The results from salt tolerance studies must be repeated and
validated to reliably determine the function of salt tolerant genes
in the development of specific traits. Our opposite results
compared to previous studies [9] are not limited to the field of
salt tolerance research for this gene only. For example, sodium
levels in the transgenic Arabidopsis overexpressing SOS1 driven by
a constitutive super promoter have shown non-significant change
compared with the wild-type [15], which is different from previous
conclusions that transgenic Arabidopsis overexpressing SOS1
driven by the 35S promoter reduces sodium accumulation [6]. Yang
et al. (2009) speculated that the super promoter may not match the
temporal and spatial expression of native SOS1, whilst the activity
of the 35S promoter significantly enhanced in the vasculature,
more closely matches the native SOS1 expression in parenchyma
cells at the xylem-symplast boundary in Arabidopsis [15