Transcriptional and physiological responses to drought stress in Populus nigra L.

Yıldırım, Kubilay
In the current study, we investigated a number of drought related physio-biochemical processes and transcriptional comparisons at different stages of water availability to understand adaptation and response mechanisms of the black poplar (Populus nigra L.). Therefore, a well-watered, successive drought and post drought recovery periods were applied to black poplar clones. According to their drought response, the most sensitive (N.03.368.A) and resistant (N.62.191) black poplar clones were selected for microarray based transcriptional comparisons. The sensitive genotype was characterized with severe defoliation under drought stress. Therefore, the sensitive genotype specific genes were mostly annotated to leaf senescence and cell death. The highest expression of the genes such as NAC (JA), and ap2/erf transcription factors in the sensitive genotype indicated a potential role of Jasmonic Acid and Ethylen hormones controlling the leaf senescence. Expression of the genes involved in proteolysis, cell wall degradation and carbohydrate catabolism in the sensitive genotype were associated with drought induced nutrient and nitrogen mobilization processes. Contrary to the sensitive genotype, the drought resistant black poplar genotypes did not defoliate until severe drought level. The maintenance and recovery of drought traded leaves of the resistant genotype attributed to enhanced synthesis of bark storage proteins during drought stress. These proteins were suggested to be remobilized under drought and re-watering period to be used as an energy source in the drought treated organs. The highest up regulation in chaperons such as Heat Shock Proteins mostly in the resistant genotype were also associated to drought tolerance.


Differential expression of cold resistant related genes in populus nigra l. clones
Zeybek, Evrim; Kaya, Zeki; Department of Biology (2014)
Poplar has been adopted as a model perennial woody species for forest tree genetics to understand molecular processes of growth, development and responses to environmental stresses. In this study, seasonal changes in antioxidant enzymes activities including glutathione reductase (GR), ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR) and catalase (CAT) were examined in black poplar (Populus nigra L.) clones. It was found that GR, APX and DHAR activities increased with low air temperatures in win...
Effect of protein aggregation in the aqueous phase on the binding of membrane proteins to membranes
Doebler, R; Basaran, N; Goldston, H; Holloway, PW (Elsevier BV, 1999-02-01)
Analysis of the binding of hydrophobic peptides or proteins to membranes generally assumes that the solute is monomeric in both the aqueous phase and the membrane. Simulations were performed to examine the effect of solute self-association in the aqueous phase on the binding of monomeric solute to lipid vesicles. Aggregation lowered the initial concentration of monomeric solute, which was then maintained at a relatively constant value at the expense of the aggregated solute, as the lipid concentration was i...
Genetic control of cellulose, lignin and glucose contents in european black poplar (populus nigra l.) populations from Turkey
Taşkıran, Bircan; Kaya, Zeki; Severcan, Feride; Department of Biology (2014)
Populus nigra L. is considered as one of the most economically significant forest tree species with respect to production of wood, biomass, timber, pulp, paper and other wood-based products, besides its ecological and evolutionary importance. Because of the increased wood needs of the world and demands of renewable energy sources, fast-growing poplar has gained importance. While wood quality, pulp mechanical strength, and biomass are directly associated with high cellulose content, lignin emerges as an unde...
Genetic and physiology of cold and drought resistance in Turkish red pine (Pinus brutia, Ten.) populations from southern Turkey
Kandemir, Gaye Eren; Kaya, Zeki; Önde, Sertaç; Department of Biology (2002)
The purpose of the study was to determine the pattern of genetic variation in morphological and physiological traits associated with cold and drought stress using seedling from over-exploited and natural populations of Pinus brutia Ten. (Turkish red pine) from southern Turkey. To determine the pattern of genetic variation existing in over-exploited and natural populations, seedlings from 6 populations each with 40 families were raised in Ankara forest nursery from 1998-2000. Three of the populations (Yaylaa...
Electronic excited states and excitation transfer kinetics in the Fenna-Matthews-Olson protein of the photosynthetic bacterium Prosthecochloris aestuarii at low temperatures
Iseri, EI; Gulen, D (Springer Science and Business Media LLC, 1999-01-01)
The molecular structure-function relationship of the Fenna-Matthews-Olson light-harvesting complex of the photosynthetic green bacterium Prosthecochloris aestuarii has been investigated. It has been assumed that the electronic excited states responsible for the function (transfer of electronic excitation energy) result from the dipole-dipole interactions between the bacteriochlorophyll molecules bound to the polypeptide chain of the complex at a specific three-dimensional geometry. The molecular structure-e...
Citation Formats
K. Yıldırım, “Transcriptional and physiological responses to drought stress in Populus nigra L.,” Ph.D. - Doctoral Program, Middle East Technical University, 2013.