Overexpression of OsHsp17.0 and OsHsp23.7 enhances drought and salt tolerance in rice

Heat shock proteins (Hsps) play an important role in plant stress tolerance. We previously reported that expression of OsHsp17.0 and OsHsp23.7 could be enhanced by heat shock treatment and/or other abiotic stresses. In this paper, stress tolerance assays of transgenic rice plants overexpressing OsHsp17.0 and OsHsp23.7 have been carried out. Both OsHsp17.0-OE and OsHsp23.7-OE transgenic lines demonstrated higher germination ability compared to wild-type (WT) plants when subjected to mannitol and NaCl. Phenotypic analysis showed that transgenic rice lines displayed a higher tolerance to drought and salt stress compared to WT plants. In addition, transgenic rice lines showed significantly lower REC, lower MDA content and higher free proline content than WT under drought and salt stresses. These results suggest that OsHsp17.0 and OsHsp23.7 play an important role in rice acclimation to salt and drought stresses and are useful for engineering drought and salt tolerance rice.     

丹参晚期胚胎蛋白基因SmLEA的克隆及表达分析

对丹参EST序列进行Blast分析,发现一条序列与晚期胚胎丰富蛋白(late embryogenesis abundant)基因有较高的相似性,在此基础上设计引物,分别从cDNA和gDNA水平克隆到该基因的全长(Genbank注册号:AY725206),命名为SmLEA.该序列全长739 bp,无内含子,包含1个长为495 bp的开放阅读框,编码164个氨基酸.序列比对结果显示,该序列与番茄的晚期胚胎丰富蛋白Lemmi9有较高的相似性(69%),推测该编码蛋白属于晚期胚胎蛋白LEA14家族成员.生物信息学显示,SmLEA所编码蛋白SmLEA的相对分子质量为17.34 kD,理论等电点为4.51,富含天冬氨酸及AS、IP、KV、VS、TIP肽段,定位于细胞质中,为稳定类蛋白.实时荧光定量PCR结果显示,该基因在丹参的根、茎、叶中均有表达,为组成型表达基因.     

Overexpression of PtAnnexin1 from Populus trichocarpa enhances salt and drought tolerance in transgenic poplars

Tree Genetics & Genomes - High numbers of endemic plants exist in subtropical China, but there have been few investigations of the phylogeography and dynamic history for endemic tree species in...     

Overexpression of the wheat salt tolerance-related gene TaSC enhances salt tolerance in Arabidopsis

A novel gene named TaSC was cloned from salt-tolerant wheat. Northern blot showed that the expression of TaSC in salt-tolerant wheat was up-regulated after salt stress. Real-time quantitative PCR analyses showed that TaSC expression was induced by salt and ABA in wheat. Localization analysis showed that TaSC proteins were localized to the plasma membrane in transgenic Arabidopsis thaliana. The overexpression of TaSC in Col-0 and atsc (SALK_072220) Arabidopsis strains resulted in increased salt tolerance of the transgenic plants. TaSC overexpression in Col-0 and atsc signi?cantly up-regulated the expression of AtFRY1, AtSAD1, and AtCDPK2. AtCDPK2 overexpression in atsc rescued the salt-sensitive phenotype of atsc. The TaSC gene may improve plant salt tolerance by acting via the CDPK pathway.     

Overexpression of a Harpin-encoding gene hrf1 in rice enhances drought tolerance

Harpin proteins are well known as eliciters that induce multiple responses in plants, such as systemic acquired resistance, hypersensitive response, enhancement of growth, resistance to the green peach aphid, and tolerance to drought. Overexpression of Harpin-encoding genes enhances plant resistance to diseases in tobacco, rice, rape, and cotton; however, it is not yet known whether the expression of Harpin-encoding genes in vivo improves plant tolerance to abiotic stresses. The results of this study showed that overexpression of a Harpin-encoding gene hrf1 in rice increased drought tolerance through abscisic acid (ABA) signalling. hrf1- overexpression induces an increase in ABA content and promotes stomatal closure in rice. The hrf1 transgenic rice lines exhibited a significant increase in water retention ability, levels of free proline and soluble sugars, tolerance to oxidative stress, reactive oxygen species-scavenging ability, and expression levels of four stress-related genes, OsLEA3-1, OsP5CS, Mn-SOD, and NM_001074345, under drought stress. The study confirmed that hrf1 conferred enhanced tolerance to drought stress on transgenic crops. These results suggest that Harpins may offer new opportunities for generating drought resistance in other crops.     

Overexpression of SaRBP1 enhances tolerance of Arabidopsis to salt stress

Abiotic stresses are the major concern in recent years as their effect on world food production is constantly increasing. We have obtained salt tolerant Arabidopsis lines overexpressing SaRBP1 (Suaeda asparagoides RNA binding protein 1) of a Korean halophyte, S. asparagoides. Homozygous T3 Arabidopsis transgenic lines were developed and used for salt stress tolerance studies. The transgenic seedlings displayed tolerance to salt and mannitol compared to the wild type (WT) seedlings. Transgenic lines produced longer primary roots, more fresh weight, and higher number of lateral roots than WT. In planta stress tolerance assay results showed that the survival rates of transgenic plants were significantly higher than WT plants. Transgenic lines showed delayed germination under 200 mM NaCl stress. In addition, the transgenics showed higher water retention ability than WT. Subcellular localization results revealed that SaRBP1 was targeted to the cytoplasm. Northwestern blot analysis results confirmed the RNA binding property of SaRBP1. Quantitative Real-Time Polymerase Chain Reaction results revealed that many stress marker genes were upregulated by SaRBP1 overexpression. Thus, our data demonstrate that SaRBP1 overexpression lines are tolerant to salt stress. Hence, this is the first report for the functional characterization of SaRBP1, a novel RBP gene isolated from S. asparagoides cDNA library.     

