DREB转录因子在植物抗逆胁迫中的作用机理及应用研究进展

干旱、高盐和低温等非生物胁迫严重影响植物的生长发育和作物产量。转录因子在调节植物生长发育以及对外界环境胁迫的响应方面起着重要作用。DREB转录因子含有一个保守的AP2/EREBP结构域,参与外界环境胁迫的应答响应,通过结合DRE(Dehydration responsive element)顺式作用元件,调控下游胁迫相关基因的转录表达,改良植物的抗性。本文在前人研究的基础上,综述了DREB转录因子的结构特征、介导的信号传递途径、对非生物胁迫的响应以及转基因的研究进展,旨在为作物的抗逆育种提供理论依据。     

植物非生物胁迫应答的分子机制

非生物胁迫因子是制约植物生长发育、影响作物产量和质量的关键因子。这些非生物胁迫的共同点是它们都会导致植物细胞缺水,使细胞的水分平衡紊乱,还可以引起蛋白质等大分子变性,破坏植物细胞内的膜结构等。为了生存,植物在遇到非生物胁迫时不得不在形态和生理生化代谢上进行一些调整,以适应或忍耐环境胁迫。揭示植物胁迫应答分子机理是人们长期以来探索的重大课题。非生物胁迫引起的应答非常复杂并且常常相互关联,干旱、高盐、低温等胁迫可以引起相似的应答反映,如积累大量的渗透调节剂、重建细胞内离子动态平衡、修复被破坏的膜系统、清除活性氧自由基等等。近年来,胁迫应答的分子机理研究成果颇丰,结合笔者等的研究,本文简要进行了综述。     

高等植物WRKY转录因子家族的演化及功能研究进展

WRKY转录因子是植物转录调节因子的最大家族之一,并且是调节植物许多生物过程的信号网络的组成部分。WRKY转录因子通过其保守结构域与靶基因启动子区域的W-box特异性结合,调节靶基因的表达,进而调控植物的叶片衰老、种子萌发与休眠、开花等生长发育过程外,还参与调控植物生物和非生物胁迫的响应过程。本文用代表性植物基因组数据,对WRKY的基因演化作了归纳,综述了近二十年来国内外WRKY转录因子的相要研究进展,并介绍了该转录因子在植物生物胁迫和非生物胁迫应答及生长发育过程中的调控作用。      

小麦TaPP2C59基因的克隆及表达分析

2C型蛋白磷酸酶(PP2C)是ABA信号途径的关键组分,在ABA信号转导及植物对非生物逆境胁迫的应答过程中发挥着重要作用。为给TaPP2C59基因功能的研究奠定基础,同时为小麦对非生物胁迫应答的信号转导机理研究提供参考,本研究从小麦中克隆了第一个PP2C基因TaPP2C59,并对其在逆境胁迫以及多种信号分子处理下的表达模式进行研究。序列分析表明,该基因开放阅读框(ORF)为855bp,编码284个氨基酸。进化树分析表明,该基因编码的蛋白与水稻OsPP2C45蛋白和拟南芥AtPP2C59蛋白的亲缘关系最近。多序列比对分析表明,TaPP2C59具有PP2C家族蛋白的保守结构特征。实时荧光定量PCR分析表明,该基因的表达显著受ABA、低温和高盐胁迫抑制。因此,可以推测TaPP2C59可能作为负调控因子参与ABA信号及非生物逆境胁迫应答。     

植物BTB/POZ蛋白及其抗病性研究进展

为了适应各种生物胁迫和非生物胁迫,植物在长期进化过程中形成了完整的调节机制,感受外界刺激,调整基因的表达,调节代谢途径。植物BTB/POZ蛋白在一系列生物过程中发挥重要作用。文中介绍了植物中的BTB/POZ蛋白的分子特征和抗病功能。此外,也就BTB/POZ蛋白在抗病应答途径、抗病反应中的作用机理等进行综述,为作物抗病的分子机理研究提供参考。     

糖料作物抗氧化酶基因应答非生物胁迫的研究进展

糖料作物是重要的经济作物,和其他作物一样会受到各种环境胁迫,恶劣的环境会造成作物产量和品质的下降,利用分子生物学手段可有效地增强作物的抗逆性,因此研究糖料作物应答非生物胁迫的分子机制在理论和实际生产上具有重大意义.本文总结了国内外文献,对非生物胁迫对植物生长发育的影响、诱发活性氧(ROS)的积累和清除途径、非生物胁迫对...     

