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1.
Background and aims
Inoculation of legumes at sowing with rhizobia has arguably been one of the most cost-effective practices in modern agriculture. Critical aspects of inoculant quality are rhizobial counts at manufacture/registration and shelf (product) life.Methods
In order to re-evaluate the Australian standards for peat-based inoculants, we assessed numbers of rhizobia (rhizobial counts) and presence of contaminants in 1,234 individual packets of peat–based inoculants from 13 different inoculant groups that were either freshly manufactured or had been stored at 4 °C for up to 38 months to determine (a) rates of decline of rhizobial populations, and (b) effects of presence of contaminants on rhizobial populations. We also assessed effects of inoculant age on survival of the rhizobia during and immediately after inoculation of polyethylene beads.Results
Rhizobial populations in the peat inoculants at manufacture and decline rates varied substantially amongst the 13 inoculant groups. The most stable were Sinorhizobium, Bradyrhizobium and Mesorhizobium with Rhizobium, particularly R. leguminosarum bv. trifolii the least stable. The presence of contaminants at the 10?6 level of dilution, i.e. >log 6.7 g?1 peat, reduced rhizobial numbers in the stored inoculants by an average of 37 %. Survival on beads following inoculation improved 2–3 fold with increasing age of inoculant.Conclusions
We concluded that the Australian standards for peat-based rhizobial inoculants should be reassessed to account for the large differences amongst the groups in counts at manufacture and survival rates during storage. Key recommendations are to increase expiry counts from log 8.0 to log 8.7 rhizobia g?1 peat and to have four levels of inoculant shelf life ranging from 12 months to 3 years. 相似文献2.
Aims
Low numbers of rhizobia in soil or inoculants delay nodulation and decrease symbiotic legume productivity. This study investigated the effect of co-inoculation with a helper bacterium, Pseudomonas fluorescens WSM3457 on the Medicago truncatula - Ensifer (Sinorhizobium) medicae WSM419 symbiosis challenged by a low inoculum dose.Methods
In a glasshouse experiment the effect of co-inoculation with WSM3457 on the kinetics of nodule initiation and development was assessed 5, 7, 10, 14, 17, 21, and 42 days after inoculation of M. truncatula cv. Caliph with 103 cells/plant of E. medicae WSM419.Results
Co-inoculated plants had enhanced rate of nodule initiation and development, greater numbers of larger crown nodules, and by day 42 accumulated more N than plants inoculated with E. medicae WSM419 alone. Nodule development was altered by co-inoculation. Approximately 25% of nodule initials on co-inoculated plants formed in closely associated pairs, young nodules were larger with multiple meristems and developed into cluster-like multi-lobed nodules compared to those on WSM419 inoculated plants. Molecular typing showed WSM3457 occupied a significant proportion of root nodules on co-inoculated plants.Conclusion
Co-inoculation with P. fluorescens WSM3457 enhanced symbiotic effectiveness of M. truncatula when inoculated with a low inoculum dose of E. medicae WSM419. 相似文献3.
Coralie Barthelemy-Delaux David Marburger Pierre-Marc Delaux Shawn Conley Jean-Michel Ané 《Plant and Soil》2014,382(1-2):165-173
Background and aims
Bradyrhizobium japonicum and soybean (Glycine max (L.) Merr.) form a symbiotic association which allows for biological nitrogen fixation (BNF) to help meet the nitrogen (N) requirement of soybean plants. Rhizobial inoculants are not always used in soybean production in the Midwestern USA because of high naturalized soil populations, but drought conditions experienced in the region during the 2012 growing season may have led to a decline in numbers resulting in the need for inoculation the following growing season. Therefore, the effect of drought on B. japonicum population size was investigated in this study.Methods
Drought conditions, 8 weeks long or 4 weeks long preceded (STOP) or followed (START) by 4 weeks of normal watering, were simulated in two contrasting soil types in a greenhouse setting with soybeans as host plants. Drought conditions were monitored by measuring water content. Population size of B. japonicum was quantified using quantitative real-time polymerase chain reaction (qPCR) and most probable number (MPN) methods and compared to population from non-drought treatment.Results
Using both quantification methods, the response of B. japonicum to drought treatments was minimal.Conclusions
Drought conditions 4 to 8 weeks long did not reduce B. japonicum population size to levels which would affect soybean growth and development. 相似文献4.
