By Jordan Strickler
A new international study co-led by the University of Kentucky Martin-Gatton College of Agriculture, Food and Environment shows how a single genetic change helps protect corn seeds during storage. This offers plant breeders a clear target for developing varieties that stay vigorous longer and waste fewer seeds.
The research, published in The Plant Cell, focuses on a damaged protein repair enzyme called Protein repair L-isoaspartyl methyltransferase 1 (ZmPIMT1). The study showed how natural changes in the regulatory region of the gene encoding the enzyme—the DNA "on/off" region that controls how much of the ZmPIMT1 RNA, and then protein, is made—affect seed aging tolerance in maize.
The team found that some corn lines carry a version of this region that turns ZmPIMT1 on more strongly, helping seeds better survive the stress of long-term storage and harsh conditions.
"Roughly 70% of the human diet comes directly from seeds, and much of the rest depends on animals fed on seeds," Downie said. "We eat them, wear them as cotton, ferment them into beverages and fuel. If seed lots fail, the costs hit farmers, companies and consumers all the way down the line."
The study, conducted in part with Tianyong Zhao at Northwest A&F University in China, Zhao's associate, Yumin Zhang, identifies two main versions of the ZmPIMT1 regulatory region across diverse corn lines. One version drives high levels of ZmPIMT1 mRNA production, while another carries a large DNA insertion that lowers expression and, consequently, weakens seed performance under aging stress.
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