脂质调控植物低氧信号的作用及其在苎麻育种研究中的展望

土壤涝渍等灾害导致的低氧胁迫是一种非生物胁迫,对植物的生长、发育、分布和产量产生极大的影响。为了在低氧环境下生存,植物进化出一系列适应性形态结构以及重新编码细胞代谢与信号网络等的生理生化策略。脂质是植物细胞膜的重要组成部分,广泛参与植物对逆境胁迫的应答调控。文章综述了低氧胁迫条件下植物脂质的适应性变化特征,以及几种重要脂质分子参与植物低氧应答信号调控的前沿进展,并对苎麻脂质代谢和信号分子参与低氧胁迫反应的作用机制及面临的挑战进行了展望,以期为苎麻低氧应答的分子机制研究提供新的思路,并为耐渍苎麻新品种选育提供参考。     

生物与非生物逆境胁迫下植物脂质调控机制及其研究进展

病虫害等生物逆境胁迫与温度、水分等非生物胁迫是影响植物生长发育与产量的关键因素。脂质参与到植物响应胁迫的各通路中，形成一套独特的反馈应答机制，如不饱和脂肪酸对生物胁迫中的抗病虫功能等。另外，非生物胁迫中脂肪酸衍生物还能够增加细胞内渗透调节，减少膜脂过氧化程度，提高植物的抗逆性。因此，脂质的含量与植物生长发育过程中的生物胁迫与非生物胁迫有密切联系。本文综合了国内外生物与非生物胁迫下植物脂质的调控机制及其研究进展，简要介绍了胁迫类型，重点总结了植物在各胁迫下脂质的变化及调控作用，意在加深对逆境下植物生理活动的了解，为进一步研究植物抗逆过程中脂质的调控提供参考。     

大豆GmDof4和GmDof11基因的非生物胁迫诱导表达及启动子分析

Dof家族是典型的植物特异性锌指转录因子家族,在植物中可以对非生物胁迫产生应答.为初步研究大豆Dof家族主要转录因子编码基因GmDof4和GmDof11在大豆抗非生物胁迫过程中的作用及调控原理,本研究通过实时荧光定量PCR检测大豆幼苗中GmDof4和GmDof11基因在非生物胁迫下的表达情况,并使用PlantCARE在...     

植物响应逆境胁迫的比较蛋白质组学研究进展

绿色植物在生长过程中遭遇的环境胁迫包括非生物胁迫(如干旱、高温、低温、高盐、营养)和生物胁迫(如病虫害)两大类。本文对植物响应上述逆境胁迫的比较蛋白质组学研究进展进行概述,并展望植物抗逆蛋白质组学的研究前景。     

Comparative Assessment of the Efficacy of Various Nitrogen Fertilizers

Summary

The efficiency of N fertilizers is usually poor; often less than 50% of the applied N is taken up by the crop. This review focuses on various N fertilizers with respect to the significance of different N loss pathways, namely (i) ammonia volatilization, (ii) dinitrogen and nitrogen oxide emissions, and (iii) nitrate leaching. Further, the significance of biological N immobilization, ammonium fixation and, finally, the impact of nitrate vs. ammonium uptake on crop yield are also discussed. The reviewed literature shows that N fertilizers may differ markedly in their susceptibility to losses. There is, however, considerable scope to improve N efficiency of each N source by proper N management practices.     

