Maize, a popular cereal in agriculture, is hard to see, especially as a deadly battlefield, but as it turns out, these invented crops are about warfare. Plagued by stemborers, a type of crop parasite, corn can launch a chemical defense that is essentially the equivalent of the parasite’s natural enemies in equestrian medicine: wasps.
In a new study published in the journal Scientific Reports, scientists have isolated genetic markers that have made this significant alarm system possible. It is hoped that the discovery will help farmers around the world protect their crops from parasitic insects that can make a living.
The Stemborers are destroying the cereal crops of sub-Saharan Africa and destroying their commercial value to farmers who depend on them. Tritrophic interactions allow plants like the popular grain corn to launch counter-attacks against aggregated parasites by summoning their sworn enemies. This effective counter-attack begins in the early stages of stemborer infestation as some corn plants lay eggs on crops. They emit a chemical signal that triggers parasitic bumps that parasitize and kill stemborers.
However, this defense is not present in all corn varieties, and researchers wanted to uncover genetics that implies this favorable trait for commercial crops. They investigated the genetic variability of landraces (varieties selected by local farmers) of 146 corn genotypes and the number of commercial hybrids. They also used samples of corn variants to see how effective they were in attracting the parasitic waste Cotesia sesame.
Their results show that plants need landraces instead of fine lines to start defending against laying parasites. Genetic analysis has identified 101 people associated with the “call for help” response, which they hope will one day help corn growers choose to help protect their crops.
Genetic mutations or GMO crops are often considered a controversial field in science, but over the centuries farmers have developed thanks to farmers actively selecting optimal crops for their desired traits. The economic impact of poor pest control on farmers can be catastrophic and so biological interventions such as selectively “sending to waste” livelihoods can be an effective means of sustainable livelihoods for the incredible quality of corn. The development of such biological defenses may reduce the need for chemical pesticides that can cause nutrient runoff and algal blooms, leading to degraded aquatic ecosystems.
Lead researcher Professor Toby Bruce from Keele University, UK, said in a statement, “Farmers urgently need alternative methods to manage crop pests because pesticide use laws and evolution have increasingly limited the use of pesticides.” “Here we show that biological control of crop pests can be enhanced. We have identified an area in the corn genome with the “cry for help” feature that allows parasitic waste bodyguards to call on them to attack insects in crops.”
