药用植物生长发育与有效成分积累关系研究进展

药用植物有效成分是其发挥临床疗效的物质基础, 也是评价药材质量的重要指标, 而这些有效成分的产生和分布通常有种属、器官、组织以及生长发育时期的特异性。明确药用植物主要药用成分在植物不同生长发育阶段的积累变化规律和形成机制, 对中药品质与临床疗效有重要的指导意义。该文主要概述了不同发育阶段对药用植物不同药用部位(根、茎、叶、花、果实和种子)中有效成分积累的影响, 并对药用植物次生代谢产物合成和积累机制的相关研究技术进行了展望, 为生产实践上调控药用植物次生物质合成、药用植物的合理利用以及提高中药材品质奠定了理论基础。     

Production of isoflavone genistein in transgenic IFS tobacco roots and its role in stimulating the development of arbuscular mycorrhiza

Flavonoids and isoflavonoids are secondary metabolites in plants. With the goal of obtaining isoflavonoids from a wide range of plants, a few key studies have proven that isoflavonoids can be produced in non-leguminous plants by transgenic engineering. Many earlier studies investigate genistein biosynthesis in leaves and petals of isoflavone synthase (IFS) transgenic tobacco. However, most reports do not attempt to analyze quantification of genistein or do not check the presence of genistein in transgenic plant roots. In addition, little is known about the influence of genistein on arbuscular mycorrhiza (AM). In this paper, we reported that genistein was obtained from transgenic IFS tobacco roots. In addition, we revealed that endogenous genistein and 10???g?g^?1 exogenous genistein enhanced the development of AM symbiosis. We also revealed the relative expression levels of pertinent genes during the development of AM symbiosis. Our results suggest that genistein plays a positive role in the development of AM symbiosis in tobacco roots.     

The Roles of Auxins and Cytokinins in Mycorrhizal Symbioses

Abstract Most land plant species that have been examined exist naturally with a higher fungus living in and around their roots in a symbiotic partnership called a mycorrhiza. Several types of mycorrhizal symbiosis exist, defined by the host/partner combination and the morphology of the symbiotic structures. The arbuscular mycorrhiza (AM) is ancient and may have co-evolved with land plants. Emerging results from gene expression studies have suggested that subsets of AM genes were co-opted during the evolution of other biotrophic symbioses. Here we compare the roles of phytohormones in AM symbiosis and ectomycorrhizas (EC), a more recent symbiosis. To date, there is little evidence of physiologic overlap between the two symbioses with respect to phytohormone involvement. Research on AM has shown that cytokinin (CK) accumulation is specifically enhanced by symbiosis throughout the plant. We propose a pathway of events linking enhanced CK to development of the AM. Additional and proposed involvement of other phytohormones are also described. The role of auxin in EC symbiosis and recent research advances on the topic are reviewed. We have reflected the literature bias in reporting individual growth regulator effects. However, we consider that gradients and ratios of these molecules are more likely to be the causal agents of morphologic changes resulting from fungal associations. We expect that once the individual roles of these compounds are explained, the subtleties of their function will be more clearly addressed.     

药用植物微生物组及其与药用植物次生代谢产物的关系

药用植物是中药的原料,是中药产业的源头,其生长发育受遗传和环境等诸多因素的影响。以往研究强调植物基因型及生态因子对药用植物产量和品质的影响。近几年,随着人类微生物组研究的推进,植物微生物组作为植物整体的重要组成部分在药用植物的生长发育、品质形成甚至药效等方面的作用也日益受到重视,有关植物微生物组的多样性,微生物组在植物生长发育中的作用已有较详细的综述,而有关药用植物微生物组及其与药用植物次生代谢产物间关系的综述较少。本文重点总结了自2010年以来药用植物微生物组的研究进展,包括药用植物微生物组物种组成、功能及其与药用植物次生代谢产物产生的关系等,并对其在药用植物提质增效及其生态种植中的潜在应用进行了展望。     

Development of arbuscular mycorrhizal biotechnology and industry: current achievements and bottlenecks

