Context:
Researchers at the National Institute of Plant Genome Research (NIPGR), New Delhi, have used CRISPR-Cas9 gene-editing technology to improve phosphorus uptake and yield in japonica rice varieties. This development has the potential to reduce India’s reliance on phosphate fertilizers and enhance crop productivity, especially in phosphorus-deficient soils.
Why It Matters
- Phosphorus (P) is vital for plant growth but is often limited in Indian soils, affecting crop yield.
- Even with phosphate fertilizers, only 15–20% is absorbed by plants; the rest is lost due to leaching or runoff.
- India is highly import-dependent for phosphate fertilizers, raising sustainability concerns.
Key Scientific Advancement
Focus on Phosphate Transport
- Rice absorbs phosphate via root transporters and transfers it to shoots through another transporter, OsPHO1;2.
- Researchers targeted the regulation of OsPHO1;2 to improve phosphate translocation from root to shoot.
Identification and Editing Strategy
- Repressor Gene Identified:
- OsWRKY6 binds to the promoter of OsPHO1;2 and represses it.
- Complete knockout of OsWRKY6 using CRISPR improved phosphate uptake but harmed plant development due to loss of other essential functions.
- Precision Edit:
- Scientists removed only the 30 base pair binding site on the promoter without removing the repressor itself.
- This increased OsPHO1;2 expression in roots while preserving other repressor functions.
Results of the Experiment
- Higher Shoot Phosphate Accumulation.
- Increased Panicle and Seed Numbers.
- Yield Boost:
- 20% increase in yield with recommended P dose.
- 40% increase with only 10% of recommended P fertilizer.
- Seed Quality: Normal in size, starch, and phosphorus content.
Japonica Rice
Japonica rice, also known as sinica rice, is a variety of Oryza sativa (Asian rice) characterized by its short to medium, round, and sticky grains. It’s a major rice type cultivated and consumed in East Asia, particularly in Japan, Korea, and China, but also grown in other regions like Italy and parts of the United States. Unlike the longer, thinner grains of indica rice, Japonica rice is known for its stickier texture when cooked, making it suitable for dishes like sushi and rice bowls.
