Progesterone and Salicylic Acid Elevate Tolerance of Poa pratensis to Salinity Stress

Russian Journal of Plant Physiology - Kentucky bluegrass (Poa pratensis L.) was exposed to salinity in the factorial study with 2 factors including salinity [irrigation with tap water and saline...     

Induction of Abiotic Stress Tolerance by Salicylic Acid Signaling

The role of salicylic acid (SA) as a key molecule in the signal transduction pathway of biotic stress responses has already been well described. Recent studies indicate that it also participates in the signaling of abiotic stresses. The application of exogenous SA could provide protection against several types of stresses such as high or low temperature, heavy metals, and so on. Although SA may also cause oxidative stress to plants, partially through the accumulation of hydrogen peroxide, the results published so far show that the preliminary treatment of plants with low concentrations of SA might have an acclimation-like effect, causing enhanced tolerance toward most kinds of abiotic stresses due primarily to enhanced antioxidative capacity. The effect of exogenous SA depends on numerous factors such as the species and developmental stage of the plant, the mode of application, and the concentration of SA and its endogenous level in the given plant. Recent results show that not only does exogenous SA application moderate stress effects, but abiotic stress factors may also alter the endogenous SA levels in the plant cells. This review compares the roles of SA during different abiotic stresses.     

Differential Accumulation of Salicylic Acid and Salicylic Acid-Sensitive Catalase in Different Rice Tissues

We previously proposed that salicylic acid (SA)-sensitive catalases serve as biological targets of SA in plant defense responses. To further examine the role of SA-sensitive catalases, we have analyzed the relationship between SA levels and SA sensitivity of catalases in different rice (Oryza sativa) tissues. We show here that, whereas rice shoots contain extremely high levels of free SA, as previously reported (I. Raskin, H. Skubatz, W. Tang, B.J.D. Meeuse [1990] Ann Bot 66: 369-373; P. Silverman, M. Seskar, D. Kanter, P. Schweizer, J.-P. Metraux, I. Raskin [1995] Plant Physiol 108: 633-639), rice roots and cell-suspension cultures have very low SA levels. Catalases from different rice tissues also exhibit differences in sensitivity to SA. Catalase from rice shoots is insensitive to SA, but roots and cell-suspension cultures contain SA-sensitive catalase. The difference in SA sensitivity of catalases from these different tissues correlates with the tissue-specific expression of two catalase genes, CatA and CatB, which encode highly distinctive catalase proteins. CatA, which encodes a catalase with relatively low sequence homology to the tobacco SA-sensitive catalases, is expressed at high levels exclusively in the shoots. On the other hand, in roots and cell-suspension cultures, with northern analysis we detected expression of only the CatB gene, which encodes a catalase with higher sequence homology to tobacco catalases. The role of catalases in mediating some of the SA-induced responses is discussed in light of these results and the recently defined mechanisms of catalase inhibition by SA.     

Salicylic Acid Confers Salt Tolerance in Giant Juncao Through Modulation of Redox Homeostasis,Ionic Flux,and Bioactive Compounds: An Ionomics and Metabolomic Perspective of Induced Tolerance Responses

We investigated the stimulatory and/or inhibitory role of exogenous SA in alleviating the salt stress (250, 500 mM NaCl) in Pennisetum giganteum (Giant Juncao) through coordinated induction of redox homeostasis, ionic flux, and bioactive compounds. Salt stress radically impaired root and shoot (growth, fresh, and dry biomass as well as tolerance indices), leaf relative water content, and leaf chlorophyll a/b ratio of Juncao due to higher Na⁺ and Cl^? accumulation followed by H₂O₂ generation, lipid peroxidation (MDA contents), and electrolyte leakage. However, the innate defense response of Juncao counteracted salt-induced damages by osmolytes accumulation combined with orchestrating antioxidants and ionic homeostasis mechanisms. Furthermore, the application of SA had an incremental impact on the development and productivity of high-salinity-exposed Juncao plants by increasing root length, plant biomass, tolerance indices, chlorophyll a/b ratio, and protein contents. Furthermore, SA treatment considerably decreased Na⁺ and Cl^? toxicity by orchestrating antioxidant enzymes, ion transport, and secondary metabolism. Notably, the application of SA substantially mitigated the adverse effects of high salinity concentration (500 mM NaCl), owing to the simultaneous upregulation in enzymatic and non-enzymatic antioxidants, nutrient ion flux, alongside chlorogenic acid production. Thus, we concluded that SA enhanced the tolerance capability of Juncao plants in a NaCl concentration-dependent manner. The findings of this study will enable environmentalists and pharmacologists to gain dual farm-level benefits, including animal therapeutics and restoration of salinized soils for arable purposes.

