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

Abstract

Maritime pine (Pinus pinaster) is an important commercial species throughout its Atlantic distribution. With the anticipated increase in desiccation of its habitat as a result of climate change, the selection of genotypes with increased survival and growth capability under these conditions for breeding programs is of great interest for this species. We aimed to study the response to a realistic drought stress under controlled conditions, looked for a method to measure dehydration resistance, and analyzed dehydrin expression in drought-resistant and drought-sensitive clones from different ecotypes. We report here the sequence characteristics and the expression patterns of five dehydrins from P. pinaster, along with the physiological characterization of drought stress responses in different genotypes (clonally replicated plants), originating from a broad geographical distribution across France and Spain (provenances). In total, we distinguished five different dehydrin genes in silico, grouped into two types-K 2 and SK n . Three of the dehydrin genes had several sequence variants, differing by multiple or single amino acid substitutions. Only two of the dehydrins (PpinDhn3 and PpinDhn4) showed an increase in transcription with increased drought stress which was dependent on provenance and genotype, suggesting their involvement in drought resistance. The other dehydrins showed decreased expression trends with increased severity of the drought stress. The lack of close association between the drought stress and expression patterns of these dehydrin genes suggest that they could have other functions and not be involved in drought resistance. Our results suggest large differences in function between different dehydrin genes.

The Landscape of Nucleotide Polymorphism among 13,500 Genes of the Conifer Picea glauca, Relationships with Functions, and Comparison with Medicago truncatula

“…The expression of dehydrin genes is responsive to cold and drought stress in species such as Pinus pinaster (Velasco-Conde et al 2012) and correlates with bud burst during Spring warming in Picea abies (Yakovlev et al 2008). Dehydrins are believed to prevent protein denaturation or restore function in denatured proteins (Hara 2010).…”

Soil water stress affects both cuticular wax content and cuticle-related gene expression in young saplings of maritime pine (Pinus pinaster Ait)

“…A full description of the primers used is provided in Additional file 2: Table S1. Statistical analyses were also performed, as previousely described by [42] and [43] to validate the expression profile obtained.…”

Water availability influences morphology, mycorrhizal associations, PSII efficiency and polyamine metabolism at early growth phase of Scots pine seedlings

“…LEA proteins, the well-known osmoprotectors (Battaglia et al, 2008), are reported to accumulate under extreme desiccation conditions in higher plants (Yang et al, 2012) including pines (Lorenz et al, 2011;Velasco-Conde et al, 2012). LEA proteins have been grouped to various families on the basis of sequence similarity (Battaglia et al, 2008).…”

“…LEA proteins have been grouped to various families on the basis of sequence similarity (Battaglia et al, 2008). Dehydrins belong to group II of LEA proteins and are important during acclimation of pines (Velasco-Conde et al, 2012). Abiotic stresses cause oxidative stress in plant cells, where one of the first responses is accumulation of reactive oxygen species (ROS), like hydrogen peroxide (H 2 O 2 ).…”