A. Cruz-Hernández A. Tomasini-Campocosio L. J. Pérez-Flores F. J. Fernández-Perrino M. Gutiérrez-Rojas 《Plant and Soil》2013,362(1-2):261-270
Background and aims
The selective inoculation of specific hydrocarbon-degrading microbes into the plant rhizosphere offers a useful means for remediating hydrocarbon-contaminated soils. The effect of inoculating a seed-borne filamentous fungus (Lewia sp.) on hydrocarbon removal by Festuca arundinacea and its growth was studied on perlite (model soil) and soil, both spiked with hydrocarbons.Methods
A hydrocarbon mixture (1,500 mg kg?1) of two polycyclic aromatic hydrocarbons (PAH), phenanthrene and pyrene, blended with hexadecane (1.0:0.5:0.5 weight) was used. Greenhouse experiments were carried out for 45 days. Inoculated and non-inoculated plants were grown in dark cylindrical glass pots containing perlite or soil.Results
Inoculation with Lewia sp. stimulated (100 %) root growth in spiked perlite. Inoculated plants showed higher phenanthrene removal (100 %) compared to non-inoculated plants in perlite and soil. Pyrene removal by inoculated plants was 37-fold higher than that by non-inoculated plants in perlite; in soil, pyrene removal by inoculated plants (97.9 %) differed significantly from that of non-inoculated plants (91.4 %). Accumulation of pyrene in roots (530.9 mg kg?1 of dry roots) was promoted in perlite.Conclusions
Our results demonstrate that Lewia sp. (endophytic fungus) improved the efficiency of PAH removal by F. arundinacea, on both perlite and soil, stimulating pyrene accumulation in roots. 相似文献5.
Souhir Soussou Stéphanie Mahieu Brigitte Brunel José Escarré Michel Lebrun Mohamed Banni Hamadi Boussetta Jean-Claude Cleyet-Marel 《Plant and Soil》2013,371(1-2):423-434
Aims
This work examines Zn accumulation in four Anthyllis vulneraria subspecies supplemented with mineral nitrogen or grown in the presence of their symbiotic bacteria.Methods
Anthyllis vulneraria subspecies were grown hydroponically in the presence of high levels of ZnSO4. The plants were either grown in symbiosis with one of two non-metallicolous or metallicolous Mesorhizobium inoculants or in the presence of KNO3.Results
When exposed to 1,000 μM Zn, shoot and root biomass of three out of our four Anthyllis subspecies cultivated with NO3 dropped significantly by about 24–28 %; carpatica, the fourth subspecies, was not affected. Subspecies carpatica Zn tolerance was confirmed when in symbiosis with the metallicolous strain. In the presence of 1,000 μM Zn, the different Anthyllis subspecies concentrated more Zn in their roots than in their shoots and only subsp. carpatica accumulated a significant amount of Zn in its shoots. The most remarkable feature was the drastic decrease in Zn concentration in both roots (up to 2.5–3 fold) and shoots (2.6-fold) of subsp. carpatica exposed to 1,000 μM Zn and nodulated whatever the Mesorhizobium strain used, compared to the N-grown plants.Conclusions
Our results bring new perspectives as regards phytostabilization, with the potential use of a rhizobium-inoculated leguminous subspecies displaying unusual Zn tolerance. 相似文献6.
