A newly discovered stem cell signaling pathway could boost yields from corn and other staple crops by up to 50 percent in the very near term, according to a paper published Monday in Nature Genetics.
In essence, it's an intraplant communications channel that acts as a "braking" mechanism to be triggered by the relatively old cellular members of a plant existing in its leaves and far-flung extremities telling the plant to stop producing totipotent stem cells.
In other words, it's a way for the well-established parts of a plant to order the plant to stop growing, most likely in response to environmental cues relating to available light, nutrients, and moisture. The signaling medium itself is a protein fragment known as FCP1.
It's a significant find, and not only for its practical potential in transgenic crops: "a regulatory system that transmits signals from differentiating cells in organ primordia back to the stem cell niche and that appears to function broadly in the plant kingdom." This is new general knowledge.
Extending this beyond corn is next on the agenda.
As the paper explains, the presence of general feedback systems between a plant's stem cell core and certain neighboring cells is well-known. This core, a pocket of stem cells known as the stem cell niche, is regulated by an underlying brain of central control cells via expression of a gene known as WUSCHEL. WUSCHEL tells stem cells to stop differentiating into other types of cells, which is akin to tell them to divide and proliferate (because differentiated cells can no longer divide).
The question posed here is whether or not those feedback systems extend beyond plant cores of undifferentiated stem cells—a region more properly known as the meristem—and out into their differentiated progeny cells, e.g. far-flung specialized cells, such as those making up a plant's leaves. Indeed, the researchers were able to identify a new receptor within the meristems of maize (corn) plants corresponding to the FCP1 protein. It appears to represent a very similar feedback pathway/mechanism to that involving the WUSCHEL gene, but at relatively long-range.
To extend their work, the Cold Spring Harbor Laboratory-based team examined maize plants that were deficient in receptors (FEA3 receptors) for the FCP1 protein. In these plants, it's as if the stem cell niche were blind to the FCP1 signals, with the result being out of control growth. The plant makes far too many stem cells, which results in the product of far too many seeds. The plant is then unable to supply enough nutrients to these seeds, which results in something called fasciation—the plant kicks out loads of baby kernels and the result is gnarly ears of corn that aren't of very much use from a food perspective (or from the corn's perspective).
The Cold Spring researchers then added a twist. They were able to produce transgenic plants that had FEA3 receptors that were only mildly impaired. So, just a bit of the "don't grow" signal was received by the meristem, but still enough to prevent the plants from turning into crappy mutants. This is where we get the 50 percent increase in corn yield per plant. And because these meristem-leaf feedback loops exist widely in the plant kingdom, this trick should be possible in a wide variety of crops useful to humans. Extending this beyond corn is next on the agenda.
Needless to say, the prospect of vastly increased food production via a fairly simple genetic trick is potentially huge. How bringing this to market will get sorted out among a wide pool of funding parties including DuPont, the US National Science Foundation, the Swedish government, and the Republic of Korea is a whole other question.