Hoping to speed up plant photosynthesis, researchers from the US and UK have successfully upgraded a carbon-fixing enzyme vital to photosynthesis in a tobacco plant with two enzymes from cyanobacteria, which function at a faster rate. If photosynthesis can be performed more efficiently, plants would grow larger and crops could have higher yields, posibly as high as 60% according to computer models.
“This is the first time that a plant has been created through genetic engineering to fix all of its carbon by a cyanobacterial enzyme,” said Cornell Professor Maureen Hanson, a co-author of the study, in the release. She added, “It is an important first step in creating plants with more efficient photosynthesis.”
The study was recently published in the journal Nature.
Photosynthesis in plants involves the capture of carbon dioxide and water followed by absorbing light to generate oxygen and sugar that’s vital to producing plant tissue and energy. Unfortunately Rubisco, the enzyme responsible for fixing carbon dioxide, also has an affinity for grabbing oxygen from the air, which inhibits it and reduces the growth rate of the plant.
However, Rubisco in cyanobacteria works faster at fixing carbon, so for some time, researchers have been trying to get the genes that code for cyanobacterial Rubisco into a vascular plant in hopes that it would lead to greater plant growth. According to Hanson, the secret to success this time was also swapping in other genes that help manufacture the improved Rubisco.
But problems remain. One of the reasons Rubisco works so well in bacteria is that the enzyme is housed in oxygen-free, microchambers called carboxysomes. The next goal, then, is to get the 10-15 genes that code for carboxysomes into plants as well, which the team has already attempted using blue-green algae genes.
Researchers are increasingly looking to manipulate genes in plants to enhance their properties. Last year, a Kickstarter campaign for glowing plants from Genome Compiler, a Singularity University Labs company, raised nearly half a million dollars. Another group is reviving the nearly extinct American chestnut tree species with an anti-fungal gene from wheat. For years, Monsanto has produced genetically modified seeds that are resistant to herbicides, an effort that has attracted its fair share of controversy.
All of this tooling around with plant genomes does have a vital purpose: improving the world’s food production.
It’s no secret that human population is on an exponential growth curve (at least for the foreseeable next few decades) and longevity continues to rise. Somehow everybody has got to eat.
The effects of climate change also loom on the horizon, threatening to cause shifts in regions of arable land. While advances in fertilizers and pesticides have managed to improve yields, more robust crops that can withstand extreme climate conditions are desirable.
While some may recoil at the thought of GMO foods, it’s difficult to imagine how the needs of future generations can be met without them.
[Media: Dennis Tang/Flickr, Genome Compiler]