Model Plant Hoodwinks Scientists: Thale Cress Lacks Usual 'Censorship' Protein

One particular plant seems to have hoodwinked scientists. It turns out that researchers have misunderstood one of the most fundamental processes in the life of plants because they've been looking at the wrong flower. The findings could inform future research as scientists are set back on the right track.

The flower in question is called Arabidopsis thaliana, also known as thale cress or mouse-ear cress. It grows abundantly in cracks in pavements all over Europe and Asia. Yet this plant also serves another purpose; it's used as a model plant within labs all over the world.

While researchers use this plant as a model, though, this latest study shows that there's something a bit unusual about thale cress. It turns out that it does not have the "censorship" protein called SMG1. This protein was known to play a vital role in the growth of animals as multicellular organisms, but researchers believed that plants built their complex life fundamentally differently--a conclusion based on Arabidopsis thaliana. The fact that thale cress is unusual in this respect means that scientists' view of plants was, in fact, incorrect.

"Everybody thought that this protein was only in animals," said Brendan Davies, one of the researchers, in a news release. "They thought that because, basically, most of the world studies one plant: Arabidopsis thaliana."

The censorship process associated with SMG1 is called Nonsense Mediated mRNA Decay (NMD). It's used by both plants and animal, but researchers once believed that the two types of organisms did it in different ways. Essentially, the system looks at the messages that come out of the nucleus and make a decision about them--either it destroys the message before it takes effect, or lets it through. Because SMG1 was not found in thale cress, though, the researchers once assumed that no plant possessed this protein.

"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 in a news release. "Rather than being just in animals, we are suggesting that the last common ancestor of animals and plants had SMG1."

Currently, the researchers plan to look at how organisms without SMG1 work without the protein. That's not to say that they won't continue to use thale cress as a model plant, though. However, scientists are now more informed about the plant, and have learned that it's not safe to make assumptions about all plants in general when it comes to thale cress.

The findings are published in The Plant Journal.