UNIVERSITY PARK, Pa. — In discovering a mutant gene that "turns on" another gene responsible for the red pigments sometimes seen in corn, researchers solved an almost six-decades-old mystery with a finding that may have implications for plant breeding in the future.
The culmination of more than 20 years of work, the effort started when, in 1997, Surinder Chopra, professor of maize genetics at Penn State, received seeds from a mutant line of corn. At the time, Chopra was a postdoctoral scholar at Iowa State University, and he brought the research with him when he joined the Penn State faculty in 2000.
The mystery involved a spontaneous gene mutation that causes red pigments to show up in various corn plant tissues, such as kernels, cobs, tassels, silk and even stalks, for a few generations and then disappear in subsequent progeny. It might seem like a minor concern to the uninitiated, but because corn genetics have long been studied as a model system, the question has significant implications for plant biology.
"In corn, genes involved in pigment biosynthesis have been used in genetic studies for more than a century — pigmentation in corn is a relatively simple trait, which makes it ideal for use as a marker for genetic research," Chopra said. "The mutant corn plants were identified in 1960 by Dr. Charles Burnham (University of Minnesota), and that seed was given to one of his students, Derek Styles. We received the seed from Styles in 1997, and we were entrusted to continue the research."
Chopra led efforts to introgress the genes from the mutant corn, dubbed Ufo1 — Unstable factor for orange1 — into various inbred corn lines to be studied. Since he came to Penn State, Chopra's research group in the College of Agricultural Sciences has grown and backcrossed lines of corn plants at both the Penn State Agronomy Farm and in greenhouses on campus. In the last three years, the researchers, who recently published their findings in The Plant Cell, have grown more than 4,000 of the backcrossed plants to map where the cause of Ufo1 is located in the genome.