Site-Directed Nuclease (SDN)

Union Agriculture Minister Shivraj Singh Chouhan announced that India has become the first country in the world to develop rice varieties using genome editing technology, marking a significant milestone in agricultural biotechnology.

Developed under the guidance of the Indian Council of Agricultural Research (ICAR), two new rice varieties have been introduced:

1. DRR Dhan 100 (Kamala)
   • Developed from high-yielding Samba Mahsuri.
   • Features: Higher yield, drought tolerance, improved nitrogen use efficiency, and 20-day earlier maturity.
   • Yield: 5.37 tonnes/ha compared to 4.5 tonnes/ha for Samba Mahsuri.
2. Pusa DST Rice 1
   • Derived from the MTU1010 variety.
   • Designed to perform under inland salinity stress.
   • Yield: 3,508 kg/ha, a 9.66% improvement over the parent variety.

Researchers used Site-Directed Nuclease (SDN-1 and SDN-2) genome editing techniques, which do not involve introducing foreign genes—unlike SDN-3 used in genetically modified (GM) crops. Therefore, these new rice varieties are not considered GMOs.

• SDN-1: Makes precise cuts in the DNA, with natural repair.
• SDN-2: Guides the repair process using a template.
• SDN-3: Involves inserting foreign genes — considered genetic modification.

Although genome editing has been used globally in crops like tomatoes, soybeans, and even fish in Japan, this is the first time rice varieties have been successfully developed using such techniques.

(Source: TH)