When scientists discovered a mutant gene that "turns on" another gene
responsible for the red pigments seen in corn, they also solved an almost
six-decades-old mystery with a finding that may have implications for plant
breeding in the future.
The mystery involved a spontaneous gene mutation causing red pigments to
show up in various corn plant tissues for a few generations and then
disappear in subsequent progeny. It seemed like a minor concern, but because
corn genetics have long been studied as a model system, the question has
significant implications for plant biology.
Surinder Chopra, professor of maize genetics at Penn State led efforts to
introgress the genes from a mutant corn, dubbed Ufo1 - Unstable factor for
orange1 - into various inbred corn lines to be studied. However, Ufo1 is not
causing the red pigments to appear, but a gene called pericarp color1 or p1.
Researchers found that the Ufo1 gene is actually controlled by a transposon
that sits close to it. When this transposon is switched on, the Ufo1 gene is
also turned on, triggering the p1 gene to signal the plant to produce the
red pigments. When the transposon is off, the Ufo1 gene goes silent and so
does the p1-controlled pigment pathway. Chopra said that this is the main
reason the Ufo1 gene went unidentified for so long and the mystery