Halotolerant Plant Growth-Promoting Rhizobacteria Induce Salinity Tolerance in Wheat by Enhancing the Expression of SOS Genes

Journal of Plant Growth Regulation - Soil salinity is one of the main yield-limiting factors in various crops. Under different environmental stresses, many rhizobacteria have demonstrated...     

DREB转录因子与植物非生物胁迫抗性研究进展

干旱、高盐、低温等非生物逆境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类转录因子即干旱应答元件结合蛋白是AP2/EREBP转录因子家族的一个亚家族,拥有保守的AP2结构域,能够与DRE/CRT顺式作用元件特异结合,在非生物逆境胁迫条件下调节一系列下游胁迫诱导逆境应答基因的表达,从而提高植物耐逆性。就DREB转录因子的结构特点、表达调控以及提高转基因植株胁迫耐受性的最新研究成果进行了评述。     

脯氨酸在植物非生物胁迫耐性形成中的作用

植物作为固着生活的有机体,经常暴露在多变且对其生长发育不利的环境条件中,这些生物或非生物的胁迫因子严重影响着植物的生长、发育、生存和分布。脯氨酸在植物抵抗逆境胁迫过程中起着重要的作用。根据国内外的最新研究进展,结合我们的研究成果,对植物体内脯氨酸的代谢途径、渗透调节、抗氧化、分子伴侣、生长发育信号和毒性等方面进行了综述,并对该研究领域作了展望。     

Plant Growth-Promoting Rhizobacteria Inoculation to Enhance Vegetative Growth,Nitrogen Fixation and Nitrogen Remobilisation of Maize under Greenhouse Conditions

Plant growth-promoting rhizobacteria (PGPR) may provide a biological alternative to fix atmospheric N₂ and delay N remobilisation in maize plant to increase crop yield, based on an understanding that plant-N remobilisation is directly correlated to its plant senescence. Thus, four PGPR strains were selected from a series of bacterial strains isolated from maize roots at two locations in Malaysia. The PGPR strains were screened in vitro for their biochemical plant growth-promoting (PGP) abilities and plant growth promotion assays. These strains were identified as Klebsiella sp. Br1, Klebsiella pneumoniae Fr1, Bacillus pumilus S1r1 and Acinetobacter sp. S3r2 and a reference strain used was Bacillus subtilis UPMB10. All the PGPR strains were tested positive for N₂ fixation, phosphate solubilisation and auxin production by in vitro tests. In a greenhouse experiment with reduced fertiliser-N input (a third of recommended fertiliser-N rate), the N₂ fixation abilities of PGPR in association with maize were determined by ¹⁵N isotope dilution technique at two harvests, namely, prior to anthesis (D₅₀) and ear harvest (D₆₅). The results indicated that dry biomass of top, root and ear, total N content and bacterial colonisations in non-rhizosphere, rhizosphere and endosphere of maize roots were influenced by PGPR inoculation. In particular, the plants inoculated with B. pumilus S1r1 generally outperformed those with the other treatments. They produced the highest N₂ fixing capacity of 30.5% (262 mg N₂ fixed plant⁻¹) and 25.5% (304 mg N₂ fixed plant⁻¹) of the total N requirement of maize top at D₅₀ and D₆₅, respectively. N remobilisation and plant senescence in maize were delayed by PGPR inoculation, which is an indicative of greater grain production. This is indicated by significant interactions between PGPR strains and time of harvests for parameters on N uptake and at. % ¹⁵N_e of tassel. The phenomenon is also supported by the lower N content in tassels of maize treated with PGPR, namely, B. pumilus S1r1, K. pneumoniae Fr1, B. subtilis UPMB10 and Acinetobacter sp. S3r2 at D₆₅ harvest. This study provides evidence that PGPR inoculation, namely, B. pumilus S1r1 can biologically fix atmospheric N₂ and provide an alternative technique, besides plant breeding, to delay N remobilisation in maize plant for higher ear yield (up to 30.9%) with reduced fertiliser-N input.     

