scholarly journals Phenotypic and Genetic Diversity in Strains of Common Blight Bacteria (Xanthomonas campestris pv. phaseoli and X. campestris pv. phaseoli var. fuscans) in a Secondary Center of Diversity of the Common Bean Host Suggests Multiple Introduction Events

2006 ◽  
Vol 96 (11) ◽  
pp. 1204-1213 ◽  
Author(s):  
Ruth López ◽  
Carmen Asensio ◽  
Robert L. Gilbertson
Keyword(s):  
Genetic Diversity ◽  
Common Bean ◽  
Xanthomonas Campestris ◽  
New World ◽  
Gene Pools ◽  
East African ◽  
Highly Pathogenic ◽  
Castilla Y Leon ◽  
Secondary Center ◽  
The Common

Common bacterial blight (CBB) disease of the common bean (Phaseolus vulgaris) is caused by Xanthomonas campestris pv. phaseoli and the brown-pigmented variant X. campestris pv. phaseoli var. fuscans. CBB first was described in Castilla y León County, Spain, in 1940, and is now a major constraint on common bean production. In this secondary center of diversity of the common bean, large-seeded Andean cultivars predominate, although medium-seeded Middle American cultivars also are grown. Xanthomonad-like bacteria associated with CBB in Castilla y León were characterized on the basis of carbohydrate metabolism, brown pigment production, genetic analyses (repetitive-element polymerase chain reaction [rep-PCR] and random amplified polymorphic DNA [RAPD]) and pathogenicity on cultivars representing the two common bean gene pools (Andean and Middle American). X. campestris pv. phaseoli was more prevalent (80%) than X. campestris pv. phaseoli var. fuscans (20%). Patterns of carbohydrate metabolism of Spanish CBB bacteria were similar to those of known strains; and only X. campestris pv. phaseoli var. fuscans strains utilized mannitol as a sole carbon source. rep-PCR and RAPD analyses revealed relatively little genetic diversity among Spanish X. campestris pv. phaseoli strains, and these strains were placed together with New World strains into a large cluster. Similar to other New World strains, representative Spanish X. campestris pv. phaseoli strains were highly pathogenic on bean cultivars of both gene pools, showing no gene pool specialization such as that found in certain East African strains. Genetic analyses and pathogenicity tests confirmed and extended previous results, indicating that these East African strains represent distinct xanthomonads that independently evolved to be pathogenic on common bean. X. campestris pv. phaseoli var. fuscans strains were more closely related and genetically distinct from X. campestris pv. phaseoli strains. However, two distinct clusters of X. campestris pv. phaseoli var. fuscans strains were identified, one having the most New World strains and the other having the most African strains. Spanish strains were placed in both clusters, but all strains tested were highly pathogenic on bean cultivars of both gene pools. Together, our results are consistent with multiple introductions of CBB bacteria into Spain. These findings are discussed in terms of breeding for CBB resistance and the overall understanding of the genetic diversity and evolution of CBB bacteria.

scholarly journals Genetic Diversity and Pathogenic Variation of Common Blight Bacteria (Xanthomonas campestris pv. phaseoli and X. campestris pv. phaseoli var. fuscans) Suggests Pathogen Coevolution with the Common Bean

2004 ◽  
Vol 94 (6) ◽  
pp. 593-603 ◽  
Author(s):  
Alexander B. C. Mkandawire ◽  
Robert B. Mabagala ◽  
Pablo Guzmán ◽  
Paul Gepts ◽  
Robert L. Gilbertson
Keyword(s):  
Genetic Diversity ◽  
Common Bean ◽  
East Africa ◽  
Gene Pool ◽  
Xanthomonas Campestris ◽  
New World ◽  
The Other ◽  
East African ◽  
Highly Pathogenic ◽  
The Common

