Le risorse genetiche vegetali. I. Principi,realtà, problemi

Abstract

Plant genetic resources. I. The problem of the conservation of plant genetic resources emerges from the examination of the consequences of the genetic erosion and of the destruction of genetic variability, which provoke decline and disappearance of plant species, of agricultural value too.

Information are given on species and primitive or local varieties desappeared or threatened by destruction, on the emergency situation already existing in various areas, including also centres of origin and diversification, and on the risks of a plant breeding work manipulating a reduced genetic basis.

Thus, it is crucial to collect and maintain an abundant germplasm of the main crops, as well as of those species of minor agricultural importance. It is wise also to pay attention to plant species of potential value as new food crops or as sources for industrial pharmaceutical or pesticide products or other products with specific chemical properties.

Finally, the author underlines the urgent need, for the future progress of agriculture and for the benefit of the mankind, to safeguard plant genetic resources, which must be considered as essential part of the problem of the conservation of the nature and of its resources.     

Identification and genetic relationships among nine Albizzia species based on morphological and molecular markers

Abstract

Identifying germplasm is an important component for efficient and effective management of plant genetic resources. This investigation was undertaken for the identification and analysis of genetic variation within 9 species of Albizzia through 33 morphological parameters, and 15 Random Amplified Polymorphic DNA (RAPD) and 17 Inter Simple Sequence Repeat (ISSR) primers. The use of selected RAPD and ISSR primers generated a total of 163 and 201 amplified DNA fragments, respectively. High frequencies of polymorphism, 95.05% for RAPD and 96.02% for ISSR, were detected. Statistical approaches were employed to construct genetic relationships by RAPD, ISSR and morphological analysis. Cluster analysis by the unweighted pair-group method (UPGMA) of Nei's similarity generated dendograms with similar topology that gave a better reflection of the diversity and affinities between species. These molecular results were comparable to main morphological characteristics. The correlation matrices generated by RAPD and ISSR markers were highly correlated (r = 0.843 at p = 1.0), thereby indicating congruence between these two marker systems. Both morphometric data and molecular markers have the potential to analyse genetic variation among the nine species of Albizzia, thus providing a major input for management strategy of plant genetic resources.     

Linear landscape elements in an Austrian viticultural landscape have limited effects on spatial patterns of plant genetic diversity

Background: The Wachau region along the river Danube in eastern Austria represents one of central Europe's hotspots of plant and animal species diversity. One of the typical landscape elements is vineyards, mostly established as linear elements on terraces along the slopes, with a characteristic and species-rich flora and fauna on terrace slopes lying between the cultivated terraces.

Aims: We addressed the question of how the genetic variation of four plant species of open grassland vegetation types is distributed. We asked if levels and distribution of genetic diversity of the plant species Aster amellus, Gentianella aspera, Pulsatilla grandis, and Stachys recta were correlated with geographic distances along the terrace slopes.

Methods: The dominant inherited molecular marker system random amplified polymorphic DNA (RAPD ) was used to estimate and compare the distribution of genetic diversity of the four selected species.

Results: We found only low levels of correlation of the distribution of genetic variation with linear geographic patterns and obtained indirect evidence for high levels of gene flow between adjacent terrace slopes.

Conclusions: We found that genetic diversity parameters of the four target species did not mirror the pattern of linear landscape elements, indicating that gene flow acts efficiently against the linear distribution of genetic variation.     

Patterns and origin of intraspecific functional variability in a tropical alpine species along an altitudinal gradient

Background : Intraspecific functional variability (IFV) along altitudinal gradients is a powerful proxy to infer the responses of plants to abrupt environmental changes. We envisage that IFV shows distinctive patterns in tropical and extratropical alpine regions.

Aims : To characterise the patterns and explore the origin of IFV in a tropical alpine species in a context of upward range extension.

Methods : We examined variations in a series of plant functional traits in Lasiocephalus ovatus, inside and outside a nurse plant along a 600 m altitudinal gradient in the Ecuadorian Andes, and we studied its genetic variability.

