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1.
Root colonization and mitigation of NaCl stress on wheat seedlings were studied by inoculating seeds with Azospirillum lipoferum JA4ngfp15 tagged with the green fluorescent protein gene (gfp). Colonization of wheat roots under 80 and 160 mM NaCl stress was similar to root colonization with this bacterial species under non-saline conditions, that is, single cells and small aggregates were mainly located in the root hair zone. These salt concentrations had significant inhibitory effects on development of seedlings, but not on growth in culture of gfp-A. lipoferum JA4ngfp15. Reduced plant growth (height and dry weight of leaves and roots) under continuous irrigation with 160 mM NaCl was ameliorated by bacterial inoculation with gfp-A. lipoferum JA4ngfp15. Inoculation of plants subjected to continuous irrigation with 80 mM NaCl or to a single application of either NaCl concentration (80 or 160 mM NaCl) did not mitigate salt stress. This study indicates that, under high NaCl concentration, inoculation with modified A. lipoferum
reduced the deleterious effects of NaCl; colonization patterns on roots were unaffected and the genetic marker did not induce undesirable effects on the interaction between the bacterium and the plants. 相似文献
2.
The present study was conducted to isolate and characterize rhizobial strains from root nodules of cultivated legumes, i.e. chickpea, mungbean, pea and siratro. Preliminary characterization of these isolates was done on the basis of plant infectivity test, acetylene reduction assay, C-source utilization, phosphate solubilization, phytohormones and polysaccharide production. The plant infectivity test and acetylene reduction assay showed effective root nodule formation by all the isolates on their respective hosts, except for chickpea isolate Ca-18 that failed to infect its original host. All strains showed homology to a typical Rhizobium strain on the basis of growth pattern, C-source utilization and polysaccharide production. The strain Ca-18 was characterized by its phosphate solubilization and indole acetic acid (IAA) production. The genetic relationship of the six rhizobial strains was carried out by random amplified polymorphic DNA (RAPD) including a reference strain of Bradyrhizobium japonicum TAL-102. Analysis conducted with 60 primers discriminated between the strains of Rhizobium and Bradyrhizobium in two different clusters. One of the primers, OPB-5, yielded a unique RAPD pattern for the six strains and well discriminated the non-nodulating chickpea isolate Ca-18 from all the other nodulating rhizobial strains. Isolate Ca-18 showed the least homology of 15% and 18% with Rhizobium and Bradyrhizobium, respectively, and was probably not a (Brady)rhizobium strain. Partial 16S rRNA gene sequence analysis for MN-S, TAL-102 and Ca-18 strains showed 97% homology between MN-S and TAL-102 strains, supporting the view that they were strains of B. japonicum species. The non-infective isolate Ca-18 was 67% different from the other two strains and probably was an Agrobacterium strain. 相似文献
3.
Using Tn5 mutagenesis of lysogenic Sinorhizobium meliloti strain L5–30 (L54), three neomycin-resistant transconjugants differing in phage-resistance profiles were isolated. Two of them increased the dry weight of plants and were capable of establishing root nodules, whereas the third one was ineffective. The bacterium-phage interaction did not have observable consequences in the Medicago sativa - S. meliloti symbiosis because it did not affect the number of nodules on M. sativa or plant dry weight. 相似文献
4.
This study aimed to investigate the effect of inoculation with plant growth-promoting Rhizobium and Pseudomonas species on NaCl-affected maize. Two cultivars of maize (cv. Agaiti 2002 and cv. Av 4001) selected on the basis of their yield
potential were grown in pots outdoors under natural conditions during July. Microorganisms were applied at seedling stage
and salt stress was induced 21 days after sowing and maintained up to 50% flowering after 120 days of stress. The salt treatment
caused a detrimental effect on growth and development of plants. Co-inoculation resulted in some positive adaptative responses
of maize plants under salinity. The salt tolerance from inoculation was generally mediated by decreases in electrolyte leakage
and in osmotic potential, an increase in osmoregulant (proline) production, maintenance of relative water content of leaves,
and selective uptake of K ions. Generally, the microbial strain acted synergistically. However, under unstressed conditions,
Rhizobium was more effective than Pseudomonas but under salt stress the favorable effect was observed even if some exceptions were also observed. The maize cv. Agaiti
2002 appeared to be more responsive to inoculation and was relatively less tolerant to salt compared to that of cv. Av 4001. 相似文献
5.
