Identification of Proteins Associated with Drought Tolerance and Post-Drought Recovery in Kentucky Bluegrass.

Protein metabolism plays critical roles in plant adaptation to drought stress. The objective of this study was to identify proteins that are involved in drought survival and rehydration and re-growth upon rewatering in Kentucky bluegrass (Poa pratensis L.). Two cultivars differing in drought resistance, ‘Midnight' (tolerant) and ‘Brilliant' (sensitive) were exposed to well-watered conditions, drought stress 15 d by withholding irrigation, and then re-watered for 6 d in growth chambers. Physiological analysis demonstrated that ‘Midnight' was better to maintain leaf hydration and photochemical activities under drought stress and regrow and was rehydrated faster upon re-watering, compared to ‘Brilliant'. Out of about 850 protein spots were reproducibly detected by two-dimensional gel electrophoresis, with 83 protein spots exhibiting a significant change in the abundance level during drought stress and recovery. Under drought stress, more protein spots were up-regulated in ‘Midnight' than in ‘Brilliant'; or less protein spots were down-regulated in ‘Midnight' than in ‘Brilliant'. By 6 d after rewatering, most proteins had restored largely or completely to the expression level of well-watered control in ‘Midnight', but fewer proteins exhibited recovery in ‘Brilliant'. Functions of the differentially-expressed proteins in response to drought stress and recovery between the two cultivars will be discussed.