Diversity in natural populations of wild Brassica oleracea as estimated by isozyme and RAPD analysis

Naturally occurring populations of wild Brassica oleracea were collected in Spain, France, and Great Britain. Allele frequencies at four isozyme loci were determined for 18 populations, while five populations were screened using five random primers to generate RAPDs. Levels of homozygosity and gene diversity, H, were computed for each population using isozyme data and RAPD data when applicable. Homozygosity levels tended to be higher in smaller populations, which could also be observed as increased numbers of homozygous loci in smaller populations. Gene diversity values based on isozymes indicated considerable within population variation regardless of population size. The RAPID based gene diversities were significantly higher and the two exceptional populations displayed diversity levels more in keeping with the rest. The coefficient of gene differentiation, G _ST , for populations in each region showed that the Spanish populations were more homogenous than the French or British. When the G _ST for all populations was calculated using isozymes vs. RAPD data, the RAPD data gave a significantly lower value, a plausible result of the higher within population variation detected using RAPDs. Genetic distances between populations from different regions were also calculated from both data sets and used to produce phenograms. Clustering according to geographic region was not evident using either isozyme or RAPD data.     

Variation in resistance to the cabbage aphid ( Brevicoryne brassicae) between and within wild and cultivated Brassica species

Seven Brassica species were evaluated for their resistance to the cabbage aphid, Brevicoryne brassicae, in a series of field experiments. Four wild Brassica species, two 8 chromosome species with similarities to the B genome of Brassica nigra (Brassica fruticulosa and Brassica spinescens) and two 9 chromosome species containing the C genome (Brassica incana and Brassica villosa) were identified as possessing consistently high levels of antibiosis mediated resistance to B. brassicae. None of the species were shown to possess consistently high levels of antixenosis resistance. In more detailed glasshouse experiments one B-like genome species, B. fruticulosa, showed considerable variation between accessions collected from different sites for resistance to B. brassicae. In addition, individual accessions of one A genome species (Brassica rapa) and one C genome species (Brassica alboglabra) were shown to be highly variable in their resistance to B. brassicae, some plants of each accession being highly resistant and others very susceptible. The implications of the variability in resistance to B. brassicae within wild Brassica species for exploitation in Brassica breeding programmes are discussed.     

甘蓝花粉特异表达的多聚半乳糖醛酸酶基因BoMF9的克隆与特征分析

根据白菜花粉特异的多聚半乳糖醛酸酶基因BcMF9的全长序列设计引物，通过PCR直接扩增的方法从结球甘蓝（Brassica. oleracea var. capitata）和芥蓝（B. oleracea var. alboglabra）中克隆得到BcMF9的同源基因BoMF9（BoMF9c和BoMF9l）。生物信息学分析和系统树构建发现BoMF9c和BoMF9l具有花粉特异表达的多聚半乳糖醛酸酶基因的序列特征。不同组织的表达特征分析发现它们分别在结球甘蓝和芥蓝的花蕾中特异表达。推测BoMF9c和BoMF9l可能在花粉萌发和花粉管伸长中起作用。     

Assessment of genetic variation in a working collection of Vigna vexillata (L.) A. Rich. by isozyme and RAPD analyses

Genetic variation based on isozyme and RAPD analyses was investigated in 47 and 34 accessions respectively of Vigna vexillata from different geographical origins and belonging to three botanical varieties. A total of 9 enzyme systems were studied, accounting for 14 putative loci, 8 of which were polymorphic. The analysis of genetic diversity revealed a low level of within accession variation (H_S=0.013), while between accession diversity (D_ST) was 0.120. Coefficient of gene differentiation (G_ST) was 0.905, indicating that most variation was among accessions. Nei's genetic distances were calculated on the basis of allelic frequencies and a UPGMA dendrogram was constructed. Twenty arbitrary 10-mer oligonucleotides were used in RAPD analysis. Amplification profiles disclosed a higher level of polymorphism than isozymes. Based on amplification patterns, the similarity index of Jaccard was calculated and a dendrogram constructed on the basis of the similarity matrix. The final clustering based on RAPD data was similar to the one obtained using isozyme allelic frequencies. The classification in botanical varieties did not reflect the allelic constitution of the different samples. On the other hand, referring to geographical origin, most accessions from Africa and from Latin America were distributed respectively in two distinct clusters in the dendrogram. This grouping might also reflect the differences observed in the germination behaviour of V. vexillata from the two continents.     