Cropping in low fertility soils, especially those poor in N, contributes greatly to the low common bean (Phaseolus vulgaris L.) yield, and therefore the benefits of biological nitrogen fixation must be intensively explored to increase yields at a low cost. Six field experiments were performed in oxisols of Paraná State, southern Brazil, with a high population of indigenous common bean rhizobia, estimated at a minimum of 103 cells g–1 soil. Despite the high population, inoculation allowed an increase in rhizobial population and in nodule occupancy, and further increases were obtained with reinoculation in the following seasons. Thus, considering the treatments inoculated with the most effective strains (H 12, H 20, PRF 81 and CIAT 899), nodule occupancy increased from an average of 28% in the first experiment to 56% after four inoculation procedures. The establishment of the selected strains increased nodulation, N2 fixation rates (evaluated by total N and N-ureide) and on average for the six experiments the strains H 12 and H 20 showed increases of 437 and 465 kg ha–1, respectively,in relation to the indigenous rhizobial population. A synergistic effect between low levels of N fertilizer and inoculation with superior strains was also observed, resulting in yield increases in two other experiments. The soil rhizobial population decreased 1 year after the last cropping, but remained high in the plots that had been inoculated. DGGE analysis of soil extracts showed that the massive inoculation apparently did not affect the composition of the bacterial community. 相似文献
6.
The genus Aegilops L. is a very important genetic resource for the breeding of bread wheat Triticum aestivum. Therefore, an accurate and easy identification of Aegilops species is required. Traditionally, identification of Aegilops species has relied heavily on morphological characters. These characters, however, are either not variable enough among Aegilops species or too plastic to be used for identification at the species level. Molecular markers that are more stable within
species, therefore, could be the alternative strategy towards an accurate identification. Since the chloroplast DNA has a
lower level of evolution compared to the nuclear genome, an attempt was made in this study to investigate polymorphism in
the chloroplast DNA among 21 Aegilops species (including Ae. mutica that is now known as Amblyopyrum muticum) and between the latter and T. aestivum to generate markers for the diagnosis of all targeted species. Cleaved amplified polymorphic sequence (CAPS) applied on 22
coding and non-coding chloroplast regions using 80 endonucleases and sequencing of two of those regions revealed little polymorphism
between T. aestivum and the various Aegilops species examined and to a less extent was the variation among Aegilops species. Polymorphism observed among species analysed allowed the discrimination of T. aestivum and 12 Aegilops species. 相似文献
7.
Amina Sirag Saied Jens Gebauer Karl Hammer Andreas Buerkert 《Genetic Resources and Crop Evolution》2008,55(7):929-937
Neglected and underutilized species often play a vital role in securing food and livestock feed, income generation and energy
needs of rural populations. In spite of their great potential little attention has been given to these species. This increases
the possibility of genetic erosion which would further restrict the survival strategies of people in rural areas. Ziziphus spina-christi is a plant species that has edible fruits and a number of other beneficial applications that include the use of leaves as
fodder, branches for fencing, wood as fuel, for construction and furniture making, and the utilization of different parts
e.g. Fruits, leaves, roots and bark in folk medicine. Moreover, the plant is adapted to dry and hot climates which make it
suitable for cultivation in an environment characterized by increasing degradation of land and water resources. Lack of research
in Z. spina-christi hinders its successful improvement and promotion. Therefore, studies are needed to fully exploit this species. This article
aims at summarizing information on different aspects of Z. spina-christi to stimulate interest in this crop which is of importance in Sudan and other countries of the semi-arid tropics.
相似文献
Amina Sirag SaiedEmail: |
8.
