Scientists and gardeners alike study and examine plants for outward signs of damage caused by disease and insects. Often, this damage takes the shape of areas chewed by insects that are easily observed. However, much of the important responses plants make to insect bites takes place out of sight. In one of the broadest studies of its kind, scientists at the University of Missouri recently studied how plant genes responded to insects that harm them. They found that plants can recognize attacks from diverse kinds of insects, such as caterpillars and aphids, and that plants respond differently to each attack. Identifying these defense genes could allow plant breeders to target specific insect species when developing pest-resistant crops.
“It was no surprise that plants responded differently to having their leaves chewed by a caterpillar or sucked by an aphid,” said Heidi Appel, senior research scientist in the Division of Plant Sciences in the College of Agriculture, Food and Natural Resources, an investigator in the Bond Life Sciences Center at MU and lead author on the paper. “What surprised us was how different plant responses were to each of the caterpillars and aphids. The plants could clearly tell insects apart—they really seem to ‘know’ who’s attacking.”
Results showed that Arabidopsis, a small flowering plant related to cabbage and mustard, recognizes and responds differently to four insect species. Two caterpillar species were placed on the plants and encouraged to chew on their leaves. Researchers also allowed two species of aphids, or small insects that pierce plants with needle-like mouthparts, to attack the plants. Then those plants were examined on the genetic level to gauge their responses.
Reviewed 2015-03-06