Due to the strategic importance of sugarcane to Brazil, FAPESP, the main São Paulo state research funding agency, launched in 2008 the FAPESP Bioenergy Research Program (BIOEN, http://bioenfapesp.org). BIOEN aims to generate new knowledge and human resources for the improvement of the sugarcane and ethanol industry. As part of the BIOEN program, a Workshop on Sugarcane Improvement was held on March 18th and 19th 2009 in São Paulo, Brazil. The aim of the workshop was to explore present and future challenges for sugarcane improvement and its use as a sustainable bioenergy and biomaterial feedstock. The workshop was divided in four sections that represent important challenges for sugarcane improvement: a) gene discovery and sugarcane genomics, b) transgenics and controlled transgene expression, c) sugarcane physiology (photosynthesis, sucrose metabolism, and drought) and d) breeding and statistical genetics. This report summarizes the roadmap for the improvement of sugarcane.
The association of cytogenetic and molecular techniques has contributed to the analysis of chromosome organization and phylogeny in plants. The fluorochrome GC-specific CMA 3 , fluorescent in situ hybridization (FISH) and RAPD (Random Amplified Polymorphic DNA) markers were used to investigate chromosome structure and genetic relationships in Hypochaeris (Asteraceae). Seven species native to South America, and two species introduced from Europe (H. glabra and Hypochaeris sp) were studied. FISH with rDNA probes identified one or two loci of 18S-5.8S-25S rDNA in the South American Hypochaeris species and one locus in the European species. Only one 5S rDNA locus was seen in all species studied. Blocks of GC-rich heterochromatin (CMA-positive bands) associated to 18S-5.8S-25SrDNA loci were detected in all species investigated. Co-location of 5S rDNA and CMA bands was also observed, except for three South American species and Hypochaeris sp. In two South American species, additional CMA bands not related to rDNA were observed on the long arm of chromosome 2, near to the centromere. Hypochaeris glabra exhibited additional CMA-positive signals distributed at pericentromeric regions, on the short arms of all chromosomes. A total of 122 RAPD markers were used to determine the genetic relationships among species. The level of polymorphism was very high, revealing two genetic groups comprising the South American and the European species, thus supporting a previous hypothesis of monophyly of the South American Hypochaeris species. The coefficients of genetic similarity between European and South American species were 0.35, on average. Polymorphism was also high within the two groups. The genetic associations observed with RAPD markers were consistent with chromosome characteristics. Species carrying similar distribution of 45S rDNA loci and CMA-positive signals were included in the same group revealed by RAPDs. Cytogenetic and molecular data support the view that not only chromosome rearrangements, but also changes in DNA sequence took place during the diversification of the South American Hypochaeris species.
Epidendrum fulgens has a patchy distribution along the Atlantic Rainforest in the Brazilian coast, due to the destruction of its native habitat. Here, we report on both the development of nine new microsatellite markers isolated from this species and the characterization of their allele variability in two distant and unrelated populations. The number of alleles observed for each locus ranged from 2 to 17 with an average of 6.4 alleles per locus. These microsatellites should be valuable tools for studying the effect of habitat fragmentation on the genetic structure of E. fulgens populations.
Stylosanthes guianensis is an important tropical pasture legume. Knowledge of genetic diversity and structure of S. guianensis populations is of great importance for the conservation and germplasm management of this species. Thus, 20 microsatellite markers were developed from a S. guianensis enriched library. The microsatellites were characterized in 20 accessions from the germplasm collection of the Empresa Brasileira de Pesquisa Agropecuária (Embrapa). The average number of alleles per locus varied from 2 to 7, with an average of 4 alleles per locus. The observed and expected heterozygosities ranged from 0 to 0.60 and 0.10 to 0.85, respectively. This new set of microsatellites will contribute towards studies of genetic diversity and conservation of S. guianensis.
Epidendrum puniceoluteum is an endemic orchid of Atlantic Rainforest, restricted to few populations only due to the destruction and fragmentation of its native habitat. Here, we report on the development of 10 microsatellite markers isolated from this orchid species. Genetic variability was characterized in two distant populations from Brazil coast. The number of alleles observed for each locus ranged from two to 12 and with an average of 6.4 alleles per locus. These microsatellites should be valuable tools for studying both fine-scale genetic structure of scattered E. puniceoluteum population and patterns will be useful genetic markers for other closely related taxa.
Microsatellites were developed for Stylosanthes macrocephala, aiming at developing tools for studying the genetic diversity of this species. A total of 13 polymorphic microsatellite markers were isolated from a S. macrocephala enriched genomic library. The isolated microsatellites were characterized in 20 accessions of the S. macrocephala germplasm collection belonging to the Empresa Brasileira de Pesquisa Agropecuária (Embrapa) Cerrados. The number of alleles per locus varied from 2 to 11, with an average of 4 alleles per locus. The observed and expected heterozygosities ranged from 0 to 0.25 and 0.05 to 0.90, respectively. Cross-amplification of the S. macrocephala polymorphic microsatellites was evaluated in three other Stylosanthes species. The microsatellites reported herein are the first set of microsatellite markers developed for S. macrocephala and are potentially useful for further studies on genetic diversity, conservation and breeding of this species.
Acca sellowiana has commercial potential because of the quality and the unique flavor of its fruit. Conservation of natural populations and management of breeding programmes would benefit from the availability of molecular markers that could be used to characterize levels and distribution of genetic variability. Thus, 13 microsatellite markers were developed from an enriched genomic library of A. sellowiana. They were characterized using 40 samples. The expected and observed heterozygosities ranged from 0.513 to 0.913 and from 0.200 to 0.889, respectively. These are the first microsatellite loci characterized from A. sellowiana that will contribute to improve researches on the genetic conservation, characterization and breeding.
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