Cecilia Fabiana Bessega

Bio: Cecilia Fabiana Bessega is an academic researcher from National Scientific and Technical Research Council. The author has contributed to research in topics: Prosopis alba & Heritability. The author has an hindex of 4, co-authored 5 publications receiving 77 citations. Previous affiliations of Cecilia Fabiana Bessega include Facultad de Ciencias Exactas y Naturales.

New microsatellite loci for Prosopis alba and P. chilensis (Fabaceae).

Abstract: Premise of the study: As only six useful microsatellite loci that exhibit broad cross-amplification are so far available for Prosopis species, it is necessary to develop a larger number of codominant markers for population genetic studies. Simple sequence repeat (SSR) markers obtained for Prosopis species from a 454 pyrosequencing run were optimized and characterized for studies in P. alba and P. chilensis. Methods and Results: Twelve markers that were successfully amplified showed polymorphism in P. alba and P. chilensis. The number of alleles per locus ranged between two and seven and heterozygosity estimates ranged from 0.2 to 0.8. Most of these loci cross-amplify in P. ruscifolia, P. flexuosa, P. kuntzei, P. glandulosa, and P. pallida. Conclusions: These loci will enable genetic diversity studies of P. alba and P. chilensis and contribute to fine-scale population structure, indirect estimation of relatedness among individuals, and marker-assisted selection.

Consistency between marker- and genealogy-based heritability estimates in an experimental stand of Prosopis alba (Leguminosae)

Abstract: Prosopis represents a valuable forest resource in arid and semiarid regions. Management of promising species requires information about genetic parameters, mainly the heritability (h(2)) of quantitative profitable traits. This parameter is traditionally estimated from progeny tests or half-sib analysis conducted in experimental stands. Such an approach estimates h(2) from the ratio of between-family/total phenotypic variance. These analyses are difficult to apply to natural populations of species with a long life cycle, overlapping generations, and a mixed mating system, without genealogical information. A promising alternative is the use of molecular marker information to infer relatedness between individuals and to estimate h(2) from the regression of phenotypic similarity on inferred relatedness. In the current study we compared h(2) of 13 quantitative traits estimated by these two methods in an experimental stand of P. alba, where genealogical information was available. We inferred pairwise relatedness by Ritland's method using six microsatellite loci. Relatedness and heritability estimates from molecular information were highly correlated to the values obtained from genealogical data. Although Ritland's method yields lower h(2) estimates and tends to overestimate genetic correlations between traits, this approach is useful to predict the expected relative gain of different quantitative traits under selection without genealogical information.

Section Mimadenia: its phylogenetic relationships within the genus Mimosa (Leguminosae, Mimosoideae) using plastid trnL–F sequence data

Abstract: Fil: Bessega, Cecilia Fabiana. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecologia, Genetica y Evolucion. Laboratorio de Genetica; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas; Argentina

Cytogeography and morphological characterisation of a taxonomic, polyploid complex of Mimosa (Leguminosae) from subtropical South America

Abstract: Mimosa subseries Dolentes Barneby and Brevipedes Barneby are ecologically and morphologically high-diversified infrageneric taxa of this genus in southern South America. We performed a cytogenetical and morphological analysis of both subseries. Chromosome numbers from accessions throughout the area of distribution were studied. The chromosome numbers 2n=8x=104 for M. dolens subsp. callosa (Benth.) Barneby, M. dolens subsp. acerba varieties acerba (Benth.) Barneby, latifolia (Benth.) Barneby and rudis (Benth.) Barneby, M. dolens subsp. rigida var. rigescens (Benth.) Barneby, var. anisitsii (Lindm.) Barneby and var. foliolosa (Benth.) Barneby; and 2n=4x=52 for M. sceptrum Barneby, M. aff. custodis Barneby and M. dolens var. pangloea Barneby are presented for the first time. Their karyotypes were symmetric, with small chromosomes. There were several areas with taxa growing in sympatry, occasionally with intermediate forms. No diploids were found, which suggests the presence of either a declining polyploid complex or ancient polyploidy in the clade of southernmost representatives of M. series Mimosa, the most derived of the genus. Some vegetative, inflorescence and carpological characters seem to be associated with chromosome duplication. The distribution pattern of the cytotypes suggests events of chromosome duplication in centres of diversity and expansion of octoploids to the southernmost areas of distribution. Our findings support the importance of polyploidy in the morphological diversity, distribution and speciation of this complex.