William S. Cuddy Brett A. Summerell Michelle M. Gehringer Brett A. Neilan 《Plant and Soil》2013,370(1-2):317-332
Background and aims
This study investigated the effect of cyanobacterial inoculants on salt tolerance in wheat.Methods
Unicyanobacterial crusts of Nostoc, Leptolyngbya and Microcoleus were established in sand pots. Salt stress was targeted at 6 and 13 dS m?1, corresponding to the wheat salt tolerance and 50 % yield reduction thresholds, respectively. Germinated wheat seeds were planted and grown for 14 (0 and 6 dS m?1) and 21 (13 dS m?1) days by which time seedlings had five emergent leaves. The effects of cyanobacterial inoculation and salinity on wheat growth were quantified using chlorophyll fluorescence, inductively coupled plasma-optical emission spectrometry and biomass measurements.Results
Chlorophyll fluorescence was negatively affected by soil salinity and no change was observed in inoculated wheat. Effective photochemical efficiency correlated with a large range of plant nutrient concentrations primarily in plant roots. Inoculation negatively affected wheat biomass and nutrient concentrations at all salinities, though the effects were fewer as salinity increased.Conclusions
The most likely explanation of these results is the sorption of nutrients to cyanobacterial extracellular polymeric substances, making them unavailable for plant uptake. These results suggest that cyanobacterial inoculation may not be appropriate for establishing wheat in saline soils but that cyanobacteria could be very useful for stabilising soils. 相似文献7.
Purple-leaved Ficus lyrata plants produced by overexpressing a grapevine VvMybA1 gene 总被引:1,自引:0,他引:1
Jietang Zhao Zhijian T. Li Juan Chen Richard J. Henny Dennis J. Gray Jianjun Chen 《Plant cell reports》2013,32(11):1783-1793
Key message
This study established an efficient method of regenerating plants of Ficus lyrata and producing purple-leaved F. lyrata plants through genetic transformation using a VvMybA1 gene of grapevine.Abstract
Ficus lyrata, a species with unique violin- or guitar-shaped leaves, was regenerated from leaf-derived calli cultured on Murashige and Skoog (MS) basal medium supplemented with 4.5 μM N-phenyl-N’-1, 2, 3-thiadiazol-5-yl urea (TDZ) and 0.5 μM α-naphthalene acetic acid (NAA). Leaf discs were inoculated with Agrobacterium tumefaciens strain EHA 105 harboring a binary vector DEAT that contains the VvMybA1 gene and neomycin phosphotransferase (npt II) gene and subsequently cultured on the established regeneration medium supplemented with 100 mg l?1 kanamycin. Results showed that 87.5 % of the leaf discs produced kanamycin-resistant callus, and 68.8 % of them produced adventitious shoots. Transgenic plants with three leaf colors including green, green-purple, and purple were produced. Regular and quantitative real-time PCR analyses confirmed the integration of transgenes into the host genome. Semi-quantitative RT-PCR analysis indicated that the VvMybA1 gene was responsible for the purple-colored phenotype. Purple-leaved plants with strong color stability grew vigorously in a greenhouse. This study illustrated the feasibility of using a genetically engineered VvMybA1 gene for drastic modification of leaf color of an important woody ornamental plant. 相似文献8.
Key message
The rate of progression of Dutch elm disease can be continuously and quantitatively estimated from sap flow measurements.Abstract
Response of sap flow to inoculation with Ophiostoma novo-ulmi, a causal agent which causes vascular mycosis called Dutch elm disease, was studied in a field experiment comprised of 4-year-old wych elm trees (Ulmus glabra). Sap flow was measured on inoculated trees using the trunk heat balance method with external heating (EMS 62, Czech Republic) throughout the experiment. The first detectable symptoms of reduction in sap flow occurred 6 days after inoculation and all inoculated trees died within 16 days. Our experiment confirmed the ability of O. novo-ulmi to quickly kill young elm trees. The disease progressed faster than in previous experiments utilizing O. ulmi. To the best of our knowledge, this is the first experiment using sap flow measurements on trees inoculated by O. novo-ulmi. The trunk heat balance sap flow method is an effective non-invasive tool for continuous quantitative monitoring of the progression of vascular tree diseases, and show increased potential for field and greenhouse studies on changes in xylem hydraulic conductivity in a wide range of broadleaved and coniferous tree species. 相似文献9.