Long-term effects of mineral fertilization on microbial biomass C (MBC), basal respiration (R
B), substrate-induced respiration (R
S), β-glucosidase activity, and the r–K-growth strategy of soil microflora were investigated using a field trial on grassland established in 1969. The experimental
plots were fertilized at three rates of mineral N (0, 80, and 160 kg ha−1 year−1) with 32 kg P ha−1 year−1 and 100 kg K ha−1 year−1. No fertilizer was applied on the control plots (C). The application of a mineral fertilizer led to lower values of the MBC
and R
B, probably as a result of fast mineralization of available substrate after an input of the mineral fertilizer. The application
of mineral N decreased the content of C extracted by 0.5 M K2SO4 (C
ex). A positive correlation was found between pH and the proportion of active microflora (R
S/MBC). The specific growth rate (μ) of soil heterotrophs was higher in the fertilized than in unfertilized soils, suggesting the stimulation of r-strategists, probably as the result of the presence of available P and rhizodepositions. The cessation of fertilization with
320 kg N ha−1 year−1 (NF) in 1989 also stimulated r-strategists compared to C soil, probably as the result of the higher content of available P in the NF soil than in the C
soil. 相似文献
9.
A greenhouse experiment was conducted with a specially designed apparatus consisting of an upper and lower chamber where the treatment with rice was carried out (treatment 1). The apparatus also had a single chamber where treatment 2, without rice plants, was carried out. The scope of this study was to elucidate the influence of rice plant growth on gaseous N losses as N2 and N2O produced by nitrification-denitrification in a flooded soil fertilized with (NH4)2SO4 (with 56.50 atom% 15N). Gas samples were withdrawn weekly and analyzed for (N2 + N2O)-15N losses by mass spectrometer and for N2O by gas chromatograph. The gaseous (N2 + N2O)-15N losses of the treatment with rice plants were significantly (P =0.01) higher than those of the treatment without rice plants, as were the amounts of N2O emitted. Rice plants facilitate the efflux of N2 and N2O from soil to atmosphere, as about half of the total gaseous 15N loss as N2 and N2O was found in the upper chamber. The proportion of N2O-15N to (N2 + N2O)-15N in the upper chamber was 10.56%, much higher than that of the lower chamber in treatment 1 and the headspace of treatment 2. 相似文献
10.
In a Robinia-pseudoacacia-dominated coastal forest in Tottori prefecture Japan, the growth and survival of Pinus thunbergii seedlings and the natural regeneration of P. thunbergii was disturbed by R. pseudoacacia. In order to improve the growth of P. thunbergii seedling in the Tottori sand dune, we tried to find a mycorrhiza helper bacteria (MHB) from P. thunbergii mycorrhizosphere in a Tottori sand dune. Two MHB, Ralstonia sp. and Bacillus subtilis, were selected from the nine bacterial species isolated from the mycorrhizosphere of P. thunbergii. The bacterial effect on the ectomycorrhizal fungus Suillus granulatus was investigated by confrontation assay and a microcosm experiment. The confrontation assay showed that Ralstonia sp. promoted the hyphal growth of S. granulatus. Moreover, the S. granulatus–P. thunbergii symbiosis was significantly stimulated by Ralstonia sp. and B. subtilis. Ralstonia sp. and B. subtilis were regarded as MHB associated with P. thunbergii. This is the first report of Ralstonia sp. as an MHB. 相似文献
11.
The genus Arachis is divided into nine taxonomic sections. Section Arachis is composed of annual and perennial species, while section Heteranthae has only annual species. The objective of this study was to investigate the genetic relationships among 15 Brazilian annual
accessions from Arachis and Heteranthae using RAPD markers. Twenty-seven primers were tested, of which nine produced unique fingerprintings for all the accessions
studied. A total of 88 polymorphic fragments were scored and the number of fragments per primer varied from 6 to 17 with a
mean of 9.8. Two specific markers were identified for species with 2n = 18 chromosomes. The phenogram derived from the RAPD data corroborated the morphological classification. The bootstrap analysis
divided the genotypes into two significant clusters. The first cluster contained all the section Arachis species, and the accessions within it were grouped based upon the presence or absence of the ‘A’ pair and the number of chromosomes.
