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1.
Coping with different kinds of biotic and abiotic stresses is the foundation of sustainable agriculture. Although conventional breeding and marker-assisted selection are being employed in mulberry (Morus indica L.) to develop better varieties, nonetheless the longer time periods required for these approaches necessitates the use of precise biotechnological approaches for sustainable agriculture. In an attempt to improve stress tolerance of mulberry, an important plant of the sericulture industry, an encoding late embryogenesis abundant gene from barley (HVA1) was introduced into mulberry plants by Agrobacterium-mediated transformation. Transgenic mulberry with barley Hva1 under a constitutive promoter actin1 was shown to enhance drought and salinity tolerance. Here, we report that overexpression of barley Hva1 also confers cold tolerance in transgenic mulberry. Further, barley Hva1 gene under control of a stress-inducible promoter rd29A can effectively negate growth retardation under non-stress conditions and confer stress tolerance in transgenic mulberry. Transgenic lines display normal morphology to enhanced growth and an increased tolerance against drought, salt and cold conditions as measured by free proline, membrane stability index and PSII activity. Protein accumulation was detected under stress conditions confirming inductive expression of HVA1 in transgenics. Investigations to assess stress tolerance of these plants under field conditions revealed an overall better performance than the non-transgenic plants. Enhanced expression of stress responsive genes such as Mi dnaJ and Mi 2-cysperoxidin suggests that Hva1 can regulate downstream genes associated with providing abiotic stress tolerance. The investigation of transgenic lines presented here demonstrates the acquisition of tolerance against drought, salt and cold stress in plants overexpressing barley Hva1, indicating that Arabidopsis rd29A promoter can function in mulberry.  相似文献   

2.
Late embryogenesis abundant (LEA) proteins are members of a large group of hydrophilic proteins found primarily in plants. The barley hva1 gene encodes a group 3 LEA protein and is induced by ABA and water deficit conditions. We report here the over expression of hva1 in mulberry under a constitutive promoter via Agrobacterium-mediated transformation. Molecular analysis of the transgenic plants revealed the stable integration and expression of the transgene in the transformants. Transgenic plants were subjected to simulated salinity and drought stress conditions to study the role of hva1 in conferring tolerance. The transgenic plants showed better cellular membrane stability (CMS), photosynthetic yield, less photo-oxidative damage and better water use efficiency as compared to the non-transgenic plants under both salinity and drought stress. Under salinity stress, transgenic plants show many fold increase in proline concentration than the non-transgenic plants and under water deficit conditions proline is accumulated only in the non-transgenic plants. Results also indicate that the production of HVA1 proteins helps in better performance of transgenic mulberry by protecting membrane stability of plasma membrane as well as chloroplastic membranes from injury under abiotic stress. Interestingly, it was observed that hva1 conferred different degrees of tolerance to the transgenic plants towards various stress conditions. Amongst the lines analysed for stress tolerance transgenic line ST8 was relatively more salt tolerant, ST30, ST31 more drought tolerant, and lines ST11 and ST6 responded well under both salinity and drought stress conditions as compared to the non-transgenic plants. Thus hva1 appears to confer a broad spectrum of tolerance under abiotic stress in mulberry.  相似文献   

3.
4.
Drought and salt stresses are two major factors that lower plant productivity. Transgenic approaches offer powerful means to better understand and then minimize loss of yield due to these abiotic stresses. In this study, we have generated transgenic rice plants expressing a wheat LEA group 2 protein (PMA80) gene, and separately the wheat LEA group 1 protein (PMA1959) gene. Molecular analysis of the transgenic plants revealed the stable integration of the transgenes. Immunoblot analysis showed the presence of the LEA group 2 protein (39 kDa) and the LEA group 1 protein (25 kDa) in most of the plant lines. Second-generation transgenic plants were subjected to dehydration or salt stress. The results showed that accumulation of either PMA80 or PMA1959 correlates with increased tolerance of transgenic rice plants to these stresses.  相似文献   

5.
大麦HVA1基因和LEA蛋白与植物抗旱性的研究   总被引:1,自引:1,他引:0  
干旱胁迫下,植物体内会积累多种蛋白以保护细胞免受脱水伤害,其中包括Lea蛋白。LEA蛋白在植物耐寒、耐盐碱、耐干旱性方面起重要作用。大麦HVA1基因编码的蛋白即属于第三组LEA蛋白,国内外学者对该基因的结构与功能进行了深入的研究。根据近年研究结果,本文对LEA蛋白的结构与功能,大麦HVA1基因的表达与调控,大麦HVA1基因高同源性序列的克隆以及转基因植物对HVA1基因抗旱性功能验证等方面进行综述。  相似文献   

6.
A late embryogenesis abundant (LEA) protein gene, ME-leaN4, from rape (Brassica napus) was successfully introduced into lettuce (Lactuca sativa L.) using Agrobacterium tumefaciens-mediated transformation. Infection by Agrobacterium strain EHA101 containing the binary vector pIG121-LEA was applied. Six independent transgenic lettuce plants were generated as a result. Transgenic lettuce demonstrated enhanced growth ability as compared to non-transformed control plants under salt-stress and water-deficit stress conditions. After 10-day growth under 100 mM NaCl condition in the hydroponics, average plant length and fresh weight of transgenic lettuce were 2.8 cm and 2.5 g plant–1, while control plants were only 0.2 cm and 0.3 g plant–1, respectively. The increased tolerance was also reflected by delayed wilting of leaves caused by water-deficit stress. These results suggest that growth characteristics were improved in transgenic lettuce plants constitutively expressing the rape LEA gene in response to salt- and water-deficit stress. Byong-Jin Park, Zaochang Liu These two authors contributed equally to this work.  相似文献   

