Characterization of abiotic stress-responsive RD29B and RD17 genes in different poplar clones

Soil salinity as one of the most important abiotic factors limiting productivity becomes a more acute problem worldwide. A significant percentage of land in Vojvodina Province (Northern part of Serbia) are halomorphic soils. Moreover, the process of salinization of land in Vojvodina Province has a tendency to increase in the years to come due to declining irrigation water quality and decreasing precipitations during the years. Consequently, new strategies to enhance yield stability on halomorphic soils become a research priority. Populus species is widely used for afforestation in the Pannonian Plain and due to its sequenced genome it is suitable for genomic analyses of diverse abiotic stresses. This paper characterizes the abiotic stress-responsive RD29B and RD17 genes in three economically important poplar clones (Populus x euramericana cl. M1, Populus deltoides cl. PE19/66 and Populus deltoides cl. 182/81). Understanding the functions of these genes has focused on their responsiveness to salt stress in revealing their expression pattern and mode of induction indicating divergence in potential salt tolerance in poplar clones. Based on the results obtained it was determined that the poplar clones reacted differently to salt stress (150 mM, 300 mM and 450 mM) and showed differential expression pattern of salt responsive genes RD29B and RD17 in each of them respectively. RD29B gene expression was elevated in the highly saturated salt conditions and the induction was noticed in the later phases of the stress. RD29B gene was selected as a candidate gene for salinity stress breeding of poplar. M1 and PE19/66 clones showed tolerance to higher concentrations of NaCl as a salt stressor and it would be recommended for afforestation of halomorphic environment.