Studies on natural repellents against potato tuber moth (Phthorimaea operculella Zeller) in country stores

Summary The effects of the leaves of five plant species, one from each of the generaAmbrosia, Anemone, Eupatorium, Eucalyptus andLantana, on potato tuber moth were investigated under indigenous storage conditions at the Central Potato Research Station, Shillong (1800 m above sea level). Their action was compared with that of a biological insecticide (spores ofBacillus thuringiensis), a chemical insecticide (carbaryl), and an untreated control. The data collected after six months storage on tuber damage, sprout damage and the rotting indicated that the leaves ofLantana aculeata provided most protection to the tubers, reducing damage from over 70% in the check to below 5%, and sprout damage from over 45% to below 3%. Next best wasEucalyptus globulus followed byB. thuringiensis. They may be used on tubers stored for table use or for seed as they had no adverse effect on germination or on the yield of a subsequent crop.     

Mineral composition of some traditional Mexican teas

Teas of plant origin traditionally consumed by the Mountain Pima of Chihuahua, Mexico, were analyzed for mineral nutritional content. Fe, Cu, Zn, Ca, and Mg composition was determined for native teas made from shoots ofTagetes lucida, T. filifolia, Elytraria imbricata, andHolodiscus dumosus, and from root xylem ofCeanothus depressus andPhaseolus ritensis. Native uses of these teas are also described.     

Novel food and non-food uses for sorghum and millets

Sorghum and millets have considerable potential in foods and beverages. As they are gluten-free they are suitable for coeliacs. Sorghum is also a potentially important source of nutraceuticals such antioxidant phenolics and cholesterol-lowering waxes. Cakes, cookies, pasta, a parboiled rice-like product and snack foods have been successfully produced from sorghum and, in some cases, millets. Wheat-free sorghum or millet bread remains the main challenge. Additives such as native and pre-gelatinised starches, hydrocolloids, fat, egg and rye pentosans improve bread quality. However, specific volumes are lower than those for wheat bread or gluten-free breads based on pure starches, and in many cases, breads tend to stale faster. Lager and stout beers with sorghum are brewed commercially. Sorghum's high-starch gelatinisation temperature and low beta-amylase activity remain problems with regard to complete substitution of barley malt with sorghum malt . The role of the sorghum endosperm matrix protein and cell wall components in limiting extract is a research focus. Brewing with millets is still at an experimental stage. Sorghum could be important for bioethanol and other bio-industrial products. Bioethanol research has focused on improving the economics of the process through cultivar selection, method development for low-quality grain and pre-processing to recover valuable by-products. Potential by-products such as the kafirin prolamin proteins and the pericarp wax have potential as bioplastic films and coatings for foods, primarily due to their hydrophobicity.     

In vitro antimicrobial activity of different accessions ofSolanum commersonii Dun. from Uruguay

Summary The in vitro antimicrobial activity of extracts from accessions ofSolanum commersonii Dun. collected in the south of Uruguay was investigated against five microorganisms including the pathogenRalstonia solanacearum. A total of 30 extracts corresponding to organic and aqueous extracts were studied. Interestingly, most of the positive results for growth inhibition were againstR. solanacearum. The extracts were also analyzed for the presence of glycoalkaloids and lectins. Six of the ten aqueous extracts showed lectin presence and a wide variation in the type and amounts of glycoalkaloids, was found. Results indicate that there is no clear relationship between the antimicrobial activity against the five microorganisms screened and the presence or amounts of lectins and glycoalkaloids, traditionally regarded as possible antimicrobial metabolites in theSolanum genus, which indicates the presence of as yet unidentified antimicrobial compounds.     

Extreme resistance to infection by potato virus X in genotypes of wild tuber-bearingSolanum species

Summary Clones derived from thirty-one different accessions (nineteen of Argentine origin) belonging to eightSolanum species were screened for resistance to infection by potato virus X strain cp (PVX cp) by mechanical inoculation of plantlets that had been micropropagated in vitro. Estimates of PVX multiplication obtained by enzyme linked immunosorbent assay and slot blot nucleic acid hybridization allowed the identification of resistant clones derived from five accessions belonging toS. commersonii S. oplocense, S. sparsipilum andS. tuberosum andigena. Resistant genotypes supported PVX concentrations 5 to 15 times smaller than did the susceptible control cultivar Spunta. Graft inoculation test confirmed the presence of extreme resistance similar to that conferred by the ‘immunity’ gene X¹ (also called RX_act).     

