Background & the “Abominable Mystery”
- Darwin termed the sudden and rapid diversification of flowering plants (around 130 million years ago) an “abominable mystery”.
- Fossil records show flowering plants (angiosperms) diversified abruptly in anatomy and habitat.
- This was an anomaly in the otherwise gradual process of evolution.
Relevance : GS 3(Science )
Findings by CCMB Scientists
- Study published in Nature Plants by CSIR-CCMB, Hyderabad.
- Researchers identified a gene called SHUKR in Arabidopsis thaliana, a model flowering plant.
- SHUKR:
- Expressed in sporophyte cells.
- Crucial for pollen (male gametophyte) development.
- Regulates F-box genes, which help remove old proteins and make room for new ones in developing pollen.
Shift in Plant Life Cycle Control
- In mosses (early land plants):
- Gametophyte is dominant; sporophyte is dependent.
- Sperm swims in water to reach egg.
- In flowering plants:
- Sporophyte is dominant.
- Gametophytes (pollen and ovules) are enclosed and reduced.
- SHUKR reveals sporophyte controls gametophyte development — overturns old assumption of independent gametophyte control.
Role of SHUKR in Evolutionary Success
- SHUKR and F-box genes are:
- Present only in eudicots (which form 75% of flowering plants).
- Rapidly evolving, enabling adaptive pollen production.
- Helps pollen adjust to variable conditions — heat, drought, humidity.
- Suggests molecular basis for flowering plants’ rapid radiation and global success.
Implications for Food Security & Climate Resilience
- Flowering plants are central to:
- Food systems (seeds = cereals, pulses, oilseeds).
- Biodiversity and ecosystem stability.
- Climate change threatens plant reproduction by damaging pollen viability.
- SHUKR could:
- Help breed climate-resilient crops.
- Enable precision pollination strategies based on environmental cues.
- Open avenues for adaptive, genetically-informed agriculture.
Scientific Significance
- Cracks part of Darwin’s puzzle by linking molecular innovation (SHUKR) to evolutionary expansion.
- Shows sporophyte’s regulatory role in gametophyte formation — a paradigm shift in plant developmental biology.
