Moss holds key to surviving drought: study

By Laura Crowley

- Last updated on GMT

Related tags Gene Organism

The moss Physcomitrella's ability to survive dehydration and then
regrow when watered could be applied to crops in drought-stricken
areas without the addition of new genes, according to scientists
who have sequenced its genome.

This moss is the first non-flowering plant to be sequenced and the researchers from the University of Leeds, with colleagues from Germany, Japan and the USA have published their findings in this month's issue of the journal Science. "By sequencing the genome, we can start to identify their genetic basis and use the knowledge for crop improvement,"​ said key scientist Andy Cuming. ​Modification of crops to resist drought continues to occupy scientists globally, spurred on by concerns over global warming and rising salinity levels in the soil. According to Cuming, the genes responsible for the moss' ability to survive dehydration and then regrow could be present in higher crops, but in an inactive form. "We believe many of the useful genes in Physcomitrella are probably still present in 'higher' crop plants, but are no longer active in the same way,"​ said Cuming. "So rather than adding newDNA, we'll just be activating what's already there to create the properties we want." ​This suggests that crops could be modified without adding foreign genes, raising the question as to whether the resulting crops would be classified as transgenic. The new study focused on the moss' ability to integrate new DNA into a defined target in the genome, unlike most plants which integrate new DNA randomly. This means that modification of the moss genome is far more controlled than with other plants. "If we can discover what mechanisms cause the Physcomitrella genome to integrateDNAin this way, we may be able to transfer those to other plants, to allow more controlled modification of their genomes,"​ said Cuming. Physocomitrella is similar to the first plants that began to grow on land around 450m years ago. They are just one cell thick and had to adapt to withstand cold, heat and drought without roots. Now that scientists have sequenced the moss's DNA, they will be able to identify which genes control these survival tactics and adapt crops to do the same. "Physocomitrellais a really useful plant to study,​" added Cuming. "In addition to being the link between water-based algae and land plants, it also has many important characteristics that make it special." ​The moss has a single 'haploid' genome instead of a double genome from male and female parents. This makes it easier to identify which characteristics link to which gene. The study was started at Leeds University over 20 years ago by David Cove, and taken over by Andy Cuming with support from the Biotechnology and Biological Services Research Council. Until now, only a small number of plant genomes have been sequenced, compared with a large number of diverse animal genomes. The scientists hope that more genetics work will now be carried out on plants. Source: Science ​13 December 2007, "The Physcomitrella Genome Reveals Evolutionary Insights into the Conquestof Land by Plants" ​Authors: Stefan A. Rensing,1 Daniel Lang,1 Andreas D. Zimmer et al.

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