دانلود رایگان مقاله انگلیسی تحلیل نقش PtDRS1 بسیار سریع در افزایش تنش نازیوا برای بهبود رشد در صنوبر ترانس ژنتیکی - الزویر 2018

Abstract

 Drought and salinity are the two main abiotic stressors that can disrupt plant growth and  survival. Various biotechnological approaches have been used to alleviate the problem of drought stress by improving water stress resistance in forestry and agriculture. The drought sensitive 1 (DRS1) gene acts as a regulator of drought stress in some model plants, such as Arabidopsis thaliana, but there have been no reports of DRS1 transformation in poplar plants to date. In this study, we transformed the DRS1 gene from Populus trichocarpa into Populus deltoides × Populus euramericana 'Nanlin895' using Agrobacterium tumefaciens-mediated transformation. We confirmed that the DRS1 gene was transformed into 'Nanlin895' poplar genomes using reverse transcription polymerase chain reaction (PCR), multiplex PCR, real-time PCR, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. All transformed and wild-type (WT) plants were then transferred into a greenhouse for complementary experiments. We analyzed the physiological and biochemical responses of transgenic plants under drought and salt stresses in the greenhouse, and these results were compared with control WT plants. Responses to abiotic stress were greater in transgenic plants compared with WT. Based on our results, introduction of the DRS1 gene into poplar 'Nanlin895' plants significantly enhanced the resistance of those plants to water deficit and high salinity, allowing higher growth rates of roots and shoots in those plants. Additionally, the clawed root rate increased in transformed poplars grown in culture medium or in soil, and improved survival under drought and salt stress conditions.

4. Discussion

Reduction of water content due to water stress can decrease cell size and growth rates in plants (Shao et al. 2008). Drought avoidance is achieved through a variety of adaptive traits, such as minimization of water loss and optimization of water uptake via reduced transpiration and increased rooting, respectively (Basu et al. 2016). An accepted physiological definition of stress in the plant sciences refers to a plant’s responses to various environmental conditions. Plants exhibit physiological, biochemical, and molecular reactions to different environmental conditions to minimize the destructive effects of both abiotic and biotic stresses, such as drought and salinity (Shao et al. 2008). Plants avoid water deficiency by modifying their root and stem growth rates as well as leaf biomass production (Wang et al. 2012). Our observations revealed that overexpression of DRS1 gene in transgenic poplar ‘Nanlin895’ plants can modify these physiological reactions and improve water uptake through larger numbers of roots under both drought and salt stresses. The root characteristics, such as root length, root length density, and the number of main roots, are essential for plants to have well-established above ground parts by capture more water from soil (Manivannan et al. 2007). One adaptation mechanism to drought stress in plants is enhancing water uptake ability by using a deep root system to escape from drought (Paez-Garcia et al. 2015). Some Populus species have been shown to exhibit a significant decrease in root length under drought stress (Nautiyal et al. 2002).