"Plants may have the genetic flexibility to respond to climate change. In experiments with the common European plant Arabidopsis thaliana, a team of researchers led by Brown University scientists learned that climate is the agent that determines the suite of genes that gives the plant the best chance of surviving and reproducing throughout its natural range. The finding may unlock the molecular basis for other plants' adaptability to climate change. Results appear in Science.
In the face of climate change, animals have an advantage over plants: They can move. But a new study led by Brown University researchers shows that plants may have some tricks of their own.
In a paper published in Science, the research team identifies the genetic signature in the common European plant Arabidopsis thaliana that governs the plant's fitness -- its ability to survive and reproduce -- in different climates. The researchers further find that climate in large measure influences the suite of genes passed on to Arabidopsis to optimize its survival and reproduction. The set of genes determining fitness varies, the team reports, depending on the climate conditions in the plant's region -- cold, warm, dry, wet, or otherwise.
"This is the first study to show evolutionary adaptation for Arabidopsis thaliana on a broad geographical scale and to link it to molecular underpinnings," said Johanna Schmitt, director of the Environmental Change Initiative at Brown and an author on the paper. "Climate is the selective agent."
The researchers believe that by identifying the genetic signatures that mark Arabidopsis' response to changing climate, scientists may understand how climate may cause the re-engineering of the genetic profiles of other plants. "There is still evolutionary flexibility to help plants take one direction or another," said Alexandre Fournier-Level, a postdoctoral researcher at Brown and the paper's first author. "It gives us good hope to see, yes, it's adapting."
"This was a truly massive undertaking, tracking more than 75,000 plants in the field, from near the arctic circle to the Mediterranean coast," said Amity Wilczek, a former postdoctoral researcher in Schmitt's lab now on the faculty at Deep Springs College. "Arabidopsis is an annual plant, so we could measure total lifetime success of an individual within a single year. We gathered plants from a variety of native climates and grew some of each in our four widely distributed European garden sites. We shipped our harvested plants back to Brown and began the laborious task of counting fruits on these plants. In the end, we were able to assemble a very large and comprehensive dataset that gives us new insight into what it takes for a plant to be succesful in nature under a broad range of climate conditions."
The team then burrowed into the Arabidopsis genome to find the molecular mechanisms that might give the plant genetic flexibility to roll with climate punches. To identify variations in the genome among the regional representatives, the researchers carried out a genome-wide association study for survival and fruiting comprising more than 213,000 single-nucleotide polymorphisms. These SNPs, Fournier-Level explained, are like signposts pointing to areas in the genome where survival and reproduction may be emphasized and areas that show variations in the regional representatives' genetic makeup.
From the experiments, the team discovered that the SNPs that determined fitness for Arabidopsis in one region are surprisingly different from those associated with the plant's fitness in another region. The team also learned from the experiments that SNP variants -- "alleles" -- associated with high fitness within each field site were locally abundant in that region, demonstrating a kind of home court advantage at the genomic level..."