Taking the P out of plants

Is there an alternative to using GM crops in agriculture to eradicate the need for applying excessive phosphate fertiliser? John Hammond of UK’s Horticulture Research International thinks so. Working in collaboration with Nottingham University, he is developing a diagnostic test that tells when plants are low on phosphorus so they can be fertilised by precision management rather than the current practice of fertilising indiscriminately. Dr Hammond will present his results at the Society for Experimental Biology Meeting in Heriot-Watt [session P4.13].

When plants are low on phosphorus a very specific set of genes is switched on and these are detected in the diagnostic test which can monitor their activity very precisely. Preliminary tests are currently being carried out on potato crops as they require a lot of phosphorus in their diet. “If you take any part of the plant from the field and put it into this test”, says Dr Hammond, “if it’s low on phosphorus specific genes light up which will tell the farmer that this is the time to add fertiliser. This will cut down pollution in rivers and will be cost effective, as well as excluding the need for phosphorus-enhanced GM crops”.

Plants respond to phosphorus starvation with a variety of physiological and biochemical changes controlled by their genetics. The test monitors the genetics of a plant and can pick up characteristic genes that indicate the lack of specific nutrients, such as phosphorus. It will ignore other environmental factors which may be affecting the plant at the same time such as cold so it is very specific. The test can only be done in high-tech labs at the moment but it is envisaged that the farmer may be able to carry out the test on the farm within the next 5 to 10 years on a range of important mineral nutrients.