A polymorphic population of Phaseolus vulgaris var. aborigineus growing at the Northwest of Argen... more A polymorphic population of Phaseolus vulgaris var. aborigineus growing at the Northwest of Argentina was studied. In order to know the origin of this polymorphism, some plants belonging to the var. aborigineus, other plants showing floral dimorphism and other individuals with particular characters were collected. Their seeds, obtained after field-work treatments of autogamy and free pollination, were sown in a greenhouse, isolated of the access of pollinators. The growth of each plant was followed until its fructification, and the number of plants that died due to infections was recorded. The number of plants that flowered and fructified was registered in order to study their reproductive success. The floral, fruit and seed qualitative and quantitative characters were documented. With the results obtained, the authors concluded that those individuals that showed floral dimorphism are probably a result of hybridization and introgression between the var. aborigineus and "old cultivars". This hypothesis is supported by the presence of divergent segregation, observed in the offspring of the plants with this segregation. Other crops should allow the genic flow between the parental entities, with the consequence of the establishment of an hybrid population coexistent with their ancestors. Perhaps, as a result of introgression, the stabilized lines exhibit characters different from their parental varieties. The results of autopollination and free pollination in those individuals assigned to var. aborigineus, showed that free pollination brings a great genetic plasticity, because next generations can persist and resist infections. The offspring of the F1 was followed. The plants that belonged to var. aborigineus, product of free pollination, exhibited fast growth and were healthy, while the descendant of the individuals with the floral dimorphism showed characteristics that allowed to conclude the possible existence of degeneration of the hybrid progeny; this characteristics were: curled radicles with cotyledons that never emerge, plantule's apex that soon die with the following development of branches from the cotyledon's axil, and death after some weeks. This degeneration indicates that an unwanted gene flow in the area could lead to a decline in the wild bean population. The vigor, high reproductive success and resistance to illnesses of the individuals corresponding to the var. vulgaris, whose progenitor was treated for free fecundation, and the offspring of the plants with cultivated characteristics, are indicative of the necessity of preserving this germplasm to evaluate its agronomic potential to brief term. The DNA analyses already initiated, will allow the confirmation of the hypotheses outlined in this work.
A polymorphic population of Phaseolus vulgaris var. aborigineus growing at the Northwest of Argen... more A polymorphic population of Phaseolus vulgaris var. aborigineus growing at the Northwest of Argentina was studied. In order to know the origin of this polymorphism, some plants belonging to the var. aborigineus, other plants showing floral dimorphism and other individuals with particular characters were collected. Their seeds, obtained after field-work treatments of autogamy and free pollination, were sown in a greenhouse, isolated of the access of pollinators. The growth of each plant was followed until its fructification, and the number of plants that died due to infections was recorded. The number of plants that flowered and fructified was registered in order to study their reproductive success. The floral, fruit and seed qualitative and quantitative characters were documented. With the results obtained, the authors concluded that those individuals that showed floral dimorphism are probably a result of hybridization and introgression between the var. aborigineus and "old cul...
Abstract Prosopis L. is a rather primitive genus within the LeguminosaeMimosoideae. This genus h... more Abstract Prosopis L. is a rather primitive genus within the LeguminosaeMimosoideae. This genus has been divided into five sections on the basis especially of the vegetative diversification of the spines. Three of the sections, Algarobia, Monilicarpa and ...
Page 1. 31 AD BURGHARDT et al. Variabilidad genética en Prosopis ferox (Mimosaceae) ISSN 0011-679... more Page 1. 31 AD BURGHARDT et al. Variabilidad genética en Prosopis ferox (Mimosaceae) ISSN 0011-6793 DARWINIANA 42(1-4): 31-36. 2004 VARIABILIDAD GENÉTICA EN PROSOPIS FEROX (MIMOSACEAE) ALICIA D. BURGHARDT1 ...
