, C, E only
• D. B, C, D only

Hint:

Fastidious vascular bacteria have true cell walls, require insect vectors for inoculation into vascular streams, and cause yellows/scorching.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Fastidious vascular-limited bacteria inhabit the specialized lumens of xylem or phloem tissues.

Step 2: Detailed Explanation:
Evaluating the characteristics of vascular-limited bacteria:
- Statement A is TRUE: Confined to deep vascular conduits, they cannot traverse the cuticular barrier and depend obligately on piercing-sucking insect vectors (leafhoppers, spittlebugs, psyllids) for spatial transmission.
- Statement B is TRUE: Fastidious bacteria (e.g., Xylella fastidiosa, Candidatus Liberibacter) possess true peptidoglycan bacterial cell walls (unlike wall-less phytoplasmas).
- Statement E is TRUE: Phloem-limited bacteria induce carbohydrate translocation blockage resulting in chlorosis and characteristic 'yellows' symptoms.
Statements C and D are not defining universal properties.

Step 3: Final Answer:
Therefore, statements A, B, and E only hold true.