Results : More conservative traits were developed at higher elevation, in contrast to extratropical alpine plants, which commonly develop opportunistic traits in response to late snowmelt close to their upper altitudinal limit. The presence of nurse cushions did not alter this trend. Increasing genetic distance along the gradient suggested that IFV might be partly genetically induced.

Conclusions : Our data combined with existing literature in tropical alpine environments lead the way to a stimulating scientific challenge: determining if patterns of plant altitudinal distribution in tropical alpine areas in response to climate change are predictable from patterns described in extratropical alpine areas.     

濒危药用植物掌裂兰根部内生真菌和根际土真菌多样性分析

【背景】植物内生真菌对宿主植物促生长、抗旱和增强抗病能力等方面有着重大的研究和利用价值,尤其对兰科植物的生长起到重要的作用。【目的】通过对掌裂兰根部内生真菌和根际土真菌多样性进行系统分析,掌握掌裂兰根部内生真菌与根际土真菌群落结构,为进一步探究掌裂兰植物与真菌共生规律提供参考。【方法】采用Illumina MiSeq高通量测序技术分析掌裂兰根部内生真菌和根际土真菌多样性。【结果】掌裂兰根部内生真菌隶属于7门89属,优势菌属为瘤菌根菌属(Epulorhiza)(16.93%)、头梗霉属(Cephaliophora)(10.41%)、酵母属(Saccharomyces)(5.73%)、角担菌属(Ceratobasidium)(5.32%)和镰刀菌属(Fusarium)(5.12%),其中Epulorhiza和Ceratobasidium为兰科植物菌根真菌;根际土真菌隶属于11门269属,优势菌属为镰刀菌属(Fusarium)(8.09%)、丛赤壳属(Neonectria)(6.79%)、Plectosphaerella (3.39%)和被孢霉属(Mortierella)(3.01%)。通过...     

哈尔滨市三级医院EICU医疗资源配置现状调查

目的 了解哈尔滨市三级医院急诊重症监护室医疗资源配置现状,找出重症监护室存在的问题并提出相应对策。 方法 通过问卷调查方式获得2010—2012年间哈尔滨市三级医院急诊重症监护室床位、人员、设备等医疗资源配置情况的相关数据并进行统计分析。结果 研究数据显示,哈尔滨市5所三级医院的急诊重症监护室存在床位使用率不高、人员配比欠合理、人员工作强度过大、医疗设备配置不均衡等问题,严重制约了急诊重症监护室的发展。结论 哈尔滨市的急诊重症监护室取得了一定的发展,但在医疗资源配置方面仍存在一些问题;通过提高床位使用率、增加医护人员数量、调整人员结构、完善设备设施等手段可进一步优化医疗资源配置,提高急诊重症监护室的整体效率,满足学科发展需要。     

Effect of neighbour presence and soil volume on the growth of Andropogon gerardii Vitman

Background: Theory predicts that plants can reduce their fitness in the presence of neighbours by allocating resources to root growth, in order to pre-empt resource capture. A number of studies that have tested this idea have done so by using experiments where neighbour presence is confounded with soil volume.

Aims : To avoid confounding effects of neighbour presence and soil volume we adjusted these variables independently from one another.

Methods: We grew Andropogon gerardii with and without neighbours, holding soil volume available to each plant constant, and compared plant performance with a treatment where both neighbour presence and soil volume were varied. We also grew plants with a quarter of the soil volume but four times the nutrient concentration to determine if changes in plant growth in response to soil volume are caused by access different levels of soil resources.

Results: We found no evidence that plants adjust root growth to the presence of neighbour roots alone. We did, however, find a significant reduction in plant growth when soil volume was reduced. The reduction was overcome by increasing nutrient concentrations in the growth media.

Conclusions: Our results suggest the effects of soil volume on plant growth are mainly due to changes in nutrient availability.     

