Abstract
ALMT1 confers aluminum (Al)-tolerance by secretion of malate from root apices, which excludes Al ions. In Japanese varieties, Al tolerance was correlated with malate efflux, but not with the ALMT1 transcription level, suggesting a possible post-transcriptional regulation for functional expression of ALMT1 (Sasaki et al., 2006). To reveal the possibility, we compared a pair of Japanese lines which were derived from the same cultivar but differed in Al tolerance. The Al-tolerant line showed less accumulation of Al and higher malate efflux. However, both lines showed the same levels of ALMT1 transcript and ALMT1 protein. We obtained F2-progenies by the cross of these lines, and Al sensitivity of them was segregated to the 1 (sensitive) : 3 (tolerant) ratio. These results suggest that at least one gene is involved in the post-translational modification of ALMT1 which is necessary for its functional expression.