Patricia S. Hoc*, Shirley M. Espert, Susana I. Drewes and Alicia D. Burghardt Laboratorio de Plan... more Patricia S. Hoc*, Shirley M. Espert, Susana I. Drewes and Alicia D. Burghardt Laboratorio de Plantas Vasculares, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina; *Author for correspondence (e-mail: [email protected])
Macroptilium is a herbaceous legume genus with 18 currently accepted species, seven of them with ... more Macroptilium is a herbaceous legume genus with 18 currently accepted species, seven of them with economic importance due to their use as forage, green fertilizer and in medicine. The genus is strictly American, with an unknown biogeographic history. The aim of this study was to infer a biogeographic pattern of Macroptilium and to estimate its divergence times, using sequences from the nuclear ribosomal DNA internal transcribed spacers.
... Patricia S. Hoc, Shirley M. Espert, Susana I. Drewes & Alicia D. Burghardt. ... l... more ... Patricia S. Hoc, Shirley M. Espert, Susana I. Drewes & Alicia D. Burghardt. ... legumbres y las semillas obtenidas de cada flor según el tratamiento, fueron caracterizadas, tomándose las siguientes mediciones: largo, ancho y espesor de la legumbre, largo de su rostro; ángulo de ...
Cladistic analyses are made based on morphological characters and chromosome basic numbers in ord... more Cladistic analyses are made based on morphological characters and chromosome basic numbers in order to test the monophyly of the nine series of genus Turnera (Turneraceae). Series Annulares and Turnera are monophyletic, and also series Anomalae with the exception of two species with unknown fruit and seed mor- phology. Series Microphyllae and Papilliferae should be merged, and also series Salicifoliae and Stenodictyae together with some species of series Capitatae. The Capitatae split in several groups and series Leiocarpae is unresolved. The Turnera sidoides complex should be separated into a new series. Biogeographic analyses show that the major diversification of the genus took place in the Chaquean subregion, with vicariance and dispersal events to other Neotropical subregions and Africa.
Chromosomic features described so far for Americans legumes are reviewed and analyzed, simultaneo... more Chromosomic features described so far for Americans legumes are reviewed and analyzed, simultaneously with morphological and molecular characters. This is an invaluable opportunity to propose hypotheses about chromosome changes during the family divergence and speciation processes. The chromosome studies showed wide inter-generic, inter and intra-specific variability, as well as marked differences in genome sizes between genera, species and populations. By postulating an ancestral basic number of seven (x=7) it is possible to deduce that polyploid hybrid speciation was very important in the diversification of the family as a whole. Due to increasing and decreasing diploidy processes, secondary basic numbers and modified polyploids series could have arised both at diploid and polyploid levels. On the other hand, recurrent origin of polyploids, occurrence of inter-genomic rearrangements, hybridization and secondary polyploidy are all processes that make it difficult to group the taxa within the Leguminosae family in a natural sequence.
Abstract
Background and aims: Macroptilium is a herbaceous legume genus with 18 currently accepte... more Abstract Background and aims: Macroptilium is a herbaceous legume genus with 18 currently accepted species, seven of them with economic importance due to their use as forage, green fertilizer and in medicine. The genus is strictly American, with an unknown biogeographic history. The aim of this study was to infer a biogeographic pattern of Macroptilium and to estimate its divergence times, using sequences from the nuclear ribosomal DNA internal transcribed spacers. Methodology: To study the historical biogeography of Macroptilium, two approaches were used: area optim- ization on a previously obtained phylogeny and a dispersal–vicariance analysis. Divergence times were calculated by Bayesian methods. Principal results: The analyses revealed that Macroptilium has its origin in the middle Pliocene, with an esti- mated age that ranges from 2.9 to 4 million years. The biogeographic analyses placed its origin in South America, specifically on the Chaquean sub-region, where most of the cladoge- netic events of the genus took place. Conclusions: Macroptilium constitutes a further example of the geographic pattern displayed by numerous Neotropical taxa that moved north from South America to dominate the Central American lowlands after the land connection across the Isthmus of Panama was established.
