Plant scientists pick wrong model
30 Oct 2013 by hhwdjwbphm.d hhwdjwbphm.d
One of the most fundamental processes in the life of plants has been misunderstood by scientists because they have been looking at the wrong flower.
Arabidopsis thaliana grows abundantly in cracks in pavements all over Europe and Asia, but also moonlights as the lab rat of the plant world. However, the model is in fact an anomaly because it lacks key censorship gene SMG1.
SMG1 is known to play a vital role in the growth of animals, but it was thought plants built their complex life fundamentally differently – this conclusion was built on a dummy sold by A. thaliana.
Gene expression relies on processed that turn genes on when their genetic messages are required, and off when they are not. Professor Brendan Davies from the University of Leeds – who led the study published in The Plant Journal – said switching genes on and off is really what life is about.
“If you can’t do that, you can’t have life,” he said. “There are various ways this is done, but one way in more complex life such as animals and plants is through a sort of ‘censorship’ process. The system looks at the messages that come out of the nucleus and effectively makes a judgement on them. It says ‘I am going to destroy that message now’ and intervenes to destroy it before it takes effect.”
This censorship process – Nonsense Mediates mRNA decay (NMD) is used by plants and animals, but scientist thought they did it in different ways. Because A. thaliana is lacking SMG1 – which plays a key part in triggering censorship in animals – it was concluded that it wasn’t present in any plant.
“We have found that SMG1 is in every plant for which we have the genome apart from Arabidopsis and we have established that it is being used in NMD,” said Davies. “Rather than being just in animals, we are suggesting that the last common ancestor of animals and plants had SMG1.”
The next key question for researchers is to explain how organisms lacking SMG1 – like fungi and A. thaliana work without the protein.
SMG1 is an ancient nonsense mediated mRNA decay effector http://onlinelibrary.wiley.com/doi/10.1111/tpj.12329/abstract
