Abstract
Both limiting and toxic soil concentrations of the essential micronutrient boron represent major limitations to crop production worldwide. We identified
Bot1
, a
BOR1
ortholog, as the gene responsible for the superior boron-toxicity tolerance of the Algerian barley landrace Sahara 3771 (Sahara).
Bot1
was located at the tolerance locus by high-resolution mapping. Compared to intolerant genotypes, Sahara contains about four times as many
Bot1
gene copies, produces substantially more
Bot1
transcript, and encodes a Bot1 protein with a higher capacity to provide tolerance in yeast.
Bot1
transcript levels identified in barley tissues are consistent with a role in limiting the net entry of boron into the root and in the disposal of boron from leaves via hydathode guttation.