Enterotoxigenic Escherichia coli (ETEC) is a gram-negative enteric pathogen that causes profuse w... more Enterotoxigenic Escherichia coli (ETEC) is a gram-negative enteric pathogen that causes profuse watery diarrhea through the elaboration of heat–labile and/or heat–stable toxins. Virulence is also dependent upon the expression of adhesive pili and afimbrial adhesins that allow the pathogen to adhere to the intestinal epithelium or mucosa. Both types of enterotoxins are regulated at the level of transcription by cAMP receptor protein (CRP). To further our understanding of virulence gene regulation, an in silico approach was used to identify putative CRP binding sites in the genome of H10407 (O78:H11), an ETEC strain that was originally isolated from the stool of a Bangledeshi patient with cholera–like symptoms circa 1971. One of the predicted binding sites was located within an intergenic region upstream of tibDBCA. TibA is an autotransporter and afimbrial adhesin that is glycosylated by TibC. Expression of the TibA glycoprotein was abolished in an H10407 crp mutant and restored when crp was provided in trans. TibA–dependent aggregation was also abolished in a cyaA::kan strain and restored by addition of exogenous cAMP to the growth medium. DNase I footprinting confirmed that the predicted site upstream of tibDBCA is bound by CRP. Point mutations within the CRP binding site were found to abolish or significantly impair CRP–dependent activation of the tibDB promoter. Thus, these studies demonstrate that CRP positively regulates the expression of the glycosylated afimbrial adhesin TibA through occupancy of a binding site within tibDBp.
The base chromosome number of x = 11 is the most probable in all the subtribes included in tribe ... more The base chromosome number of x = 11 is the most probable in all the subtribes included in tribe Phaseoleae, although some aneuploid reduction is evident in Collaea and Galactia (Diocleinae) and chromosome duplications are seen in Amphicarpaea, Cologania and Glycine (Glycininae). The aims of this study were to improve the cytological knowledge of some species of Collaea and Galactia and to examine the anomalous counts reported for Calopogonium (Glycininae) and verify its taxonomic position. In addition, a molecular phylogeny was constructed using nuclear ribosomal DNA sequences (internal transcribed spacer region), and the chromosome number was optimized on the topology. In this work, the chromosome counts for Galactia lindenii, Galactia decumbens and Collaea cipoensis (all 2n = 20), and Calopogonium sericeum (2n = 22) are reported for the first time. The new reports for Galactia and Collaea species are in agreement with the chromosome number proposed for subtribe Diocleinae. The study rejects the concept of a cytologically anomalous Calopogonium and, based on the phylogenetic analysis, corroborates the position of this genus within subtribe Glycininae. The ancestral basic chromosome number of x = 11 proposed for Phaseoleae is in agreement with the evolutionary pathway of chromosome numbers analysed in this work.
Prosopis L. is a rather primitive genus within the Leguminosae–Mimosoideae. This genus has been d... more Prosopis L. is a rather primitive genus within the Leguminosae–Mimosoideae. This genus has been divided into five sections on the basis especially of the vegetative diversification of the spines. Three of the sections, Algarobia, Monilicarpa and Strombocarpa, are distributed in America. In order to elucidate systematic relationships between the American sections of Prosopis, a morphological and biochemical phylogeny were obtained. Twenty-two morphological characters were scored for 27 species of Prosopis and the outgroup taxon following polyacrilamide gel electrophoresis of seed storage proteins. The results obtained clearly prove that the secction Strombocarpa is a natural taxon. The section Algarobia, on the other hand, seems to comprise an artificial grouping of species. Members of the series Denudantes appear isolated from the remaining species, therefore this taxon should be treated as a new section within Prosopis. The section Algarobia should be circumscribed to series Chilenses, Ruscifoliae and Pallidae, which are always united in a monophyletic clade. Finally, no evidence was found to confirm the existence of the section Monilicarpa.
