Abstract
Aluminum (Al) tolerance in wheat is primarily controlled by the expression of the ALMT1 gene encoding Al-activated malate transporter at root apex. We investigated genomic sequences of the ALMT1-upstream region in several wheat lines varied in Al tolerance. The first 1,000-bp immediately upstream of the ALMT1 was variable and exhibited six different patterns with some repeats (duplication or triplication) in lines of non-Japanese origin. The number of repeats positively correlated with the ALMT1-expression level and Al tolerance. Thus it is possible that the upstream sequence of the ALMT1 is involved in the control of the gene expression level and degree of Al tolerance in wheat. In lines of Japanese origin, however, Al tolerance was correlated with level of Al-activated malate efflux but not with ALMT1-expression level, suggesting that some other gene(s) are involved in the post-transcriptional process to control the functional expression of ALMT1 protein and Al tolerance.
