Which of the following is known as "natural genetic engineer "?

Agrobacterium tumefaciens

The correct answer is Option (1) -Agrobacterium tumefaciens

Agrobacterium tumefaciens is known as the "natural genetic engineer" because it has the unique ability to transfer a portion of its DNA (called the T-DNA) into the genome of a plant. This process happens naturally when A. tumefaciens infects a plant, causing a tumor-like growth called a crown gall.

Scientists have exploited this mechanism for genetic engineering in plants, using A. tumefaciens to introduce desired genes into plants, making it a valuable tool in plant biotechnology. The tumor inducing (Ti) plasmid of Agrobacterium tumifaciens has now been modified into a cloning vector which is no more pathogenic to the plants but is still able to use the mechanisms to deliver genes of our interest into a variety of plants.

The other organisms mentioned, such as Penicillium notatum, Haemophilus parainfluenzae, and Saccharomyces cerevisiae, do not possess this natural capability of transferring DNA into plant cells.