Macroptilium (Benth.) Urban (Phaseoleae, Papilionoideae, Leguminosae) is an American genus of leg... more Macroptilium (Benth.) Urban (Phaseoleae, Papilionoideae, Leguminosae) is an American genus of legumes, belonging to subtribe Phaseolinae along with other economically important genera, such as Vigna Savi and Phaseolus L. (the common bean genus). Cladistic analyses based on morphological, biochemical (storage seed proteins) and molecular (nuclear and plastid DNA sequences) data were performed on the 18 species currently ascribed to the genus, exploring several character weighting strategies. Equal weights, implied weighting and different transversion⁄transition costs were applied. The three data sets were first analyzed with separate partitions, and then combined into a single matrix. This study is the first one to analyze all the species of the genus from a cladistic point of view. In all the most parsimonious trees obtained, Macroptilium is monophyletic with excellent support values. Two monophyletic clades are recovered in almost all the analyses. Both are compound by nine species, and they constitute two sections of Macroptilium. Several interspecific relationships inside the genus are discussed.
A polymorphic population of Phaseolus vulgaris L. var. aborigineus (Burkart) Baudet growing in no... more A polymorphic population of Phaseolus vulgaris L. var. aborigineus (Burkart) Baudet growing in north- western Argentina was studied. In order to know the origin of this polymorphism, plants belonging to the var. aborigineus, others showing floral dimorphism and individuals with weedy type characters were col- lected. Their seeds, obtained after fieldwork treatments of autogamy and free pollination in order to know their reproductive system, were sown in a greenhouse. Information of their growth was recorded and several numerical analyses were performed. With the results obtained, we concluded that those individuals that showed floral dimorphism are probably a result of hybridization and/or introgression between the var. aborigineus and cultivated forms that grow in the area. This hypothesis is supported by the presence of divergent segregation in the offspring. Also, the offspring of the F1 was followed and allowed us to conclude the possible existence of degeneration of the hybrid progeny. This degeneration indicates that an unwanted gene flow in the area could lead to a decline in the wild bean population. The vigour and high reproductive success of the offspring belonging to the individuals corresponding to the var. aborigineus, whose progenitor was treated for outcrossing, and the existence of plants with weedy type characteristics, are indicative of the necessity to preserve this germplasm in order to evaluate its agronomic potential as brief as possible. The population here studied constitutes a wild-weed–crop complex growing in Argentina.
Burghardt, A. D., Espert, S. M. & Braun Wilke, R. H. 2004. Genetic variation in Prosopis ferox (M... more Burghardt, A. D., Espert, S. M. & Braun Wilke, R. H. 2004. Genetic variation in Prosopis ferox (Mimosaceae). Darwiniana 42(1-4):
A polymorphic population of Phaseolus vulgaris var. aborigineus growing at the Northwest of Argen... more A polymorphic population of Phaseolus vulgaris var. aborigineus growing at the Northwest of Argentina was studied. In order to know the origin of this polymorphism, some plants belonging to the var. aborigineus, other plants showing floral dimorphism and other individuals with particular characters were collected. Their seeds, obtained after field-work treatments of autogamy and free pollination, were sown in a greenhouse, isolated of the access of pollinators. The growth of each plant was followed until its fructification, and the number of plants that died due to infections was recorded. The number of plants that flowered and fructified was registered in order to study their reproductive success. The floral, fruit and seed qualitative and quantitative characters were documented. With the results obtained, the authors concluded that those individuals that showed floral dimorphism are probably a result of hybridization and introgression between the var. aborigineus and "old cultivars". This hypothesis is supported by the presence of divergent segregation, observed in the offspring of the plants with this segregation. Other crops should allow the genic flow between the parental entities, with the consequence of the establishment of an hybrid population coexistent with their ancestors. Perhaps, as a result of introgression, the stabilized lines exhibit characters different from their parental varieties. The results of autopollination and free pollination in those individuals assigned to var. aborigineus, showed that free pollination brings a great genetic plasticity, because next generations can persist and resist infections. The offspring of the F1 was followed. The plants that belonged to var. aborigineus, product of free pollination, exhibited fast growth and were healthy, while the descendant of the individuals with the floral dimorphism showed characteristics that allowed to conclude the possible existence of degeneration of the hybrid progeny; this characteristics were: curled radicles with cotyledons that never emerge, plantule's apex that soon die with the following development of branches from the cotyledon's axil, and death after some weeks. This degeneration indicates that an unwanted gene flow in the area could lead to a decline in the wild bean population. The vigor, high reproductive success and resistance to illnesses of the individuals corresponding to the var. vulgaris, whose progenitor was treated for free fecundation, and the offspring of the plants with cultivated characteristics, are indicative of the necessity of preserving this germplasm to evaluate its agronomic potential to brief term. The DNA analyses already initiated, will allow the confirmation of the hypotheses outlined in this work.
