Browsing by Author "Jiang, Weijia"
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Item Co-overexpression of AVP1 and PP2A-C5 in Arabidopsis makes plants tolerant to multiple abiotic stresses(2018) Sun, Li (TTU); Pehlivan, Necla; Esmaeili, Nardana (TTU); Jiang, Weijia; Yang, Xiaojie; Jarrett, Philip (TTU); Mishra, Neelam (TTU); Zhu, Xunlu (TTU); Cai, Yifan (TTU); Herath, Maheshika (TTU); Shen, Guoxin; Zhang, Hong (TTU)Abiotic stresses are major threats to agricultural production. Drought and salinity as two of the major abiotic stresses cause billions of losses in agricultural productivity worldwide each year. Thus, it is imperative to make crops more tolerant. Overexpression of AVP1 or PP2A-C5 was previously shown to increase drought and salt stress tolerance, respectively, in transgenic plants. In this study, the hypothesis that co-overexpression of AVP1 and PP2A-C5 would combine their respective benefits and further improve salt tolerance was tested. The two genes were inserted into the same T-DNA region of the binary vector and then introduced into the Arabidopsis genome through Agrobacterium-mediated transformation. Transgenic Arabidopsis plants expressing both AVP1 and PP2A-C5 at relatively high levels were identified and analyzed. These plants displayed enhanced tolerance to NaCl compared to either AVP1 or PP2A-C5 overexpressing plants. They also showed tolerance to other stresses such as KNO3 and LiCl at harmful concentrations, drought, and phosphorus deficiency at comparable levels with either AVP1 or PP2A-C5 overexpressing plants. This study demonstrates that introducing multiple genes in single T-DNA region is an effective approach to create transgenic plants with enhanced tolerance to multiple stresses.Item The Effects of Transcription Directions of Transgenes and the gypsy Insulators on the Transcript Levels of Transgenes in Transgenic Arabidopsis(2017) Jiang, Weijia; Sun, Li (TTU); Yang, Xiaojie; Wang, Maohua; Esmaeili, Nardana (TTU); Pehlivan, Necla; Zhao, Rongli; Zhang, Hong (TTU); Zhao, YunManipulation of a single abiotic stress-related gene could improve plant performance under abiotic stress conditions. To simultaneously increase plant tolerance to multiple stresses, it is usually required to overexpress two (or more) genes in transgenic plants. The common strategy is to assemble two or more expression cassettes, where each gene has its own promoter and terminator, within the same T-DNA. Does the arrangement of the two expression cassettes affect expression of the two transgenes? Can we use the Drosophila gypsy insulator sequence to increase the expression of the two transgenes? Answers to these questions would contribute to design better transformation vectors to maximize the effects of multi-gene transformation. Two Arabidopsis genes, PP2A-C5 and AVP1, and the gypsy insulator sequence were used to construct six transformation vectors with or without the gypsy insulator bracketing the two expression cassettes: uni-directional transcription, divergent transcription, and convergent transcription. Total RNAs were isolated for reverse transcription- quantitative real-time polymerase chain reaction (RT-qPCR) assays and a thorough statistical analysis was conducted for the RT-qPCR data. The results showed that the gypsy insulator does promote the expression of two transgenes in transgenic plants. Besides, the plants containing the divergent transcription cassettes tend to have more correlated expression of both genes.