The second cluster grouped all accessions belonging to section Heteranthae. 相似文献
12.
M. R. Naghavi M. J. Aghaei A. R. Taleei M. Omidi J. Mozafari M. E. Hassani 《Genetic Resources and Crop Evolution》2009,56(4):499-506
Simple sequence repeats (SSRs), highly dispersed nucleotide sequences in genomes, were used for germplasm analysis and estimation
of the genetic relationship of the D-genome among 52 accessions of T. aestivum (AABBDD), Ae. tauschii (DtDt), Ae. cylindrica (CCDcDc) and Ae. crassa (MMDcr1Dcr1), collected from 13 different sites in Iran. A set of 21 microsatellite primers, from various locations on the seven D-genome
chromosomes, revealed a high level of polymorphism. A total of 273 alleles were detected across all four species and the number
of alleles per each microsatellite marker varied from 3 to 27. The highest genetic diversity occurred in Ae. tauschii followed by Ae. crassa, and the genetic distance was the smallest between Ae. tauschii and Ae. cylindrica. Data obtained in this study supports the view that genetic variability in the D-genome of hexaploid wheat is less than in
Ae. tauschii. The highest number of unique alleles was observed within Ae. crassa accessions, indicating this species as a great potential source of novel genes for bread wheat improvement. Knowledge of
genetic diversity in Aegilops species provides different levels of information which is important in the management of germplasm resources. 相似文献
13.
Calamintha nepeta and Micromeria thymifolia have been traditionally used in the Mediterranean area as condiments and medicinal plants for a long time. Whereas in parts of Italy C. nepeta (special recipes have been developed in Lazio and Tuscany) is also an established garden plant showing different evolutionary products and their interaction among each other and the wild progenitor, M. thymifolia is being developed into a new crop plant. Both plants and their uses are described with regard to Italy. There is a marked tendency to broaden the use of condiments and spices which results in new crop plants which have to be documented and elaborated in further studies. Many species of Labiatae are predisposed to use by man and new items can be found even in areas which have to be considered as well studied. 相似文献
14.
Re-vegetation of fly ash, the principal by-product of coal fired power stations, is hampered by its unfavourable chemical
and physical properties for plant growth. In the present study, we evaluated the use of inoculation with a mycorrhiza-associated
bacterial strain (Sphingomonas sp. 23L) to promote mycorrhiza formation and plant growth of three willow clones (Salix spp.) on fly ash from an over-burdened dump in a pot experiment. The high pHH2O (8.7) and low nitrogen content (Nt = 0.1 g kg−1) in combination with hydrophobicity of the particle surfaces caused low plant growth. Inoculation of the willows with Sphingomonas sp. 23L improved the nitrogen uptake by plants, increased plant growth and stimulated formation of ectomycorrhizae with an
autochthonous Geopora sp. strain on all three willow clones. The ectomycorrhiza formed by the Geopora sp. was morphologically and anatomically described. The inoculation significantly increased the shoot growth of two Salix viminalis clones and the root growth of a S. viminalis x caprea hybrid clone. We conclude that inoculation with mycorrhiza promoting bacterial strains might be a suitable approach to support
mycorrhiza formation with autochtonous site-adapted ectomycorrhizal fungi in fly ash and thereby to improve re-vegetation
of fly ash landfills with willows. 相似文献
15.
