Low potassium availability has always been a major constraint to sugarcane
production. Previously, two genes, CBL9 and CIPK23, were found to be
responsible for the activation of the AKT1 gene, which controls a potassium
channel, responsible for potassium uptake in roots.

Based on these previous studies, three components of the signaling pathway,
AtCBL9, AtCIPK23, and AtAKT1 from Arabidopsis thaliana were co-overexpressed
in sugarcane (Saccharum spp.). This resulted in a 31% increase in potassium
content of transgenic plants at low-potassium stress. The evaluation was
also done in hydroponic culture in which a 35% increase in potassium content
was observed in transgenics compared to non-transgenic lines.

Under low potassium conditions, transgenic lines had longer roots, higher
plant height, heavier dry weight than non-transgenic lines, indicating
better growth of transgenic lines. This study showed that co-overexpression
of AtCBL9, AtCIPK23 and AtAKT1 could significantly increase sugarcane
potassium uptake ability and tolerance to low-potassium stress. These
findings would have significant implications for improving stress tolerance
of sugarcane in areas where potassium supply is scarce.

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