Area biologist helps unravel plant puzzle

A worldwide team of researchers, including biologists from UCSD, has unraveled a 40-year-old mystery that may be the key to engineering drought tolerance in plants.

Area resident Julian Schroeder played a role in the discovery, which also involved researchers from UC Riverside, led by Sean Cutler, and laboratories in Wisconsin, Toronto, Santa Barbara and Valencia, Spain.

Detailed in the April 30 issue of Science is their discovery of the receptor for the hormone that triggers plants’ defense mechanism to drought, Schroeder said.

The team discovered the receptor for the hormone that triggers plants’ defense mechanism to drought, said Schroeder.

Forty years ago scientists identified the hormone abscisic acid, called ABA, which plants produce in response to drought.

Schroeder explained that the hormone causes a range of reactions when a plant is stressed by drought, from shutting down the stomata--or holes--in the leaves to reduce water loss to causing roots to grow deeper into the ground to find water.

The reaction is created when the proteins, or receptors, bind to the hormone, so the “Holy Grail” was to find the receptors that are at the top of the pyramid, he said.

As Schroeder and post-doctoral researcher Noriyuki Nishimura worked on the challenge at UCSD, using what is called “protein fishing,” or protemics, Sean Cutler and his team pursued the same puzzle at UC Riverside using chemical genetics.

“We have been doing these experiments in my lab for nine years,” Schroeder said. “We failed and we failed and kept running into brick walls.”

But then, “Dr. Nishimura did everything right,” he added, and came to him and said he had found nine genes. “When we found the proteins we got very excited.”

Cutler, who is the senior author on the Science journal article, had also indentified a chemical that stimulates one of the ABA receptors and had identified the same proteins. Cutler approached Schroeder with his lab’s findings and suggested that Schroder join his team on the project.

“He was a step ahead of us,” Schroeder added. When they compared notes they realized that by collaborating they could advance their work more rapidly.

Their multinational collaboration “is a model of how science can move fast and effectively to break down huge barriers … and it’s been great fun.”

Twelve years ago, his lab was conducting basic research on modifying genes in plants.

Today a biotech firm is in field trials, applying his work, he said, noting that there is a long way to go before they can apply their newest find to engineering drought tolerance in plants.

“It will require a lot more science.”