This corn gene releases a scent that fights caterpillars
Sorg A, Liu H, Tang HV, Mendoza J, Tran K
Crop Improvement
The corn growing in home gardens and farm fields relies on genes like this one to release invisible chemical alarms that recruit help against pests, so losing that gene means more caterpillar damage on the ear and stalk.
Corn plants make a cocktail of scented chemicals when insects start chewing on them, and scientists found the specific gene responsible for one important scent, called germacrene D. When they used gene editing to switch off that gene, corn plants lost some of their smell-based defenses and fall armyworm caterpillars grew bigger and did more damage. The same gene also helped the plant resist a virus and a fungus, but oddly made no difference against a root-eating beetle or two other fungal diseases, showing that this one gene is a specialist, not a cure-all.
Key Findings
A genome-wide association study pinpointed ZmTPS8 as the primary gene controlling herbivore-induced release of the sesquiterpene volatile germacrene D in maize.
CRISPR/Cas9 knockout mutants of tps8 showed reduced emission of germacrene D, alpha-copaene, and delta-cadinene during Spodoptera frugiperda (fall armyworm) feeding, and these mutants suffered increased larval growth of the pest.
ZmTPS8 loss also reduced resistance to sugarcane mosaic virus and Fusarium verticillioides (affecting fungal toxin production), but had no measurable effect on the root herbivore Diabrotica virgifera virgifera or on Cochliobolus heterostrophus and Pythium spp. infections.
chevron_right Technical Summary
Scientists identified a corn gene that helps the plant fight off caterpillars and some diseases by producing defensive scent compounds. Turning off the gene made corn more vulnerable to fall armyworm caterpillars and a virus, but had no effect against other pests, showing that plant defenses are often threat-specific.
Abstract Preview
Original paper
Maize terpene synthase 8 (ZmTPS8) produces a blend of sesquiterpenes and contributes to defense against pests and pathogens.
Maize (Zea mays) produces terpenoid-based chemical defenses through a large family of terpene synthases, but the contributions of individual enzymes to specific compounds and stress resistance rema...
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