A tiny soil worm can act like a plant seed during times of drought, going into suspended animation until a drop of rain gets it moving again. The gene that allows this survival trick is a duplicate of one already known in plants and implies a distant common ancestry.
Researchers at NUI Maynooth discovered the drought gene in a one millimetre long soil worm, Aphelenchus avenae, and publish their findings this morning in the science journal, Nature. Dr John Browne, post-doctoral fellow, and Dr Ann Burnell, senior lecturer, in the department of biology, Maynooth, and Dr Alan Tunnacliffe of the University of Cambridge, are joint authors of the report.
The worm is the first animal discovered to have the gene, according to Dr Burnell who is also Maynooth's dean of science. "The gene was known to be in plants but wasn't discovered in animals before," she said yesterday.
The ability of certain worms and bugs to spring back to life after even decades of desiccation has been known for more than two centuries, she said. Early experimenters were astounded to see worms emerge when drops of water were added to dust. They believed it was spontaneous generation from a form of matter called anamalicules, but later work showed that certain species of worm could survive long-term desiccation.
The process is known as anhydrobiosis and the newly discovered gene works in a similar way whether in plants or animals. When things get really dry the gene comes into action, triggering changes inside the cells.
High concentrations of sugars are produced and these form something called a "bio-glass". This gel-like substance helps stabilise structures inside the cells and prevents them from collapsing.
The worm or nematode curls up and apparently dies but in fact only suspends all cellular processes. "When it gets water, within 24 hours it is wriggling around again," Dr Burnell said.
She has spent 15 years studying the use of nematode insect parasites as a natural alternative to chemical insecticides. One recurring problem is the short shelf life of the nematodes, hence her excitement at the discovery of the drought gene.
"If we could figure out how these other nematodes could go into suspended animation, it would be a major breakthrough," she said.