Comparative proteomics analysis reveals important drought responsive proteins in the leaves of a potato variety tolerant to drought stress

摘要

Drought stress inhibits the growth and productivity of potato. The mechanism of drought tolerance in potato remains largely unclear. Potato Dongnong 308, tolerant to drought stress, was selected to perform an identification of different abundance proteins using 2D-PAGE and LC-MS/MS accompanying with a physiological and ultrastructural observation to uncover its drought tolerant mechanism in potato leaves. Potato plants can adapt morphologically and physiologically to reduce the damage of drought stress to the plant cell. Under drought condition, the water content in potato leaves had a weak reduction and resulted in a significantly decreased root activity. The SOD activity and MDA content showed a significant increase, suggested that physiological changes occurred in potato leaves under drought stress. After inducing water deficitstress, some chloroplasts separated from cell wall and moved to cell center and grana lamella become netty with increased space between lamellas. In addition, a few chloroplasts became swelled, suggesting its function become weak. With the decreasing supply of energy from chloroplast, other energy supply metabolic pathways were active. Sixteen proteins were accumulated differentially and were involved in chloroplast structure and function, secondary metabolism activation, protein folding/processing and synthesis, glycolysis regulation, and stimulation of ATP synthesis. Their functions in potato leaves were mainly related to activate the process of metabolism adjustment and to mobilize the defense system under drought stress. The abundance of heat shock proteins (HSP) correlated with alleviating the accumulation of reactive oxygen species (ROS) against abiotic stresses, which should facilitate the increase of drought tolerance in potato. The identified physiological parameters and proteins provide new insight of the molecular mechanism to drought tolerance in potato.