Dehydrins expression related to timing of bud burst in Norway spruce

Abstract

Cold deacclimation and preparation to flushing likely requires rehydration of meristems. Therefore, water stress related genes, such as dehydrins (DHN), might play an important role in providing protection during winter dormancy, deacclimation and bud burst timing processes. Here we report the sequence analysis of several Norway spruce DHN identified in late and early flushing suppressive subtraction hybridization cDNA libraries and in our Norway spruce EST database. We obtained 15 cDNAs, representing eight genes from three distinct types of DHN, and studied differential expression of these genes before and during bud burst in spring, using qRT-PCR. We found the visible reduction in transcript level of most DHN towards the bud burst, supported by a significant down-regulation of the DHN in needles during experimental induction of bud burst applied at three time points during autumn in Norway spruce grafts. For most of the DHN transcripts, their expression levels in late-flushing spruces were significantly higher than in the early flushing ones at the same calendar dates but were remarkably similar at the same bud developmental stage. From our results we may conclude that the difference between the early and the late families is in timing of the molecular processes leading to bud burst due to differences in their response to the increasing temperature in the spring. They are induced much earlier in the early flushing families.

Dehydrins in maritime pine (Pinus pinaster) and their expression related to drought stress response

“…Only one of the dehydrins found (PpinDhn5) was of the K-type and had two K-segments. All the dehydrins in this study were shown to have a similar structure, i.e., they lack a Y-segment, as do the dehydrins from other conifers like P. abies (Yakovlev et al 2008), P. sylvestris, P. concorta, P. ponderosa, or C. sempervires (Fig. 4, Electronic supplementary material 3).…”

“…In trees, levels of dehydrins have been associated with cold hardiness/dormancy and content/state of water in the tissue (Rowland and Arora 1997;Erez et al 1998;Kalberer et al 2006). It seems that accumulation of dehydrins is a common feature of cold acclimation and onset of dormancy, and levels of dehydrin transcripts stay very high during the winter (Wisniewski et al 1996;Yakovlev et al 2008). Many studies report a positive correlation between the accumulation of dehydrin transcripts or proteins and tolerance to freezing, drought, or salinity (Karlson et al 2003;Kosová et al 2007;Mehta et al 2009;Rampino et al 2006;Rorat et al 2006;Tommasini et al 2008;Wisniewski et al 2008;Hara 2010).…”

“…Among the genes involved in stress responses identified, dehydrins are, so far, those most often considered relevant to dehydration stress. They are desiccation-induced proteins produced in response to dehydration during environmental stress such as drought (Campbell and Close 1997), low temperatures or freezing (Rinne et al 1999;Welling et al 2004;Yakovlev et al 2008), and increased salinity (Close 1997;Rorat et al 2006). Dehydrins are also known as the late embryogenesis abundant (LEA) proteins, belonging to the LEA DII family, and they accumulate in plant tissues in response to cellular dehydration resulting from developmental events (Tompa and Kovacs 2010) such as during the late stage of seed maturation, but their exact function remains unclear.…”

“…In the last 20 years, different, but structurally related dehydrins have been isolated from crops (Close et al 1989;Ismail et al 1999;Zhu et al 2000;Borovskii et al 2002;Lee et al 2005;Bhattarai and Fettig 2005;Hinniger et al 2006), herbaceous plants (Ouvrard et al 1996;Volaire 2002;OlaveConcha et al 2004;Yakubov et al 2005;Pulla et al 2008;Bies-Ethève et al 2008), and woody plants (Arora and Wisniewski 1994;Muthalif and Rowland 1994;Rinne et al 1999;Wisniewski et al 1999Wisniewski et al , 2006Richard et al 2000;Kontunen-Soppela et al 2000;Caruso et al 2002;Welling et al 2004;Porat et al 2004;Deng et al 2006;Yakovlev et al 2008;Bassett et al 2009;Hara et al 2009;Vornam et al 2011). An accumulation in leaves and stems has been demonstrated, which appears to change during the yearly seasonal cycle.…”

Cold tolerance in cypress (Cupressus sempervirens L.): a physiological and molecular study

“…Since their discovery, numerous reports have shown their accumulation in both herbaceous (Welin et al 1995) and woody species upon cold stress (KontunenSoppela and Laine 2001;Dhanaraj et al 2005). It has been suggested that dehydrins play a role also in winter dormancy, as some members of the family were gradually down-regulated in Norway spruce plants approaching flushing (Yakovlev et al 2008). For the dehydrin cyplp015, no difference in the up-regulation rate was detected between the two accessions, suggesting that the clonal difference in cold tolerance is not related to transcriptional regulation of these genes.…”