Drought is a major threat to world agriculture. In order to identify proteins associated
with plant drought tolerance, barley varieties bred in the UK (Golden Promise) and Iraq
(Basrah) were compared.
The variety Basrah showed physiological adaptations to drought when compared to
Golden Promise, for example relative water content after one week of drought was
much higher for Basrah than for Golden Promise in the leaves as well as the roots. Also
the water loss rate was significantly different between the two varieties, with the Basrah
variety loosing water at about half the rate of Golden Promise.
DIGE analyses were carried out on proteins from roots and leaves under control and
drought conditions. 24 leaf and 45 root proteins were identified by MALDI-TOF MS
spectrometry. The relative expression patterns of the identified proteins fell into a
number of distinct classes. The variety Basrah is characterised by constitutive
expression or higher drought-induced expression levels of proteins regulating ROS
production and protein folding. Photosynthetic enzymes, by contrast, were downregulated
in Basrah. Enzyme assays showed a good correlation between DIGE-derived
protein abundance estimates and enzyme activity in extracts.
Overall this study shows that the enhanced drought tolerance of variety Basrah is driven
by an enhanced regulation of ROS under drought. A number of transcription factors
with enhanced expression in Basrah under drought conditions were also identified; it is
hypothesised that these may contribute to the drought tolerant phenotype and thus make
interesting targets for barley breeding experiments.Scotch Whisky Associatio
