Researchers at IISER Bhopal have revealed how a single protein, BBX32, helps plants time their emergence from underground into the light—a crucial step for successful seedling growth.

Key Discovery

• BBX32, a protein in plants, helps control when a seedling opens its protective hook as it grows up from the soil into the light.
• This hook, called the apical hook, protects the shoot tip as it pushes through the soil. Timing its opening is critical: too early, and the shoot could be damaged; too late, and growth may be stunted.

How Does It Work?

• The study shows that BBX32 keeps the hook closed longer so the seedling is better protected during its underground journey.
• Ethylene, a plant hormone that builds up underground, activates BBX32, while light protects BBX32 from being destroyed.
• BBX32 activates another protein (PIF3), which turns on a gene (HLS1) that keeps the hook closed.

Why Do Seedlings Have a Hook Shape?

• When a seed sprouts underground, its stem forms a hook to protect the delicate shoot tip.
• The hook must stay closed until the seedling reaches the surface and encounters light.
• Key Factors Controlling Hook Opening
  • Ethylene, a plant hormone, builds up underground and signals growth adjustments.
    • High ethylene levels delay hook opening until the seedling reaches the surface, preventing premature exposure.
  • Light exposure helps regulate BBX32, preventing premature hook opening.

What Is BBX32?

• BBX32 is a gene that helps keep the hook closed longer.
• It is activated by ethylene .
  • Light protects BBX32 from being broken down inside the plant.
• Interaction with Other Proteins
  • BBX32 increases activity of PIF3 (Phytochrome-Interacting Factor 3), which activates HLS1 (Hookless 1), keeping the hook shut.
  • If PIF3 is missing, BBX32 cannot prevent the hook from opening.

Significance of Study

• The findings show how plants integrate hormonal (ethylene) and environmental (light) signals to make a precise developmental decision
• BBX32 builds up only when it’s useful: in darkness with ethylene and when light first appears.
  • This system helps the plant time its growth perfectly to survive the stress of emerging from soil.
• Understanding the role of BBX32 can help scientists grow crops that can push through dense soil more easily. By using this knowledge, we can develop stronger crops that survive better in tough conditions.

DOWNLOAD PDF