P. Smyda H. Jakuczun K. Dębski J. Śliwka R. Thieme M. Nachtigall I. Wasilewicz-Flis E. Zimnoch-Guzowska 《Plant cell reports》2013,32(8):1231-1241
Key message
Phytophthora infestans resistant somatic hybrids of S. × michoacanum (+) S. tuberosum and autofused 4 x S. × michoacanum were obtained. Our material is promising to introgress resistance from S. × michoacanum into cultivated potato background.Abstract
Solanum × michoacanum (Bitter.) Rydb. (mch) is a wild diploid (2n = 2x = 24) potato species derived from spontaneous cross of S. bulbocastanum and S. pinnatisectum. This hybrid is a 1 EBN (endosperm balance number) species and can cross effectively only with other 1 EBN species. Plants of mch are resistant to Phytophthora infestans (Mont) de Bary. To introgress late blight resistance genes from mch into S. tuberosum (tbr), genepool somatic hybridization between mch and susceptible diploid potato clones (2n = 2x = 24) or potato cultivar Rywal (2n = 4x = 48) was performed. In total 18,775 calli were obtained from postfusion products from which 1,482 formed shoots. The Simple Sequence Repeat (SSR), Cleaved Amplified Polymorphic Sequences (CAPS) and Random Amplified Polymorphic DNA (RAPD) analyses confirmed hybrid nature of 228 plants and 116 autofused 4x mch. After evaluation of morphological features, flowering, pollen stainability, tuberization and ploidy level, 118 somatic hybrids and 116 autofused 4x mch were tested for late blight resistance using the detached leaf assay. After two seasons of testing three somatic hybrids and 109 4x mch were resistant. Resistant forms have adequate pollen stainability for use in crossing programme and are a promising material useful for introgression resistance from mch into the cultivated potato background. 相似文献10.
11.
Marcio Reis Martins Claudia Pozzi Jantalia Verônica Massena Reis Ingbert Döwich José Carlos Polidoro Bruno José Rodrigues Alves Robert Michael Boddey Segundo Urquiaga 《Plant and Soil》2018,422(1-2):239-250
Background and aims
The inoculation of cereal crops with plant growth-promoting bacteria (PGPB) is a potential strategy to improve fertilizer-N acquisition by crops in soils with low capacity to supply N. A study was conducted to assess the impact of three inoculants on grain yield, protein content, and urea-15 N recovery in maize (Zea mays L.) under Cerrado soil and climate conditions.Methods
The main treatments included inoculants containing (i) Azospirillum brasilense strain Sp245, (ii) A. brasilense strains AbV5 + AbV6, (iii) Herbaspirillum seropedicae strain ZAE94, and (iv) a non-inoculated control. The subtreatments were (i) urea-N fertilization (100 kg N ha?1) at 30 days after sowing and (ii) no N addition at the stage. To determine fertilizer-N recovery, 15N–labelled urea was applied in microplots.Results
Inoculants carrying A. brasilense improved urea-15 N acquisition efficiency in maize and also improved grain yield compared to the non-inoculated control, while urea-N fertilization enhanced grain quality by providing higher protein content.Conclusion
Our results suggest that the inoculation of maize grains with PGPB represents a strategy to improve fertilizer-N recovery and maize yield in Cerrado soil with a low capacity to supply N.12.
Faxiang Wan Yu Pan Jinghua Li Xiangfu Chen Yanglu Pan Yongqing Wang Shibing Tian Xingguo Zhang 《Plant cell reports》2014,33(12):1951-1961
Key message
Our study shows that the expression of AtCBF3 and AtCOR15A improved the chilling tolerance in transgenic eggplant.Abstract
In an attempt to improve chilling tolerance of eggplant (Solanum melongena L) plants, Arabidopsis C-repeat binding factor 3 (AtCBF3) and cold-regulated 15A (AtCOR15A) genes both driven by an Arabidopsis RESPONSIVE TO DESSICATION 29A promoter (AtRD29A) were transferred into the plants of eggplant cultivar Sanyueqie. Two independent homozygous transgenic lines were tested for their cold tolerance. The leaves of the transgenic plants in both lines withered much slower and slighter than the wild-type plants after exposure to cold stress treatment at 2 ± 1 °C. The gene expression of AtCBF3 and AtCOR15A was significantly increased as well as the proline content and the levels of catalase and peroxidase activities, while the relative electrical conductivity and the malondialdehyde content were remarkably decreased in the transgenic plants compared with the wild type at 4 ± 0.5 °C. The results showed that the expression of the exogenous AtCBF3 and AtCOR15A could promote the cold adaptation process to protect eggplant plants from chilling stress. 相似文献13.
