Serpentine plants survive harsh soils thanks to borrowed genes
Scientists from the John Innes Centre have analysed the genomes of plants that grow in harsh, serpentine soils to find out how they survive in such conditions. It appears that they have used two strategies: adapting to their environment through natural selection that acted on genetic variants which arose locally, as well as by borrowing useful variants from a related plant growing nearby.
If a plant could choose where it wanted to grow, it probably wouldn't choose serpentine soil.
Derived from serpentinite rocks, serpentine soil is dry, low in nutrients, and typically contains metals like nickel and chromium in concentrations that would be toxic to most species.
Nevertheless, a few hardy plants have put down roots in these 'serpentine barrens' – but just what it is that makes these plants so well adapted to such an extreme environment?
An international team of scientists, which included Dr Kirsten Bomblies and Dr Levi Yant from the John Innes Centre, has taken advantage of advances in genomics to work out which genes give serpentine plants their incredible tolerance.
"Improved technology and a much reduced cost means we can now conduct more complex genomic analysis than ever before," said Dr Yant, a research group leader at the John Innes Centre and corresponding author of a new paper published in PNAS. "We wanted to compare plants of the same species from serpentine and non-serpentine populations to try and find the differences between them at the genomic level."
Seeds of a flowering plant called Arabidopsis arenosa were collected from all over Europe. "We have been working on adaptation in A. arenosa for some years, but then we found a botanical survey published back in 1955, which recorded a population growing in a serpentine barren in Austria, which is an extreme habitat even for this species," explains Dr Bomblies. "It was still growing there when we visited the same site in 2010, so we collected its seeds, as well as those from about 30 non-serpentine populations, and grew them all in common gardens back at the lab to compare them."
This study, published today in the journal Proceedings of the National Academy of Sciences further affirms that A. arenosa is an excellent model for studying the genetic basis of adaptation. It is closely related to A. thaliana and A. lyrata – two well-studied species used as model organisms for plant research, which helps tremendously in the assessment of gene function.
Tissues from plants grown from the collected seeds were used for genomic analysis. As expected, the researchers found that the serpentine population of A. arenosa in particular possessed gene variants that may help them cope with challenges such as drought and low soil nutrient status.
"Knowing which genes help serpentine A. arenosa to thrive in poor soils should be useful for crop breeders, who may be able to use this knowledge to rationally develop stress resilient crop varieties," said Dr Yant.
So how did serpentine-tolerant A. arenosa get the genetic changes that have helped it to colonise serpentine barrens?
"We think some of A. arenosa's adaptations evolved completely independently through natural selection, but interestingly, we also found some distinctly A. lyrata gene variants in the genome of the serpentine-tolerant A. arenosa, but not the other A. arenosa populations," said Dr Yant.
"This suggests that serpentine A. arenosa has 'borrowed' some advantageous migrant genes from populations of its cousin growing nearby."
He concludes: "The findings of this study advance our knowledge of the complex ways in which plants adapt to – and even thrive – in harsh conditions, and that knowledge is very important as we seek to mitigate the effects of degrading agricultural lands and a rapidly changing climate."
This research was funded by the European Research Council, a Ruth L. Kirschstein National Research Service Award (US), the National Science Foundation (US) and the UK's Biotechnology and Biological Sciences Research Council (BBSRC).
Notes to editors
1. The paper 'Borrowed alleles and convergence: serpentine adaptation' will be published in the Proceedings of the National Academy of Sciences on Monday 27 June 2016.
2. Images to accompany this press release can be downloaded from: http://bit.ly/28Vt5IS
3. If you have any questions or would like to interview Dr Yant or Dr Bomblies, please contact:
Communications Manager, The John Innes Centre
T: 01603 450 238
4. About the John Innes Centre
The John Innes Centre is an independent, international centre of excellence in plant science and microbiology.
Our mission is to generate knowledge of plants and microbes through innovative research, to train scientists for the future, to apply our knowledge of nature's diversity to benefit agriculture, the environment, human health and wellbeing, and engage with policy makers and the public.
To achieve these goals we establish pioneering long-term research objectives in plant and microbial science, with a focus on genetics. These objectives include promoting the translation of research through partnerships to develop improved crops and to make new products from microbes and plants for human health and other applications. We also create new approaches, technologies and resources that enable research advances and help industry to make new products. The knowledge, resources and trained researchers we generate help global societies address important challenges including providing sufficient and affordable food, making new products for human health and industrial applications, and developing sustainable bio-based manufacturing.
This provides a fertile environment for training the next generation of plant and microbial scientists, many of whom go on to careers in industry and academia, around the world.
The John Innes Centre is strategically funded by the Biotechnology and Biological Sciences Research Council (BBSRC). In 2014-2015 the John Innes Centre received a total of £36.9 million from the BBSRC.
The John Innes Centre is the winner of the BBSRC's 2013 – 2016 Excellence With Impact award.
5. About the BBSRC
The Biotechnology and Biological Sciences Research Council (BBSRC) invests in world-class bioscience research and training on behalf of the UK public. Our aim is to further scientific knowledge, to promote economic growth, wealth and job creation and to improve quality of life in the UK and beyond.
Funded by Government, BBSRC invested over £509M in world-class bioscience in 2014-15. We support research and training in universities and strategically funded institutes. BBSRC research and the people we fund are helping society to meet major challenges, including food security, green energy and healthier, longer lives. Our investments underpin important UK economic sectors, such as farming, food, industrial biotechnology and pharmaceuticals.
For more information about BBSRC, our science and our impact see: http://www.bbsrc.ac.uk
For more information about BBSRC strategically funded institutes see: http://www.bbsrc.ac.uk/institutes
6. About the ERC: https://erc.europa.eu/about-erc
7. About the Ruth L. Kirschstein National Research Service Award: https://researchtraining.nih.gov/programs/training-grants/T32
8. The National Science Foundation (US): http://www.nsf.gov/