Maize, the world’s most widely grown grain, faces increasing threats from pests and climate change. Recent research reveals a natural plant communication system using linalool. This discovery offers new ways to enhance maize resilience and manage crop productivity.
Origins and Importance of Maize
Maize (Zea mays) was domesticated from teosinte in Mesoamerica over 9,000 years ago. It evolved from a small, hard-kernelled grass to a high-yielding crop essential for food, animal feed, biofuel, and industry. Its global cultivation under monoculture systems makes it vulnerable to pests and diseases, risks amplified by climate change.
Climate Change Impact on Maize Productivity
Under high-emission scenarios like SSP585, maize yields could decline by up to 24% by the late 21st century. Rising temperatures and erratic weather patterns increase pest outbreaks and reduce crop resilience, threatening food security and economies dependent on maize.
Linalool as a Plant Communication Signal
Researchers from Zhejiang University and partners discovered that maize plants emit linalool, a floral-scented volatile compound, when attacked by insects. This compound acts as a warning to neighbouring plants in dense fields, triggering defensive responses that reduce pest damage. Crowded plants show less insect harm but grow slower, indicating a trade-off between defence and growth.
Mechanism of Linalool-Induced Defence
Linalool activates jasmonate signalling in maize roots, which induces the release of HDMBOA-Glc, a defensive metabolite. This metabolite enriches beneficial soil bacteria that stimulate salicylic acid signalling in neighbouring plants. This primes them against multiple threats, including insects, fungi, nematodes, and viruses.
Experimental Validation and Effects
The study confirmed the process using linalool-deficient maize mutants and synthetic linalool treatments. Plants exposed to linalool showed reduced damage from fall armyworm larvae, root-knot nematodes, fungal infections, and viral diseases. This broad-spectrum defence mechanism was consistent across experiments.
Applications in Breeding and Agriculture
Maize expert James Schnable suggests using reporter genes like Bx1 and Bx6 to identify maize varieties responsive to linalool. Marker-assisted selection and genomic prediction models could enhance breeding for pest resilience. Farmers might apply synthetic linalool to induce defences when pest risk is high or suppress responses to boost yield when pests are absent.
Managing Growth-Defence Trade-Off
Plants balance energy between growth and defence. Linalool signalling influences this trade-off. About and manipulating this pathway could allow tailored pest management in high-density maize cultivation, reducing chemical pesticide use and improving sustainability.
Future Prospects
Harnessing linalool-driven plant communication offers a promising route to strengthen crop resilience amid climate challenges. Integrating this knowledge with breeding and farming practices could transform maize production globally.
Questions for UPSC:
- Point out the impact of climate change on global food security and suggest sustainable agricultural practices to mitigate these effects.
- Critically analyse the role of plant signalling molecules in pest resistance. How can biotechnology enhance these natural mechanisms?
- What is genetic marker-assisted selection? Explain its importance in crop improvement with suitable examples.
- Estimate the advantages and challenges of monoculture farming systems. How can diversified cropping systems contribute to ecological sustainability?