     

微拟球藻属对盐度的耐受及其产油特性分析

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水杨酸诱导植物抗性的研究进展

水杨酸是一种重要的内源信号分子,能够激活一系列植物抗性防卫反应.为了研究这种抗性反应,对水杨酸诱导植物抗病性、抗旱性、抗盐性及与乙烯作用的新进展作了概述,并从水杨酸与过氧化氢及其代谢酶类相互作用的角度探讨了水杨酸诱导植物抗性生理的分子机理.     

Foliar-Applied GR24 and Salicylic Acid Enhanced Wheat Drought Tolerance

Russian Journal of Plant Physiology - Phytohormones salicylic acid and strigolactones play critical roles in mediating plant responses to environmental stress including drought stress. This study...     

外源水杨酸对NaCl胁迫下白榆幼苗光合作用及离子分配的影响

以1年生白榆幼苗为研究对象,设置0、0.5、1.0和2.0 mmol·L^-1水杨酸(SA)与0、50、100和150 mmol·L^-1 NaCl处理组合,考察盐胁迫下白榆幼苗生物量、光合色素含量、光合作用参数及根叶离子含量、分配、运输的情况,探讨外源SA对NaCl胁迫下白榆幼苗耐盐生理特征的影响。结果表明:(1)NaCl胁迫显著抑制了白榆幼苗的生长、光合色素含量及光合能力,并破坏了白榆体内离子平衡。(2)喷施外源SA使盐胁迫下白榆幼苗的干重和根冠比均不同程度升高,0.5和2.0 mmol·L^-1 SA不同程度提高了50和100 mmol·L^-1 NaCl处理组幼苗叶片光合色素含量。(3)0.5 mmol·L^-1 SA显著提升了50 mmol·L^-1 NaCl处理组白榆幼苗的净光合速率(Pn)、气孔导度(Gs)和蒸腾速率(Tr),1.0和2.0 mmol·L^-1 SA对150 mmol·L^-1 NaCl处理组幼苗净光合速率改善效果较好,外源SA对100 mmol·L^-1 NaCl处理组幼苗的光合作用参数无显著影响。(4)NaCl胁迫下,外源SA处理的白榆幼苗叶和根Na^+含量及Na^+/K^+、Na^+/Ca^2+和Na^+/Mg^2+显著降低,离子选择运输系数SK,Na、SCa,Na和SMg,Na升高,从而促进了幼苗K^+、Ca^2+和Mg^2+由根向叶片的转运;隶属函数分析发现对白榆幼苗叶和根中离子含量改善效果最好的SA浓度分别为1.0和2.0 mmol·L^-1。因此,适宜浓度的外源水杨酸能够有效改善NaCl胁迫下白榆幼苗的光合能力,有效调节白榆幼苗体内离子状态,从而增强白榆对NaCl胁迫的抗性。     

水杨酸诱导植物抗病性的新进展

水杨酸是一种重要的能激活一系列植物抗病防卫反应的内源信号分子.首先介绍了水杨酸在植物抗病性中的作用,并从水杨酸与过氧化氢及其代谢酶类相互作用的角度初步探讨了水杨酸诱导植物抗病性的分子机理,最后概述了目前这一领域中需要进一步研究的若干问题.     

