Discovered gene keeps corn in line
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An Illinois farmer's decision to save an unusual ear of corn in 1909 has led a new faculty member in genetics, development and cell biology to identify a gene that's key for efficient corn production.
The gene that was lacking in the bizarrely shaped cob is vital to producing straight rows and compact ears, said Erik Vollbrecht, an affiliate of the Center for Plant Transformation. His research found that the gene – called ramosa1 – is conserved in every modern corn variety. That's unusual for corn, a plant noted for its genetic diversity, Vollbrecht said.
If ramosa1 isn't present or is less active, corn ears develop with crooked rows or branched cobs, he said.
Vollbrecht was working as a postdoctoral researcher at the Cold Spring Harbor Laboratory in New York state when he and lead researcher Robert Martienssen isolated the gene. Their paper was featured on the cover of the August 25 issue of Nature, one of the most prestigious journals in science.
Ancient farmers who bred the wild grass teosinte into domesticated corn selected for ramosa1 by choosing ears with compact cobs and straight rows, Vollbrecht said. They found those ears packed in the most grain. "It's a matter of yield, a matter of packing efficiency," he added.
The researchers found nearly identical DNA sequences for ramosa1 in 40 unique corn varieties. They also found that plants in which the gene's effect was reduced produced ears with less straight rows. Grasses like rice and sorghum have more, longer branches because ramosa1 isn't present or isn't as active, Vollbrecht said.
Discovery of the gene may have implications for improving corn and other grains. Ramosa1 also influences tassel branch production. It takes only a few tassel branches to produce more than enough pollen, Vollbrecht said, and corn bred to produce fewer tassel branches can devote more resources to producing grain. Rice and other grains also might be made to produce more compact, better-yielding ears.
