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    Abiotic stress tolerance and growth responses of transgenic potato (Solanum tuberosum L. cv. Kennebec) plants expressing rice Osmyb4 gene
    (ELSEVIER SCIENCE BV, 2012) Aydin, Gulsum; Yucel, Meral; Oktem, Huseyin Avni
    [Abstract not Available]
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    Antioxidative and physiological responses of two sunflower (Helianthus annuus) cultivars under PEG-mediated drought stress
    (TUBITAK SCIENTIFIC & TECHNICAL RESEARCH COUNCIL TURKEY, 2012) Baloglu, Mehmet Cengiz; Kavas, Musa; Aydin, Gulsum; Oktem, Huseyin Avni; Yucel, Ayse Meral
    Drought stress is one of the most important yield-reducing factors in crop production. Sunflower, an oilseed crop, is severely affected by abiotic stress. In this study, 2 sunflower cultivars (Musala and Aydin) were evaluated in terms of various biochemical and physiological responses under 2 different polyethylene glycol-mediated drought stress conditions. Stress-determining parameters such as malondialdehyde (MDA), hydrogen peroxide (H2O2), and proline contents were determined. Both cultivars showed similar responses at osmotic potentials of both -0.4 and -0.8 MPa. Aydin was less affected than Musala under these stress conditions. MDA, H2O2, and proline levels were similar at both -0.4 and -0.8 MPa osmotic potentials in the 2 different cultivars. The 2 cultivars differed significantly in ascorbate peroxidase and catalase enzyme activities, which were more prominent in Aydin for both stress levels. However, glutathione reductase activity did not appear to be an essential part of the antioxidative system in either of the cultivars. Engineering antioxidative enzyme levels might provide a potential mechanism to cope with drought stress in sunflower.
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    Cold-induced comparative transcriptome analysis of Potato (Solanum tuberosum L. cv. Kennebec) that heterologously expresses the rice Osmyb4 gene
    (ELSEVIER SCIENCE BV, 2016) Aydin, Gulsum; Oz, Mehmet Tufan; Yucel, Meral; Oktem, Huseyin Avni
    [Abstract not Available]
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    Evaluation of abiotic stress tolerance and physiological characteristics of potato (Solanum tuberosum L. cv. Kennebec) that heterologously expresses the rice Osmyb4 gene
    (SPRINGER, 2014) Aydin, Gulsum; Yucel, Meral; Chan, Ming-Tsair; Oktem, Huseyin Avni
    MYB transcription factors are involved in diverse biochemical and physiological processes, including hormone signaling, defense, and stress responses. In the present study, we developed a transgenic potato (Solanum tuberosum L. cv. Kennebec) expressing the rice Osmyb4 gene, which encodes the transcription factor MYB4. The transgene was under the control of either the constitutive CaMV35S promoter or the stress-induced Arabidopsis COR15a promoter. The potential involvement of MYB4 in certain physiological processes and the abiotic stress response in the potato was evaluated. The transgenic plants did not exhibit growth retardation, and they showed no significant difference (P < 0.05) in tuber yield from that of non-transgenic wild-type plants. Although the chlorophyll a and b as well as the anthocyanin contents of the six transgenic lines were similar to those of the wild type, the transgenic line S2 presented a significantly higher carotenoid content. The total sugar contents of the lines S2 and M48 were significantly higher than that of the wild-type plants. S2 and M48 were significantly more tolerant of salinity than the wild type, according to measured growth parameters. Transgenic plants grown under a high concentration of boric acid (3 mM) exhibited greater survival rates than non-transgenic control plants. On the other hand, the transgenic plants did not show an improvement in freezing tolerance. Overall, our results indicated that MYB4 may affect diverse processes such as carotenoid biosynthesis, sugar metabolism, and salinity tolerance in potato, and that it may be an upstream regulatory element of these processes.