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Title:	Physiological and biochemical studies of transgenic RNAi ACO1 (T2) tomato fruit during normal ripening and low temperature storage
Authors:	Najat Mohamed Eglous (P57563)
Supervisor:	Zamri Zainal, Prof. Dr.
Keywords:	Transgenic tomato Ripening Biochemical analyses Superoxide dismutase Catalase Dissertations, Academic -- Malaysia
Issue Date:	Feb-2016
Description:	Physiological and biochemical responses in transgenic tomato (RNAi ACO1-21) were studied during normal ripening and low temperature storage. The aims of this study were to investigate not only the changes in weight, firmness and colour, but also to understand the relationship between ethylene and how its roles in regulating the oxidative stress pathway and antioxidant status changes in transgenic and non-transgenic tomato fruit under different circumstances (ripening and storage). Results showed that non-transgenic tomato fruit lost weight faster than transgenic RNAi ACO1 line-21 fruit. In addition, the firmness of the transgenic RNAi ACO1 line-21 declined steadily and reached firmness values (5.13 ± 0.12 N) at 22 d, as compare to those of non-transgenic (5.39± 0.22 N) at 10 d. No significant different changes in color between transgenic and non-transgenic fruits at the final stage of ripening, with average hue angles generally being close to 20 degrees. Biochemical analyses of the oxidative stress such as LOX activity, H2O2 concentration and MDA content showed significant decrease with 2.6-fold, 1.6-fold and 1.2-fold, respectively, as compared to the non-transgenic fruit. Whereas, the activities of antioxidant enzymes like superoxide dismutase (SOD) and catalase (CAT) were higher in transgenic RNAi ACO1 line-21, with 1.6 fold and 1.1 fold respectively at the final stage of normal ripening as compare to non transgenic. For the non-enzymatic antioxidant, the level of ascorbic acid was higher in non-transgenic during stages of ripening.Whereas, the ratios of reduced glutathione/oxidized glutathione (GSH/GSSG) were decreased in both transgenic RNAi ACO1 line-21 and non transgenic. For postharvest treatment, results showed that, low temperatures could maintained the level of quality changes during storage ripening. However, this treatment is also accompanied by other side effects, the chilling injury (CI). The main CI symptoms observed on non-transgenic tomato fruit were uneven ripening, discoloration and followed by pitting and rotten. However, transgenic RNAiACO1-21 tomato fruit stored at 10°C for 28d showed low chilling injury symptoms and followed normal ripening. Furthermore, low temperature treatment storage was effective in delaying fruit ripening and senescence, via regulating activity of the antioxidant enzymes, which is essential for maintaining quality and prolonging storage life of transgenic RNAi ACO1-21 tomato fruit. For the non-transgenic tomato fruit showed a faster rate of ripening, parallel to the declined in the rate of enzymatic antioxidant systems as compared to the transgenic RNAi ACO1 line-21 tomato fruit. The regulated ethylene in transgenic RNAi ACO1-21 have shown significant contribution toward lengthening postharvest shelf life by improving the physiological and biochemical properties of ripening fruits.,Certification of Master's/Doctoral Thesis" is not available
Pages:	256
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Science and Technology / Fakulti Sains dan Teknologi

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