植物挥发物代谢工程在改良香气品质和植物防御中的应用

挥发物次生代谢在植物繁殖、植物防御和改良食物品质方面发挥着重要作用。近年来,随着参与挥发物生物合成的基因和酶类的鉴定以及代谢途径和调控机理等研究的不断发展和深入,挥发物代谢工程已经具备较高的可行性。应用代谢工程改良花、果实的香气品质以及提高植物防御能力的研究成效显著。主要介绍了这些方面的最新进展,同时也讨论了植物挥发物代谢工程应用存在的问题和挑战以及研究思路。     

Bacteria with ACC deaminase can promote plant growth and help to feed the world

To feed all of the world's people, it is necessary to sustainably increase agricultural productivity. One way to do this is through the increased use of plant growth-promoting bacteria; recently, scientists have developed a more profound understanding of the mechanisms employed by these bacteria to facilitate plant growth. Here, it is argued that the ability of plant growth-promoting bacteria that produce 1-aminocyclopropane-1-carboxylate (ACC) deaminase to lower plant ethylene levels, often a result of various stresses, is a key component in the efficacious functioning of these bacteria. The optimal functioning of these bacteria includes the synergistic interaction between ACC deaminase and both plant and bacterial auxin, indole-3-acetic acid (IAA). These bacteria not only directly promote plant growth, they also protect plants against flooding, drought, salt, flower wilting, metals, organic contaminants, and both bacterial and fungal pathogens. While a considerable amount of both basic and applied work remains to be done before ACC deaminase-producing plant growth-promoting bacteria become a mainstay of plant agriculture, the evidence indicates that with the expected shift from chemicals to soil bacteria, the world is on the verge of a major paradigm shift in plant agriculture.     

植物次生代谢基因工程

植物次生代谢基因工程,是利用基因工程技术对植物次生代谢途径的遗传特性进行改造,进而改变植物次生代谢产物。植物次生代谢基因工程的出现是人类对次生代谢途径的深入了解和分子生物学向纵深发展的结果,同时它又促进了次生代谢分子生物学的发展。调控因子的应用和多基因的协同转化为植物次生代谢基因工程拓宽了思路。从次生代谢图谱、植物基因工程策略和植物转基因方法等方面对植物次生代谢的基因工程研究进展做一简要概述。     

Targeted protein accumulation promoted by autoassembly and its recovery from plant cells

The expression of a fusion protein formed between the avian infectious bronchitis virus M protein and the bacterial enzyme beta-glucuronidase (GUS) in plants promotes the formation of new organization of the endoplasmic reticulum in tobacco plants. This unusual organization of the membranes, never present in nontransformed plants, has been explained by the oligomerization of the GUS domains of the IBVM-GUS fusion proteins. These specific organized membranes could have broad implications for biotechnology since their formation could be used as a mechanism for retaining and accumulating resident proteins in specific and discrete membrane compartments. In this study, we have shown that the unusual organization of native membranes due to overexpression of the IBVM-GUS fusion gene in tobacco transgenic plants and calli is present at higher levels in plant cell suspensions than in plant tissues. In these cell suspensions, IBVM-GUS protein was continuously synthesized and accumulated throughout the cell culture. An enrichment of the chimeric IBVM-GUS protein corresponding to a five-fold increase in the microsomal fractions was achieved and the GUS enzyme did not show any modification on enzyme kinetics. However, the GUS activity could be differentially distributed in the fractions eluted at different pH suggesting differences in the surface topography of histidine residues for this recombinant GUS.     

Ri质粒在植物科学中应用的新进展

本文综述了发根农杆菌Ｒｉ质粒在植物学理论研究、有用植物次生代谢物生产、植物品种改良及植物栽培四个方面应用的最新进展。     

Comparative population studies of threePieris butterflies,P. rapae,P. melete andP. napi,living in the same area

The adult populations of three Pieris butterflies, P. rapae, P. melete and P. napi, were studied in an area of their coexistence throughout the flight seasons by using the mark-and-recapture method. The study area, about 3×1.5 km, was set up in a farm village surrounded by the mountainous area in Inabu, Aichi Prefecture. The habitats were qualified by the four factors, i. e., oviposition plants, adult nector plants, roosting-sites and light conditions. Between P. rapae and P. napi, there were sharp differences with regards to overall habitat preferences. P. melete had the widest preferences for all the habitat resources, which overlapped greately with requirements of P. rapae and P. napi. P. melete and P. rapae showed similar preferences for oviposition plants, but the former preferred shaded habitats while the latter preferred sunny places. P. melete and P. napi, having similar preferences for shaded situations, showed differences in the preferences for oviposition plants. Moreover, three species of Pieris were different in their preferences for adult nector plants. Thus, they were more likely to partition habitat resources rather than competing for them. The habitat structures of each species in respect of time, space and stability to weather changes were much different each other in the same area. The habitat of P. rapae was temporary, localized and unstable. While, that of P. melete was more permanent, widespread and stable than that of P. rapae. P. napi seemed to live in the intermediate habitat, i. e., permanent, localized and stable one.     

