Question

Natural genetic engineer of the plant is:
(a) Yeast
(b) Agrobacterium tumefaciens
(c) E.coli
(d) Mycoplasma

Answer 1

Hint: Genetic engineering is the manipulation of genes using biotechnology. It is used to produce new varieties by making some changes in the DNA of original varieties. Natural genetic engineering takes place by insertion of a pathogen in the host to cure the defect of the gene.

Complete Answer:
The natural genetic engineer of a plant is Agrobacterium tumefaciens. Natural genetic engineering was proposed by James A. Shapiro in 1992.
In 1907, Erwin and Charles Townsend discovered that the bacterium tumefaciens cause plant tumours and crown galls in a variety of plants, later many scientists experimented on DNA of Agrobacterium and introduced it as T-DNA which helps to suppress the function of plant nematode. Most common root-knot disease in tomato, brinjal, and tobacco-caused by Meloidogyne incognita. Due to this disease, the nutrient of plants flushes out which leads to the cause of secondary infections. RNAi is the technique which inhibits the activity of pathogen genes by the production of sense and antisense RNAs. Tumor inducing plasmid of Agrobacterium tumefaciens helps in the production of sense and antisense double-stranded RNA which cause silencing of mRNA of the nematode by which the nematode is not able to survive and later die. It is the most common cellular defense in eukaryotes.
The transgenic plant produced by genetic engineering is not only useful for producing a new variety of disease-resistant plants but it also causes hazards to the environment like genetic pollution, weed formation, toxicity, allergies, etc.

So, the correct answer is Agrobacterium tumefaciens.

Note: Still, the research on Agrobacterium has not come to an end, the chemical signal between Agrobacterium and rhizophore has not fully explored. The research on the full potential of Agrobacterium as a mutagenic and transfer system of the gene is still in process.