Climate changes with decreasing regional rainfall and increasing temperatures emphasize the importance of the development of new drought tolerant cultivars from germplasm collections, especially for agriculturally important crops.
Plants mainly respond to water deficit by reducing water loss in leaves through stomatal closure causing reduction in photosynthesis and by metabolic protection via accumulation of compatible solutes or production of antioxidant enzymes against the adverse effects of oxidative stress. A rapid accumulation of reactive oxygen species (ROS), mainly hydrogen peroxide (H2O2), was observed during drought stress adaptation in many plants.
(Figure. Antioxidant gene expression during dehydration time course (0-8h) and slow developing water stress (right) in two barley vaieties, Erginel90 and Marti)
Study of gene expression, termed as transcriptomics is an essential step in understanding of plant cellular response to environmental stresses.
Any data of physiological mechanisms of drought and salinity adaptations will also be helpful to explain regulation of plant responses. (Following picture shows the decrease of water loss and increase in osmolyte accumulation in the leaves of two different barley plants by hours of dehydration)
Plant genetic engineering, particularly genome editing technologies can greatly facilitate the study of gene function and development of tolerant plants to drought/salinity/heat stresses.
Analysis of sequence diversity and biochemical features of stress-associated genes in wild relatives of crop plants, can provide information on tolerance and stress response. For example, dehydrins play a fundamental role in response of plants to different abiotic stresses especially dehydration, salinity and low temperatures by accumulating in vegetative tissues. We reported the genetic structure and variation of near-complete Dhn3 alleles in H. spontaneum plants collected from South-eastern Turkey.
For more information.
Assessment of the response of barley to the separate and joint effects of heat shock and salinity stress (Michele Faralli M.Sc. thesis)