Defying gravity

Plant & zo

The science of plants and more

Defying gravity

Roots, for a plant how the grow is life shaping. Straight down, for groundwater uptake. Or maybe sideways, for phosphate uptake. To regulate this precisely is crucial. Plants use gravity for growing downwards. About this lots is already known. But growing sideways, against gravity, that is more of a mystery.

To find out how plants do this, researchers from the UK and Italy searched for a mutant in barley that didn’t do this. And successfully so. They found a plant whose roots grew more downwards than sideways. This mutant, it turned out, had a mutation in the gene EGT1.

EGT1 organises that the cells are sturdier

Only the roots of plants with a mutation in the EGT1 gene didn’t grow sideways. Above ground, the plant looked undistinguishable from plants without the mutation. Thus, EGT1 is only influencing the roots. And not only in barley, a mutation in a comparable gene in wheat has the same effect. Roots of the EGT1 wheat mutant where not growing sideways.

Subsequently the researchers wanted to know how EGT1 helps roots to overcome gravity. For this, the researchers looked at the genes disrupted in the EGT1 mutant. This, it turned out, were genes for producing parts of the cell wall. This disruption translated into less sturdy cell walls. With as consequence less support against gravity.

EGT1 organises that the cells are sturdier. In this way roots can defy gravity and grow sideways. We do not know exactly how EGT1 organises for sturdier cells. But knowing that EGT1 organises this brings opportunities, breeders can now actively select. For plants that grow deep roots. Or maybe for plants with more sideways growing roots. For a crop with the optimal root system for the soil it is growing in.


Fusi R., Rosignoli S., Lou H., Sangiorgi G., Bovina R., Pattem J.K., Borkar A.N., Lombardi M., Forestan C., Milner S.G., Davis J.L., Lale A., Kirschner G.K., Swarup R., Tassinari A., Pandey B.K., York L.M., Atkinson B.S., Sturrock C.J., Mooney S.J., Hochholdinger F., Tucker M.R., Himmelbach A., Stein N., Mascher M., Nagel K.A., De Gara L., Simmonds J., Uauy C., Tuberosa R., Lynch J.P., Yakubov G.E., Bennett M.J., Bhosale R., and Salvi S. (2022) Root angle is controlled by EGT1 in cereal crops employing an antigravitropic mechanism. PNAS 119 (31) e2201350119

Published by Femke de Jong

A plant scientist who wants to let people know more about the wonders of plant science. Follow me at @plantandzo

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