Laura Milazzo Anna Maria Peri Cristina Mazzali Romualdo Grande Chiara Cazzani Davide Ricaboni Antonio Castelli Ferdinando Raimondi Carlo Magni Massimo Galli Spinello Antinori 《Mycopathologia》2014,178(3-4):227-241
Background
Candida species represent the fourth leading cause of nosocomial bloodstream infections (BSI) worldwide. However, candidaemia rates and species involved vary geographically.Objectives
To evaluate the epidemiological pattern, risk factors for mortality and antifungal therapy of Candida BSI over a 5-year period (2008–2012) in a university hospital in northern Italy together with a review of the recent literature concerning candidaemia.Methods
A retrospective cohort study cross-linked with microbiology database was performed.Results
A total of 89 Candida BSI were identified in 42 males (47 %) and 47 females (52.8 %). The median age was 69 years (interquartile range 55–78) with 61.8 % of patients being older than 65 years. Considering all hospitalized patients, the overall incidence rate of candidaemia increased significantly from 2008 to 2012 (from 0.4 to 1.68 episodes per 10,000 patient/days) (p = 0.0001) with a mean linear increase in 5 new cases per year. Candida albicans was the predominant species isolated (64 %) followed by C. glabrata (19.1 %). The latter species was observed with significantly higher frequency in Internal Medicine and Intensive Care Units (ICU). In-hospital crude mortality was 41.6 %.Conclusions
Candidaemia is an increasing BSI in our university hospital, in accordance with that observed in northern Italy, and it is still associated with high in-hospital crude mortality. 相似文献14.
Peter E. Mortimer Marcellous R. Le Roux Maria A. Pérez-Fernández Vagner A. Benedito Aleysia Kleinert Jianchu Xu Alexander J. Valentine 《Plant and Soil》2013,366(1-2):229-241
Background and aims
Acacia cyclops is an invasive species within Mediterranean ecosystems, characteristically low in soil nutrients. Thus associations with nitrogen-fixing bacteria (NFB) and arbuscular mycorrhiza (AM) may provide an advantage to these legumes. This study investigated the role of AM and NFB in the growth and nutritional physiology of A. cyclops.Methods
Seedlings were inoculated with?naturally occurring?NFB, Glomus mosseae or both, and grown under glasshouse conditions for 5 months. Plants were cultivated in sand and supplied with a 20 % strength nutrient solution.?Xylem sap nutrients, photosynthetic rates, biomass and chemical compositions, were recorded.Results
The dual inoculation decreased the colonization of both symbionts, compared to a single symbiosis with either symbiont. Despite low colonization levels, the dual symbiosis increased host biomass and relative growth rates. This was associated with increased photosynthetic rates and enhanced nutrition. Additionally, dual symbiotic plants had enhanced N and P acquisition and utilization rates. Xylem sap analysis showed higher levels of NH 4 + being exported from the roots to the shoots in the dual symbiotic plants compared with other treatments.Conclusions
These findings suggest the dual symbiosis is an important factor in the growth and development of A. cyclops under nutrient limiting conditions. 相似文献15.
Ahmed Galal Shiveta Sharma Salah Fatouh Abou-Elwafa Shailendra Sharma Friedrich Kopisch-Obuch Eberhard Laubach Dragan Perovic Frank Ordon Christian Jung 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2014,127(6):1399-1407
Key message
This study demonstrates for the first time that resistance to different root lesion nematodes ( P. neglectus and P. penetrans ) is controlled by a common QTL. A major resistance QTL ( Rlnnp6H ) has been mapped to chromosome 6H using two independent barley populations.Abstract
Root lesion nematodes (Pratylenchus spp.) are important pests in cereal production worldwide. We selected two doubled haploid populations of barley (Igri × Franka and Uschi × HHOR 3073) and infected them with Pratylenchus penetrans and Pratylenchus neglectus. Nematode multiplication rates were measured 7 or 10 weeks after infection. In both populations, continuous phenotypic variations for nematode multiplication rates were detected indicating a quantitative inheritance of resistance. In the Igri × Franka population, four P. penetrans resistance QTLs were mapped with 857 molecular markers on four linkage groups (2H, 5H, 6H and 7H). In the Uschi × HHOR 3073 population, eleven resistance QTLs (P. penetrans and P. neglectus) were mapped with 646 molecular markers on linkage groups 1H, 3H, 4H, 5H, 6H and 7H. A major resistance QTL named Rlnnp6H (LOD score 6.42–11.19) with a large phenotypic effect (27.5–36.6 %) for both pests was mapped in both populations to chromosome 6H. Another resistance QTL for both pests was mapped on linkage group 5H (Igri × Franka population). These data provide first evidence for common resistance mechanisms against different root lesion nematode species. The molecular markers are a powerful tool for the selection of resistant barley lines among segregating populations because resistance tests are time consuming and laborious. 相似文献16.