A polymorphic population of Phaseolus vulgaris var. aborigineus growing at the Northwest of Argen... more A polymorphic population of Phaseolus vulgaris var. aborigineus growing at the Northwest of Argentina was studied. In order to know the origin of this polymorphism, some plants belonging to the var. aborigineus, other plants showing floral dimorphism and other individuals with particular characters were collected. Their seeds, obtained after field-work treatments of autogamy and free pollination, were sown in a greenhouse, isolated of the access of pollinators. The growth of each plant was followed until its fructification, and the number of plants that died due to infections was recorded. The number of plants that flowered and fructified was registered in order to study their reproductive success. The floral, fruit and seed qualitative and quantitative characters were documented. With the results obtained, the authors concluded that those individuals that showed floral dimorphism are probably a result of hybridization and introgression between the var. aborigineus and "old cul...
Abstract Prosopis L. is a rather primitive genus within the LeguminosaeMimosoideae. This genus h... more Abstract Prosopis L. is a rather primitive genus within the LeguminosaeMimosoideae. This genus has been divided into five sections on the basis especially of the vegetative diversification of the spines. Three of the sections, Algarobia, Monilicarpa and ...
Page 1. 31 AD BURGHARDT et al. Variabilidad genética en Prosopis ferox (Mimosaceae) ISSN 0011-679... more Page 1. 31 AD BURGHARDT et al. Variabilidad genética en Prosopis ferox (Mimosaceae) ISSN 0011-6793 DARWINIANA 42(1-4): 31-36. 2004 VARIABILIDAD GENÉTICA EN PROSOPIS FEROX (MIMOSACEAE) ALICIA D. BURGHARDT1 ...
Patricia S. Hoc*, Shirley M. Espert, Susana I. Drewes and Alicia D. Burghardt Laboratorio de Plan... more Patricia S. Hoc*, Shirley M. Espert, Susana I. Drewes and Alicia D. Burghardt Laboratorio de Plantas Vasculares, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina; *Author for correspondence (e-mail: [email protected])
Macroptilium is a herbaceous legume genus with 18 currently accepted species, seven of them with ... more Macroptilium is a herbaceous legume genus with 18 currently accepted species, seven of them with economic importance due to their use as forage, green fertilizer and in medicine. The genus is strictly American, with an unknown biogeographic history. The aim of this study was to infer a biogeographic pattern of Macroptilium and to estimate its divergence times, using sequences from the nuclear ribosomal DNA internal transcribed spacers.
... Patricia S. Hoc, Shirley M. Espert, Susana I. Drewes & Alicia D. Burghardt. ... l... more ... Patricia S. Hoc, Shirley M. Espert, Susana I. Drewes & Alicia D. Burghardt. ... legumbres y las semillas obtenidas de cada flor según el tratamiento, fueron caracterizadas, tomándose las siguientes mediciones: largo, ancho y espesor de la legumbre, largo de su rostro; ángulo de ...
