Effect of Water Stress on Protein Content of Some Calvin Cycle Enzymes in Different Wheat Genotypes

The dynamics of protein content changes of some photosynthetic enzymes under water stress has been
studied by immunoblotting method in bread (Triticum aestivum) and durum (Triticum durum) wheat
genotypes differing in their drought tolerance. In all tested genotypes protein content of studied en-
zymes under weak and mild drought stress was similar to their content in normal watered variants.
While protein content of phosphoribulokinase (PRK) and fructose-1,6-bisphosphatase (FBP) remained
unchanged, sedoheptulose-1,7-bisphosphatase (SBP), transketolase (TK), NADP-glyceraldehyde-3-P-
dehydrogenase (NADP-GAPDH) and Rubisco activase decreased under severe water stress. This de-
crease was more apparent for TK, SBP and Rubisco activase. However in drought tolerant genotypes
Azamatli-95 and Barakatli-95 this decrease was less pronounced compared to genotypes Garagylchyg-
2 and Giymatli-2/17, which are sensitive to drought. At the early stage of heading of the genotype Ga-
ragylchyg-2, during 2-3 days of water stress protein content of PRK, FBP and NADP-GAPDH was
unchanged in flag leaves, while in ear elements protein content of these enzymes decreased significantly.