Increased Tolerance to Salinity and Drought in Transgenic Indica Rice by Mannitol Accumulation

The osmolytes, including mannitol have been shown to be very important in abiotic stress tolerance. Thus, the present study was undertaken with the aim to enhance abiotic stress tolerance in basmati indica rice by introduction of the E. coli mannitol-1-phospho dehydrogenase (mt/D) gene, which is involved in mannitol synthesis in plants. Several putative transgenic rice plants were generated by Agrobacterium-mediated transformation. The presence of the transgene in the primary transformants was confirmed by PCR using hygromycin phosphotransferase (hpt) and mt/D gene specific primers. Southern hybridization also revealed the integration of the transgene. Transgenic lines exhibited mannitol accumulation, which was correlated to the increased tolerance of the transgenics against salinity and drought stress. The T₁ transgenic seed germination and seedlings growth showed better performance than that of wild type during abiotic stresses under in vitro and in vivo growth conditions.     

Effect of Short-Term Salinity on Lipid Metabolism and Ion Accumulation in Tomato Roots

To examine the ion accumulation and membrane lipid metabolism in response to salinity we compared two tomato cvs. Pera and Hellfrucht Fruhstamm (HF), considered to be salt-tolerant and sensitive respectively. Na⁺ and K⁺ accumulation was significantly higher in roots of cv. Pera after 24 h and 72 h of 100 mM NaCl. While in cv. HF, a temporary increase in K⁺ accumulation at 24 h was accompanied by a sustained increase in Na⁺ content. Both cultivars enhanced incorporation of [³²P]orthophosphate into phosphatidylinositol 4,5-bisphosphate at 24 h and 72 h of NaCl. In parallel to the increase of phosphatidylinositol 4,5-bisphosphate a decrease in phosphorylation of phosphatidic acid and phosphatidylcholine were observed in the sensitive cv. HF. Structural and signal lipid changes in response to salinity were more evident in the sensitive cv. HF. Salt tolerant cv. Pera accumulated Na⁺ ions in the roots without considerable modifications in lipid metabolism. This revised version was published online in July 2006 with corrections to the Cover Date.     

Evidence that Accumulation of Mutants in a Biofilm Reflects Natural Selection Rather than Stress-Induced Adaptive Mutation

The accumulation of mutant genotypes within a biofilm evokes the controversy over whether the biofilm environment induces adaptive mutation or whether the accumulation can be explained by natural selection. A comparison of the virulence of two strains of the dental pathogen Streptococcus mutans showed that rats infected with one of the strains accumulated a high proportion (average, 22%) of organisms that had undergone a deletion between two contiguous and highly homologous genes. To determine if the accumulation of deletion mutants was due to selection or to an increased mutation rate, accumulations of deletion mutants within in vitro planktonic and biofilm cultures and within rats inoculated with various proportions of deletion organisms were quantified. We report here that natural selection was the primary force behind the accumulation of the deletion mutants.     

Variable Salinity Responses of 25 Alfalfa Genotypes and Comparative Salt-Response Ion Distribution

Russian Journal of Plant Physiology - This study was carried out to evaluate the effects of salinity stress on ion distribution in different alfalfa genotypes and its relation with stress tolerance...     

Salicylic Acid Induces Salinity Tolerance in Tomato (Lycopersicon esculentum cv. Roma): Associated Changes in Gas Exchange, Water Relations and Membrane Stabilisation

The present study investigates the role of salicylic acid (SA) in inducing plant tolerance to salinity. The application of 0.1 mM SA to tomato [Lycopersicon esculentum Mill.] plants via root drenching provided protection against 150 mM or 200 mM NaCl stress. SA treated plants had greater survival and relative shoot growth rate compared to untreated plants when exposed to salt stress. At 200 mM salt, shoot growth rates were approximately 4 times higher in SA treated plants than untreated plants. Application of SA increased photosynthetic rates in salt stressed plants and may have contributed to the enhanced survival. Transpiration rates and stomatal conductance were also significantly higher in SA treated plants under saline stress conditions. SA application reduced electrolyte leakage by 44% in 150 mM NaCl and 32% in 200 mM NaCl, compared to untreated plants, indicating possible protection of integrity of the cellular membrane. Beneficial effects of SA in saline conditions include sustaining the photosynthetic/transpiration activity and consequently growth, and may have contributed to the reduction or total avoidance of necrosis. SA, when used in appropriate concentrations, alleviates salinity stress without compromising the plants ability for growth under a favourable environment.     

