Sweetpotato

Tina Kyndta and collaborators ((Kyndt T, Quispe D, Zhai H, Jarret R, Ghislain M, Liu Q, Gheysen G, & Kreuze JF (2015). The genome of cultivated sweet potato contains Agrobacterium T-DNAs with expressed genes: An example of a naturally transgenic food crop. Proceedings of the National Academy of Sciences of the United States of America PMID: 25902487)) have found that all cultivated sweetpotatoes are naturally transgenic because they contain transfer DNA (T-DNA) sequences from Agrobacterium. Gene-transfer via Agrobacterium is a naturally occurring process, that is used to make genetically modified crops in the lab. We did not know that one of our main food crops was once naturally transformed via the same process.

Kyndta et al. did not find any T-DNA in the wild relatives of sweetpotato, suggesting that the transformation(s) provided a beneficial trait that was selected for during domestication. The introduced genes are intact and expressed in different organs of the “Huachano” variety that they studied in detail, but we’ll have to wait for future expression studies to find out about the benefit of these paleo-GMOs.

The authors also suggest that, as people have been eating these swollen roots for millennia, we might now consider all transgenic crops to be “natural”. I don’t know about that. Didn’t most of these people suffer and die young? I predict that sweetpotato consumption will plummet now that the word is out.

Sweetpotatoes come in different colors and tastes (and sizes). The “yams” eaten in the United States are sweet and have orange and moist flesh. The staple of parts of Africa and the Pacific (and pig feed in China), is typically white-fleshed and not very sweet nor moist (notwithstanding variations like this purple variety.)

Anyway, the orange fleshed sweetpotato is stacked with beta-carotene, the stuff you need to eat for your body to make vitamin A. Many poor people have vitamin A deficiencies, which leads to stunted growth and blindness. So why don’t the poor sweetpotato eaters eat orange fleshed varieties? In part because they simply do not have them, or know about their health benefits. In part because they do not grow well in Africa (decimated by pests and diseases). And also because they do not taste right: too sweet for a staple.

The International Potato Center and partners have been trying to fix all that. Now they have made a nice video about getting orange-fleshed sweetpotatoes into the food-chain in Mozambique. The orange revolution:

https://vimeo.com/2278794

I wonder if they also promote mixing more sweetpotato leaves into the diet — even of white fleshed varieties. The leaves are a very good source of micro-nutrients, including beta-carotene! More fodder for the biofortification discussion.

Fresh Nibbles

A paean to diverse diets is just what we all need.
And another one, from the MIT Technology Review of all places.
Menawhile, there’s only one reference to dietary diversity in the World Bank’s investment framework for nutrition.
Maybe you have to quantify that diversity before you can save it? Now where have I heard that before?
Meanwhile, Europe reports on biodiversity-friendly farming practices. Does that include the biodiversity of the actual crops? Perhaps surprisingly, yes!
You want biodiversity-friendly farming practices? Talk to Indigenous people. The Committee on World Food Security (CFS) has launched an e-consultation on “Preserving, strengthening and promoting Indigenous Peoples’ food and knowledge systems and traditional practices for sustainable food systems.”
There’s diversity in asparagus too.
Genebanks can help with those biodiversity-friendly practices, diverse diets and rops and Indigenous practices.
Even big international genebanks.
Even the Svalbard Global Seed Vault.
But some are in trouble.
Though others are coming back.

Published on November 7, 2024

Tag: Sweetpotato

All sweetpotatoes are transgenic

Orange revolution