Scientists speak at international conference

PULLMAN – WSU scientists will present headline addresses June 28-July 1 in Mérida, Mexico at the 2008 conference of the American Society of Plant Biologists.

 

Their work ranges from the dawn of agriculture in the New World to the invention of new tools to explore the inner workings of plant genomes.

 

 

John G. Jones, assistant professor in the Department of Anthropology, will kick off the conference with an update on his intriguing findings about the beginnings of maize agriculture in the New World.

 

Jones has analyzed core samples taken from lowland areas along the Gulf Coast of Mexico.

 

Jones said he will raise the possibility that maize was domesticated at different times, and for different reasons, at more than one area of Central America.

 

He will show evidence that at the same time early forms of maize were being cultivated in the lowlands of Mexico, more advanced forms were already being cultivated in the highlands of nearby Belize.

 

“We might be talking about two different domestication trajectories,” he said. “Some evidence suggests that when people from the highlands moved to lower elevations, they brought their forms of maize with them, and that the lowland people quickly adopted the more desirable varieties.”

 

Different forms of maize likely differed in features such as disease resistance, sugar content and their adaptations to conditions such as amount of rainfall.

 

Since all current varieties of corn are derived from earlier forms of maize and, ultimately, from teosinte, tracing their genetic and adaptive history can provide information vital to today’s corn breeders.

 

 

Vaccinating plants against disease? It’s a possibility, according to new findings by Alisa Huffaker, a post-doctoral researcher in the Institute of Biological Chemistry.

 

Earlier work at WSU showed that when plants are attacked by fungi, bacteria or insects, they produce small protein fragments called peptide hormones that trigger the release of chemicals throughout the plant that actively defend against the invaders.

 

Huffaker tested whether giving a plant a peptide hormone before exposure to bacteria would protect against infection.

 

In a procedure resembling vaccination, she injected a peptide hormone into a leaf. A day later, she injected the same plant with the bacterium Pseudomonas syringae.

 

Other experiments in the same lab had previously shown that the peptides also protect against a root-eating fungus.

 

Huffaker said with the new evidence of protection against bacteria, the peptide hormones appear to prime several defense mechanisms that then give the plant a jump start in combating new invaders.

 

“It’s not targeted to any specific organism, but it’s enough of a boost that it’s able to protect [the plant] against many different kinds of pathogens at the same time,” she said.

 

The research could lead to methods for protecting crop plants against a wide range of pathogens, increasing yields and allowing farmers to reduce their use of fungicides and other chemical control agents.

 

 

John Browse, Regents’ Professor in the Institute of Biological Chemistry, explores another aspect of plant defenses—how a hormone called jasmonate causes plants to turn on genes that provide immunity to pathogens and defense against insects.

 

Jasmonate, which helps give jasmine flowers their lush scent, is one of the hormones released after a plant is injured or invaded.

 

Jasmonate also functions in plant reproduction. Despite its central role in plant biology, said Browse,  “jasmonate is the last major plant hormone for which the central signaling components have not been described.”
 
He and his co-workers are changing that. They have discovered that jasmonate causes the removal and destruction of repressor proteins that were preventing defense-related genes from being activated.

 

The repressors, called JAZ proteins, keep the defense genes turned off until they’re needed.

 

“The findings from this basic research will help scientists engineer plants that can better defend themselves against disease and attacking insects,” he said.

 

 

Amit Dhingra, assistant professor in the Department of Horticulture and Landscape Architecture, will chair the session on emerging technologies in plant research and give a presentation describing a technique he devised to make genome sequencing easier, faster and less costly.

 

Dhingra, in collaboration with WSU computer scientist Ananth Kalyanaraman, has developed a new algorithm and software to efficiently automate processes that he had previously accomplished in his wet-lab work.

 

The new method, called targeted resequencing, allows researchers to sequence the DNA of a species by using a known sequence of a related organism as a starting point.

 

“We’re utilizing existing knowledge to generate more knowledge,” he said.

 

Targeted resequencing enables researchers to generate short, overlapping fragments of the complete genome without cloning or the logistical puzzle of fitting the pieces together.

 

“The biggest problem with sequencing is, how do you put it together?” said Dhingra. “This solves that problem right at the beginning, because it’s already generating overlapping regions. So when you sequence all these fragments, everything will just line up because they overlap.” 

 

Dhingra said targeted resequencing allows researchers to do in a week what would take six to eight months using the conventional method.

 

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