Effects of Drought Pre-Conditioning On Protein Expression In Kentucky Bluegrass Under Heat Stress.

Effects of drought pre-conditioning on protein expression in Kentucky bluegrass under heat stress

Chenping Xu¹, Yan Peng² and Bingru Huang¹

¹ Department of Plant Biology & Pathology, Rutgers University

² College of Animal Science and Technology, Sichuan Agricultural University, Yaan, China 625014

Heat stress is one of the most typical kinds of stress the cool-season turf-grass species received from their high temperature surroundings.  Previous study indicates drought preconditioning could improve Kentucky bluegrass tolerance to subsequent heat stress. In order to investigate the effects of drought preconditioning on protein expression under heat stress, Kentucky bluegrass (cv. Brilliant) was subjected to a moderate drought (12d) and re-watering (2 d) to allow turf quality recovered to the level of well watered control before being exposed to 25 d of heat stress (35^oC/30 ^oC) in growth chambers. Under heat stress, the abundance of proteins involved in active oxygen species scavenging (glutathione-S-transferase and catalase), protein destination and protection (chaperonin, heat shock protein 70 /HSP 70 and HSP 90) and respiration (cytosolic glyceraldehyde-3-phosphate dehydrogenase) increased, while proteins involved in amino acid metabolism (glutamine synthetase, glycine decarboxylase P subunit and alanine aminotransferase) and RNA stability (RNA binding protein) were down-regulated.  Drought preconditioning enhanced heat tolerance and accelerated the up-regulation of chaperonin and HSP 90, inhibited the down-regulation of proteins related to amino acid metabolism, and induced the expression of lipoxygenase which might increase lipid saturation level and decrease membrane fluidity.