一氧化氮在植物生长发育和抗逆过程中的作用研究进展

NO不仅在植物的抗病过程中发挥重要作用,同时也参与植物生长、发育和对干旱、高盐、高温、低温等非生物胁迫的响应等过程。该文对近年来国内外有关NO在植物生长、发育、非生物胁迫抗性过程中的作用及其与植物激素之间的互作关系等方面的研究进展进行综述,为相关研究提供信息和资料。     

热激转录因子在植物抗非生物胁迫中的功能研究进展

植物在遭受环境胁迫时会产生一系列应激反应,而热激转录因子可通过介导热激蛋白或其他热诱导基因的转录和表达,来参与调控植物抵抗逆境胁迫过程和其他生命活动。主要介绍了植物热激转录因子的基本蛋白结构域,阐述了3类热激转录因子在抗极端温度（高温、低温）胁迫、干旱胁迫、高盐胁迫、活性氧胁迫中的功能与作用机制,并探讨和展望了植物热激转录因子在植物育种和提高植物抗逆性的研究中的发展与应用前景,以期为深入研究热激转录因子在调控植物抵抗逆境胁迫中的生物学功能与机制提供理论参考。     

Alleviation of Mercury Toxicity in Wheat by the Interaction of Mercury-Tolerant Plant Growth-Promoting Rhizobacteria

Heavy metal contamination of agricultural soils has increased along with industrialization. Mercury is a toxic heavy metal and a widespread pollutant in the ecosystem. Mercury-tolerant and plant growth-promoting rhizobacteria (PGPR) HG 1, HG 2, and HG 3 were isolated from the rhizosphere of plants growing in a mercury-contaminated site. These isolates were able to grow in the presence of mercury ranging from 10 to 200 µM in minimal medium and 25 to 500 µM in LB medium. The strains were characterized by morphological, biochemical, and plant growth-promoting traits. In the present study, these PGPR strains were analyzed for their involvement in metal stress tolerance in Triticum aestivum (wheat). Two bacterial strains, namely, Enterobacter ludwigii (HG 2) and Klebsiella pneumoniae (HG 3), showed better growth promotion of T. aestivum seedlings under metal stress. Different growth parameters like, water content and biochemical properties were analyzed in the PGPR-inoculated wheat plants under 75 µM HgCl₂. Shoot length, root length, shoot dry weight, root dry weight and relative water content (RWC) were significantly higher in inoculated plants compared to uninoculated plants under stress condition. Proline content, electrolyte leakage, and malondialdehyde content (shoots and roots) were significantly lower in inoculated plants with respect to uninoculated plants under mercury stress. Therefore, it could be assumed that all these parameters collectively improve plant growth under mercury stress conditions in the presence of PGPR. Hence, these PGPRs can serve as promising candidates for increasing plant growth and also have immense potential for bioremediation of mercury-contaminated soils.     

Glutathione Peroxidases in Plants: Innumerable Role in Abiotic Stress Tolerance and Plant Development

Journal of Plant Growth Regulation - Glutathione peroxidases (GPXs) are key reactive oxygen species (ROS) scavenging enzyme that catalyses the reduction of H2O2 to prevent the cellular machinery...     

Inoculation with Rhizobacteria Enhanced Tolerance of Tomato (Solanum lycopersicum L.) Plants in Response to Cadmium Stress

Journal of Plant Growth Regulation - In this study, cadmium (Cd)-tolerant bacteria Serratia sp. D23 (D23) and Sphingomonas sp. D36 (D36) were isolated from Cd-contaminated rhizospheric soil. Both...     

Effect of Wild-Type and Mutant Plant Growth-Promoting Rhizobacteria on the Rooting of Mung Bean Cuttings

Mung bean cuttings were dipped in solutions of wild type and mutant forms of the plant growth-promoting rhizobacterium Pseudomonas putida GR12-2 and then incubated for several days until roots formed. The bacteria P. putida GR12-2 and P. putida GR12-2/aux1 mutant do not produce detectable levels of the enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase, whereas P. putida GR12-2/acd36 is an ACC deaminase minus mutant. All bacteria produce the phytohormone indole-3-acetic acid (IAA), and P. putida GR12-2/aux1 overproduces it. Treatment of cuttings with the above-mentioned bacteria affected the rates of ethylene production in the cuttings in a way that can be explained by the combined effects of the activity of ACC deaminase localized in the bacteria and bacterial produced IAA. P. putida GR12-2 and P. putida GR12-2/acd36-treated cuttings had a significantly higher number of roots compared with cuttings rooted in water. In addition, the wild type influenced the development of longer roots. P. putida GR12-2/aux1 stimulated the highest rates of ethylene production but did not influence the number of roots. These results are consistent with the notion that ethylene is involved in the initiation and elongation of adventitious roots in mung bean cuttings. Received October 21, 1998; accepted January 3, 1999     

