Identification of a Chloroplast Dehydrin in Leaves of Mature Plants

Abstract

Several types of proteins are known to accumulate as a result of dehydration stress in plants, and many of these are thought to serve a protective function. This includes the dehydrin family of proteins, which accumulate in cells in response to drought, low temperatures, or salinity and in embryo tissues during the maturation phase of seed development, when the seed is losing water in preparation for dormancy. Many studies to date have concentrated on the expression, localization, and function of dehydrins in seed tissues. Our study provides some of the first evidence for a chloroplast-localized dehydrin by using cell fractionation combined with immunofluorescence and immunogold electron microscopy to determine dehydrin location in mature leaf tissues of Pisum sativum and Zea mays. This article also documents constitutive expression of the chloroplast dehydrin as well as expression during different dehydrative stresses. The chloroplast-dehydrin expression pattern differs from most other dehydrins studied to date and suggests a role in basic cell metabolism for this particular dehydrin.

Overexpression ofMtCAS31enhances drought tolerance in transgenic Arabidopsis by reducing stomatal density

“…Previous studies found that DHNs can be localized in the nucleus, chloroplasts, vacuole, rough endoplasmic reticulum, mitochondria, cytoplasm and membranes (Heyen et al. , 2002; Mueller et al. , 2003; Carjuzaa et al.…”

Role of plant dehydrins in antioxidation mechanisms

“…Some dehydrins also accumulated in the vicinity of plasma membrane and were suggested to inhibit lipid peroxidation caused by ROS (Danyluk et al 1998). In the last a few years, dehydrins have been proved to be distributed in mitochondria and chloroplast (Borovskii et al 2000;Mueller et al 2003), which are known to be important ROS-generating places and susceptible to the attack of free radicals (Salin 1991). These results argued that the function of dehydrins is associated with ROS or dehydrins may play an antioxidative role in plants under environmental stresses.…”

Overexpression of a maize dehydrin gene, ZmDHN2b, in tobacco enhances tolerance to low temperature

“…Some dehydrins can also be expressed constitutively during normal growth (Rodriguez et al 2005;Rorat et al 2004Rorat et al , 2006. Under stress conditions, DHNs accumulate in most tissues and cells and are mainly localized to the cytoplasm and nucleus of the plant cell (Close 1997;Mehta et al 2009;Rorat 2006;Tunnacliffe and Wise 2007), although some DHNs have been found to interact with the chloroplasts (Mueller et al 2003), mitochondria (Borovskii et al 2002), plasma membrane (Danyluk et al 1998;Puhakainen et al 2004), and tonoplasts (Heyen et al 2002;Saavedra et al 2006). Such a wide distribution and expression pattern suggests that these proteins play essential roles in plant growth and stress tolerance.…”