Why some grasses got better photosynthesis

Brown University News: Even on the evolutionary time scale of tens of millions of years there is such a thing as being in the right shape at the right time. An anatomical difference in the ability to seize the moment, according to a study led by Brown University biologists, explains why more species in one broad group, or clade, of grasses evolved a more efficient means of photosynthesis than species in another clade.

Biologists refer to the grasses that have evolved this better means of making their food in warm, sunny, and dry conditions with the designation “C4.” Grasses without that trait are labeled “C3.” What scientists had already known is that while all of the grasses in the BEP and PACMAD clades have the basic metabolic infrastructure to become C4 grasses, the species that have actually done so are entirely in the PACMAD clade. A four-nation group of scientists wondered why that disparity exists.

To find out, Brown postdoctoral researcher and lead author Pascal-Antoine Christin spent two years closely examining the cellular anatomy of 157 living species of BEP and PACMAD grasses. Using genetic data, the team also organized the species into their evolutionary tree, which they then used to infer the anatomical traits of ancestral grasses that no longer exist today, a common analytical technique known as ancestral state reconstruction. That allowed them to consider how anatomical differences likely evolved among species over time.

…Erika Edwards“Now that we have this increasingly detailed bird’s-eye view, we can start to become a more predictive science. ... In terms of genetic engineering we’re going to be able to provide some useful information to people who want to improve species, such as important crops.”

“Now that we have this increasingly detailed bird’s-eye view, we can start to become a more predictive science. ... In terms of genetic engineering we’re going to be able to provide some useful information to people who want to improve species, such as important crops.” Credit: Mike Cohea/Brown UniversityIn C4 plants, such an anatomical arrangement facilitates a more efficient transfer and processing of CO2 in the bundle sheath cells when CO2 is in relatively short supply. When temperatures get hot or plants become stressed, they stop taking in as much CO2, creating just such a shortage within the leaf…

A grassland in Canastra, Brazil, shot by BDG2007, Wikimedia Commons via Flickr, under the Creative Commons Attribution-Share Alike 2.0 Generic license

Should we label genetically modified food?

Bhaskar Vira and David Nally in the "PovertyMatters" blog in the Guardian (UK): On the sidelines of the US presidential election, battle lines were drawn on a Californian ballot that has potential implications for broader debates about the challenges of global food security. Proposition 37, which was narrowly defeated (52.8% of voters opposed the measure), would have required mandatory labelling for all genetically engineered food sold to consumers in California.

...There seems little doubt that achieving food security will involve biotechnology. What is more contentious is the way in which these technologies are rolled out and, more to the point, who stands to benefit. The development, deployment and control of agricultural biotechnology is likely to result in winners and losers. There is no such thing as socially neutral or apolitical technology.

There are, for example, considerable differences between publicly funded genetic research, which is made freely available to farmers and other producers, and patented and protected technologies that are distributed under the proprietary control of private companies. In reality, biotechnological development is likely to involve compromise between the need to provide adequate incentives for research and development within the private sector, including allowing patents and intellectual property to protect profitability, and the need for these technologies to be used on a sufficient scale to offer sustainable solutions to the challenge of feeding 7 billion people.

Concerns about biosafety are equally important. For proponents of genetic technologies to dismiss these as the irrational fears of misinformed consumers is short-sighted, and potentially underestimates the power of consumer voice, especially in the digital age. It's also patronising, suggesting consumers should have choice on the shelves but not on the labels....