药用植物刺山柑不同部位细菌群落结构及其多样性

【目的】研究传统药用植物刺山柑（Capparis spinosa L.）不同部位细菌群落结构、物种组成和多样性特征,为药用植物微生物资源的开发及微生物与宿主互作提供理论依据。【方法】本研究以刺山柑地上部植物组织（果实、茎）和地下部土壤（根际土壤、非根际土壤）为研究材料,采用高通量测序技术分析刺山柑不同部位细菌的16S rRNA基因多样性,比较其细菌群落结构和物种组成特征。【结果】刺山柑4种样本共获得的3 649个操作分类单元（operational taxonomic unit,OTU）,属于34门、88纲、248目、464科和1 051属。土壤样本的细菌多样性大于植物组织,细菌群落多样性以根际土壤、非根际土壤、茎和果实的顺序逐渐降低,果实内生细菌群落多样性始终最低,显著低于根际土壤。不同部位相对丰度较高的细菌门如下：植物组织中以变形菌门为主,根际土壤中为变形菌门和放线菌门,非根际土中为厚壁菌门和放线菌门。无色杆菌属（Achromobacter）、欧文氏菌属（Erwinia）、肠球菌属（Enterococcus）、微小杆菌属（Exiguobacterium）、乳杆菌属（Lactobacillus）和克雷伯氏菌属（Klebsiella）主要存在于刺山柑植物组织中。游动球菌属（Planomicrobium）、库克菌属（Kocuria）、类芽孢杆菌属（Paenibacillus）、链霉菌属（Streptomyces）、微枝形杆菌属（Microvirga）和节杆菌属（Arthrobacter）主要分布于土壤中。β多样性分析结果表明,刺山柑植物组织和土壤的细菌群落结构具有显著差异,同类型样本的细菌群落结构相似。【结论】刺山柑土壤样本中细菌群落的多样性和丰富度均高于植物组织,刺山柑不同部位的细菌群落组成不同。本研究对刺山柑不同部位细菌群落结构进行了初步分析,鉴定了各部位细菌群落中的核心菌群,为以后挖掘刺山柑的功能研究和利用提供了准确的微生物信息。     

一株污水源多重耐药大肠杆菌的耐药性检测及全基因组测序分析

【背景】水体环境分布广、流动性强,是耐药菌和耐药基因传播的主要媒介。【目的】了解北方污水厂大肠杆菌携带的耐药基因及可移动遗传元件情况。【方法】从北方污水厂筛选出一株多重耐药大肠杆菌,通过药敏试验进行耐药性检验,采用96孔板法测定菌株的最小抑菌浓度,利用酶标仪探究亚抑菌浓度抗生素对菌株生长的影响,并对菌株进行全基因组测序,对其携带的耐药基因及可移动遗传元件进行预测。【结果】大肠杆菌WEC对四环素、环丙沙星、诺氟沙星和红霉素具有耐药性,亚抑菌浓度的四环素、环丙沙星和诺氟沙星能够延缓或抑制菌株的生长。WEC菌株的基因组中包含一条大小为4 782 114 bp的环状染色体和2个大小分别为60 306 bp (pWEC-1)和92 065 bp (pWEC-2)的环状质粒。菌株共携带129个耐药基因,其中128个位于染色体上,在染色体上预测到原噬菌体、基因岛及插入序列的存在,部分可移动遗传元件携带有耐药基因。质粒pWEC-1中无耐药基因,pWEC-2含有1个耐药基因,在质粒基因组中预测到原噬菌体和插入序列。【结论】污水源大肠杆菌WEC是一株多重耐药菌株,其基因组中携带耐药基因和多种可移动遗传元件...     

Agrobacterium as a tool for gene transfer in woody species: The state of the art and practical perspectives. A review

Abstract

The Agrobacterium-mediated ability to transfer genes into organisms without sexual crossing provides breeders with new opportunities to improve the efficiency of plant production. Gene transfer offers advantages over classical genetic manipulation since plants are improved without disruption of the integrity of their genomes. Several useful genes isolated from microrganisms and affecting pest resistance, rooting ability, hormonal metabolism etc., are now available. These genes can be easily cloned into suitable Ti and Ri derived plasmid vectors and transferred into woody species. The scarce ability of most fruit trees to regenerate the whole plant from in vitro-cultured cells remains the main obstacle to a wider use of gene transfer technology.     