Common bacterial blight (CBB), caused by Xanthomonas campestris pv. phaseoli and X. campestris pv. phaseoli var. fuscans, is one of the most important diseases of common bean (Phaseolus vulgaris) in East Africa and other bean-growing regions. Xanthomonad-like bacteria associated with CBB in Malawi and Tanzania, East Africa, and in Wisconsin, U.S., were characterized based on brown pigment production, pathogenicity on common bean, detection with an X. campestris pv. phaseoli- or X. campestris pv. phaseoli var. fuscans-specific PCR primer pair, and repetitive element polymerase chain reaction (rep-PCR) and restriction fragment length polymorphism (RFLP) analyses. The common bean gene pool (Andean or Middle American) from which each strain was isolated also was determined. In Malawi, X. campestris pv. phaseoli and X. campestris pv. phaseoli var. fuscans were isolated predominantly from Andean or Middle American beans, respectively. In Tanzania, X. campestris pv. phaseoli var. fuscans was most commonly isolated, irrespective of gene pool; whereas, in Wisconsin, only X. campestris pv. phaseoli was isolated from Andean red kidney beans. Three rep-PCR fingerprints were obtained for X. campestris pv. phaseoli strains; two were unique to East African strains, whereas the other was associated with strains collected from all other (mostly New World) locations. RFLP analyses with repetitive DNA probes revealed the same genetic diversity among X. campestris pv. phaseoli strains as did rep-PCR. These probes hybridized with only one or two fragments in the East African strains, but with multiple fragments in the other X. campestris pv. phaseoli strains. East African X. campestris pv. phaseoli strains were highly pathogenic on Andean beans, but were significantly less pathogenic on Middle American beans. In contrast, X. campestris pv. phaseoli strains from New World locations were highly pathogenic on beans of both gene pools. Together, these results indicate the existence of genetically and geographically distinct X. campestris pv. phaseoli genotypes. The rep-PCR fingerprints of X. campestris pv. phaseoli var. fuscans strains from East African and New World locations were indistinguishable, and were readily distinguished from those of X. campestris pv. phaseoli strains. Genetic diversity among X. campestris pv. phaseoli var. fuscans strains was revealed by RFLP analyses. East African and New World X. campestris pv. phaseoli var. fuscans strains were highly pathogenic on Andean and Middle American beans. Breeding for CBB resistance in East African beans should utilize X. campestris pv. phaseoli var. fuscans and New World X. campestris pv. phaseoli strains in order to identify germ plasm with the highest levels of resistance.

scholarly journals Genetic diversity and selection of genotypes to enhance Zn and Fe content in common bean

2010 ◽  
Vol 90 (1) ◽  
pp. 49-60 ◽  
Author(s):  
Z I Talukder ◽  
E Anderson ◽  
P N Miklas ◽  
M W Blair ◽  
J Osorno ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Common Bean ◽  
Allelic Variation ◽  
Gene Pools ◽  
Gene Sequences ◽  
Mineral Contents ◽  
Discriminatory Ability ◽  
Fe Content ◽  
Mapping Populations ◽  
Selection Of

Common bean (Phaseolus vulgaris L.) is an important source of dietary protein and minerals worldwide. Genes conditioning variability for mineral contents are not clearly understood. Our ultimate goal is to identify genes conditioning genetic variation for Zn and Fe content. To establish mapping populations for this objective, we tested mineral content of 29 common bean genotypes. Chemical analyses revealed significant genetic variability for seed Zn and Fe contents among the genotypes. Genetic diversity was evaluated with 49 primer pairs, of which 23 were simple sequence repeats (SSR), 16 were developed from tentative consensus (TC) sequences, and 10 were generated from common bean NBS-LRR gene sequences. The discriminatory ability of molecular markers for identifying allelic variation among genotypes was estimated by polymorphism information content (PIC) and the genetic diversity was measured from genetic similarities between genotypes. Primers developed from NBS-LRR gene sequences were highly polymorphic in both PIC values and number of alleles (0.82 and 5.3), followed by SSRs (0.56 and 3.0), and markers developed from TC (0.39 and 2.0). genetic similarity values between genotypes ranged from 14.0 (JaloEEP558 and DOR364) to 91.4 (MIB152 and MIB465). Cluster analysis clearly discriminated the genotypes into Mesoamerican and Andean gene pools. Common bean genotypes were selected to include in crossing to enhance seed Zn and Fe content based on genetic diversity and seed mineral contents of the genotypes. Key words: Common bean, genetic diversity, mineral nutrients, breeding

scholarly journals Molecular genetic diversity and differentiation of Nile tilapia (Oreochromis niloticus, L. 1758) in East African natural and stocked populations