Advanced scientific knowledge on arbuscular mycorrhizal symbioses recently enhanced potential for implementation of mycorrhizal biotechnology in horticulture and agriculture plant production, landscaping, phytoremediation and other segments of the plant market. The advances consist in significant findings regarding:—new molecular detection tools for tracing inoculated fungi in the field;—the coexistence mechanisms of various fungi in the single root system;—new knowledge on in vitro physiology of the AM fungi grown in root organ cultures;—mechanisms of synergistic interactions with other microbes like PGPR or saprotrophic fungi; discovery of mycorrhiza supportive compounds such as strigolactones. Scientific knowledge has been followed by technological developments like novel formulations for liquid applications or seed coating, mycorrhiza stimulating compounds or new application modes. Still the missing components of biotechnology are appropriate, cheap, highly reproducible and effective methods for inocula purity testing and quality control. Also there is a weak traceability of the origin of the mycorrhizal fungi strains used in commercial inocula. Numerous poor quality products can still be found on the markets claiming effective formation mycorrhiza which have very low capacity to do so. These products usually rely in their effects on plant growth not on support of host plants via formation of effective mycorrhizal symbiosis but on fertilizing compounds added to products. There is growing number of enterprises producing mycorrhiza based inocula recently not only in developed world but increasingly in emerging markets. Also collaboration between private sector and scientific community has an improving trend as the development of private sector can fuel further research activities. Last but not least there is apparent growing pull of the market and increasing tendency of reduction of agrochemical inputs and employment of alternative strategies in planting and plant production. These circumstances support further developments of mycorrhizal inocula production and applications and maturation of the industry.     

丛枝菌根（AM）生物技术在现代农业体系中的生态意义

菌根是植物根系与特定的土壤真菌形成的共生体,有利于生态系统中养分循环,协助植物抵御不良环境胁迫．自然条件下,大多数植物表现一定的菌根依赖性,在植株根系发育过程中如能与适宜的菌根真菌形成良好的菌根结构,可提高产量,改善品质,其中丛枝菌根是最普遍的类型．丛枝菌根帮助植物抵御不良环境胁迫及病虫害,促进植物健康生长,可减少化学肥料、杀虫剂施用量,以减少对环境、生态不利的化学物质施用量．丛枝菌根共生体可加速根系生长,提高对移动性低的无机离子吸收,加速养分循环利用,增强植物对不良胁迫(生物与非生物)因素的耐受力,形成良好的土壤结构,提高植物群体的多样性．文章综述了丛枝菌根真菌生态特征,丛枝菌根对寄主植物的影响,丛枝菌根生物技术应用于农业体系的生态意义及其应用潜力．     

丛枝菌根真菌对植物生长影响的研究

菌根是自然界中一种极为普遍和重要的共生现象,其中分布最为广泛的菌根类型就是丛枝菌根,可以增强植物从土壤中获取水分的能力,改善植物根系对磷、镉等矿质元素及养分的吸收,从而促进植物的生长。本文综述了丛枝菌根真菌对植物生长影响的概况。有关丛枝菌根真菌对植物水分和矿质营养的利用,尤其是磷素营养的研究较为深入,而对植物光合特性的研究较少,这些研究工作为深入理解菌根真菌与植物的相互关系提供基础资料。     

Successful joint ventures of plants: arbuscular mycorrhiza and beyond

Among the oldest symbiotic associations of plants are arbuscular mycorrhiza (AM) with fungi of the phylum Glomeromycota. Although many of the symbiotic signaling components have been identified on the side of the plant, AM fungi have long evaded genetic analysis owing to their strict biotrophy and their exceptional genetics. Recently, the identification of the fungal symbiosis signal (Myc factor) and of a corresponding Myc factor receptor, and new insights into AM fungal genetics, have opened new avenues to address early communication and functional aspects of AM symbiosis. These advances will pave the way for breeding programs towards adapted AM fungi for crop production, and will shed light on the ecology and evolution of this remarkably successful symbiosis.     

AM真菌在有机农业发展中的机遇

在农田生态系统中,许多农作物均为丛枝菌根(AM)真菌的优良宿主植物,当AM真菌与这些宿主植物建立共生关系之后,AM真菌的存在有益于宿主植物的生长。然而,传统农业耕作模式中化学肥料和农药的施用、耕作制度的不断调整和非宿主植物的种植等都不利于AM真菌的建植。有机农业生态系统排除了化学肥料和农药的施用,减少了对AM真菌生长不利的因素,促进了土壤中AM真菌数量的增加和群落多样性的提高。同时,AM真菌可以通过多种方式改善土壤物理结构、提高农作物对干旱胁迫的耐受能力以及宿主植物对病虫害的抗性/耐性、抑制杂草生长、促进营养物质的吸收,进而提高植物的生长和改善产品的品质。基于此,围绕AM真菌在有机农业发展中的生态学功能展开论述,分析当前有机农业生态系统存在的问题,探讨利用AM真菌发展有机农业的可行性及其发展的机遇,以期促进AM真菌在有机农业发展中的应用。     