关于IUCN和WWF联合植物保护研究计划工作的成就和今后的任务

植物是人类和动物生活所必需,由于缺乏长远规划的目标,无计划的滥用已导致许多植物灭绝或陷入濒临灭绝的境地。为此,IUCN—WWF联合建立了“植物保护研究计划”,并把其列入他们各自工作的重点。主要工作内容有下列各项:1)传播信息宣传群众;2)建立必要的植物保护的工作条件:3)植物遗传资源的保护:4)野生经济植物的保护:5)加强植物园开展植物保护的工作条件:6)促进植物丰富的国家开展植物保护工作。     

Plant cell biology 150 years after Matthias Schleiden

Summary Exactly 150 years after the publication of the so-called cell theory the role of the botanist Schleiden has been reconsidered. It is emphasized that the study of plant sexual reproduction systems has contributed considerably to the development of the general cell concept. Recent examples show that 150 years later plant cell biology is flourishing, not least because of the great impact of the increasing use of plant reproductive cells and organs.     

植物实验生殖生物学与生殖细胞工程:现在与未来

植物实验生殖生物学是植物实验胚胎学发展的新阶段,其主要特征为操作技术水平的提高与多学科综合性研究的加强。花粉原生质体、生殖细胞、精子,胚囊、卵细胞的操作、雌雄配子体外融合、配子-体细胞杂交等,代表了当前的主要研究趋势。实验生殖生物学与基因工程相结合,开辟了植物生殖工程新技术领域的前景。对生殖工程的意义与内容提出了轮廓设想。     

植物蛋白oleosin及其在植物基因工程中的应用

Oleosin是一类特殊贮藏蛋白,主要在植物种子特异表达,覆盖于油体表面,在油体发生到分解消失过程中起着重要的生物学作用,在植物基因工程研究中有重要的应用价值。介绍oleosin的分类、分布、基本组成、结构与功能、oleosin基因及其表达,讨论oleosin在植物基因工程中的应用 。     

甜茶组织培养研究

甜茶的茎段和实生苗培养在MS基本培养基中,研究植物激素对器官形成的影响,试验结果表明BA0.5-2.0毫克/升明显促进芽的形成和增殖;而对照(基本培养基)无形成芽。细胞分裂素对芽的起动是必需的。BA0.5-2.0毫克/升和GA_s1.0毫克/升配合使用,对茎段形成芽和增殖反而减少,但形成的苗较高和幼叶生长良好。通过继代培养,可繁殖大量小苗,它揭示出同一块外植体生长出许多小植株的可能,将无根苗转入含有IBA0.25-0.50毫克/升的1/2MS培养基中,能诱导生根,发展完整植株。试管苗移植土壤中,获得成功,幼苗生长良好。     

电子计算机在植物学中的应用

电子计算机技术的广泛应用和蓬勃发展是本世纪科学技术的卓越成就之一,它将逐渐成为各项科学技术现代化的一个重要标志。电子计算机从1946年问世以来,在近四十年内迅速经历了三代更新。目前正处在第     

ethylene receptor 1 (etr1) Is Sufficient and Has the Predominant Role in Mediating Inhibition of Ethylene Responses by Silver in Arabidopsis thaliana

Ethylene influences many processes in Arabidopsis thaliana through the action of five receptor isoforms. All five isoforms use copper as a cofactor for binding ethylene. Previous research showed that silver can substitute for copper as a cofactor for ethylene binding activity in the ETR1 ethylene receptor yet also inhibit ethylene responses in plants. End-point and rapid kinetic analyses of dark-grown seedling growth revealed that the effects of silver are mostly dependent upon ETR1, and ETR1 alone is sufficient for the effects of silver. Ethylene responses in etr1-6 etr2-3 ein4-4 triple mutants were not blocked by silver. Transformation of these triple mutants with cDNA for each receptor isoform under the promoter control of ETR1 revealed that the cETR1 transgene completely rescued responses to silver while the cETR2 transgene failed to rescue these responses. The other three isoforms partially rescued responses to silver. Ethylene binding assays on the binding domains of the five receptor isoforms expressed in yeast showed that silver supports ethylene binding to ETR1 and ERS1 but not the other isoforms. Thus, silver may have an effect on ethylene signaling outside of the ethylene binding pocket of the receptors. Ethylene binding to ETR1 with silver was ～30% of binding with copper. However, alterations in the K(d) for ethylene binding to ETR1 and the half-time of ethylene dissociation from ETR1 do not underlie this lower binding. Thus, it is likely that the lower ethylene binding activity of ETR1 with silver is due to fewer ethylene binding sites generated with silver versus copper.     

