WEST LAFAYETTE, Ind. - A Purdue University scientist has found genetic evidence of how some plants adapt to live in unfavorable conditions, a finding he believes could one day be used to help food crops survive in new or changing environments.
David Salt, a professor of horticulture, noticed several years ago that a variant of the research plant Arabidopsis thaliana that could tolerate higher levels of sodium had come from coastal areas. To test the observation, Salt grew more than 300 Arabidopsis thaliana plants from seeds gathered across Europe. The plants were grown in non-saline soil and their leaf-sodium content was measured.
Each plant's origination was mapped, and those with the highest sodium contents were found to have come from seeds collected close to a coast or area with high saline soil. All plants were analyzed using genome-wide association mapping, which compares the genomes of a number of plants with a shared physical trait - in this case leaf sodium accumulation - to identify genes that may account for variation in this characteristic. Salt found that the plants that accumulate the highest sodium levels in their leaves had a weak form of the gene HTK1, which regulates sodium intake distribution to leaves.
"The major gene that is controlling variation in leaf sodium accumulation across the whole European population of Arabidopsis thaliana is HTK1," said Salt, whose findings were published in the journal PLoS Genetics. "The Arabidopsis thaliana plants that accumulated high levels of sodium had a reduced level of HTK1 gene expression. The populations that have this altered form of HTK1 are on the coast. There are a few exceptions that prove the rule, such as populations in the Czech Republic, which isn't near the coast, but come from an area containing high saline soils derived from an ancient beach."
It has long been known that plants are adapted to their local soil environments, but the molecular basis of such
|Contact: Brian Wallheimer|