Cladistic analyses are made based on morphological characters and chromosome basic numbers in ord... more Cladistic analyses are made based on morphological characters and chromosome basic numbers in order to test the monophyly of the nine series of genus Turnera (Turneraceae). Series Annulares and Turnera are monophyletic, and also series Anomalae with the exception of two species with unknown fruit and seed mor- phology. Series Microphyllae and Papilliferae should be merged, and also series Salicifoliae and Stenodictyae together with some species of series Capitatae. The Capitatae split in several groups and series Leiocarpae is unresolved. The Turnera sidoides complex should be separated into a new series. Biogeographic analyses show that the major diversification of the genus took place in the Chaquean subregion, with vicariance and dispersal events to other Neotropical subregions and Africa.
Chromosomic features described so far for Americans legumes are reviewed and analyzed, simultaneo... more Chromosomic features described so far for Americans legumes are reviewed and analyzed, simultaneously with morphological and molecular characters. This is an invaluable opportunity to propose hypotheses about chromosome changes during the family divergence and speciation processes. The chromosome studies showed wide inter-generic, inter and intra-specific variability, as well as marked differences in genome sizes between genera, species and populations. By postulating an ancestral basic number of seven (x=7) it is possible to deduce that polyploid hybrid speciation was very important in the diversification of the family as a whole. Due to increasing and decreasing diploidy processes, secondary basic numbers and modified polyploids series could have arised both at diploid and polyploid levels. On the other hand, recurrent origin of polyploids, occurrence of inter-genomic rearrangements, hybridization and secondary polyploidy are all processes that make it difficult to group the taxa within the Leguminosae family in a natural sequence.
Abstract
Background and aims: Macroptilium is a herbaceous legume genus with 18 currently accepte... more Abstract Background and aims: Macroptilium is a herbaceous legume genus with 18 currently accepted species, seven of them with economic importance due to their use as forage, green fertilizer and in medicine. The genus is strictly American, with an unknown biogeographic history. The aim of this study was to infer a biogeographic pattern of Macroptilium and to estimate its divergence times, using sequences from the nuclear ribosomal DNA internal transcribed spacers. Methodology: To study the historical biogeography of Macroptilium, two approaches were used: area optim- ization on a previously obtained phylogeny and a dispersal–vicariance analysis. Divergence times were calculated by Bayesian methods. Principal results: The analyses revealed that Macroptilium has its origin in the middle Pliocene, with an esti- mated age that ranges from 2.9 to 4 million years. The biogeographic analyses placed its origin in South America, specifically on the Chaquean sub-region, where most of the cladoge- netic events of the genus took place. Conclusions: Macroptilium constitutes a further example of the geographic pattern displayed by numerous Neotropical taxa that moved north from South America to dominate the Central American lowlands after the land connection across the Isthmus of Panama was established.
Enterotoxigenic Escherichia coli (ETEC) is a gram-negative enteric pathogen that causes profuse w... more Enterotoxigenic Escherichia coli (ETEC) is a gram-negative enteric pathogen that causes profuse watery diarrhea through the elaboration of heat–labile and/or heat–stable toxins. Virulence is also dependent upon the expression of adhesive pili and afimbrial adhesins that allow the pathogen to adhere to the intestinal epithelium or mucosa. Both types of enterotoxins are regulated at the level of transcription by cAMP receptor protein (CRP). To further our understanding of virulence gene regulation, an in silico approach was used to identify putative CRP binding sites in the genome of H10407 (O78:H11), an ETEC strain that was originally isolated from the stool of a Bangledeshi patient with cholera–like symptoms circa 1971. One of the predicted binding sites was located within an intergenic region upstream of tibDBCA. TibA is an autotransporter and afimbrial adhesin that is glycosylated by TibC. Expression of the TibA glycoprotein was abolished in an H10407 crp mutant and restored when crp was provided in trans. TibA–dependent aggregation was also abolished in a cyaA::kan strain and restored by addition of exogenous cAMP to the growth medium. DNase I footprinting confirmed that the predicted site upstream of tibDBCA is bound by CRP. Point mutations within the CRP binding site were found to abolish or significantly impair CRP–dependent activation of the tibDB promoter. Thus, these studies demonstrate that CRP positively regulates the expression of the glycosylated afimbrial adhesin TibA through occupancy of a binding site within tibDBp.