中国植物病毒研究40年

本文综述我国自20世纪70年代以来在植物病毒学领域的研究概况,较全面地介绍各个时间段具有代表性的研究成果,并对国内高水平的植物病毒学研究室及其研究领域进行了较详细的介绍。     

Tissue culture of Alhagi camelorum – a legume of high regenerative capacity

Alhagi camelorum cultures provide a system with a high propensity for plantlet regeneration from root, hypocotyl, stem, and leaf explants. Excluding leaf explants, all explants regenerate to form shoot-buds on a simple basal medium suggesting a differential morphogenic potential of different parts of the same plant. All parts of the plant including leaves, form shoot-buds on cytokinin-containing media which markedly promote shoot-bud differentiation, alone or in combination with indoleacetic acid or naphthaleneacetic acid. Rooting occurs on media containing indoleacetic acid and naphthaleneacetic acid. 2, 4-Dichlorophenoxyacetic acid is inhibitory for differentiation and induces callusing. Callus induced on benzylaminopurine and 2,4-dichlorophenoxyacetic acid differentiates to form shoot-buds on transfer to cytokinin-containing medium. Upon transfer to basal medium shoots produce roots. Plants have been transferred to soil.     

Bioactivity of secondary metabolites and thallus extracts from lichen fungi

Fungal secondary compounds and total extracts are known to affect growth of bacteria, fungi, and plants. This study tested the effects of purified compounds and total extracts from three lichens on the growth of two plant pathogens, Ophiostoma novo-ulmi ssp. americana and Sclerotinia sclerotiorum. Usnic acid showed no reduction in relative growth rates (RGR), whereas vulpinic acid reduced RGR for both fungi and atranorin reduced RGR of S. sclerotiorum only. However, purified vulpinic acid showed stronger effects than total extracts on fungal growth. The results suggest that these lichens show further promise as a source for bioactive compounds against fungi.     

A comparison of the LDL-cholesterol lowering efficacy of plant stanols and plant sterols over a continuous dose range: results of a meta-analysis of randomized, placebo-controlled trials

Purpose

To determine if plant stanols and plant sterols differ with respect to their low-density lipoprotein cholesterol (LDL-CH) lowering efficacies across a continuous dose range.

Methods

Dose-response relationships were evaluated separately for plant stanols and plant sterols and reductions in LDL-CH, using a first-order elimination function.

Results

Altogether, 113 publications and 1 unpublished study report (representing 182 strata) complied with the pre-defined inclusion and exclusion criteria and were included in the assessment. The maximal LDL-CH reductions for plant stanols (16.4%) and plant stanol ester (17.1%) were significantly greater than the maximal LDL-CH reductions for plant sterols (8.3%) and plant sterol ester (8.4%). These findings persisted in several additional analyses.

Discussion and conclusions

Intakes of plant stanols in excess of the recommended 2 g/day dose are associated with additional and dose-dependent reductions in LDL-CH, possibly resulting in further reductions in the risk of coronary heart disease (CHD).     

植物G蛋白与植物防卫反应

近年来, 植物G蛋白(包括异三聚体G蛋白和小G蛋白)的存在及其信号调控途径已经成为人们研究细胞信号转导过程的热点问题。从多种植物细胞中相继分离克隆出多个与动物G蛋白同源的编码植物G蛋白的基因, 并且植物G蛋白的种类和数量有其独特性。植物G蛋白在植物细胞跨膜信号转导中发挥重要的作用, 参与多种生命活动的调控。本文主要综述了植物G蛋白参与植物防卫反应调节作用的研究进展。     

Carbon dioxide fluxes in a spatially and temporally heterogeneous temperate grassland

Landscape position, grazing, and seasonal variation in precipitation and temperature create spatial and temporal variability in soil processes, and plant biomass and composition in grasslands. However, it is unclear how this variation in plant and soil properties affects carbon dioxide (CO₂) fluxes. The aim of this study is to explore the effect of grazing, topographic position, and seasonal variation in soil moisture and temperature on plant assimilation, shoot and soil respiration, and net ecosystem CO₂ exchange (NEE). Carbon dioxide fluxes, vegetation, and environmental variables were measured once a month inside and outside long-term ungulate exclosures in hilltop (dry) to slope bottom (mesic) grassland throughout the 2004 growing season in Yellowstone National Park. There was no difference in vegetation properties and CO₂ fluxes between the grazed and the ungrazed sites. The spatial and temporal variability in CO₂ fluxes were related to differences in aboveground biomass and total shoot nitrogen content, which were both related to variability in soil moisture. All sites were CO₂ sinks (NEE>0) for all our measurments taken throughout the growing season; but CO₂ fluxes were four- to fivefold higher at sites supporting the most aboveground biomass located at slope bottoms, compared to the sites with low biomass located at hilltops or slopes. The dry sites assimilated more CO₂ per gram aboveground biomass and stored proportionally more of the gross-assimilated CO₂ in the soil, compared to wet sites. These results indicate large spatio-temporal variability of CO₂ fluxes and suggest factors that control the variability in Yellowstone National Park.