2019 ◽  
Author(s):  
Papius Dias Tibihika ◽  
Manuel Curto ◽  
Esayas Alemayehu ◽  
Herwig Waidbacher ◽  
Charles Masembe ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Genetic Structure ◽  
East Africa ◽  
Oreochromis Niloticus ◽  
Nile Tilapia ◽  
Anthropogenic Activities ◽  
Genetic Erosion ◽  
Gene Pools ◽  
East African ◽  
Nile Tilapia Oreochromis Niloticus

Abstract Background The need for enhancing the productivity of fisheries in Africa triggered the introduction of non-native fish, causing dramatic changes to local species. In East Africa, the extensive translocation of Nile tilapia (Oreochromis niloticus) is one of the major factors in this respect. Using 40 microsatellite loci with SSR-GBS techniques, we amplified a total of 664 individuals to investigate the genetic structure of O. niloticus from East Africa in comparison to Ethiopian and Burkina Faso populations. Results All three African regions were characterized by independent gene-pools, however, the Ethiopian population from lake Tana showed to be more divergent than expected suggesting that it might be a different species. In East Africa, the genetic structure was congruent with both geographical location and anthropogenic activities. O. niloticus from Lake Turkana (Kenya) was isolated, while in Uganda, despite populations being rather similar to each other, two main natural catchments were able to be defined. We show that these two groups contributed to the gene-pool of different non-native populations. Moreover, admixture and possible hybridization with other tilapiine species may have contributed to the genetic divergence found in some populations such as Lake Victoria. We detected other factors that might be affecting Nile tilapia genetic variation. For example, most of the populations have gone through a reduction of genetic diversity, which can be a consequence of bottleneck caused by overfishing, genetic erosion due to fragmentation or founder effect resulting from stoking activities. Conclusions The anthropogenic activities particularly in the East African O. niloticus translocations, promoted admixture and contact with the native congenerics which may contribute to outbreeding depression and hence compromising the sustainability of the species in the region.

scholarly journals Differential Pathogenicity of Xanthomonas campestris pv. phaseoli and X. fuscans subsp. fuscans Strains on Bean Genotypes with Common Blight Resistance

Plant Disease ◽  
2008 ◽  
Vol 92 (4) ◽  
pp. 546-554 ◽  
Author(s):  
N. Mutlu ◽  
A. K. Vidaver ◽  
D. P. Coyne ◽  
J. R. Steadman ◽  
P. A. Lambrecht ◽  
...  
Keyword(s):  
Common Bean ◽  
Bacterial Blight ◽  
Xanthomonas Campestris ◽  
South American ◽  
Bacterial Strains ◽  
Genetic Changes ◽  
Germplasm Screening ◽  
Lack Of Information ◽  
Pathogenic Variation ◽  
The Common

Both the common bacterial blight (CBB) pathogen (Xanthomonas campestris pv. phaseoli) and X. fuscans subsp. fuscans, agent of fuscous blight, cause indistinguishable symptoms in common bean, Phaseolus vulgaris. Yield losses can exceed 40%. Lack of information about the specificity between X. campestris pv. phaseoli strains and major quantitative trait loci (QTL) or alleles conferring resistance makes the task of identifying genetic changes in host–pathogen interactions and the grouping of bacterial strains difficult. This, in turn, affects the choice of pathogen isolates used for germplasm screening and complicates breeding for CBB resistance. Common bean host genotypes carrying various sources and levels of resistance to CBB were screened with 69 X. campestris pv. phaseoli and 15 X. fuscans subsp. fuscans strains from around the world. Differential pathogenicity of the CBB pathogen was identified on the 12 selected bean genotypes. The X. fuscans subsp. fuscans strains showed greater pathogenicity than X. campestris pv. phaseoli strains having the same origin. African strains were most pathogenic. The largest variation in pathogenicity came from X. campestris pv. phaseoli strains that originated in Caribbean and South American countries. Pathogenic variation was greater within X. campestris pv. phaseoli than within X. fuscans subsp. fuscans strains. Implications for breeding for CBB resistance are discussed.

