Genome duplication aids plant's survival in saline soils

Having more than two sets of chromosomes can increase a plant's ability to take up nutrients and survive in saline soils, a joint study by Purdue University and the University of Aberdeen shows.

Researchers found that polyploidy, the condition of having more than two genome copies, causes the flowering plant Arabidopsis thaliana to accumulate a greater amount of potassium in its leaves and demonstrate a higher tolerance to saline environments. Most flowering plants are diploid, having two copies of a genome.

"Polyploidy has an immediate, direct influence on the accumulation of required nutrient elements in plant leaves," said Brian Dilkes, an assistant professor of horticulture and landscape architecture at Purdue. "This shows how polyploidy can play a role in plant adaptation and may explain why genomes in plants evolve the way they do."

Dilkes says the altered nutrient uptake observed in A. thaliana could hold true for other plant species.

"Many crops are already polyploids, but we can make use of these findings in a variety of species," he said. "Polyploidy could be used as a tool for expanding the range of current diploid crops. For example, it opens up a new way of manipulating plants' abilities to absorb nutrients and survive in nutrient-poor or toxic environments." 

The sodium resistance of polyploids could make them valuable cultivars in regions with saline soils.

Due to its recurrence throughout plant history, polyploidy was long thought to have adaptive benefits. Most laboratory studies, however, found polyploids with four identical genome copies to be equal or weak compared with diploids. Dilkes' study demonstrates that polyploidy's positive effects depend on the environment in which polyploids are grown.