Effect of Compost on Rhizosphere Microflora of the Tomato and on the Incidence of Plant Growth-Promoting Rhizobacteria

Four commercial composts were added to soil to study their effect on plant growth, total rhizosphere microflora, and incidence of plant growth-promoting rhizobacteria (PGPR) in the rhizosphere of tomato plants. Three of the compost treatments significantly improved plant growth, while one compost treatment significantly depressed it. Compost amendments caused only small variations in the total numbers of bacteria, actinomycetes, and fungi in the rhizosphere of tomato plants. A total of 709 bacteria were isolated from the four compost treatments and the soil control to determine the percentage of PGPR in each treatment. The PGPR tests measured antagonism to soilborne root pathogens, production of indoleacetic acid, cyanide, and siderophores, phosphate solubilization, and intrinsic resistance to antibiotics. Our results show that the addition of some composts to soil increased the incidence in the tomato rhizosphere of bacteria exhibiting antagonism towards Fusarium oxysporum f. sp. radicis-lycopersici, Pyrenochaeta lycopersici, Pythium ultimum, and Rhizoctonia solani. The antagonistic effects observed were associated with marked increases in the percentage of siderophore producers. No significant differences were observed in the percentage of cyanogens, whereas the percentages of phosphate solubilizers and indoleacetic acid producers were affected, respectively, by one and two compost treatments. Intrinsic resistance to antibiotics was only marginally different among the rhizobacterial populations. Our results suggest that compost may stimulate the proliferation of antagonists in the rhizosphere and confirm previous reports indicating that the use of composts in container media has the potential to protect plants from soilborne root pathogens.     

盐胁迫下外生菌根真菌与根际有益细菌互作对杨树光合特性的影响

以美洲黑杨幼苗为对象,利用盆栽试验,在100 mmol/L NaCl胁迫条件下研究单接种和双接种外生菌根真菌红绒盖牛肝菌(Xerocamus chrysenteron,简称Xc)、溶磷细菌恶臭假单胞菌(Pseudomonas putida,简称JW-SX1)和菌根辅助细菌蜡状芽孢杆菌(Bacillus cereus,简称HB59)对杨树幼苗的气体交换参数、叶绿素荧光和光响应曲线参数的影响。结果表明:盐胁迫下,接种Xc、JW-SX1及HB59的杨树幼苗净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)显著增强,且均显著高于对照,而单接JW-SX1和双接Xc+JW-SX1处理的胞间CO2浓度(Ci)低于对照,但与对照相比差异不显著;各接种处理显著增强了杨树的最大光化学效率(Fv/Fm),但处理之间差异不显著性;不同接种处理杨树的实际光化学效率(ΦPSⅡ)与对照(CK)差异不明显,其中接种HB59和Xc+JW-SX1处理分别高于对照14.36%和19.33%;同时接种处理还明显提高了宿主的最大光合速率(Pmax)、光饱和点(LSP)、表观有效利用效率(YAQ),降低了光补偿点(LCP)和暗呼吸速率(RD),且双接种菌根真菌Xc和JW-SX1处理效果更为明显。研究发现,外生菌根真菌、溶磷细菌和菌根辅助细菌可通过改善叶片叶绿素荧光和光合参数、光响应参数来减轻盐胁迫对宿主造成的伤害,从而提高杨树的耐盐性能力。     

植物microRNAs在植物发育和非生物胁迫响应中的作用

microRNAs(miRNAs)是一类内源的长度约为22个核苷酸的非编码小分子RNA,其通过对靶基因mRNA进行切割或翻译抑制调节mRNA的表达,在植物中起到重要的作用.主要介绍了植物miRNAs的特征、合成和作用机制,综述了miRNAs在植物生长发育和非生物胁迫响应中的作用.     