The genetic make-up of the European landraces of the common bean

2011 ◽  
Vol 9 (2) ◽  
pp. 197-201 ◽  
Author(s):  
S. A. Angioi ◽  
D. Rau ◽  
L. Nanni ◽  
E. Bellucci ◽  
R. Papa ◽  
...  
Keyword(s):  
Common Bean ◽  
Gene Pool ◽  
Chloroplast Microsatellites ◽  
Gene Pools ◽  
Mesoamerican Gene Pool ◽  
Hybridization Event ◽  
South Eastern Europe ◽  
Andean Type ◽  
The Common ◽  
African Sample

Here, we present a brief overview of the main studies conducted on the common bean (Phaseolus vulgaris L.) in Europe and other countries outside its centres of origin. We focus on the proportions of the Andean and Mesoamerican gene pools, and on the inter-gene pool hybridization events. In Europe, for chloroplast microsatellites, 67% of European germplasm is of Andean origin. Within Europe, interesting trends have been seen; indeed, the majority of the Andean type is found in the three macro-areas of the Iberian Peninsula, Italy and central-northern Europe, while, in eastern and south-eastern Europe, the proportion of the Mesoamerican type increased. On a local scale, the contribution of the Mesoamerican type is always low. On other continents, various situations are seen using different markers: in China and Brazil, the Mesoamerican gene pool prevails, while in an African sample, overall, both gene pools are equally represented, with differences in individual countries. The frequency of European bean genotypes deriving from at least one hybridization event was 44% with an uneven distribution. Interestingly, hybrids tend to have intermediate seed size in comparison with ‘pure’ Andean or Mesoamerican types. On other continents, very few hybrids are found, probably because of the different marker systems used.

scholarly journals Genotyping-by-Sequencing Reveals Molecular Genetic Diversity in Italian Common Bean Landraces

Diversity ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 154 ◽  
Author(s):  
Lucia Lioi ◽  
Diana L. Zuluaga ◽  
Stefano Pavan ◽  
Gabriella Sonnante
Keyword(s):  
Genetic Diversity ◽  
Common Bean ◽  
Genotyping By Sequencing ◽  
Fixation Index ◽  
Most Probable Number ◽  
Probable Number ◽  
Individual Snps ◽  
Starting Point ◽  
Genetic Diversity And Structure ◽  
The Common

The common bean (Phaseolus vulgaris L.) is one of the main legumes worldwide and represents a valuable source of nutrients. Independent domestication events in the Americas led to the formation of two cultivated genepools, namely Mesoamerican and Andean, to which European material has been brought back. In this study, Italian common bean landraces were analyzed for their genetic diversity and structure, using single nucleotide polymorphism (SNP) markers derived from genotyping-by-sequencing (GBS) technology. After filtering, 11,866 SNPs were obtained and 798 markers, pruned for linkage disequilibrium, were used for structure analysis. The most probable number of subpopulations (K) was two, consistent with the presence of the two genepools, identified through the phaseolin diagnostic marker. Some landraces were admixed, suggesting probable hybridization events between Mesoamerican and Andean material. When increasing the number of possible Ks, the Andean germplasm appeared to be structured in two or three subgroups. The subdivision within the Andean material was also observed in a principal coordinate analysis (PCoA) plot and a dendrogram based on genetic distances. The Mesoamerican landraces showed a higher level of genetic diversity compared to the Andean landraces. Calculation of the fixation index (FST) at individual SNPs between the Mesoamerican and Andean genepools and within the Andean genepool evidenced clusters of highly divergent loci in specific chromosomal regions. This work may help to preserve landraces of the common bean from genetic erosion, and could represent a starting point for the identification of interesting traits that determine plant adaptation.

Genetic diversity of Colombian landraces of common bean as detected through the use of silver-stained and fluorescently labelled microsatellites

2011 ◽  
Vol 9 (01) ◽  
pp. 86-96 ◽  
Author(s):  
Lucy M. Díaz ◽  
Héctor F. Buendía ◽  
Myriam C. Duque ◽  
Matthew W. Blair
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Microsatellite Markers ◽  
Common Bean ◽  
Gene Pool ◽  
Major Gene ◽  
Gene Pools ◽  
Silver Stain ◽  
Fluorescent Marker ◽  
Fluorescent Markers

