Saturday, February 8, 2014

Genetics May Hold the Key to Climate Change Solutions for Plants

Genetics-based research could help identify individual plants that possess superior traits to allow them to survive droughts and temperature shifts.

 As the effects of climate change rapidly alter communities, economies and natural systems, the need to advance new solutions to what may be the most pressing biological challenge of our time has never been more urgent. One important part of the puzzle involves unlocking the natural genetic diversity of plants to identify those species and populations best able to cope with changing conditions.

Just as researchers have used genetics to improve food production, it can also provide solutions that maintain biodiversity and protect the services provided by native ecosystems. Genetics holds the potential to benefit native systems that range from prairies to pine forests and coral reefs.

Plants are well known to possess extensive genetic variation in drought and temperature tolerance, water-use efficiency, and other traits that can prove critical for surviving climate changes and avoiding extinction. Changing climatic conditions not only affect the plants themselves, but also other organisms that influence plant communities. For example, changing conditions may increase pest and pathogen outbreaks or allow an invasive species to move into an area that was previously inhospitable. Importantly, plants also exhibit genetic variation in their responses to pests and invasive species that can be used to mitigate their negative effects.

The use of genetics will become increasingly important in regions suffering from climate change. For example, in western US, drought and higher temperatures have doubled the rate of tree mortality since 1995, with mortality rates accelerating over time. Pinyon pine, an iconic and dominant species in the West, has suffered nearly 100% mortality at sites in Colorado and Arizona, where climate change has made trees more susceptible to bark beetle outbreaks that in turn result in increased wildfires.

Fortunately, plant genomes – all of an organism’s genetic information – are a vast storehouse of genetic variability that can be used to help prevent the loss of species suffering from climate change. New technology and research platforms are making it possible for researchers to identify those individuals and populations that will survive in the climates of the future and in the face of the myriad cascading effects of climate change.

Genetics-based environmental research is already helping to restore damaged and degraded landscapes. For more than 30 years, a consortium of researchers has examined how genetic variation in the cottonwood tree can affect entire communities of organisms from microbes to mammals. This research has been involved with a 50-year, $626 million effort on the lower Colorado River that shows major genetics-based differences in the success of different populations that the Bureau of Reclamation and other agencies are using to restore riparian habitat. From such combined restoration-research experiments, scientists can learn which genetic lines are most likely to survive future climates.

Understanding a plant’s response to climate conditions requires the integration of diverse sciences to examine how changing conditions influence the plant through its life history and that of its offspring. Plant species become adapted to local conditions over thousands of years, meaning that what is locally adapted today could do poorly tomorrow as the climate changes. Thus, genetics-based research can help identify those individuals that possess superior traits that will allow them to survive in a future climate. This type of research involves interdisciplinary teams of climate-change scientists, biologists, geneticists, modellers and engineers who are using and developing new technologies and research platforms to unlock the vast stores of information within plant genomes.

One of these advances is the Southwest Experimental Garden Array, or SEGA, a US$5m facility which was made possible with support from the National Science Foundation, Northern Arizona University and diverse public and private land owners. SEGA is a new genetics-based climate-change research platform that allows scientists to quantify the ecological and evolutionary responses of species exposed to changing climate conditions. SEGA will create a system of 10 gardens along a steep elevation gradient in northern Arizona. Because temperature and moisture predictably change with elevation, these gardens reflect climate differences – ranging from desert to alpine forest – that mimic the effects of climate change. By planting the same plant species and genotypes in different environments, scientists can identify which ones perform best and are most likely to survive changing conditions.

SEGA is the first research platform of its kind in the world, but it must be transferred to, and replicated by, global partners, if the potential benefits of genetics-based approaches are to be realised on a broader scale. Similarly, this approach requires the education of a new generation of scientists trained in diverse disciplines – individuals who can collaborate on complex biological problems involving whole communities of organisms.

Despite the enormous challenges, we live in a time when knowledge and technology can be used to ensure the survival of whole ecosystems and the people who depend upon them. Genetics-based approaches seek to harness the natural genetic variation that exists in wild-populations to restore damaged natural systems and mitigate climate and other global change impacts. While native ecosystems are being challenged as never before, the use of genetics offers new solutions that hold great promise.

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