Morphological responses and molecular modifications in tomato plants after mechanical stimulation. Plant Cell Physiol

Study of the growth responses of Lycopersicon escu-lentum (Mill. cv. VFN8) to mechanical stimulation applied to a single young internode showed a rapid and sharp decrease in stem elongation and an inhibition of elongation of several internodes, indicative of information transmis-sion in the plant. A new tomato cDNA partial clone en-coding calmodulin was isolated and used to study the time course of the gene induction in response to the rubbing treatment. Northern blot analysis showed a maximum accu-mulation of calmodulin mRNA 2 h after mechanical stimulation, not only in the rubbed internode, but also in upper and lower internodes and in young leaves. Treatment of the plant with calcium and EGTA showed the involve-ment of calcium and, in particular, intracellular calcium in calmodulin gene expression and cellular response