GM phytoremediators suck up explosives, carcinogens.
A history of viruses
We’re fond of reminding ourselves here that agrobiodiversity isn’t just crops and livestock and their wild relatives — it’s also pests and pathogens and weeds and pollinators and earthworms and brewer’s yeast. It’s one of our leitmotifs. Another is that agricultural and “wild” biodiversity interact. Here’s a paper that kind of brings these two leitmotifs together, into a sort of counterpoint, if I may be allowed to push the metaphor ((C.M. Malmstrom et al. (2007) Barley yellow dwarf viruses (BYDVs) preserved in herbarium specimens illuminate historical disease ecology of invasive and native grasses. Journal of Ecology (OnlineEarly Articles). doi:10.1111/j.1365-2745.2007.01307.x)).
Carolyn Malmstrom and her team at Michigan State University isolated RNA of barley and cereal yellow dwarf viruses from old herbarium specimens of Californian grasses, dating back to 1917. They used such historical samples to trace the history of these agriculturally important viruses back through time, building up a sort of family tree. The analysis suggests that the viruses were present in the Californian native flora in the 18th and 19th centuries, when invasive Eurasian annual grasses (some of them weedy crop relatives) displaced native perennial grasses. In fact, they may have facilitated this invasion by helping the exotic grasses outcompete the natives ((“Non-native invaders amplify spring aphid populations and increase BYDV infection in natives, which in turn suffer substantially reduced survivorship when infected.”)).
The team also found “potential correspondence in the timing of virus diversification events and the beginning of extensive human exchange between the Old and New Worlds.” Humans may have caused the branching of the family tree of some viruses by moving them and their hosts around the world.
Here’s Malmstrom on the significance of her work:
This work points out that the virus world does have an active, long-term role in nature, not just in agriculture… We very much need to understand how viruses can move and influence our crops. If we care about our crops, we need to care about what’s happening in nature.
So: aphids, viruses, native grasses, exotic weedy invaders, crops. Quite a fugue.
Seeds are not enough
An article in the NY Times tells a frustrating tale of agrobiodiversity use: stunning use by researchers, followed by disappointing use by farmers. It’s the story of Nerica ((The piece has been picked up elsewhere. The Economist’s Free Exchange blog also comments on it.)) — New Rice for Africa. This is a family of varieties derived in the 90s from a biotechnological breakthrough, the hybridization of African and Asian rice. ((Don’t get me wrong, these are not transgenics, though molecular methods were used to overcome the huge challenge of interspecific hybridization.)) Combining “the toughness of O. glaberrima with the productivity of O. sativa,” Nerica varieties have:
– Higher yields (by 50% without fertilizer, and 200% with).
– Earlier maturity (by 30-50 days).
– Resistance to local stresses.
– Higher protein content (by 2%).
A great example of researchers really unleashing the potential of genetic diversity. And one that has been rightly widely recognized. So why have the resulting varieties “spread to only a tiny fraction of the land in West Africa where they could help millions of farming families escape poverty”? It hasn’t been for want of trying:
To quickly move the NERICA technology into farmers’ hands, WARDA and its partners have adopted farmer-participatory approaches, such as the Participatory Varietal Selection (PVS) and community-based seed production systems (CBSS).
The NY Times piece suggests that the reason for Nerica’s disappointing use by farmers comes down to infrastructure. The seeds — even information about them — are not getting to the farmers that need them, and the harvest finds it hard to get to market. That’s because there are few seed companies, roads are bad, telecommunications poor, credit not available. The article also suggests that yield of Nerica has been known to decrease over time “because the new seed was not pure.”
It is undeniable that seed systems could be strengthened in Africa, and that doing so would improve the lot of smallholders. But I don’t know. Farmers are not stupid. They know how to select material for next year’s sowing, and they exchange seeds all the time, often over large distances. Their lives depend on it. Is there something else holding Nerica back? Or maybe it’s just too soon to be expecting miracles of adoption?
Creating and curing obesity
Better late than never, I guess. I’ve only just realized that the September issue of Scientific American was entitled Feast and Famine, and juxtaposed the ironic twin killer trends of hunger and obesity. Most of the material is unfortunately behind a paywall, but I have borrowed a hardcopy from a colleague and will be reading through it in the near future. If you’ve already done so and have any comments on what the various high-profile authors involved say about agrobiodiversity, let us know. One commentator has said:
This issue of Scientific American tells us there’s money to be made by creating and then curing obesity. That’s what the science approach to obesity is about and what the prevention-based approach is up against. ((I’ve borrowed my title from this article.))
Do you agree with this take?
Genome of cereal disease fungus sequenced
Fusarium head blight fungus genome decoded.