A recent study published in Science by researchers from Zhejiang University (China), in collaboration with the Netherlands and Switzerland, found that clustering maize plants enhances insect resistance through plant–soil signalling.

About Plant Communication Mechanism

• Function: When maize plants are attacked by insects, densely planted crops release more linalool, alerting neighbouring plants and triggering defensive responses.
• Observation: Plants in middle rows of crowded plots suffered less insect damage than edge plants, indicating stronger defence in dense clusters.
• Trade-off: While insect protection increased, plants grew more slowly and produced less biomass, highlighting the balance between growth and defence.

Mechanism of Defence

• Hormonal signalling: Linalool exposure activates jasmonate signalling in roots.
• Metabolite release: Jasmonates trigger the release of HDMBOA-Glc, a defensive metabolite, into the soil.
• Microbial interaction: HDMBOA-Glc enriches beneficial bacteria, inducing salicylic acid signalling in neighbouring plants.
• Result: Plants are primed against multiple threats.

Broad-Spectrum Protection

• Insect pests: Reduced damage from fall armyworm (Spodoptera frugiperda).
• Nematodes: Root-knot nematodes (Meloidogyne incognita) formed fewer galls.
• Fungal pathogens: Increased resistance against Exserohilum turcicum.
• Viral diseases: Reduced spread of rice black-streaked dwarf virus (RBSDV)

Broader Implications

• Growth-defence trade-off: Plants allocate resources either for defence (against pests) or for growth (yield). Linalool signalling mediates this balance.
• Farmer’s role: Farmers, with broader knowledge of pest pressures, could externally manipulate linalool signalling.
• Engineering plants: Plants can be modified to:
  • Ignore linalool signals in low-pest environments → higher productivity.
  • Respond strongly in high-pest settings → lower crop losses.
• Sustainable farming: Harnessing linalool signalling could reduce chemical pesticide use and support breeding for resilient, high-density cultivation systems.

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