A&M International Faculty Member Published in Journal

Dr. Mario G. Garcia-Rios, Assistant Professor of Biology at Texas A&M International University has become the first faculty member in the University's history to be published in the prestigious Proceeding of the National Academy of Sciences (PNAS), the second most-cited scientific journal in the world.

His research report, "Cloning of a Polycistronic cDNA from Tomato Encoding gamma-glutamyl kinase and gamma-glutamyl phosphate reductase," was published recently in Volume 94 of the PNAS. Publication in this scientific journal is highly selective. Papers may be submitted by invitation only.

The published report details drought gene research Dr. Garcia-Rios completed while a McKnight Fellow at Purdue University.

For the research, Garcia-Rios cloned a gene from a tomato for potential use in genetically engineered drought resistant plants. He and a team of six researchers worked for over five years to isolate the drought resistant properties of the cloned gene.

According to Garcia-Rios, agriculture productivity is severely limited by environmental stresses--heat, cold, and water stress or drought. Plants have various mechanisms to cope with such stresses, such as small molecules known as compatible solutes.

One compatible solute is proline, an amino acid synthesized by three enzymes, including gamma-glutamyl kinase (GK). Because most organisms produce very little proline, Garcia-Rios cloned the GK gene from a tomato so that the proline-producing gene could be manipulated into other plants.

"By manipulating the GK gene, which controls the stingy production of proline, we hoped to genetically engineer plants that produce lots of proline under drought conditions. We reasoned that if proline production was increased, the levels of tolerance to stressful conditions would increase," explained Garcia-Rios.

The cloned fragment, which he called "tomPRO1," contains genetic information not only for the GK but for another enzyme, gamma-glutamyl phosphate reductase (GPR).

"Analysis of the DNA sequence of this clone revealed that GK and GPR are specified by two distinct open messages similar to those seen in bacteria. That was astonishing because nuclear messengers in animals and plants are almost exclusively single message DNA pieces," he said.

His research yielded two items of scientific importance--the tomPRO1 clone proved to control the proline production, and a gene with highly unusual structure was discovered.

TomPRO1, the gene Garcia-Rios cloned, has since been genetically modified and reintroduced into tomato plants. Researchers at Purdue University are testing the genetically engineered tomato plants for enhanced drought tolerance. Results obtained thus far are very encouraging.

Garcia-Rios is philosophical about his discovery of the unusual gene.

"I was fortunate. The discovery adds to the beautiful picture of finely-tuned genetic controls that scientists are continuously enhancing," he said.

Garcia-Rios will continue his research towards genetically engineering plants with enhanced drought tolerance. Since joining A&M International in 1995, he has cloned two tomPRO1-related DNA fragments from "solanum spp" or "nightshade," which he explained is "a drought tolerant cousin of the tomato."

"I hope that the sequence information provided by these two clones will enhance our understanding of the mechanisms that plants use to adapt to conditions of drought stress," he added.

Last year, A&M International students enrolled in his advanced biology courses replicated his nightshade cloning experiments. Garcia-Rios believes they were the first students to successfully clone a gene in Laredo.

A native of Monterrey, Nuevo Leon, Mexico, Garcia-Rios holds a Bachelor of Science degree in Biochemical Engineering and a minor in Marine Biology from the Instituto Tecnologico y de Estudios Superiores de Monterrey (ITESM), and a Ph.D. in Molecular Genetics from Purdue University.

Prior to beginning his graduate studies, he worked for the Cuauhtemoc Brewery, famed for Bohemia, Tecate and XX beverages.

He and his wife Kathleen Pletsch de Garcia, an Assistant Professor of English and Spanish at A&M International, have two children, Magali, 6, and Alejandra, 4.

For additional information on Dr. Garcia-Rios' research, please contact the Office of Public Affairs at 326-2180.

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