Effect of Salicylic Acid Formulations on Induced Plant Defense against Cassava Anthracnose Disease

This study was to investigate defense mechanisms on cassava induced by salicylic acid formulation (SA) against anthracnose disease. Our results indicated that the SA could reduce anthracnose severity in cassava plants up to 33.3% under the greenhouse condition. The β-1,3-glucanase and chitinase enzyme activities were significantly increased at 24 hours after inoculation (HAI) and decrease at 48 HAI after Colletotrichum gloeosporioides challenge inoculation, respectively, for cassava treated with SA formulation. Synchrotron radiation–based Fourier-transform infrared microspectroscopy spectra revealed changes of the C=H stretching vibration (3,000–2,800 cm⁻¹), pectin (1,740–1,700 cm⁻¹), amide I protein (1,700–1,600 cm⁻¹), amide II protein (1,600–1,500 cm⁻¹), lignin (1,515 cm⁻¹) as well as mainly C–O–C of polysaccharides (1,300–1,100 cm⁻¹) in the leaf epidermal and mesophyll tissues treated with SA formulations, compared to those treated with fungicide carbendazim and distilled water after the challenged inoculation with C. gloeosporioides. The results indicate that biochemical changes in cassava leaf treated with SA played an important role in the enhancement of structural and chemical defense mechanisms leading to reduced anthracnose severity.     

水杨酸诱导果实采后抗病性机制研究进展

水杨酸(Salicylic acid, SA)是一种重要的内源信号分子,具有激活果实抗性防卫反应的能力。本文综述SA对多种果实采后病害的抑制效果及其诱导果实采后抗病性机制(如诱导果实抗氧化反应、诱导果实防御反应、调控果实呼吸代谢、诱导果实抗病基因表达和抗性相关蛋白表达),并展望该领域SA未来研究趋势与方向,对推动果实采后抗病理论的发展和指导生产实践具有重要意义。     

水杨酸诱导的烟草抗性相关序列的分离

通过已分离鉴定的水杨酸诱导烟草‘云烟85’中与抗性相关的差异表达基因,采用差示筛选和反式Northern检测以及序列分析得到94个烟草差异表达的EST序列。经测序及同源性比较,其中87个有同源序列,7个为新序列;有51个与抗性相关,占总序列的54.3%,其中有系统获得抗性蛋白基因和病程相关蛋白基因等。     

水杨酸诱导下人参培养物差异表达基因片段的克隆

本研究以人参愈伤悬浮细胞为材料,在其生长的第28天添加1x10-3 mg/L水杨酸,测定水杨酸添加后,过氧化物酶、多酚氧化酶和苯丙氨酸解氨酶等3种酶在72 h内的变化及皂苷含量,结果表明:水杨酸添加后对过氧化物酶和苯丙氨酸解氨酶的活力影响最大,分别在24 h和48 h达到最大峰值,在18 h开始影响多酚氧化酶的活力,培养物生长的第28天添加水杨酸可以明显提高人参愈伤组织中皂苷的合成.确定添加水杨酸后24 h提取总RNA,进行cDNA-RDA分析,筛选差异片段.确定差异基因并在GenBank中注册,注册号为FE900130.为探讨水杨酸作为诱导子对人参次生代谢的影响奠定基础.     

2,4-二氯苯氧乙酸(2,4-D)对雨生红球藻中虾青素积累的影响

本文初步研究了一定浓度范围内的2,4-D对雨生红球藻积累虾青素的影响.在对数生长 期的藻液中分别加入一系列不同浓度的2,4-D溶液,然后进行胁迫培养(25℃、24h、5000Lx连续光照 营养盐饥饿),诱导细胞内虾青素的合成积累.在诱导过程中,显微观察不同浓度2,4-D处理后细胞形态和虾青素积累的动态变化,并定期取样测定虾青素含量.结果表明,20.0mg/L的2,4-D能够明显促进雨生红球藻中积累虾青素.它不仅可以加快虾青素积累进程(比对照提前15 d),而且比对照能提高13.4%的虾青素产量.