过表达SmERF1提高了丹参耐盐性

ERF(ethylene-responsive factor)蛋白是植物中一大类转录因子家族,在植物的生长发育及逆境胁迫中发挥着重要作用.为研究丹参中新的转录因子SmERF1的功能,本研究对其编码序列、表达模式进行分析,并在丹参中进行过表达,检测过表达后转基因植株耐盐性、次生代谢物和激素的变化.研究结果表明,SmERF1含有一个AP2结构域,是典型的ERF转录因子.SmERF1受到MeJA和酵母诱导子(YE)的诱导表达.在盐胁迫下,过表达SmERF1的丹参株系中脯氨酸含量、SOD和POD活性较野生型丹参植株高,MDA含量降低,说明转基因株系的抗盐特性增强.而且过表达SmERF1的丹参株系中ABA含量升高,GA含量降低;过表达SmERF1对丹参酮、丹酚酸等代谢物的合成调控效果不强.综合以上结果,表明SmERF1可能通过调节ABA的合成,提高了丹参耐盐性.     

Overexpression of a TFIIIA-type zinc finger protein gene ZFP252 enhances drought and salt tolerance in rice (Oryza sativa L.)

We previously identified a salt and drought stress-responsive TFIIIA-type zinc finger protein gene ZFP252 from rice. Here we report the functional analysis of ZFP252 using gain- and loss-of-function strategies. We found that overexpression of ZFP252 in rice increased the amount of free proline and soluble sugars, elevated the expression of stress defense genes and enhanced rice tolerance to salt and drought stresses, as compared with ZFP252 antisense and non-transgenic plants. Our findings suggest that ZFP252 plays an important role in rice response to salt and drought stresses and is useful in engineering crop plants with enhanced tolerance to salt and drought stresses.     

Overexpression of MtCAS31 enhances drought tolerance in transgenic Arabidopsis by reducing stomatal density

? Dehydrins are a type of late embryogenesis abundant protein. Some dehydrins are involved in the response to various abiotic stresses. Accumulation of dehydrins enhances the drought, cold and salt tolerances of transgenic plants, although the underlying mechanism is unclear. MtCAS31 (Medicago Truncatula cold-acclimation specific protein 31) is a Y(2)K(4)-type dehydrin that was isolated from Medicago truncatula. ? We analyzed the subcellular and histochemical localization of MtCAS31, and the expression patterns of MtCAS31 under different stresses. Transgenic Arabidopsis that overexpressed MtCAS31 was used to determine the function of MtCAS31. A yeast two-hybrid assay was used to screen potential proteins that could interact with MtCAS31. The interaction was confirmed by bimolecular fluorescence complementation (BiFC) assay. ? After a 3-h drought treatment, the expression of MtCAS31 significantly increased 600-fold. MtCAS31 overexpression dramatically reduced stomatal density and markedly enhanced the drought tolerance of transgenic Arabidopsis. MtCAS31 could interact with AtICE1 (inducer of CBF expression 1) and the AtICE1 homologous protein Mt7g083900.1, which was identified from Medicago truncatula both in vitro and in vivo. ? Our findings demonstrate that a dehydrin induces decreased stomatal density. Most importantly, the interaction of MtCAS31 with AtICE1 plays a role in stomatal development. We hypothesize that the interaction of MtCAS31 and AtICE1 caused the decrease in stomatal density to enhance the drought resistance of transgenic Arabidopsis.     

Overexpression of the Arabidopsis AtEm6 gene enhances salt tolerance in transgenic rice cell lines

The Arabidopsis thaliana late embryogenesis abundant gene AtEm6 is required for normal seed development and for buffering the rate of dehydration during the latter stages of seed maturation. However, its function in salt stress tolerance is not fully understood. In this investigation, cell suspension cultures of three plant species rice (Oryza sativa L.), cotton (Gossypium hirsutum L.), and white pine (Pinus strobes L.) were transformed using Agrobacterium tumefaciens strain LBA4404 harboring pBI-AtEm6. Integration of the AtEm6 gene into the genome of rice, cotton, and white pine has been confirmed by polymerase chain reaction, Southern blotting, and northern blotting analyses. Three transgenic cell lines from each of O. sativa, G. hirsutum, and P. strobus were used to analyze salt stress tolerance conferred by the overexpression of the AtEm6 gene. Our results demonstrated that expression of the AtEm6 gene enhanced salt tolerance in transgenic cell lines. A decrease in lipid peroxidation and an increment in antioxidant enzymes ascorbate peroxidase, glutathione reductase and superoxide dismutase activities were observed in the transgenic cell lines, compared to the non- transgenic control. In rice, AtEM6 increased expression of Ca²⁺-dependent protein kinase genes OsCPK6, OsCPK9, OsCPK10, OsCPK19, OsCPK25, and OsCPK26 under treatment of salt. These results suggested that overexpression of the AtEM6 gene in transgenic cell lines improved salt stress tolerance by regulating expression of Ca²⁺-dependent protein kinase genes. Overexpression of the AtEM6 gene could be an alternative choice for engineering plant abiotic stress tolerance.