Stress proteins co-expressed in suberized and lignified cells and in apical meristems

We report the cloning of a small heat shock protein, Qs_HSP17, and an osmot in like protein? Qs_OLP, from cork oak phellem tissue (cork cells). Both ge nes are expressed in suberizing cells and in other cells subject to endogen ous stress associated with free radicals. We provide evidence that smHSPs a nd OLPs accumulate in overwintering buds and speculate that their role is s imilar to that in seed dormancy. We also show that both stress proteins are mainly located in the region of the quiescent center in root apex and in c entral meristem in the shoot apex. We emphasize that smHSPs and OLPs are ex pressed in cells growing under endogenous stress or facing ion life-span. W e discuss a possible role of these stress proteins against oxidative stress . (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.