植物苯丙烷代谢途径

众所周知,固着生长的植物经常受到环境中各种生物和非生物胁迫的威胁。所以在漫长的进化过程中,植物必须将多样的环境信号整合到其发育过程中,以实现适应性形态的发生和代谢途径的精确调控,最终使植物完成整个生长周期。研究显示,苯丙烷代谢作为植物重要的次级代谢途径之一,其代谢产物,例如木质素、孢粉素、花青素和有机酸等,在调控植物适应性生长的过程中发挥着重要功能。特别是在药用植物中,苯丙烷代谢还与众多药用活性成分的合成息息相关,几乎所有包含苯丙烷骨架的天然药效成分均由苯丙烷代谢途径直接或间接合成,例如黄酮类、萜类和酚类等。此外,经苯丙烷代谢途径产生的一些次级代谢产物还能由植物根系外泌到周际土壤中,通过改变根系微生物的菌群生态,而影响植物生长和抵抗生物或非生物胁迫的能力。同时,苯丙烷代谢介导的这种植物-微生物互作也与药用植物的道地品质密不可分。本文综述了近年来植物苯丙烷代谢途径的最新研究进展,重点对该代谢途径中代谢产物的生理功能及表达调控机制进行了介绍,以期更深入地理解药用植物苯丙烷代谢与药材性状之间的潜在关系,旨在指导优良中草药的遗传育种,以进一步促进我国中医药事业的蓬勃发展。     

Interactions between arbuscular mycorrhizal fungi and soil bacteria

The soil environment is interesting and complicated. There are so many interactions taking place in the soil, which determine the properties of soil as a medium for the growth and activities of plants and soil microorganisms. The soil fungi, arbuscular mycorrhiza (AM), are in mutual and beneficial symbiosis with most of the terrestrial plants. AM fungi are continuously interactive with a wide range of soil microorganisms including nonbacterial soil microorganisms, plant growth promoting rhizobacteria, mycorrhiza helper bacteria and deleterious bacteria. Their interactions can have important implications in agriculture. There are some interesting interactions between the AM fungi and soil bacteria including the binding of soil bacteria to the fungal spore, the injection of molecules by bacteria into the fungal spore, the production of volatiles by bacteria and the degradation of fungal cellular wall. Such mechanisms can affect the expression of genes in AM fungi and hence their performance and ecosystem productivity. Hence, consideration of such interactive behavior is of significance. In this review, some of the most important findings regarding the interactions between AM fungi and soil bacteria with some new insights for future research are presented.     

Wild aromatic plants bioactivity: a function of their (poly)phenol seasonality? A case study from Mediterranean area

Wild medicinal and aromatic plants are in the market as herbal raw or processed and packaged materials, playing, even today, a strategic role in the production of plant-based products. Indeed, their content in active ingredients, mainly specialized secondary metabolites, is not constant; it undergoes significant seasonal variations, as abiotic stress heavily affects secondary metabolism network. The present review deals with the seasonality influence on the polyphenolic composition on antioxidant and anti-inflammatory properties of medicinal and aromatic plants. To this aim, firstly the factors influencing the content of active ingredients in a plant drug will be discussed, and, in particular, the increased occurrence of phenols as a response to abiotic stress. In the last part of the review a brief reference will be made to four meaningful case studies, which involve wild medicinal aromatic herbs, native to the Mediterranean area: Calamintha nepeta L. Savi, Foeniculum vulgare Mill., Ruta graveolens L. and Thymus longicaulis C. Presl. These species, grown in the same geographical area and collected at the same harvesting time, showed a great variability in phenol constituents throughout the year. The comparison among data acquired clearly evidences that the seasonal variation in polyphenols’ occurrence and amount leads to a more/less pronounced antioxidant and anti-inflammatory activity of the hydroalcoholic extract therefrom. It is worth of note that the presence of the same metabolite, but in different phytochemical complexes, could result in different biological activities.     

