Biologists at New York’s Cold Spring Harbor Laboratory have discovered a regulatory pathway in corn that could help explain how plants regulate the proliferation of stem cells, and could potentially be used to increase yields of corn and other staple crops by as much as 50 percent. The pathway works by channeling signals from emerging young leaves in corn to the meristem, which is located at the plant’s growing tip.
Plant biologists have long known of another pathway,the Clavata-Wuschel pathway, that regulates stem-cell proliferation from within a portion of the meristem itself called the meristem organizing center.
“In this pathway, the receptor and ligand are expressed in the stem cells, which send signals down to the cells just below, in the organizing center,” said David Jackson from the Cold Spring Harbor Laboratory.
The newly discovered pathway establishes similar feedback, although since its signal begins in the leaves, it could signal stem cells in the meristem to stop proliferating and act as a brake in response to environmental cues such as available light, nutrients or moisture. The research team discovered that releasing this brake system could lead to slightly more stem cells and increases in yield.
Jackson’s team studied corn plants in which FEA3, the receptor responsible for initiating the brake system once the signal reaches it from the leaves, was dysfunctional. The dysfunctional receptor inhibited the signal from reaching it, causing the plant to make too many stem cells, and resulting in too many new seeds. In FEA3 mutant plants, corn ears develop with too many kernels, which don’t yield well.
When the researchers grew plants with “weak alleles” of the FEA3 gene, the receptor’s function was only mildly impaired, which resulted in a manageable increase in stem cells, and led to ears that were significantly larger than ears in wild-type plants. The ears from these plants had more rows of kernels, and averaged up to 50 percent higher yield than wild-type plants. Researchers plan to test the newly discovered FEA3 alleles in elite varieties of corn and other crops.
The research was supported by the National Science Foundation’s (NSF) Plant Genome Research Program, Dupont Pioneer, the Gatsby Charitable Foundation, Swedish Research Council, and the Rural Development Administration of the Republic of Korea. More information can be found here