Gene-edited Mustard

GS Paper III Science and Technology

Context:

Indian scientists have developed the first ever low-pungent mustard based on CRISPR/Cas9 gene editing, while being non-GM and transgene-free.

About Gene-edited Mustard:

Gene-edited mustard refers to a variety of mustard plant that has been altered using gene editing techniques, specifically the CRISPR/Cas9 system.

CRISPR:

CRISPR stands for “Clustered Regularly Interspaced Short Palindromic Repeats”.
CRISPR is a gene editing technology that allows scientists to precisely modify DNA within living organisms.

Cas 9:

Cas9 is an enzyme that acts as molecular scissors, guided by RNA molecules synthesized to match a specific DNA sequence.

In this process, specific genes within the mustard plant’s DNA are modified to achieve desired traits, such as reduced pungency and increased resistance to pests and diseases.
In it, precise changes to the existing DNA are made without introducing foreign genes from other species.
This approach is often considered non-GMO (genetically modified organism) and transgene-free, as it involves modifying the plant’s own genetic material to achieve the desired characteristics.

22.1

How did Scientists Created this Gene-Edited Mustard?

Scientists at the National Institute of Plant Genome Research (NIPGR) have “edited” 10 out of the 12 GTR genes in ‘Varuna’, a high-yielding Indian mustard variety.
For this, they used CRISPR/Cas9 – a gene-editing tool deploying an enzyme, which acts as a “molecular scissors” to cut the DNA at precisely targeted locations of the gene, and then letting the natural DNA repair process take over.
Results:
- The GTR-edited mustard contained low-seed high-leaf glucosinolates
- It showed resistance against the virulent fungal pathogen Sclerotinia sclerotiorum and the insect pest Spodoptera litura.

Benefit of Gene Edited Mustard:

Less Pungent: Gene Edited Mustard is less pungent as normal mustard seeds have high levels of glucosinolates, a group of sulfur and nitrogen-containing compounds contributing to the characteristic pungency of their oil and meal.
Pest and Disease Resistance: Gene-edited mustard can be engineered to be more resilient against pests and diseases, leading to increased crop yield and reduced reliance on chemical pesticides.
Improved Shelf Life: By enhancing the plant’s natural defense mechanisms, gene-edited mustard may have a longer shelf life due to its increased resistance to spoilage organisms.
Non-GMO Approach: Gene-edited mustard can be developed without introducing genes from unrelated organisms, which aligns with non-GMO principles and may help alleviate concerns associated with genetically modified crops.
Import Bill of India: Edible oils imports were valued at $20.84 billion (Rs 167,270 crore) during the fiscal year ended March 2023, thus there is a need to augment domestic production.

Genetically Modified (GM) versus Gene Editing (GE)

22.2

Aspect	Genetically Modified (GM)	Gene Editing (GE)
Source of Genes	Foreign genes from unrelated species	Uses the organism’s own genetic material
Precision	May have variable precision in gene insertion	Highly precise, enabling targeted changes
Ethical Concerns	May involve ethical considerations related to introducing foreign genes	Often considered more ethically acceptable due to working with the organism’s own genes
Ecosystem Impact	Potential ecological impact due to introduction of foreign genes	Lesser ecological impact as changes are made to the organism’s own genes
Example	Bt Brinjal	Gene-edited Mustard

Rapeseed-Mustard:

India’s most significant domestically-grown oilseed is rapeseed-mustard.
Its share in the country’s production of vegetable oils has been estimated at 42.6% (more than soyabean’s 19.2%) and in that of meal at 30.3% (next to soyabean’s 38.9%), as per the US Department of Agriculture’s data for the marketing year ending September 2023.

Glucosinolates:

Glucosinolates, a group of sulfur and nitrogen-containing compounds
They are synthesized in the leaves and pod walls of mustard plants.
Their translocation and accumulation in the seeds happens through the action of glucosinolate transporter or GTR genes.
- There are 12 such genes under two distinct classes of GTR1 and GTR2 with six copies each.
They serve as a defense mechanism for mustard against herbivores, pests, and pathogens due to their pungent and sometimes toxic properties that deter herbivores and pests from feeding on the plants.

News Source: The Indian Express