A fertile amphidiploid × Brassicoraphanus (RRCC, 2n = 36) between Raphanus sativus cv. HQ-04 (2n = 18, RR) and Brassica alboglabra Bailey (2n = 18, CC) was synthesized and successive selections for seed fertility were made from F4 to F10. F10 plants exhibited good fertility with 14.9 seeds per siliqua and 32.3 g seeds per plant. Cytological observation revealed
that frequent secondary pairing occurred among 3 chromosome pairs in pollen mother cells of plants (F4) with lower fertility, but not of plants with high fertility (F10). GISH analysis indicated that these F10 plants included the expected 18 chromosomes from R. sativus and B. alboglabra, respectively, but they lost approximately 27.6% R. sativus and 35.6% B. alboglabra AFLP (amplified fragment length polymorphism) bands. The crossability of the Raphanobrassica with R. sativus and 5 Brassica species (13 cultivars) were investigated. Seeds or F1 seedlings were easy to be produced from crosses × Brassicoraphanus × R. sativus, and B. napus, B. juncea and B. carinata × Brassicoraphanus. Fewer seeds or seedlings were obtained from crosses × Brassicoraphanus × B. napus, B. juncea and B. carinata. However, few seeds were harvested in the reciprocals of × Brassicoraphanus with B. rapa and B. oleracea. The possible cause of fertility improvements and the potential of the present × Brassicoraphanus for breeding were discussed. 相似文献
16.
The classification and phylogeny of the species belonging to Solanum section Lycopersicon is a complex issue that has not yet reached a widely accepted consensus. These species diverged recently, are still closely
related and, in some cases, are still even capable of interspecific hybridization, thereby blurring the difference between
intra- and interspecific variation. To help resolve these issues, in the present study, several accessions covering the natural
range for each species were used. In addition, to avoid biases due to the molecular method employed, both AFLP markers and
two nuclear-gene sequences, CT179 and CT66, were used to characterize the plant materials. The data obtained suggest a classification
similar to those previously proposed by other authors, although with some significant changes. Twelve species were recognized
as distinct based on this dataset. According to the data presented, the recently proposed species, S. corneliomulleri, is indistinguishable from S. peruvianum s.str. In addition, both the sequence and the AFLP trees suggest that S. arcanum could represent a complex of populations composed of two cryptic species. With regard to phylogenetic relationships among
these species, some clear groups were found: the Lycopersicon group formed by S. pimpinellifolium, S. lycopersicum, S. cheesmaniae and S. galapagense; the Arcanum group constituted by S. chmielewskii, S. neorickii, S. arcanum and S. huaylasense; and the Eriopersicon group made up of S. peruvianum and S. chilense. Solanum pennellii and S. habrochaites are not included in any group, but are the closest to the S. lycopersicoides outgroup.
Jose Blanca and Fernando Nuez have contributed equally to this work and should be regarded as co-second authors. 相似文献
17.
Parveen Chhuneja Satinder Kaur R. K. Goel M. Aghaee-Sarbarzeh M. Prashar H. S. Dhaliwal 《Genetic Resources and Crop Evolution》2008,55(6):849-859
Aegilops umbellulata acc. 3732, an excellent source of resistance to major wheat diseases, was used for transferring leaf rust and stripe rust
resistance to cultivated wheat. An amphiploid between Ae. umbellulata acc. 3732 and Triticum durum cv. WH890 was crossed with cv. Chinese Spring Ph
I
to induce homoeologous pairing between Ae. umbellulata and wheat chromosomes. The F1 was crossed to the susceptible Triticum aestivum cv. ‘WL711’ and leaf rust and stripe rust resistant plants were selected among the backcross progenies. Homozygous lines
were selected and screened against six Puccinia triticina and four Puccinia striiformis f. sp. tritici pathotypes at the seedling stage and a mixture of prevalent pathotypes of both rust pathogens at the adult plant stage. Genomic
in situ hybridization in some of the selected introgression lines detected two lines with complete Ae. umbellulata chromosomes. Depending on the rust reactions and allelism tests, the introgression lines could be classified into two groups,
comprising of lines with seedling leaf rust resistance gene Lr9 and with new seedling leaf rust and stripe rust resistance genes. Inheritance studies detected an additional adult plant
leaf rust resistance gene in one of the introgression lines. A minimum of three putatively new genes—two for leaf rust resistance
(LrU1 and LrU2) and one for stripe rust resistance (YrU1) have been introgressed into wheat from Ae. umbellulata. Two lines with no apparent linkage drag have been identified. These lines could serve as sources of resistance to leaf rust
and stripe rust in breeding programs. 相似文献
18.