The base chromosome number of x = 11 is the most probable in all the subtribes included in tribe ... more The base chromosome number of x = 11 is the most probable in all the subtribes included in tribe Phaseoleae, although some aneuploid reduction is evident in Collaea and Galactia (Diocleinae) and chromosome duplications are seen in Amphicarpaea, Cologania and Glycine (Glycininae). The aims of this study were to improve the cytological knowledge of some species of Collaea and Galactia and to examine the anomalous counts reported for Calopogonium (Glycininae) and verify its taxonomic position. In addition, a molecular phylogeny was constructed using nuclear ribosomal DNA sequences (internal transcribed spacer region), and the chromosome number was optimized on the topology. In this work, the chromosome counts for Galactia lindenii, Galactia decumbens and Collaea cipoensis (all 2n = 20), and Calopogonium sericeum (2n = 22) are reported for the first time. The new reports for Galactia and Collaea species are in agreement with the chromosome number proposed for subtribe Diocleinae. The study rejects the concept of a cytologically anomalous Calopogonium and, based on the phylogenetic analysis, corroborates the position of this genus within subtribe Glycininae. The ancestral basic chromosome number of x = 11 proposed for Phaseoleae is in agreement with the evolutionary pathway of chromosome numbers analysed in this work.
Prosopis L. is a rather primitive genus within the Leguminosae–Mimosoideae. This genus has been d... more Prosopis L. is a rather primitive genus within the Leguminosae–Mimosoideae. This genus has been divided into five sections on the basis especially of the vegetative diversification of the spines. Three of the sections, Algarobia, Monilicarpa and Strombocarpa, are distributed in America. In order to elucidate systematic relationships between the American sections of Prosopis, a morphological and biochemical phylogeny were obtained. Twenty-two morphological characters were scored for 27 species of Prosopis and the outgroup taxon following polyacrilamide gel electrophoresis of seed storage proteins. The results obtained clearly prove that the secction Strombocarpa is a natural taxon. The section Algarobia, on the other hand, seems to comprise an artificial grouping of species. Members of the series Denudantes appear isolated from the remaining species, therefore this taxon should be treated as a new section within Prosopis. The section Algarobia should be circumscribed to series Chilenses, Ruscifoliae and Pallidae, which are always united in a monophyletic clade. Finally, no evidence was found to confirm the existence of the section Monilicarpa.
Macroptilium (Benth.) Urban (Phaseoleae, Papilionoideae, Leguminosae) is an American genus of leg... more Macroptilium (Benth.) Urban (Phaseoleae, Papilionoideae, Leguminosae) is an American genus of legumes, belonging to subtribe Phaseolinae along with other economically important genera, such as Vigna Savi and Phaseolus L. (the common bean genus). Cladistic analyses based on morphological, biochemical (storage seed proteins) and molecular (nuclear and plastid DNA sequences) data were performed on the 18 species currently ascribed to the genus, exploring several character weighting strategies. Equal weights, implied weighting and different transversion⁄transition costs were applied. The three data sets were first analyzed with separate partitions, and then combined into a single matrix. This study is the first one to analyze all the species of the genus from a cladistic point of view. In all the most parsimonious trees obtained, Macroptilium is monophyletic with excellent support values. Two monophyletic clades are recovered in almost all the analyses. Both are compound by nine species, and they constitute two sections of Macroptilium. Several interspecific relationships inside the genus are discussed.
