Two brief introductions about how to overcome stress damage in crops have appeared in this months ISB April 2011 newsletter, coming out of Virginia Polytech.
They cover manipulation of leaf pore (stomata) density and better triggering of plant stress responses:
Regulation of Stomatal Density by GTL1 Transcription Factor for Improved Water Use Efficiency (pdf file)
Chan Yul Yoo, Paul M. Hasegawa, and Michael V. Mickelbart
A decline in global water availability and increased agricultural drought have resulted in significant reductions in crop production, which in turn has intensified research into more efficient water use in plants. Stomatal pore size or number (density) influences transpiration, CO2 uptake, and water use efficiency. Methods to induce stomatal closure reduce stomatal pore size, thereby increasing drought tolerance and, potentially, water use efficiency. However, this drought tolerance strategy usually results in a reduction in biomass and/or yield, due to reduced CO2 uptake for carbon assimilation, often referred to as yield penalty. Recently, we determined that the Arabidopsis GTL1 transcription factor negatively regulates water use efficiency through stomatal density control by which AtGTL1 transrepresses SDD1, a negative regulator of stomatal density.
Engineering Stress Tolerance in Cereals Using DREB/CBF Genes: Outcomes, Problems and Perspectives (pdf file)
Sergiy Lopato and Peter Langridge
The dehydration-responsive element-binding proteins (DREBs), or C-repeat-binding proteins (CBFs), are among the first families of transcriptional regulators that are transcriptionally up-regulated by water deficit or low temperature. We recently demonstrated that constitutive over-expression of two wheat DREB factors in barley substantially improved survival under severe drought or cold. In a cyclic type of drought, expression of DREB factors under control of an inducible promoter may give some advantages by providing protection at the depth of the drought cycle when plants are under severe stress, and by accelerating the rate of recovery in response to rainfall events.