Cornell University agricultural scientists have discovered that a gene and
the protein it expresses play a major role in allowing rice tolerance to
toxic metal in acidic soils. Leon Kochian, senior author of the paper,
co-directs the project with Cornell rice geneticist Susan McCouch.

The researchers had previously targeted the NRAT1 gene in McCouch's lab to
genetically map aluminum tolerance using diverse lines of rice. Based on the
resulting DNA sequences, they identified aluminum tolerant- and
aluminum-sensitive versions of the NRAT1 gene. They found key sequence
alterations, which resulted in a tolerant NRAT1 protein that effectively
transported aluminum ions from the root cell wall into the cell, preventing
aluminum toxicity that occurs in rice due to damage to the cell wall in the
growing root tip. They also found sequence differences that led to higher
expression of the NRAT1 gene in the tolerant rice lines. The researchers
then inserted the tolerant and sensitive versions of the rice NRAT1 genes
into Arabidopsis plants and found that both versions, but especially the
aluminum-tolerant NRAT1 gene, greatly boosted aluminum tolerance in
Arabidopsis plants.

The research findings suggest that this gene can be used to increase the
aluminum tolerance of rice and other plant species, which would be
beneficial for crop species often grown on acid soils throughout the world.

[www.news.cornell.edu]