Assertion : Agrobacterium tumefaciens is popular in genetic engineering because this bacterium is associated with the roots of all cereal and pulse crops. Reason : A gene incorporated in the bacterial chromosomal genome gets automatically transferred to the crop with which the bacterium is associated.

Step-by-step solution

Agrobacterium tumefacines is a gram negative non sporing, motile, rod shaped bacterium, closely related to Rhizobium. It is found commonly on and around root surfaces. The region termed rhizosphere where it seems to survive by using nutrients that leak from the root tissues. But it infects only through the wound-site either naturally occurring or caused by transplanting of seedling and nursery stock. It is harmful to plants and useful to scientists for the same reason i.e. it transfers DNA into plant genomes found