THE EFFECT OF DROUGHT STRESS ON PHOTOSYNTHETIC TRAITS AND THE EXPRESSION OF SOME GENES FOR A FEW IRANIAN GRAPEVINE CANDIDATE ROOTSTOCKS
Grapevine rootstocks are able to increase cultivar adaptation to different climates, soil types and a variety of adverse conditions. The main objective of this study was to study the photosynthetic traits and gene expression of candidate genes in drought tolerant rootstock cultivars. Three selected Iranian candidate rootstocks (Yaquti, Askari and Rotabi) as well as Sultana (control) were exposed to moderate (-1 MPa), severe (-1.5 MPa) and very severe (≤1.5 MPa) drought stress, based on predawn soil water potential. Results showed that drought stress and cultivar had significant effect on leaf photosynthesis rate, internal concentration of CO2, chlorophyll A content, as well as Rubisco activase gene expression. Drought stress reduced photosynthesis rate, internal concentration of CO2 and chlorophyll A compared to control. Cultivars showed two distinct behaviors under stress levels. Yaquti and Rotabi, as tolerant cultivars, showed higher photosynthesis rate than Askari and Sultana, semi tolerant and sensitive respectively. The concentration of CO2 was more stable in Yaquti and Rotabi under stress levels than in Askari and Sultana. The relative expression of Rubisco activase gene increased rapidly in tolerant cultivars (Rotabi and Yaquti) after exposition to moderate stress, but these reactions occurred later in semi tolerant and sensitive cultivars (Askari and Sultana) after severe stress. Increase of Rubisco activase resulted in higher photosynthetic rate under stress conditions and reduced negative effects of low stomatal conductivity. The timing and intensity of the responses to different levels of drought stress could discriminate tolerant cultivars (Yaquti and Rotabi) from semi tolerant (Askari) and sensitive (Sultana) cultivars, especially at gene expression level.
Hadadinejad, M., Ebadi, A., Fatahi, R., Mousavi, A., Santesteban, L.G. and Nejatianc, M.A. 2014. THE EFFECT OF DROUGHT STRESS ON PHOTOSYNTHETIC TRAITS AND THE EXPRESSION OF SOME GENES FOR A FEW IRANIAN GRAPEVINE CANDIDATE ROOTSTOCKS. Acta Hort. (ISHS) 1045:133-138
photosynthetic rate, internal concentration of CO2, chlorophyll A, gene expression, Rubisco activase