MycoRed: Betalain pigments enable in vivo real-time visualisation of arbuscular mycorrhizal colonisation

Arbuscular mycorrhiza (AM) are mutualistic interactions formed between soil fungi and plant roots. AM symbiosis is a fundamental and widespread trait in plants with the potential to sustainably enhance future crop yields. However, improving AM fungal association in crop species requires a fundamental understanding of host colonisation dynamics across varying agronomic and ecological contexts. To this end, we demonstrate the use of betalain pigments as in vivo visual markers for the occurrence and distribution of AM fungal colonisation by Rhizophagus irregularis in Medicago truncatula and Nicotiana benthamiana roots. Using established and novel AM-responsive promoters, we assembled multigene reporter constructs that enable the AM-controlled expression of the core betalain synthesis genes. We show that betalain colouration is specifically induced in root tissues and cells where fungal colonisation has occurred. In a rhizotron setup, we also demonstrate that betalain staining allows for the noninvasive tracing of fungal colonisation along the root system over time. We present MycoRed, a useful innovative method that will expand and complement currently used fungal visualisation techniques to advance knowledge in the field of AM symbiosis.

Arbuscular mycorrhiza are mutualistic interactions formed between soil fungi and plant roots. This study presents the MycoRed system, which uses red plant pigments derived from beetroot to reveal how fungi establish symbiosis with living legume and wild tobacco roots.     

miRNA调控药用植物生长发育和次生代谢

microRNA(miRNA)作为一类内源性的短链非编码RNA,广泛存在于真核细胞中,主要通过对转录本剪切和抑制翻译等方式,参与转录后基因的表达调控。近年来研究表明,多种药用植物中鉴定出大量的miRNA。这些miRNA对药用植物的生长发育和次生代谢产物合成具有调控功能。次生代谢产物是药用植物的主要有效成分,研究miRNA对药用植物次生代谢过程的调控作用具有十分重要的意义。本文综述了miRNA在植物中的产生途径、作用方式和体内功能,在此基础上重点介绍了miRNA对药用植物生长发育和次生代谢产物生物合成的调控作用,并对药用植物miRNA的研究进行了展望,以期为提高药用植物产量,高效获得药用植物有效成分以及临床应用开拓新的思路。     

The Ecology of Arbuscular Mycorrhizal Fungi

Arbuscular mycorrhiza is a mutually beneficial biological association between species in the fungal phylum Glomeromycota and higher plants roots. The symbiosis is thought to have afforded green plants the opportunity to invade dry land ca 450 Ma ago and the vast majority of extant terrestrial plants retain this association. Arbuscular mycorrhizal (AM) fungi perform various ecological functions in exchange for host photosynthetic carbon that almost always contribute to the fitness of hosts from an individual to community level. Recent AM fungal research, increasingly delving into the ‘Black Box’, suggests that species in this phylum may play a key facilitative role in below-ground micro- and meso-organism community dynamics, even more perhaps, that of a bioengineer. The ubiquitous nature of the symbiosis in extant flora and the fact that variations from the AM symbiosis are recent events suggest that Glomeromycota and plant roots coevolved. This review considers aspects of AM fungal ecology emphasizing past and present importance of the phylum in niche to global ecosystem function. Nutrient exchange, evolution, taxonomy, phenology, below-ground microbial interaction, propagule dissemination, invasive plants interactions, the potential role in phytoremediation and some of the factors affecting AM fungal biology are discussed. We conclude that it is essential to include AM association in any study of higher plants in natural environments in order to provide an holistic understanding of ecosystems.     

AM fungi root colonization increases the production of essential isoprenoids vs. nonessential isoprenoids especially under drought stress conditions or after jasmonic acid application

Previous studies have shown that root colonization by arbuscular mycorrhiza (AM) fungi enhances plant resistance to abiotic and biotic stressors and finally plant growth. However, little is known about the effect of AM on isoprenoid foliar and root content. In this study we tested whether the AM symbiosis affects carbon resource allocation to different classes of isoprenoids such as the volatile nonessential isoprenoids (monoterpenes and sesquiterpenes) and the non-volatile essential isoprenoids (abscisic acid, chlorophylls and carotenoids). By subjecting the plants to stressors such as drought and to exogenous application of JA, we wanted to test their interaction with AM symbiosis in conditions where isoprenoids usually play a role in resistance to stress and in plant defence. Root colonization by AM fungi favoured the leaf production of essential isoprenoids rather than nonessential ones, especially under drought stress conditions or after JA application. The increased carbon demand brought on by AM fungi might thus influence not only the amount of carbon allocated to isoprenoids, but also the carbon partitioning between the different classes of isoprenoids, thus explaining the not previously shown decrease of root volatile isoprenoids in AM plants. We propose that since AM fungi are a nutrient source for the plant, other carbon sinks normally necessary to increase nutrient uptake can be avoided and therefore the plant can devote more resources to synthesize essential isoprenoids for plant growth.     