一株具有防病促生功能的贝莱斯芽孢杆菌SF327

【目的】筛选植物根际促生贝莱斯芽孢杆菌,分析菌株的生防潜力和全基因组特征。【方法】通过温室小青菜促生试验以及植物益生表型的分析,明确具有促生功能的菌株SF327。用滤纸片法测定菌株SF327对5种植物病原真菌以及4种植物病原细菌的拮抗活性。通过大田喷雾接种的方式评价菌株SF327对水稻白叶枯病的防治潜力。利用antiSMASH分析预测菌株SF327产生的二次代谢产物。通过比较基因组分析SF327与2株植物根际益生贝莱斯芽孢杆菌的代表性菌株FZB42和SQR9的亲缘关系、核心基因以及二次代谢产物合成基因簇。【结果】菌株SF327能够产生生长素吲哚-3-乙酸,是一株有益的根围促生菌;对稻瘟病菌、黄瓜枯萎病菌、辣椒疫霉菌、橡胶树胶孢炭疽菌、尖孢炭疽病菌都具有明显的拮抗作用;也具有防治水稻白叶枯病的生防潜力。菌株SF327基因组全长4.08 Mb,GC含量为46.49%,共编码4 033个基因,含有13个潜在的次生代谢产物编码基因簇,不含有质粒。SF327与FZB42和SQR9具有较近的亲缘关系,有87%以上的核心基因相同,但与SQR9的亲缘关系较近。【结论】B. velezensis SF327是一株具有宽广拮抗谱的多功能菌株,具有较好的生防应用潜力。     

Genetic diversity of Helosciadium repens (Jacq.) W.D.J. Koch (Apiaceae) in Germany,a Crop Wild Relative of celery

• Helosciadium repens (Jacq.) W.D.J. Koch is threatened by genetic erosion. It is a Crop Wild Relative (CWR) of celery and celeriac and a potentially valuable genetic resource for plant breeding. The objective of this study was the analysis of distribution of genetic diversity with a set of selected populations in Germany. The results of the genetic analysis and data obtained during the site visits were used to identify a subset which was chosen to best represent the genetic diversity of H. repens in Germany. The chance of long‐term conservation by securing the identified populations in genetic reserves is distinctly possible.
• Seven hundred and fifteen individuals from 27 sites were assessed using six simple sequence repeat markers. Discriminant analysis of principal components was used to identify six clusters of genetically similar individuals. The complementary compositional genetic differentiation Δj was calculated to designate a subset of populations chosen to best represent the overall genetic diversity. Entry 18R (Δ_18R = 0.2498) represented its pooled remainder the best, while entry 22R (Δ_22R = 0.4902) differed the most from its complement.
• Based on the results of the genetic analysis and information regarding the current conservation status, 14 most appropriate wild populations for potential genetic reserve were identified. The used markers display a low level of genetic variation between the analyzed populations, and a split between Northern and Southern populations was observed.
• CWR species are essential genetic resources for plant breeding and food security. However, 11.5% of the European CWRs are threatened. Therefore, it is of utmost importance to determine their genetic compositions. These insights will provide the fundamental basis for making crucial decisions concerning future conservation strategies for H. repens.

     

