A study reports that the defense mechanisms plants use to recognize and
respond to the caterpillar, a common plant pest, has arisen from a
single genethat evolved over millions of years. The study also found
that some plants, such assoybeans, have lost this protective gene over
time and suggests that geneticlly engineeringplants to reintroduce the
gene could protect against crop failure.

The research team at the University of Washington looked at key
evolutionary events that allowed plants to respond to the caterpillar.
It has been known that several legume species, including mung beans and
black-eyed peas, are uniquely able to respond to peptides that
caterpillars produce in their mouths as they munch through plant leaves.
The researchers looked at thegenomesof these plants to see whether a
common pattern recognition receptor called the Inceptin Receptor (INR)
had changed over millions of years.

The researchers found that a single, 28-million-year-old receptor gene
perfectly corresponds with plant immune response to the caterpillar
peptides. They also found that among the descendants of the oldest plant
ancestors that first evolved the receptor gene, a few species that could
not respond to the caterpillar peptides had lost the gene.

[elifesciences.org]