Colombia, situated at the northern end of the Andes mountains of South America and in proximity to Central America, is an important centre of diversity for common bean (Phaseolus vulgarisL.) that has a mix of cultivated germplasm from both major gene pools (Andean and Mesoamerican) for the species. Microsatellites are a useful marker system for analyzing genetic diversity of this crop and can be analyzed with manual (silver-stain) or automated (ABI) detection systems and using unlabelled or fluorescently labelled markers, respectively. The objectives of this research were to evaluate the genetic diversity of 92 Colombian landraces and gene pool controls with 36 fluorescent and 30 non-fluorescent microsatellite markers and to determine the extent of introgression between the Andean and Mesoamerican gene pools for this germplasm. A comparison of fluorescentversusnon-fluorescent marker systems was performed with 14 loci, which were evaluated with both methods; the fluorescent markers were found to be more precise than the non-fluorescent markers in determining population structure. A combined analysis of 52 microsatellites using the 36 fluorescent markers and 16 non-overlapping, silver-stained markers produced an accurate population structure for the Andean gene pool that separated race Nueva Granada and race Peru genotypes and clearly identified introgression between these races and the gene pools. The results of this research are important for the application of microsatellite markers to diversity analysis in common bean and for the conservation of landraces in Colombia and neighbouring countries of Latin America, where similar germplasm exists and where gene pool or race mixtures also occur.

RFLP diversity of common bean (Phaseolus vulgaris) in its centres of origin

Genome ◽  
1994 ◽  
Vol 37 (2) ◽  
pp. 256-263 ◽  
Author(s):  
Viviana L. Becerra Velasquez ◽  
Paul Gepts
Keyword(s):  
Genetic Diversity ◽  
Phaseolus Vulgaris ◽  
Common Bean ◽  
Restriction Fragment ◽  
Fragment Length ◽  
Gene Pool ◽  
Geographical Area ◽  
Rflp Markers ◽  
Gene Pools ◽  
Restriction Fragment Length

Eighty-five wild and cultivated accessions of common bean (Phaseolus vulgaris L.), representing a wide geographic area in the centres of domestication were tested for restriction fragment length polymorphisms (RFLPs). Genomic DNA was digested with one of three restriction enzymes (EcoRI, EcoRV, and HindIII) and hybridized to 12 probes distributed throughout the common bean genome. Accessions could be classified into two major groups with a distinct geographical distribution in Middle America and the Andes. Within each gene pool, cultivated accessions clustered together with wild forms from the same geographical area supporting the multiple domestications hypothesis for this crop. Estimates of Nei's genetic distances among the cultivated races from the two different gene pools varied from 0.12 to 0.56 and among races from the same gene pool from 0.04 to 0.12, suggesting that the divergence in Phaseolus vulgaris has reached the subspecies level. The level of genetic diversity (Ht = 0.38) was twice the value obtained with isozyme analysis. Genetic diversity within races (Hs = 0.27) was four to five times higher compared with isozymes, but genetic diversity between races (Dst = 0.11) was similar for both categories of markers. These results corroborate previous studies on the characterization of genetic diversity in common bean that clearly showed two distinct gene pools, Middle American and Andean. Moreover, RFLP markers are superior to isozymes because they provide better coverage of the genome and reveal higher level of polymorphisms.Key words: common bean, restriction fragment length polymorphism, domestication, genetic diversity.

scholarly journals Paleobiolinguistics of New World Crops and the Otomanguean Language Family

2015 ◽  
Vol 6 (1) ◽  
pp. 189-191 ◽  
Author(s):  
Cecil H. Brown
Keyword(s):  
Common Bean ◽  
New World ◽  
Common Ancestor ◽  
Chili Pepper ◽  
Language Family ◽  
World Language ◽  
Way Of Life ◽  
Language Groups ◽  
The Common

Several studies recently published in Ethnobiology Letters treat respectively the paleobiolinguistics of chili pepper, manioc, maize, and the common bean in New World language families. This includes the Otomanguean family of Mexico, one of the oldest language groups of the hemisphere, whose parent language may have been spoken at the latest around 6500 years ago. This communication addresses the possibility that Otomanguean paleobiolinguistics should be considered tentative since languages of the grouping are not yet conclusively demonstrated to be descended from a common ancestor. This challenges the proposal that words for chili pepper, manioc, and maize were in vocabularies of languages spoken two thousand or more years before development of a village-farming way of life in the New World.

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