A polymorphic population of Phaseolus vulgaris L. var. aborigineus (Burkart) Baudet growing in no... more A polymorphic population of Phaseolus vulgaris L. var. aborigineus (Burkart) Baudet growing in north- western Argentina was studied. In order to know the origin of this polymorphism, plants belonging to the var. aborigineus, others showing floral dimorphism and individuals with weedy type characters were col- lected. Their seeds, obtained after fieldwork treatments of autogamy and free pollination in order to know their reproductive system, were sown in a greenhouse. Information of their growth was recorded and several numerical analyses were performed. With the results obtained, we concluded that those individuals that showed floral dimorphism are probably a result of hybridization and/or introgression between the var. aborigineus and cultivated forms that grow in the area. This hypothesis is supported by the presence of divergent segregation in the offspring. Also, the offspring of the F1 was followed and allowed us to conclude the possible existence of degeneration of the hybrid progeny. This degeneration indicates that an unwanted gene flow in the area could lead to a decline in the wild bean population. The vigour and high reproductive success of the offspring belonging to the individuals corresponding to the var. aborigineus, whose progenitor was treated for outcrossing, and the existence of plants with weedy type characteristics, are indicative of the necessity to preserve this germplasm in order to evaluate its agronomic potential as brief as possible. The population here studied constitutes a wild-weed–crop complex growing in Argentina.
Burghardt, A. D., Espert, S. M. & Braun Wilke, R. H. 2004. Genetic variation in Prosopis ferox (M... more Burghardt, A. D., Espert, S. M. & Braun Wilke, R. H. 2004. Genetic variation in Prosopis ferox (Mimosaceae). Darwiniana 42(1-4):
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Papers by Shirley Espert
Background and aims: Macroptilium is a herbaceous legume genus with 18 currently accepted species, seven of them with economic importance due to their use as forage, green fertilizer and in medicine. The genus is strictly American, with an unknown biogeographic history. The aim of this study was to infer a biogeographic pattern of Macroptilium and to estimate its divergence times, using sequences from the nuclear ribosomal DNA internal transcribed spacers.
Methodology: To study the historical biogeography of Macroptilium, two approaches were used: area optim- ization on a previously obtained phylogeny and a dispersal–vicariance analysis. Divergence times were calculated by Bayesian methods.
Principal results: The analyses revealed that Macroptilium has its origin in the middle Pliocene, with an esti- mated age that ranges from 2.9 to 4 million years. The biogeographic analyses placed its origin in South America, specifically on the Chaquean sub-region, where most of the cladoge- netic events of the genus took place.
Conclusions: Macroptilium constitutes a further example of the geographic pattern displayed by numerous Neotropical taxa that moved north from South America to dominate the Central American lowlands after the land connection across the Isthmus of Panama was established.
Background and aims: Macroptilium is a herbaceous legume genus with 18 currently accepted species, seven of them with economic importance due to their use as forage, green fertilizer and in medicine. The genus is strictly American, with an unknown biogeographic history. The aim of this study was to infer a biogeographic pattern of Macroptilium and to estimate its divergence times, using sequences from the nuclear ribosomal DNA internal transcribed spacers.
Methodology: To study the historical biogeography of Macroptilium, two approaches were used: area optim- ization on a previously obtained phylogeny and a dispersal–vicariance analysis. Divergence times were calculated by Bayesian methods.
Principal results: The analyses revealed that Macroptilium has its origin in the middle Pliocene, with an esti- mated age that ranges from 2.9 to 4 million years. The biogeographic analyses placed its origin in South America, specifically on the Chaquean sub-region, where most of the cladoge- netic events of the genus took place.
Conclusions: Macroptilium constitutes a further example of the geographic pattern displayed by numerous Neotropical taxa that moved north from South America to dominate the Central American lowlands after the land connection across the Isthmus of Panama was established.