定殖植物根内和根围放线菌的分离鉴定及其体外抑菌促生效应

【目的】旨在分离、筛选并鉴定体外具抑菌促生作用的定殖于植物根内和根围的放线菌,以期丰富放线菌种质资源,为研制植物病害生防菌剂提供技术依据。【方法】采用稀释涂布平板法分离盐碱地、湿地、工业污染土壤中优势植物根内及其根围中的放线菌;通过平板对峙试验筛选具有抑菌效应的菌株,进而采用Salkowski比色法、CAS平板检测法和无氮源培养法进一步检测抑菌菌株的促生作用;通过形态观测、生理生化特性检测及16SrRNA基因序列分析鉴定菌种。【结果】共分离到链霉菌属(Streptomyces)、诺卡氏菌属(Nocardia)和小单孢菌属(Micromonospora) 3属共283株定殖于植物根内和根围的放线菌,3个采样地中湿地数量最多,均为根围土根内;其中链霉菌属占总数的77%,可分为10个类群。经筛选获得7株抑菌活性和促生效应较强的菌株,其中菌株H6-1抑菌效应最大,其无菌发酵液对尖孢镰刀菌(Fusariumoxysporum)、禾谷镰刀菌(Fusariumgraminearum)、灰葡萄孢菌(Botrytis cinerea)、立枯丝核菌(Rhizoctoniasolani)、轮纹大茎点霉(Macrophomakawatsukai)和瓜类炭疽菌(Colletotrichumorbiculare)的抑制率分别为32.3%、42.6%、48%、72.2%、58.1%和60.5%;而D11-4菌株的促生作用最强,能产吲哚乙酸(22.3 mg/L)、产铁载体(晕圈直径25.2 mm)和固氮。经鉴定这7株放线菌是吸水链霉菌变种(Streptomyces angustmyceticus) H4-6、娄彻氏链霉菌(Streptomyces rochei) S2-2、浑圆链霉菌(Streptomycesglobosus)H6-1、(Streptomycesiakyrus)GD8-4、波卓链霉菌(Streptomyces bottropensis) GH8-6、(Streptomyces paradoxus) H8-2和(Streptomyces coralus) D11-4。【结论】三个生境中定殖于植物根内和根围的放线菌类群丰富且所筛选获得的7株放线菌具有生防潜力,值得进一步研发。     

The origin and distribution of Senecio cambrensis rosser in Edinburgh

Background: Range expansion often results in colonisation bottlenecks that should both deplete genetic diversity and increase genetic differentiation towards the margins of a species' geographic distribution.

Aims: We tested whether genetic differentiation increased among populations of the annual plant Mercurialis annua after its colonisation of the Iberian Peninsula from Morocco. Previous work showed that this colonisation resulted in a decrease of phenotypic and genetic diversity from the core in North Africa towards the distribution margins of M. annua in north-eastern and north-western Spain.

Methods: Seeds were sampled from 20 populations located across the hexaploid range of M. annua. Patterns of phenotypic and genetic differentiation among experimentally grown populations were analysed and compared between the Iberian Peninsula and North Africa.

Results: The level of phenotypic and genetic differentiation among populations in the expanded range of the Iberian Peninsula was similar to that in the core range in North Africa.

Conclusions: Our findings imply that the observed effects of range expansion on genetic differentiation may be independent of the effects on genetic diversity. They point to the importance of taking both historic and contemporary processes of migration into account when predicting the results of range expansion.     

Genetic and phenotypic variation,dispersal limitation and reproductive success in the invasive herb Eschscholzia californica along an elevation gradient in central Chile

Background: Reductions of genetic diversity and phenotypic changes in invasive plants are often observed to occur at high elevations. Genetic/phenotypic changes of invasive plants along elevation help to understand mechanisms of the presumed resistance of mountain ecosystems to invasion.

Aims: To assess genetic variability and phenotypic plasticity along an elevation gradient of Eschscholzia californica in the Andes, central Chile.

Methods: Eleven microsatellites were used to describe the genetic structure and the allelic diversity individuals, distributed at three elevations and two sites. We assessed the number of flowers per plant, floral biomass, leaf area, number of leaves, vegetative biomass and plant height of plants at each elevation.

Results: Genetic diversity as genetic structure did not decrease with elevations. Plant height and flower numbers decreased while leaf number and vegetative biomass increased with elevation. The ratio of the number of flowers to vegetative biomass, decreased significantly with elevation.

Conclusions: Strong genetic differences among elevations and similar genetic diversity along elevation do not suggest dispersal limitation to higher elevation. Reduction of reproductive and vegetative traits concomitantly with an increase of the reproductive cost suggests reproductive stress with increasing elevation, reducing the invasiveness of this species to higher elevation.     

