This cutting edge science has the potential to feed into food security issues in two major areas: Striga control, and post-harvest spoilage.
Strigolactones are recently described plant hormones that hold key roles in root development and shoot branching. The mechanism of perception of strigolactones that has been described so far is similar to that of other plant hormones. However, data from the Transport Group suggest that this may not actually be the whole story and that these hormones may convey messages through another mechanism, in particular to control the root response to a mechanical stimulus.
The team is investigating a potential novel mode of action by which strigolactones would interact directly with the plasmamembrane, as GR24 (a synthetic strigolactone) has been shown to affect endocytosis – the budding off of plasmamembrane into vesicles inside the cell. They want to investigate this possible mode of action by looking at whether strigolactones and related compounds 1) can move into a phospholipid monolayer (which is like a plasma membrane), 2) affect the qualities of this monolayer, and 3) alter the diffusion of lipids through the monolayer. It is vital that the pathway is completely understood if we are to be able to manipulate it with any success.
But why is this very molecular work of use to wider issues of food security?
Firstly, if we can understand how the plant’s response to mechanical stimulation (such as bumping along in a truck) is controlled, this can be applied to protect crops from post-harvest spoilage. Currently damage to produce causes unsightly cell death and lesions, which can easily get colonised by moulds and fungi, leading to the produce not staying in a saleable condition for very long. If we can understand how the response to mechanical stimulation works, there is the possibility of modifying it to reduce the amount of damage that occurs, and therefore the amount of produce wasted before it is sold or eaten.
Secondly, the mode of action of strigolactones is important to understand as they induce the germination of parasitic weeds, in particular Striga hermonthica. Striga plumbs itself into the roots of cereal crops such as maize, millet, sorghum and upland rice, and hugely stunts their growth, causing yield losses of between 30% and 100% in sub-Saharan Africa. There are ongoing efforts to synthesise a strigolactone mimic, which could be sprayed on fields before planting, to induce Striga to germinate – as if the parasite germinates before there are any roots to attack it will die. Currently these mimics have all been very costly, but the more the mechanism of action of strigolactones is understood, the more opportunities there are to find ways to mimic them and trick Striga into suicidal early germination.
The Seed Award money will be used to employ an undergraduate for a summer project to start investigating these issues at the Cavendish lab. The groups then hope to use the results as a basis for joint grant applications to further work in this area.
Joanna Wolstenholme, Communications intern