Relationships of Vigna unguiculata (L.) Walp., V. vexillata (L.) A. Rich. and species of section Vigna based on isozyme variation

Summary Isozyme variation in 25 accessions of wild and cultivated Vigna unguiculata, 49 accessions of seven wild species belonging to section Vigna, and 11 accessions of V. vexillata (subgenus Plectrotropis) was scored at 17 putative loci to assess genetic relationships within and among species. The wild species selected for this study are among those which carry important agronomical traits useful in cowpea (V. unguiculata) breeding programs. Allelic frequencies were calculated and Nei's genetic distances were obtained. Low levels of intraspecific variation were observed for V. heterophylla, V. luteola and V. racemosa, whereas the other species showed a higher polymorphism. Vigna unguiculata possessed intraspecific genetic distances comparable to those previously found by other authors. Most of the isozyme variation was apportioned among species. Although V. luteola and V. marina had an interspecific genetic distance resembling the range observed at intraspecific level, all the other species showed very high interspecific distances. Vigna unguiculata was relatively closer genetically to V. vexillata than to the species belonging to section Vigna.Abbreviations AUS Australia - BDI Burundi - BRA Brazil - BWA Botswana - CAF Central African Republic - GHA Ghana - CMR Cameroon - COG Congo - RI Costa Rica - EGY Egypt - ETE Ethiopia - GAB Gabon - GRC Greece - ITA Italy - KEN Kenya - MOZ Mozambique - NER Niger - NGA Nigeria - PAN Panama - RWA Rwanda - TCD Chad - TZA Tanzania - ZAF South Africa - ZAR Zaire - ZMB Zambia     

利用酵母双杂交系统鉴定羽衣甘蓝臂重复蛋白(ARC1)与结球甘蓝S位点受体激酶(SRK)激酶结构域的相互作用

S位点受体激酶(SRK)和臂重复蛋白(ARC1)是芸薹属植物自交不亲和反应的两种重要的信号元件,SRK-ARC1之间的互作决定着自交不亲和反应的进程。本研究利用PCR技术获得结球甘蓝(Brassicaoleracea var.capitata)SRK激酶结构域(SRKJ)的编码区以及羽衣甘蓝(B.oleracea var.acephala)ARC1基因不同片段长度的基因组DNA与编码区,分别构建以pGBKT7为载体的长度依次递减的ARC1a、ARC1b、ARC1c和ARC1d的重组诱饵质粒和以pGADT7为载体的SRKJ的重组猎物质粒,并将重组质粒转化酵母菌株进行蛋白质相互作用检测。结果显示:羽衣甘蓝ARC1存在5个连续的臂重复区,与结球甘蓝ARC1的氨基酸序列一致性达到98%;构建的重组表达载体在酵母细胞中无毒性和自激活作用产生;3个实验组Y2HGold[pGBKT7-ARC1a]×Y187[pGADT7-SRKJ]、Y2HGold[pGBKT7-ARC1c]×Y187[pGADT7-SRKJ]和Y2HGold[pGBKT7-ARC1d]×Y187[pGADT7-SRKJ]同时激活了4种报告基因AUR1-C...     

Variation of cultivated flax (Linum usitatissimum L. subsp.usitatissimum) and its wild progenitor pale flax (subsp.angustifolium (Huds.) Thell.)

The domestication of cultivated flax (Linum usitatissimum L. subsp.usitatissimum) is briefly discussed. Using data documented as a matter of routine in genebank work, 63 accessions of cultivated flax from the flax germplasm collection of the Gatersleben Genebank are compared with 73 accessions of its wild progenitor pale flax (subsp.angustifolium (Huds.) Thell.), which have been observed in systematic field trials. Range of variation, genetically based variation, heritability and correlation of several characters are considered, especially with respect to the influence of domestication. Cultivated flax shows higher variation in the characters of generative plant parts, while pale flax varies more in the vegetative parts of the plant. The character correlations are similar in both subspecies. Of the 29 characters studied in pale flax the parameters describing tillering, height of plant, weight of seeds, width of petals and width of leaves are especially suitable for distinguishing between different accessions. In spite of the high heritabilities of most of the characters, the influence of the environment is significant in most cases.     

Growth and iron nutrition of broccoli (Brassica oleracea L. var. italica Plenck), grown in a Typic Ustochrept, as influenced by vesicular-arbuscular mycorrhizal fungi in the presence of pyrite and farmyard manure

Greenhouse experiments were conducted using potted soil (Fe-deficient Typic Ustochrept) to study the influence of the vesicular-arbuscular mycorrhizal fungi (VAM), Glomus macrocarpum and G. fasciculatum, on the mobilisation of Fe in broccoli (Brassica oleracea L. var. italica Plenck) in the presence of pyrite and farmyard manure (FYM). Individual applications of either VAM or pyrite with NPK fertiliser significantly enhanced both the Fe²⁺ content in leaf tissue and total uptake of Fe and resulted in increased curd and straw yields of broccoli compared to those observed with NPK alone. Though the application of FYM decreased the Fe²⁺ content in leaf tissue relative to plants supplied NPK alone, this result was not statistically significant. The available Fe content in soil, after harvest of broccoli, was found to be lower in the presence of VAM than in the control. Received: 18 June 1997     

Comparative Efficacy of White Mustard (Sinapis alba L.) and Soybean (Glycine max L. Merr.) Seed Meals as Bioherbicides in Organic Broccoli (Brassica oleracea Var. Botrytis) and Spinach (Spinacea oleracea) Production

