A possible mechanism and sequence of events that lead to the Al3+-induced [Ca2+]cyt transients and inhibition of root growth.

Fluorescence resonance energy transfer (FRET)- sensitized emission imaging of Arabidopsis thaliana roots expressing the yellow cameleon 3.60 calcium (Ca(2+)) reporter showed that the concentration of calcium in the cytosol ([Ca(2+)]cyt) increased upon aluminum ion (Al(3+)) treatment in root cells from the transition zone within seconds. The Al(3+)-induced [Ca(2+)]cyt transients were biphasic and were modified by Ca(2+) channel blockers and by an antagonist of neuronal glutamate receptors, 2-amino-5-phosphonopentanoate (AP-5), and by the anion channel blocker, 5-nitro-2-(3'-phenylpropyl-amino) benzoate (NPPB).

Fluorescence resonance energy transfer-sensitized emission of yellow cameleon 3.60 reveals root zone-specific calcium signatures in Arabidopsis in response to aluminum and other trivalent cations.

Fluorescence resonance energy transfer-sensitized emission of the yellow cameleon 3.60 was used to study the dynamics of cytoplasmic calcium ([Ca(2+)](cyt)) in different zones of living Arabidopsis (Arabidopsis thaliana) roots. Transient elevations of [Ca(2+)](cyt) were observed in response to glutamic acid (Glu), ATP, and aluminum (Al(3+)).