Drought and salinity are two major constraints to agricultural
productivity worldwide. The molecular basis of plant
tolerance tothese stresseshasbeenheavily investigatedover
the past two decades. These research efforts have identified
numerous genes that are induced under drought and
salt stress, with the hope that overexpression of stressresponsive
genes would improve plant stress tolerance.
However, these transgenic plants exhibited very small
improvements in stress tolerance or no improvement at
all [20], largely because the complicated genetic interactions
underlying plant stress tolerance are not completely
understood.