Crown gall properties — Once induced by Agrobacterium, what are the in vitro characteristics of crown gall tissue?

Introduction / Context:Crown gall results from stable integration of T-DNA into the plant genome. After transformation, the tissue becomes autonomous: it can grow without Agrobacterium and often without exogenous hormones, reflecting the expression of T-DNA oncogenes and opine synthesis genes.

Given Data / Assumptions:

• T-DNA integration is stable and heritable in cultured cells.
• Opine synthesis and auxin/cytokinin biosynthesis genes alter metabolism and growth control.
• Eliminating the bacteria does not remove the integrated T-DNA.

Concept / Approach:Because the tumor phenotype is encoded by plant-integrated T-DNA, crown gall tissue remains tumorous in culture without the bacterium. This autonomy is a cornerstone of Agrobacterium-mediated transformation evidence.

Step-by-Step Solution:

Verification / Alternative check:Opine assays and hormone-free growth of tumor lines confirm persistent T-DNA function.

Why Other Options Are Wrong:

Common Pitfalls:Assuming antibiotic curing of bacteria will cure the tumor; integrated T-DNA remains.

Final Answer:Both (a) and (b).