I don’t do a lot of posts on plant biochemistry here, but this news is pretty notable, and it illustrates several points that apply across other fields as well. This new paper has as its background the role of a particular methyl group in the structure of RNA molecules: N6-methyladenosine. The presence or absence of this methyl group is a very important epigenetic marker across pretty much all eukaryotic life – there are quite a few of these, and their activities are wide-ranging. These modifications of RNA can affect the stability of a given RNA species, how mRNAs get translated into protein and under what conditions, and more. Meanwhile, similar markers on DNA residues affect winding around histones (histone proteins have their own marker systems as well), transcription into RNA, and other processes. In plants, there’s a substantial amount of work showing the m6A signaling network is involved in development from seeds, flowering, resistance to viral infection, and a long list of growth and physiology effects.
Humans have an enzyme called FTO that demethylates N6-methyladenosine (and some other substrates as well) through oxidation. It’s part of a large family of enzymes that do this sort of thing using an iron atom in their active sites (although not as a heme group), along with molecular oxygen. Plants, though, don’t have an FTO homolog – they have some other enzymes that can demethylate this substrate, but not like FTO itself. So the team behind this paper wanted to see what would happen if you engineered the FTO enzyme into plants – they reasoned that it was unlikely to fit into the existing cellular regulatory networks (as a foreign protein more or less dropped in from the sky), and its robust demethylation activity would surely have some interesting effects.
Nature Biotechnology It sure did. In rice and potatoes, the crop yields went up by about 50% in field trials. Grain size in the rice plants didn’t change, nor did the height of the plants – they just produced a lot more rice grains in general. Shown at right are the potatoes from 20 control plants and 20 FTO-modified ones – in this case, the total number of potatoes doesn’t seem to go up, but the overall potato weight certainly does. Neither the rice nor the potatoes showed changes in their starch, protein, total carbohydrate, or vitamin C content.
How does this happen? The plants’ root systems were deeper and more extensive, and photosynthetic efficiency went up by a startling 36%. Transpiration from the leaves was up 78%, but at the same time, the plants of both species showed significantly higher drought tolerance. These are highly desirable traits, and it’s worth noting that a lot of this extra biomass is coming from increased usage of carbon dioxide from the air. As the paper notes, this both demonstrates an extremely useful effect right off the bat, and also points to many lines of investigation about how RNA demethylation affects all these plant growth pathways (indeed, the latter part of the paper shows a number of preliminary work to try to untangle all this, but there’s going to be a lot more work needed on that).
Agriculture, national and international regulations, and customer attitudes being what they are, you’re not going to see FTO-modified plants showing up in the grocery stores any time soon. But this is a really promising area to investigate: the addition to plants of a protein that we all already have in our bodies might increase agricultural productivity immensely. Increased yields are key to not plowing up more of the planet’s arable (and potentially arable) land to grow food on, so this could also be good news for preservation of wild habitats in general. It will be fascinating to see what happens when FTO is introduced into other food crops (corn, wheat, soybeans, cassava, oil seeds and more), or whether this could be used to make some chemical feedstock ideas more feasible. Would FTO-modified trees produce wood more quickly and in greater amounts? Could study of the enhanced photosynthesis pathways lead to modified species that would be useful in carbon dioxide uptake? This is quite a result, and I hope it leads to many useful consequences.
The post One Lost Methyl Group = Huge Amounts of Food Production first appeared on In the Pipeline.
