| More than 600 promoter trap lines from Arabidopsis were screened off using T-DNA insertion technique, and a mutant with altered pleiotropic phenotype was isolated. The most remarkable characteristic of this mutant was growth retardation, lengthened vegetative growth stage, decreased leaf volume, shortened hypocotyls as well as total length of the whole plant, and reduced resistance to harmful enviroment. Cloning and sequencing of the related gene showed this gene was similar to HSP101, named Athspr (heat shock protein- related in Arabidopsis thaliana). In this study, the difference between mutant and the wild type in sensitivity to environment stress, response to exogenous auxin and endogene auxin level were analysed. Meanwhile, the expression level of Athspr in both transcriptional and translational levels was studied by using molecular biology methods. The main results were reported as following:1: In comparison with wild type, reproductive growth of Athspr mutant was inhibited seriously under the long-term temperate heat-shock stress. The mutant was still at vegetative growth stage till 100 day. Whole plant dwarfted and the rosette leaves grew thickly. While under the short-term limiting temperature heat-shock stress, the mutant exhibited an induced heat tolerance, similar with the wild type. Growth of the muant plant has not received suppresses obviously.2: The physiological results revealed that Athspr and C24 had a similar response replied to exogenous auxin, but high-concentration IAA suppressed germination of the Athspr. When treated with TIBA, mutant was less sensitive to this exogenous component than wild type, and seed germination did not obviously suppressed. Those results indicated that the endogenous auxin level of the mutant was reduced, and/or this mutant was defected in the response to IAA singnal. Determine of the endogenous hormone content through HPLC showed that the amount of endogenous auxin in mutant decreased obviously, was about 46.25% to the wild type.3: Clone of Athspr gene was performed, and 3233bp as well as 3054bp sequences were obtained, respectively. Sequencing results indicated that thoes sequences were the Arabidopsis Athspr gene sequence and its CDS sequence, respectively. 4: RT-PCR was performed in both normal growth conditions and heat-shocked environment, displaying that the expression level of the Athspr gene was identical in both mutant and the wild type. And under 38℃heat-shock stress, the expression of this gene was similar too, and no obvious difference was detected.5: Total proteins from leaves of Arabidopsis wild type and mutant Athspr, subjected to heat shock, were isolated, and about 1000 spots were detected, respectively. Analysis of expression pattern of those proteins showed that protein expression changed more violent in wild type compared to the mutant in both 2- and 8-hour heat-shock condition, revealed that wild type responsed to heat stress can be more intense, while the mutant was quite weak. Moreover, three abundant differentially expressed protein spots between mutant and wild type plant were identified through mass spectrometry analysis, which were Glycine- rich RNA-binding protein 7(GRP 7), Cytochrome b6-f complex iron-sulfur subunit, and Oxygen-evolving enhancer protein 1-2(OEE1), respectively, and all of them were related with plant resistance under stress.In conclusion, the T-DNA insertion indeed caused the functional alterations of the trapped gene, and further affected a series of changes involving in morphology, structure, development and heat resistance, which indicated that the Athspr gene may play an important role in the signal pathway which is necessary for regulating normal growth and development of Arabidopsis, as well as in the heat resistance of Arabidopsis under heat shock.
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