Genetic Variation Patterns of “Algarrobos” from the “Great American Chaco” (Prosopis alba, P. nigra, P. hassleri, P. fiebrigii, P. ruscifolia, P. chilensis, and P. flexuosa)

Abstract: The “algarrobos complex of species” (Prosopis spp.) has its center of diversity in the “Gran Chaco Americano.” Hybrid swarms and a continuum of morphological and genetic variation difficult the taxonomic identification as well as the definition of conservation and management units. Therefore, the development and use of morphological markers in leaves and fruits helped in species delimitation. In addition, the genetic characterization through neutral markers (isozymes, microsatellites) with the existence of species-specific alleles provided further insights. Natural interspecific hybridization processes were evaluated through morphological traits and molecular markers. Discrimination of species, morpho-groups within species and interspecific hybrids is presented in this chapter. Phylogeny and phylogeography of the genus through maternally inherited markers (noncoding sequences of chloroplasts) showed the underlying historical process shaping the disjunct distribution of some species. For evaluating adaptation, genetic characterization through the analysis of variation in quantitative traits is also presented. Finally, estimations of mating system parameters and pollen dispersal as well as spatial genetic structure provide information on the reproductive biology and migration abilities of the species.

Microsatellite markers: what they mean and why they are so useful.

Abstract: Microsatellites or Single Sequence Repeats (SSRs) are extensively employed in plant genetics studies, using both low and high throughput genotyping approaches. Motivated by the importance of these sequences over the last decades this review aims to address some theoretical aspects of SSRs, including definition, characterization and biological function. The methodologies for the development of SSR loci, genotyping and their applications as molecular markers are also reviewed. Finally, two data surveys are presented. The first was conducted using the main database of Web of Science, prospecting for articles published over the period from 2010 to 2015, resulting in approximately 930 records. The second survey was focused on papers that aimed at SSR marker development, published in the American Journal of Botany's Primer Notes and Protocols in Plant Sciences (over 2013 up to 2015), resulting in a total of 87 publications. This scenario confirms the current relevance of SSRs and indicates their continuous utilization in plant science.

Legume phylogeny and classification in the 21st century: Progress, prospects and lessons for other species-rich clades

Abstract: The Leguminosae, the third-largest angiosperm family, has a global distribution and high ecological and economic importance We examine how the legume systematic research community might join forces to produce a comprehensive phylogenetic estimate for the ca 751 genera and ca 19,500 species of legumes and then translate it into a phylogeny-based classification We review the current state of knowledge of legume phylogeny and highlight where problems lie, for example in taxon sampling and phylogenetic resolution We review approaches from bioinformatics and next-generation sequencing, which can facilitate the production of better phylogenetic estimates Finally, we examine how morphology can be incorporated into legume phylogeny to address issues in comparative biology and classification Our goal is to stimulate the research needed to improve our knowledge of legume phylogeny and evolution; the approaches that we discuss may also be relevant to other species-rich angiosperm clades

The Leguminosae of Madagascar

Abstract: A revision of the Leguminosae of Madagascar is soon to be completed, covering some 670 species (c. 565 native to Madagascar of which 449 endemic) including 6 new genera and 121 new species. It has provided the basis for a pilot project applying computer mapping (GIS) to the investigation of ecological parameters which determine the extent of species distributions. Vegetation maps, based on these parameters, are being used for planning and managing the conservation of biodiversity in Madagascar.

Evolutionary potential in the Alpine: trait heritabilities and performance variation of the dwarf willow Salix herbacea from different elevations and microhabitats.

Abstract: Alpine ecosystems are seriously threatened by climate change. One of the key mechanisms by which plants can adapt to changing environmental conditions is through evolutionary change. However, we still know little about the evolutionary potential in wild populations of long-lived alpine plants. Here, we investigated heritabilities of phenological traits, leaf size, and performance traits in natural populations of the long-lived alpine dwarf shrub Salix herbacea using relatedness estimates inferred from SSR (Simple Sequence Repeat) markers. Salix herbacea occurs in early- and late-snowmelt microhabitats (ridges and snowbeds), and we assessed how performance consequences of phenological traits and leaf size differ between these microhabitats in order to infer potential for evolutionary responses. Salix herbacea showed low, but significant, heritabilities of leaf size, clonal and sexual reproduction, and moderate heritabilities of phenological traits. In both microhabitats, we found that larger leaves, longer intervals between snowmelt and leaf expansion, and longer GDD (growing-degree days) until leaf expansion resulted in a stronger increase in the number of stems (clonal reproduction). In snowbeds, clonal reproduction increased with a shorter GDD until flowering, while the opposite was found on ridges. Furthermore, the proportion of flowering stems increased with GDD until flowering in both microhabitats. Our results suggest that the presence of significant heritable variation in morphology and phenology might help S. herbacea to adapt to changing environmental conditions. However, it remains to be seen if the rate of such an evolutionary response can keep pace with the rapid rate of climate change.