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61.
62.
The molecular characteristics of markers in the chromosome region surrounding the supernodulation gene (nts-1) of soybean (Glycine max L. Merr.) were investigated in 187 F2 plants from a cross of G. max cv. Bragg (nts) and G. soja PI468.397 (wild-type nodulation). RFLP marker pUTG-132a, linked tightly (0.7±0.5 cM) to nts-1, was converted to a PCR marker. The polymorphism resides within a 1.72 kb PstI fragment and consists of an 832 bp insertion in G. max relative to the wild progenitor G. soja. The insertion is flanked by a 35 bp direct duplication that was found only once in G. soja. Data suggest that the pUTG-132a sequence exists only once in the genome, which is compatible with the recessive nature of
nts-1. Accordingly, pUTG-132a is a valuable marker for map-based cloning. Another RFLP marker, pA-381, was mapped 4.8 cM distal
to nts-1. Marker order, established by Maximum Likelihood Analysis, placed nts-1 between pUTG-132a and pA-381. To generate additional molecular markers, a segregating F2 population was analysed using bulked segregant analysis (BSA) and single oligonucleotide primer-based PCR (DNA amplification
fingerprinting; DAF). PCR marker pcr5-4L was mapped to soybean linkage group H and sequenced. The data revealed (i) recombination
events and marker order in the nts-1 region; (ii) the molecular nature and cause of polymorphisms in linked molecular markers; (iii) a low density of polymorphisms
around nts-1, and (iv) diploidy of the distal region of linkage group H of soybean.
Received: 18 January 1996 / Accepted: 9 October 1996 相似文献
63.
64.
A set of oligonucleotides has been developed to study the competitivity of two Frankia strains in the nodulation of the roots of two host plant species: Alnus glutinosa and Alnus incana. Two 20 mer-oligonucleotides, complementary to highly conserved sequences inside the nifH gene, were used as primers for the polymerase chain reaction (PCR) system in order to amplify microsymbiont DNA extracted from actinorhizae. PCR products were analyzed using two strain-specific 15-mer oligonucleotides identified in the amplified region. Hybridization data indicate that strain ACoN24d is more competitive than train ArI3 in the nodulation of both hosts. 相似文献
65.
Summary Effects of increasing rates of lime (0, 900, 1725, and 3000 kg Ca(OH)2/ha producing soil pH of 4.0, 4.7, 5.1 and 5.6) and P (50, 150, 250 and 350 kg P/ha) on top and root yield, root morphology
and chemical composition of lotus (Lotus pedunculatus Cav.) and white clover (Trifolium repens L.), were studied, using an acid soil in a greenhouse experiment.
Increasing rates of applied lime and phosphate resulted in substantial increases in top yields of both species but concomitant
increases in root yield were small. In the unlimed soil, lotus out-yielded (tops and roots) white clover at all P levels.
However, in the three limed treatments, white clover clearly out-yielded lotus. Yield response curves to applied P levelled
off at the two highest lime rates for lotus but not for white clover.
Nodulation and N content of white clover increased significantly with increasing lime applications, but for lotus there was
a significant decrease in nodulation at the highest lime rate. Increased P rates had a small stimulatory effect on nodulation
in both species.
Of the total root weight, the percentage contribution of the tap and primary lateral root fractions was smaller and that of
the secondary plus tertiary lateral roots was greater for lotus than for white clover although root length per unit weight
tended to be larger for white clover at the two highest lime rates. Furthermore, lotus possessed longer and more numerous
root hairs than white clover. Lime applications significantly decreased the percentage contribution of the tap and primary
lateral roots to the total root weight and increased the percentage contribution of the secondary plus tertiary lateral roots.
Al and Mn contents of tops and roots of both species decreased with increasing lime rates. There was a highly significant
negative correlation between relative yield and Al content of lotus and white clover tops. In comparison with the limed treatments,
in the unlimed treatments a greater percentage of total P, Al, Mn and N content accumulated in the roots of both species.
In addition, lotus accumulated a much greater percentage Al in its roots than white clover. 相似文献
66.
D. Barry Scott Chris B. Court Clive W. Ronson Kieran F. Scott John M. Watson Peter R. Schofield John Shine 《Archives of microbiology》1984,139(2-3):151-157
A Rhizobium trifolii symbiotic plasmid specific gene library was constructed and the physical organisation of regions homologous to nifHDK, nifA and nod genes was determined. These symbiotic gene regions were localised to u 25 kb region on the sym-plasmid, pPN1. In addition four copies of a reiterated sequence were identified on this plasmid, with one copy adjacent to nifH. No rearrangement of these reiterated sequences was observed between R. trifolii bacterial and bacteroid DNA. Analysis of a deletion derivative of pPN1 showed that these sequences were spread over a 110 kb region to the left of nifA. 相似文献
67.
Rosemary Sylvester-Bradley 《Plant and Soil》1984,82(3):377-386
Summary Three phases of Rhizobium inoculation trials were carried out as part of a programme to select forage legume germplasm adapted to acid, infertile Oxisols of tropical America. Firstly, a range of tropical forage legumes were evaluated for their response to N fertilization or inoculation with strains previously shown to be effective in Leonard jars, using cores of undisturbed soil or in the field at Carimagua, Meta, Colombia. In pure legume stands onlyCentrosema macrocarpum andC. pubescens showed increases in N yield due to both inoculation and N fertilization;C. brasilianum responded only to N fertilization;Zornia latifolia, Z. brasiliensis andStylosanthes capitata responded to neither treatment. Trials in cores and in grass-legume mixtures showed responses ofDesmodium ovalifolium, Pueraria phaseoloides andS. capitata to N fertilization but not to inoculation. In the second phase of experiments strains were screened in soil cores with 16 ecotypes ofDesmodium, Centrosema, Stylosanthes andPueraria spp. Significant increases in N yield due to inoculation occurred with at least one strain in all the legumes exceptS. guianensis tardio, and in some trials withS. capitata. In the third phase of trials the most effective strains were tested in the field. Significant response ofP. phaseoloides andC. macrocarpum to inoculation at two sites and in the second year after establishment were shown. Further screening trials and field trials at different sites are needed in order to provide better recommendations for inoculation of grazing trials being set up in the region under study. 相似文献
68.
以发光酶基因luxAB为标记,在根盒缩影条件下研究了费氏中华根瘤菌HN01DL在大豆根圈的定殖动态、分布范围及其结瘤情况.结果表明,HN01DL在根盒.灭菌土壤和非灭菌土壤缩影中的大豆全根系定殖动态与水平明显不同,前者在第12d时达到最高定殖密度(8.65log cfu·g^-1),而后者的早期定殖数量下降较快,且于第15d时达到最高定殖密度(6.88log cfu·g^-1).HN01DL在大豆播种5d后在大豆根部的A(0~4cm)区根段上达到最高定殖密度(7.05log cfu·g^-1),然后开始缓慢下降,至第19d时仍维持相对稳定,在第33d时又开始回升.至播种后第46d时HN01DL可散布至种子下方16cm处的根段部位.HN01DL在A区根段的定殖密度持续较高,所形成的发光根瘤总数(16.3个)及发光比例(68.8%)最高,且发光根瘤主要集中于该区段主根上.发光根瘤比例沿A-E区段逐渐下降,在E区段未检测到发光根瘤. 相似文献
69.
70.