To combat caterpillar infestations, modern plants rely on a gene that evolved 28 million years ago

modern plants rely on a gene; shallow focus photography of green caterpillar on green leaf
Photo by Egor Kamelev on

To combat caterpillar infestations, modern plants rely on a gene that evolved 28 million years ago

According to a paper published today in eLife, the defense systems plants use to identify and react to a common pest—the caterpillar—have developed from a single gene over millions of years.

According to the study, some plants, like soybeans, have lost this protective gene over time, and it is possible to prevent crop failure by breeding plants or genetically altering them to reintroduce the gene.

The immune system a plant inherits determines its state of health. In plants, this entails inheriting particular kinds of pattern recognition receptors that can distinguish between various diseases and peptides derived by herbivores and elicit the proper immune response.

According to main author Simon Snoeck, postdoctoral researcher at the Department of Biology of the University of Washington, inheriting the proper types of pattern recognition receptors will help plants to sense dangers and manage with illnesses and pests. The researchers said that their  understanding of how plants evolved the capacity to recognize new dangers is limited, despite the fact that they are aware of numerous chemicals from pests that trigger immune responses in plants.

To solve these issues, the scientists set out to identify the crucial evolutionary processes that enabled plants to defend themselves against a widespread threat—the caterpillar. It was already known that certain kinds of legumes, such as mung beans and black-eyed peas, have a special ability to react to peptides produced by caterpillars as they eat plant leaves.

In order to determine whether a common pattern recognition receptor known as the inceptin receptor had evolved over millions of years, acquiring or losing the ability to recognize caterpillars, researchers thoroughly examined the genomes of this group of plants.

They discovered that the plant immune response to the caterpillar peptides is exactly correlated with a single receptor gene that is 28 million years old. Additionally, they discovered that a few species that were unable to respond to the caterpillar peptides among the offspring of the earliest plant ancestors that originally evolved the receptor gene had lost the gene.

The scientists used a method called ancestral sequence reconstruction where they integrated data from all current receptor genes to predict the 28 million year old original sequence in order to comprehend how this ancient gene came to be able to recognize novel peptides from modern infections. Caterpillar peptides could trigger the response of this ancient receptor. The receptor sequence of a somewhat older variant with 16 modifications could not, though.

These genetic details offer insights into the receptor’s evolutionary process, as do computer simulations that highlight potential differences between the ancient and modern receptor architectures. It implies that a crucial new gene was inserted into the genome of the ancestor plant more than 32 million years ago, and that this was followed by a rapid evolution of many forms of the novel receptor. Numerous descendent legume species now share the ability that one of these forms gained to respond to caterpillar peptides.

According to senior author Adam Steinbrenner, an assistant professor in the biology department at the University of Washington, they have found the emergence and secondary loss of an important immune feature over plant evolution.

The researchers intend to uncover novel immune receptors within plant groupings and understand more about genome-level processes that create new receptor diversity in the future. Such methods will find “missing” receptors that are valuable features to restore into plants to help safeguard harvests when more genetic data becomes accessible.


Simon Snoeck et al. (2022). Evolutionary gain and loss of a plant pattern-recognition receptor for HAMP recognition, eLifeDOI: 10.7554/eLife.81050

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