菠萝蜜低聚肽对db/db小鼠炎症反应、血糖及血脂的影响

目的：研究菠萝蜜低聚肽（JOPs）干预对db/db糖尿病模型小鼠炎症反应、血糖及血脂的影响作用。方法：选择db/db糖尿病小鼠模型,将其随机分为3个JOPs组（0.2、0.4、0.8g/kg·BW）以及糖尿病模型对照组、二甲双胍对照组、乳清蛋白对照组,并选用db/m小鼠作为非糖尿病小鼠空白对照。经过为期6个月的干预,检测小鼠空腹血糖（FPG）、血清胰岛素（INS）、白细胞介素6（IL 6）、白细胞介素8（IL 8）、白细胞介素10（IL 10）和肿瘤坏死因子α（TNF α）、C反应蛋白（CRP）以及脂代谢指标。结果：JOPs可显著降低db/db糖尿病小鼠空腹血糖水平及胰岛素抵抗指数;可使血清IL 6、TNF α、总胆固醇（TC）和甘油三酯（TG）显著降低,并使高密度脂蛋白胆固醇（HDL C）显著升高。结论：JOPs干预可有效降低糖尿病小鼠的血糖水平,改善胰岛素抵抗,同时有效调节炎症反应及血脂代谢。     

脯氨酸在植物生长和非生物胁迫耐受中的作用

脯氨酸是生物界分布最广的渗透保护物质之一,干旱、高盐、高温及重金属等非生物胁迫条件都会导致植物体内脯氨酸含量的增加,其作用是防止渗透胁迫对植物造成的伤害、清除自由基,还可以作为氮、碳以及NADPH的重要来源。近年来,在转化脯氨酸代谢相关基因提高植物胁迫抗性方面也取得了很大进展。本文概要介绍了脯氨酸在植物生长和耐受非生物胁迫中的作用、与植物脯氨酸累积有关的信号转导、胁迫条件下脯氨酸的吸收和器官间的运输途径,以及通过转基因技术过量表达脯氨酸提高植物胁迫耐性的代谢工程的进展。     

Roles of Nitric Oxide in Conferring Multiple Abiotic Stress Tolerance in Plants and Crosstalk with Other Plant Growth Regulators

Journal of Plant Growth Regulation - Nitric oxide (NO) is a free-radical gasotransmitter signaling molecule associated with a varied spectrum of signal transduction pathways linked to inducing...     

Reactive Oxygen,Nitrogen, Carbonyl and Sulfur Species and Their Roles in Plant Abiotic Stress Responses and Tolerance

Plants being sessile organisms are often exposed to various abiotic stress conditions, which greatly hamper the growth, yields as well as the quality of produce. Plants respond to abiotic stresses in an exceptionally complex and coordinated manner, involving the interactions and crosstalk with many metabolic-molecular pathways. One of the most common responses is generation of reactive chemical species including reactive oxygen species (ROS), reactive nitrogen species (RNS), reactive carbonyl species (RCS) and reactive sulfur species (RSS). ROS and RNS have long attracted attention from the plant researchers for both their damaging as well as protective effects. However, several reports are emerging to confirm similar roles played by the relatively newer 'reactive' members, the RCS and RSS. Plant reactive species are also hailed as vivacious signaling molecules that play regulatory roles in many plant metabolic procedures. Undeniably, these reactive species are involved in virtually all aspects of plant cell functions. Reactive species and the antioxidant machinery maintain a delicate but critical cellular redox-balance which gets disturbed under stress conditions, where their biosynthesis, transportation, scavenging and the overall metabolism gets decisive for plant survival. The current review aims to highlight and discuss the role of ROS, RNS, RCS, and RSS in plants especially under abiotic stresses, cross-talks between them, current approaches and technological advents for their characterization, and a perspective view on exploration/manipulation of the pathways and check-points involved in biosynthesis, transport and scavenging of these reactive species for engineering abiotic stress tolerant crop plants.

     

马铃薯bHLH转录因子家族全基因组鉴定与表达分析

对马铃薯bHLH转录因子进行全基因组鉴定与表达模式分析,为其生物学功能研究提供借鉴.基于马铃薯基因组数据库和Pfam数据库,运用HMMER对马铃薯bHLH家族成员进行全基因组鉴定,剔除冗余序列后,利用ExPASy和MEME软件对候选序列进行基本理化性质及保守元件分析,并使用MEGA-X软件进行聚类分析;用MG2C和TB...