A Bioengineered Climate Change Bandage Lies in Decoded Plant Genes

The operative word here is "bandage"—not solution or cure or fix. It's an adaptation or, rather, it's the kickstarting of an adaptation in plants rendered vulnerable to increasing temperatures and droughts by their own protective biology. Understand that a thing plants do in response to increasing levels of CO2 in the atmosphere is to in effect blockade themselves from that atmosphere by reducing the numbers of pores (stomata, technically) that coat their leaves. The logic behind this strategy is that plants lose water for every CO2 molecule they absorb, at a nearly 200 to one ratio, and so shutting down pores means stemming this loss. That's a near-term benefit, but in the larger scheme of survival and in the context of sustained climate change, it means something more like doom, as plants forfit a critical evaporative cooling mechanism, according to a study out this week in Nature.

Like many things that go wrong in nature, from neurotransmitters in the human brain to genetic super-redundancy, the mechanism at work is an overreaction. Sealing off pores keeps water in, but plants also need to let water out. “Because elevated CO2 reduces the density of stomatal pores in leaves, this is, at first sight beneficial for plants as they would lose less water," explained lead author Julian Schroeder in a University of California, San Diego press release. "However, the reduction in the numbers of stomatal pores decreases the ability of plants to cool their leaves during a heat wave via water evaporation. Less evaporation adds to heat stress in plants, which ultimately affects crop yield.”

This general mechanism is not in itself a new revelation. What the team behind the current research has uncovered, however, are the genetic roots of the pore-limiting process. This process depends on a peptide hormone called EPF2, which acts on plant stem cells as a morphogen, or a substance that dictates what and how much of a given tissue a living thing is going to produce. The production of EPF2 is itself dictated by another chemical, CRSP (CO2 Response Secreted Protease), which is a whole new discovery.

“We identified CRSP, a secreted protein, which is responsive to atmospheric CO2 levels,” said co-author Cawas Engineer (using apparently his real name). “CRSP plays a pivotal role in allowing the plant to produce the right amount of stomata in response to the concentration of CO2 in the atmosphere. You can imagine that such a ‘sensing and response’ mechanism involving CRSP and EPF2 could be used to engineer crop varieties which are better able to perform in the current and future high CO2 global climate where fresh water availability for agriculture is dwindling.”

That then is the bandage: crops that don't burn up in Earth's probable future climate because we've managed to suppress a bit of plant genome. Just the suggestion of genetic modification as a global warming adaptive scheme is, of course, sure to be unpopular, as will a great deal of the engineering-based adaptive strategies that will continue pouring out of labs and greenhouses as we progress into the Big Mess. At the very least, take heart that there's nothing "franken" about this one, just the quieting of a self-destructive genetic command (one that has implications for our own destruction as well). Adapt or perish, as they say: "nature's exorable imperative."