White mustard and soybean seed meals were compared for weed control and yield of organically grown broccoli and spinach. The meals were incorporated into the soil 2 weeks before crop planting at two rates (1.24 and 4.48 t ha^?1). Weed densities and hand-weeding time were recorded twice during the growing seasons and weed biomass was measured at crop harvest. Compared to the 1.24 t ha^?1 soybean treatment, weed densities were 52 to 95% and 41 to 45% less at 3 and 6 weeks after planting, respectively, in both crops with the 4.48 t ha^?1 white mustard seed meal treatment. Time required for hand weeding at these times was also reduced by up to 82% and 48%, respectively. Broccoli yield was similar in all the treatments, but spinach yield was greatest in the 4.48 t ha^?1 treatments for both seed meals. Petiole nitrate and nutrient concentrations in both crops were generally similar in all the treatments.     

芸薹属作物脂肪酸链延长酶基因（FAE1）拷贝数和序列变异分析

利用拟南芥脂肪酸合成途径中的脂肪酸链延长酶FAE1基因序列的保守性设计PCR简并引物,对芸薹属(Brassica)作物3个基本种和3个复合种进行了标记,并且对每个栽培种的PCR产物进行克隆和测序,进而对所获得的FAE1基因部分序列(C-端编码区序列)进行了分析。结果表明,拟南芥(Arabidopsisthaliana)和芸薹属作物基因组中具有不同拷贝数(1￣3)的FAE1基因,所测定的部分基因序列相互之间具有很高的同源性,并与其它酶基因如3-氧乙酰-乙酰载体蛋白合成酶,超长链脂肪酸合成酶和酮乙酰CoA合成酶基因具有共同的起源。     

Genetic variability at the Glu-1 loci in old and modern wheats (triticum aestivum L.) cultivated in Slovakia

The high molecular weight glutenin subunits (HMW-GS) composition at the Glu-1 complex loci, in 23 old original wheat genotypes cultivated in Slovakia several decades ago and 32 modern Slovak and Czech wheat cultivars growed in Slovakia at present were studied by SDS-PAGE. Some of the HMW-GS – subunit pairs 3+12, 17+18, and subunit 20, present in old historical wheats were missing in modern cultivars utilized in Slovakia nowadays. There were observed 15 different HMW-GS encoded by 11 alleles or allelic pairs in old genotypes. Lower number of different HMW-GS and competent alleles were observed in a set of modern wheat cultivars – 11 different HMW glutenin subunits encoded by 8 alleles or allelic pairs. The same number of different HMW-GS patterns was revealed in both sets of wheats. From the point of view of genetic variability, it could be concluded that long-term effort of breeders and decreasing of cultivation of landraces and old cultivars are associated with the loss of several HMW-GS alleles and decreasing of genetic variability of wheats. Molecular characterization can reveal broad allelic variability of old wheat genotypes and landraces. Their maintenance in genetic resource collections can prevent losses of these interesting genes.     

Development and characterization of microsatellite markers,genetic diversity and population structure analysis in Sapota (Manilkara zapota (L.) P. Royen)

Genetic Resources and Crop Evolution - Manilkara zapota (L.) P. Royen, a widely adapted and popular tree meant for its appetizing fruits in tropics with no genomic resources like microsatellite...     

Investigation of recent population bottlenecks in Kenyan wild sorghum populations (<Emphasis Type="Italic">Sorghum bicolor</Emphasis> (L.) Moench ssp. <Emphasis Type="Italic">verticilliflorum</Emphasis> (Steud.) De Wet) based on microsatellite diversity and genetic disequilibria

Identifying populations that have recently suffered a severe reduction in size is particularly important for their conservation as they are likely to suffer an increased risk of genetic erosion. We investigated the presence of recent bottlenecks in two wild sorghum populations from different eco-geographical conditions in Kenya employing 18 microsatellite markers. Microsatellite analysis showed high allelic diversity in the two populations, with a mean of 4.11 and 6.94 alleles per locus in the North-West wild sorghum population (NWWSP) and the South-East wild sorghum population (SEWSP), respectively. The mean observed heterozygosity was 0.34 and 0.56 in NWWSP and SEWSP, respectively. A large long-term effective populations size for both populations was observed assuming either an infinite allele model or a stepwise mutation model. There was no apparent loss of genetic variability for either of the populations. Test of heterozygosity excess indicated that a recent bottleneck in the two populations is highly unlikely. Furthermore, analysis of the allele frequency distribution revealed an L-shaped distribution which would not have been observed in case a recent bottleneck had reduced genetic variability in the two populations. The fact that most loci displayed a significant heterozygosity deficiency could be explained by population subdivision and the mixed mating system exhibited by wild sorghum populations. Furthermore, the possibility of a historical expansion of wild sorghum populations and presence of null alleles could not be ruled out.