Fertilization and forb:graminoid ratio affect arbuscular mycorrhiza in seedlings but not adult plants of Plantago lanceolata

Aims

Nutrients play a key role in arbuscular mycorrhizal (AM) symbiosis. We quantified the response of AM symbiosis of seedlings and adult plants of Plantago lanceolata to fertilization under field conditions in managed grasslands differing in nutrient availability and soil moisture.

Methods

The AM symbiosis was measured as the total extent of AM fungal colonization and frequency of arbuscules or vesicles, and as the relative proportions of morphotypes. We further examined the effects of the surrounding vegetation upon AM symbiosis.

Results

Fertilization decreased total AM colonization and relative arbuscular frequency of the whole mycorrhizal community and of Acaulospora and “fine endophyte” morphotypes in seedling roots, but it had no effect upon the mycorrhiza in adult plants. The decline in arbuscular frequency in seedling roots due to fertilization was greater at the sites with higher nutrient availability and lower N:P ratio. Seedlings surrounded by more forbs had a greater total AM colonization and higher vesicular frequency.

Conclusions

Increased nutrient availability in the initial stages of seedling development has a prominent effect upon AM symbiosis development, but these effects seem to diminish over the long term, as evidenced by the results obtained for adult plants and from the limited effects of parameters characterizing long-term nutrient availability.     

Extraction methods and chemical standardization of botanicals and herbal preparations

Botanicals and herbal preparations are medicinal preparations, containing a single or two or more medicinal plants. The focus of this review paper is on the analytical methodologies, which included the combination of sample preparation tools and chromatographic techniques for the chemical standardization of marker compounds or active ingredients in botanicals and herbal preparations. The common problems and key challenges in the chemical standardization of botanicals and herbal preparations were discussed. As sample preparation is the most important step in the development of analytical methods for the analysis of constituents present in botanicals and herbal preparations, the strength and weakness of different extraction techniques are discussed. For the analysis of compounds present in the plant extracts, the applications of common chromatographic techniques, such as HPLC, CE, HRGC/MS, HPLC/MS and HPLC/MS/MS are discussed. The strength, weakness and applicability of various separation tools are stated. Procedures for the identification of marker or active compounds in plant extracts, using HPLC/MS, were proposed. Finally, the effects of batch-to-batch variation of the medicinal plants are investigated and discussed.     

块菌人工栽培现状及菌根苗培育方法的研究进展

松露(块菌)是名贵的地下真菌,因其独特的香味和口感享誉全球,具有重要的经济价值、食药用价值和生态价值。块菌必须与宿主植物共生形成外生菌根后才能形成子实体(子囊果)。由于块菌具有较高的经济价值而野生块菌资源被严重破坏,以块菌菌根苗制备技术为基础的人工栽培手段受到广泛关注。本文以块菌菌根苗培育为切入点,阐述了块菌资源面临的较大威胁、人工栽培手段的进步和人工种植园的快速发展,通过综述菌根苗培育前对共生组合的选择,菌根苗培育时使用的基质、接种剂、培养方式、与其他生物间的互作,以及菌根苗培育后进行检测的方法等研究进展,为外生菌根食用菌的菌根苗培育技术和人工栽培推广提供参考。     

添加物及植物组合对瞿麦幼苗铅吸收、生长及品质的影响

通过盆栽试验研究了接种丛枝菌根真菌(AM真菌)、种植共生植物(三叶草)、添加重金属螯合物EDTA和磷肥磷酸钙对铅污染下瞿麦生长和品质的影响,为科学种植中药材提供理论依据.结果表明: 接种AM真菌可以显著抑制铅的吸收(P＜0.05),促进根部发育,使根冠比增大,且活性成分累积最多,大黄素含量为6.5 mg·g^-1;与三叶草共生后,抑制铅吸收的效果不佳且药材品质下降,大黄素含量低于对照组,降至3.2 mg·g^-1.但在AM真菌共同参与后瞿麦的生长量和活性成分有所增加,铅含量达到最低,低至1.3 mg·g^-1;添加重金属螯合剂会使瞿麦生长量下降并促进根部对铅的吸收,铅含量最高可达340.0 mg·g^-1;磷酸钙可固定土壤中其他重金属元素,故更适宜在复合型污染时使用.综合考虑,在保护中药材安全、品质方面AM真菌具有良好的应用价值.