Cyanobacteria Secondary Metabolites as Biotechnological Ingredients in Natural Anti-Aging Cosmetics: Potential to Overcome Hyperpigmentation,Loss of Skin Density and UV Radiation-Deleterious Effects

The loss of density and elasticity, the appearance of wrinkles and hyperpigmentation are among the first noticeable signs of skin aging. Beyond UV radiation and oxidative stress, matrix metalloproteinases (MMPs) assume a preponderant role in the process, since their deregulation results in the degradation of most extracellular matrix components. In this survey, four cyanobacteria strains were explored for their capacity to produce secondary metabolites with biotechnological potential for use in anti-aging formulations. Leptolyngbya boryana LEGE 15486 and Cephalothrix lacustris LEGE 15493 from freshwater ecosystems, and Leptolyngbya cf. ectocarpi LEGE 11479 and Nodosilinea nodulosa LEGE 06104 from marine habitats were sequentially extracted with acetone and water, and extracts were analyzed for their toxicity in cell lines with key roles in the skin context (HaCAT, 3T3L1, and hCMEC). The non-toxic extracts were chemically characterized in terms of proteins, carotenoids, phenols, and chlorophyll a, and their anti-aging potential was explored through their ability to scavenge the physiological free radical superoxide anion radical (O₂^•−), to reduce the activity of the MMPs elastase and hyaluronidase, to inhibit tyrosinase and thus avoid melanin production, and to block UV-B radiation (sun protection factor, SPF). Leptolyngbya species stood out for anti-aging purposes: L. boryana LEGE 15486 presented a remarkable SPF of 19 (at 200 µg/mL), being among the best species regarding O₂^•− scavenging, (IC₅₀ = 99.50 µg/mL) and also being able to inhibit tyrosinase (IC₂₅ = 784 µg/mL), proving to be promising against UV-induced skin-aging; L. ectocarpi LEGE 11479 was more efficient in inhibiting MMPs (hyaluronidase, IC₅₀ = 863 µg/mL; elastase, IC₅₀ = 391 µg/mL), thus being the choice to retard dermal density loss. Principal component analysis (PCA) of the data allowed the grouping of extracts into three groups, according to their chemical composition; the correlation of carotenoids and chlorophyll a with MMPs activity (p < 0.01), O₂^•− scavenging with phenolic compounds (p < 0.01), and phycocyanin and allophycocyanin with SPF, pointing to these compounds in particular as responsible for UV-B blockage. This original survey explores, for the first time, the biotechnological potential of these cyanobacteria strains in the field of skin aging, demonstrating the promising, innovative, and multifactorial nature of these microorganisms.     

Marine Pharmacology in 2009–2011: Marine Compounds with Antibacterial,Antidiabetic, Antifungal,Anti-Inflammatory,Antiprotozoal, Antituberculosis,and Antiviral Activities; Affecting the Immune and Nervous Systems,and other Miscellaneous Mechanisms of Action ?

The peer-reviewed marine pharmacology literature from 2009 to 2011 is presented in this review, following the format used in the 1998–2008 reviews of this series. The pharmacology of structurally-characterized compounds isolated from marine animals, algae, fungi and bacteria is discussed in a comprehensive manner. Antibacterial, antifungal, antiprotozoal, antituberculosis, and antiviral pharmacological activities were reported for 102 marine natural products. Additionally, 60 marine compounds were observed to affect the immune and nervous system as well as possess antidiabetic and anti-inflammatory effects. Finally, 68 marine metabolites were shown to interact with a variety of receptors and molecular targets, and thus will probably contribute to multiple pharmacological classes upon further mechanism of action studies. Marine pharmacology during 2009–2011 remained a global enterprise, with researchers from 35 countries, and the United States, contributing to the preclinical pharmacology of 262 marine compounds which are part of the preclinical pharmaceutical pipeline. Continued pharmacological research with marine natural products will contribute to enhance the marine pharmaceutical clinical pipeline, which in 2013 consisted of 17 marine natural products, analogs or derivatives targeting a limited number of disease categories.