Natures wonders: new found plant defenses (Introduction)

by David Turell , Monday, December 07, 2020, 00:41 (1230 days ago) @ David Turell

How cow peas signal an attack:

https://www.sciencedaily.com/releases/2020/12/201204110239.htm

"Plants can fight back, unleashing an array of chemical defenses to discourage wayward foragers -- from releasing chemicals that attract caterpillar predators to secreting compounds that make the plant taste so foul that desperate caterpillars resort to cannibalism. But scientists know little about how plants detect these attacks and marshal defenses.

"In a paper published Nov. 23 in the Proceedings of the National Academy of Sciences, a team led by scientists at the University of Washington and the University of California, San Diego reports that cowpeas -- a type of bean plant -- harbor receptors on the surface of their cells that can detect a compound in caterpillar saliva and initiate anti-herbivore defenses.

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"The receptor is a protein known by the acronym INR. The team showed that, in response to both leaf wounds and the presence of a protein fragment specific to caterpillar saliva, the cowpea's INR protein boosts the production of ethylene, a hormone that plants often produce in response to munching by herbivores and other types of environmental stress. The protein fragment in caterpillar spit that elicited this response, Vu-IN, is actually a fragment of a cowpea protein, which gets broken down by the caterpillar as it dines on cowpea leaves.

"Researchers have fewer methods to study cowpeas compared to other plants. So to learn more cellular details about INR's function, they popped the gene for INR into tobacco plants. These tobacco plants, when exposed to Vu-IN, increased production of ethylene as well as reactive oxygen species, another anti-herbivore defense that consists of chemically reactive forms of oxygen. In addition, the team's experiments showed that a tobacco-eating caterpillar -- the beet armyworm -- munched less on INR-harboring tobacco plants than plants without INR.

"The research shows that plants like the cowpea sound the alarm only after their cells detect specific molecules associated with herbivory. Vu-IN is a trigger for cowpea defenses. Other plants likely have different molecular triggers for their own defensive systems, the researchers believe."

Comment: I see no way that chance mutation or trial an error can produce this type of specific molecular response signaling. Only design fits.