7.
Three oat ( Avena sativa L.) cultivars have been successfully transformed using an efficient and reproducible in vitro culture system for differentiation of multiple shoots from shoot apical meristems. The transformation was performed using microprojectile bombardment with two plasmids (pBY520 and pAct1-D) containing linked ( hva1-bar) and non-linked ( gus) genes. The hva1 and bar genes cointegrated with a frequency of 100% as expected, and 61.6% of the transgenic plants carried all three genes. Molecular and biochemical analyses in R0, R1 and R2 progenies confirmed stable integration and expression of all transgenes. Localization of the GUS protein in R0 and R1 plants revealed that high-expression of gus occurred in vascular tissues and in the pollen grains of mature flowers. The constitutive expression of HVA1 protein was observed at all developmental stages of transgenic plants, and was particularly stronger during the early seedling stages. R2 progeny of five independent transgenic lines was tested in vitro for tolerance to osmotic (salt and mannitol) stresses. As compared to non-transgenic control plants, transgenic plants maintained a higher growth and showed significantly ( P < 0.05) increased tolerance to stress conditions. Less than 10% of transgenic plants showed symptoms of wilting or death of leaves and, when these symptoms present were delayed in transgenic plants as compared to 80% of non-transgenic plants, either wilted or died. These symptoms confirmed the increased in vitro tolerance in hva1-expressing transgenic plants to non-transgenic plants, providing strong evidence that the HVA1 protein may play an important role in the protection of oats against salinity and possible water-deficiency stress conditions.  相似文献   

8.
To confer abscisic acid (ABA) and/or stress-inducible gene expression, an ABA-response complex (ABRC1) from the barley (Hordeum vulgare L.) HVA22 gene was fused to four different lengths of the 5′ region from the rice (Oryza sativa L.) Act1 gene. Transient assay of β-glucuronidase (GUS) activity in barley aleurone cells shows that, coupled with ABRC1, the shortest minimal promoter (Act1–100P) gives both the greatest induction and the highest level of absolute activity following ABA treatment. Two plasmids with one or four copies of ABRC1 combined with the same Act1–100P and HVA22(I) of barley HVA22 were constructed and used for stable expression of uidA in transgenic rice plants. Three Southern blot-positive lines with the correct hybridization pattern for each construct were obtained. Northern analysis indicated that uidA expression is induced by ABA, water-deficit, and NaCl treatments. GUS activity assays in the transgenic plants confirmed that the induction of GUS activity varies from 3- to 8-fold with different treatments or in different rice tissues, and that transgenic rice plants harboring four copies of ABRC1 show 50% to 200% higher absolute GUS activity both before and after treatments than those with one copy of ABRC1.  相似文献   

9.
Previous studies have shown that the late embryogenesis abundant (LEA) gene of Tamarix androssowii can enhance the drought tolerance of transgenic tobacco. In this study, the cloned LEA gene was transformed into half-high bush Northland blueberry in order to enhance its ability to tolerate cold stress. The cephalosporin antibiotics ceftriaxone, cefotaxime and cefazolin were used to optimize transformation of leaf explants, and kanamycin sulfate was used to select for transgenic shoots. PCR and Southern blot analysis confirmed 8 transformants with LEA gene copy numbers ranging from 1 to 7. The LEA chimeric gene was found to be normally transcribed in 6 transgenic lines by RT-PCR. The 8 transgenic lines were tested for cold tolerance by measuring the activities of peroxidase (POD) and superoxide dismutase (SOD), malondialdehyde (MDA) content and relative electrolyte leakage (REL). Overexpression of the LEA gene enhanced the activity of both POD and SOD under low temperature stress conditions. Lipid peroxidation in the transgenic lines was significantly lower than in non-transgenic plants after cold stress, as determined by MDA content and REL. Thus, our findings indicate that the LEA gene confers increased cold tolerance in the Northland blueberry and implicate the metabolic pathways through which it exerts this effect.  相似文献   

10.
The HVA1 protein belongs to the LEA3 group, which is expressed during the late stage of seed maturation. It is also induced by exogenous abscisic acid (ABA) and a variety of environmental stresses in germinating barley (Hordeum vulgare L.). In the present work, the potential role of HVA1 was investigated by studying its tissue distribution and subcellular localization in mature and stressed seeds by immuno-microscopic methods. In the mature seed, HVA1 protein was detected in all tissues except the non-living starchy endosperm. During germination the amount of HVA1 protein decreased but did not totally disappear. Incubation with 100 μM ABA, cold treatment or drought stress dramatically increased HVA1 expression in the germinated seed. In this work, the distribution of a LEA3 group protein was studied in a cereal seed for the first time by immuno-electron microscopy. In the scutellum and aleurone layer, HVA1 was localized both in the cytoplasm and protein storage vacuoles (PSVs). HVA1 protein was found to be threefold more abundant in PSVs than in the cytoplasm of an unstressed seed tissue. The ratio increased with ABA or stress treatments to at least ninefold. The role of HVA1 in PSVs remains unclear: a previously suggested possibility is ion sequestration to prevent precipitation during stress. On the other hand, HVA1 protein could also be degraded in PSVs. HVA1 protein does not have the signal peptide typical of proteins which are glycosylated and targeted into the vacuole via the Golgi complex. Because HVA1 is not glycosylated, it may use an alternative, ER-independent vacuolar pathway, also found in yeast cells.  相似文献   

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