Stéphanie Mahieu José Escarré Brigitte Brunel Angélique Méjamolle Souhir Soussou Antoine Galiana Jean-Claude Cleyet-Marel 《Plant and Soil》2014,375(1-2):175-188
Background and aims
The association of the legume Anthyllis vulneraria and the grass Festuca arvernensis, was found to be very efficient for the phytostabilisation of highly multi-metal contaminated mine tailings. Our objective was to quantify the contribution of Anthyllis inoculated with its symbiotic bacteria Mesorhizobium metallidurans to the soil N pool and to test whether a starter nitrogen fertilization may improve symbiotic nitrogen fixation and the growth of Festuca.Methods
Plants of Festuca and of Anthyllis inoculated with M. metallidurans were grown separately during eight months in pots filled with mine contaminated soil. Estimation of the N fluxes was realized using 15?N isotopic methods.Results
Starter N fertilization (28 kg N ha?1) improved symbiotic N2 fixation and the growth of both species. Belowground N balance (N rhizodeposition – soil N uptake) of the non-fertilized Anthyllis at maturity was negative (?30.6 kg N ha?1). However, the amount of N derived from fixation, including above- and belowground parts, was 78.6 kg N ha?1, demonstrating the ability of this symbiotic association to improve soil N content after senescence.Conclusions
i) soil N enrichment by the N2-fixing symbiotic association occurs after plant senescence, when decaying leaves and shoots are incorporated into the soil; ii) application of a starter fertilization is an efficient solution to improve phytostabilisation of highly contaminated sites. 相似文献17.
Macarena Gerding John Gregory Howieson Graham William O’Hara Daniel Real Lambert Bräu 《Plant and Soil》2013,370(1-2):235-249
Background and aims
The South African herbaceous legume species Lessertia capitata, L. diffusa, L. excisa L. incana and L. herbacea were introduced to Australia to assess plant establishment and survival, as well as the saprophytic ability of their root nodule bacteria (RNB).Methods
Five Lessertia spp., were inoculated with selected RNB strains and were sown in five different agroclimatic areas of the Western Australian wheat-belt during 2007 and 2008. Plant population and summer survival were evaluated in situ. Soil samples and nodules from host plants were also taken from each site. The re-isolated rhizobia were RPO1-PCR fingerprinted and their partial dnaK and nodA genes were sequenced to confirm their identity.Results
Plants achieved only poor establishment followed by weak summer survival. More than 83 % of the rhizobia re-isolated from Lessertia did not correlate with the original inoculants’ fingerprints, and were identified as Rhizobium leguminosarum. The nodA sequences of the naturalised strains were also clustered with R. leguminosarum sequences, thus eliminating the likelihood of lateral gene transference from Mesorhizobium and suggesting a competition problem with indigenous rhizobia.Conclusion
The stressful soil conditions and high numbers of resident R. leguminosarum strains in Western Australian soils, and their ability to rapidly nodulate Lessertia spp. but not fix nitrogen are likely to preclude the adoption of Lessertia as an agricultural legume in this region. 相似文献18.
19.
Population structure and association mapping of yield contributing agronomic traits in foxtail millet 总被引:1,自引:0,他引:1
Sarika Gupta Kajal Kumari Mehanathan Muthamilarasan Swarup Kumar Parida Manoj Prasad 《Plant cell reports》2014,33(6):881-893