Molecular Analysis of In Vitro Shoot Organogenesis

Shoot organogenesis is one of the in vitro plant regeneration pathways. It has been widely employed in plant biotechnology for in vitro micropropagation and genetic transformation, as well as in study of plant development. Morphological and physiological aspects of in vitro shoot organogenesis have already been extensively studied in plant tissue culture for more than 50 years. Within the last ten years, given the research progress in plant genetics and molecular biology, our understanding of in vivo plant shoot meristem development, plant cell cycle, and cytokinin signal transduction has advanced significantly. These research advances have provided useful molecular tools and resources for the recent studies on the genetic and molecular aspects of in vitro shoot organogenesis. A few key molecular markers, genes, and probable pathways have been identified from these studies that are shown to be critically involved in in vitro shoot organogenesis. Furthermore, these studies have also indicated that in vitro shoot organogenesis, just as in in vivo shoot development, is a complex, well-coordinated developmental process, and induction of a single molecular event may not be sufficient to induce the occurrence of the entire process. Further study is needed to identify the early molecular event(s) that triggers dedifferentiation of somatic cells and serves as the developmental switch for de novo shoot development.     

Genetic diversity in Cytisus aeolicus Guss. (Leguminosae), a rare endemite of the Italian flora

ABSTRACT

Cytisus aeolicus Guss, is an endemic plant restricted to the isles of Vulcano, Stromboli and Alicudi in the Aeolian archipelago. All known populations were assayed for genetic variability using enzyme polymorphism. Allozyme variation at 16 loci coding for 10 enzyme systems was examined. The great majority of loci turned out to be monomorphic or fixed heterozygous. The observed genetic depauperation is indicative of historical factors, such as the bottleneck effect associated with migration, and the founder effect in population re-establishment. The low genetic diversity is largely partitioned within rather than among populations, indicating that extant populations have not been established long enough for divergence to have occurred. The genetic uniformity, combined with the scattered distribution of small populations, and the negative shift of population size point to a critically endangered species. Strategies for conservation are considered.     

I. Introduction

Background: Past research and ecological theory supports the hypothesis that alpine plants should be predominantly clonal, long-lived and reproduce by seed infrequently.

Aims: To challenge the entrenched view that alpine seedling establishment is uncommon and perhaps unsuccessful in maintaining alpine plant populations.

Methods: We looked for patterns in seedling establishment across a stress gradient of alpine sites and tested the notion that natural seedling recruitment would be reduced at higher altitudes due to a combination of stressful environmental conditions such as frosts, wind and extended snow cover.

Results: Seedlings were common at all study sites and there was a partial trend in mean seedling density with altitude. Seedling emergence was best predicted by a combination of altitude, plant litter and soil wilting point. Many seedlings survived to become established plants (37–61%) but there was no significant relationship between establishment and altitude. There was low similarity between the seedling flora and the standing vegetation, suggesting that patterns in seedling establishment are unlikely to be driving the patterns in the standing vegetation assemblage.

Conclusions: Although Australian alpine species predominantly reproduce vegetatively, this study shows that many plants depend on recruitment from seed in order to become established.     

Plant growth enhancement is not a conserved feature in the Caulobacter genus

Aims

Species within the Caulobacter genus have been termed ‘hub species’ in the plant microbiome. To understand these interactions, we assessed the interactions between several Caulobacter strains and a common host plant.

Methods

We identified a set of 11 Caulobacter strains that range in genetic diversity and tested them for their ability to increase the growth of Arabidopsis thaliana. In addition, biochemical assays were employed to determine if these Caulobacter strains produce common plant growth promoting (PGP) biosynthates. To identify potential PGP-related genes, genomic analyses were performed to compare the genomes of PGP Caulobacter strains to those of non-PGP Caulobacter strains.

Results

For the PGP Caulobacter strains, we observed that common PGP biosynthates did not contribute to the observed Caulobacter-mediated plant growth stimulation. Genomic analyses suggested that the genomes of PGP strains maintain similar metabolic pathways compared to those of non-PGP strains, and that common genes related to PGP factors do not explain the PGP mechanisms for the Caulobacter strains we analyzed.

Conclusions

Plant growth enhancement is not a conserved feature in the Caulobacter genus, and some Caulobacter strains even inhibit plant growth. Moreover, common PGP factors do not fully explain Caulobacter-mediated plant growth enhancement.