Hong-sheng Wu Yang Wang Wei Bao Dong-yang Liu Waseem Raza Qi-wei Huang Ze-sheng Mao Qi-rong Shen 《Biology and Fertility of Soils》2009,45(4):443-447
To assess the influence of phenolic acids from plant root exudates on soil pathogens, we studied the effect of sinapic acid
added to chemically defined media on the growth and virulence factors of Fusarium oxysporum f. sp. niveum. Sinapic acid inhibited the growth and conidial formation and germination of F. oxysporum f. sp. niveum by 6.7–8.8% and 11.2–37.3%, respectively. Mycotoxin production by F. oxysporum f. sp. niveum was stimulated by 81.6–230.7%. Pectinase, proteinase, cellulase, and amylase activities were stimulated at a lower concentration
of sinapic acid, while they were inhibited at a higher concentration. It is concluded that sinapic acid inhibited the growth
and conidial germination of F. oxysporum f. sp. niveum and decreased the pathogenic enzymes’ activity at higher doses. 相似文献
19.
S. Desai Ch. Narayanaiah Ch. Kranti Kumari M. S. Reddy S. S. Gnanamanickam G. Rajeswara Rao B. Venkateswarlu 《Biology and Fertility of Soils》2007,44(1):229-234
Jatropha (Jatropha curcas L.) is a non-edible oil-seed plant with adaptability to marginal semi-arid lands and wastelands. The Indian Government is
promoting jatropha to reduce dependence on the crude oil and to achieve energy independence by the year 2012, under the National
Biodiesel Mission. Selected strains of Bacillus spp., either supplemented with or without chitin, were tested for their ability to promote growth of jatropha seedlings in
pot culture studies. The strains supported growth of jatropha seedlings up to 42 days after sowing. Among all strains, Bacillus pumilus (IM-3) supplemented with chitin showed over all plant growth promotion effect resulting in enhanced shoot length (113%),
dry shoot mass (360%), dry root mass (467%), dry total plant mass (346%), leaf area (256%), and chlorophyll content (74%)
over control. Treating seeds with strain IM-3 without chitin resulted in enhanced dry shoot mass (473%), dry total plant mass
(407%), and chlorophyll content (82%). However, Bacillus polymyxa (KRU-22) with chitin supported maximum root length (143%). Either strain IM-3 alone or in combination with other promising
strains could be promoted further for enhanced initial seedling growth of jatropha. 相似文献
20.
Tobias W. Eschholz Roland Peter Peter Stamp Andreas Hund 《Genetic Resources and Crop Evolution》2008,55(7):971-983
About 65 years ago, more than 150 Swiss maize landraces (Zea mays L. ssp. mays) of the flint type were collected and conserved ex situ. Due to the climatically and culturally diverse environment of the Alps, a considerable genetic diversity of this material
was assumed. To prove this, an efficient method was required to carry out genetic profiling of all the accessions in the Swiss
Gene Bank. Simple sequence repeat marker (SSR) profiling in combination with the visualization of the polymerase chain reaction
(PCR) products on agarose gels was chosen. Here a set of 19 different landrace accessions was analyzed to: (i) investigate
their genetic diversity, (ii) investigate and display the population structure and (iii) determine whether DNA bulks rather
than single plants can be used for such analyses. Four repeated samples of one accession were found to be much closer to one
another than to the rest of accessions. Furthermore, specific alleles were identified for several accessions. The PCR products
of the bulked DNA samples represented only a small part of the variation revealed by the analysis of individuals. Loci with
four base repeat motifs performed better in the analysis of bulks than loci with other repeat motifs. The correlation between
genetic distance matrices, based on the analysis of individuals and bulks, respectively, was significant. Thus, the single
plant approach allowed for sufficient differentiation of accessions, and DNA bulks visualized on agarose gels led to correlated
genetic distances although a limited number of alleles were detected. Although the limited resolution of agarose gels likely
causes some bias, profiling of larger sets with the individual plant approach appears feasible and more informative compared
to the bulk analysis we conducted. 相似文献