Root hair research could lead to crop yield increase

Scientists have made strides into understanding how to increase crop yields by boosting a plant’s intake of nutrients and water, which could help improve food sustainability.

New research published in Nature Cell Biology has shown how the length of root hairs on plants can be increased, potentially improving crop yields, as plants with longer root hairs take up minerals and water more efficiently.

In a climate of rising food insecurity where food manufacturers face volatile commodity prices and supply issues, strides made in improving crop yields could help ease the supply pressures faced.

Claire Grierson, the senior author on this paper, told FoodNavigator.com that the research could potentially impact a wide range of crops, including cereals such as wheat, maize, and barley and possibly some fibre and fuel crops.

She said: “So far we have been working on a laboratory plant, the cress Arabidopsis. The next step will be to find out how well our discoveries translate to crop plants.

“The main aim here is not to increase yield per plant or hectare, but to increase the efficiency of crop production in terms of fertilisers and water.

“Fertilisers and water cost a lot of carbon and money to produce and deliver, and at the moment there is significant waste.

“In the long term, if the follow-up work goes well, this could help to sustain supplies in the face of increasing competition for land and resources, and/or reduce the costs of crop production.”

Auxin transport

Angharad Jones, a PhD student in biological sciences at the University of Bristol, and lead author on the paper, said: "Each root hair is a single, elongate cell and the length of each hair depends on having an adequate supply of the plant hormone auxin.

“Auxin is used, for example, in hormone rooting powders to encourage cuttings to root.

“The difficulty has been in understanding how auxin is delivered to the root hairs in order to promote their growth."

Auxin cannot be observed directly, so Jones used a computer model to calculate where auxin was likely to be in plants.

It showed that auxin is not delivered to root hair cells directly, but via the cells next door which act as canals through which the auxin is transported.

During transport, some of the auxin leaks out, supplying hair cells with the auxin signal to grow.

The results also suggest that increasing the number of root hairs is likely to interfere with auxin supply and cause problems with other important traits like a plant's response to gravity and root branching.

So understanding how to increase the length of roots hairs, rather than their numbers, is expected to help avoid these kinds of problems.

Source: Nature Cell Biology

Published online: 14 December 2008 doi:10.1038/ncb1815

“Auxin transport through non-hair cells sustains root-hair development”

Authors: Angharad R. Jones, Eric M. Kramer, Kirsten Knox, Ranjan Swarup, Malcolm J. Bennett, Colin M. Lazarus, H. M. Ottoline Leyser & Claire S. Grierson