95 research outputs found
The effect of pyramiding Phytophthora infestans resistance genes RPi-mcd1 and RPi-ber in potato
Despite efforts to control late blight in potatoes by introducing Rpi-genes from wild species into cultivated potato, there are still concerns regarding the durability and level of resistance. Pyramiding Rpi-genes can be a solution to increase both durability and level of resistance. In this study, two resistance genes, RPi-mcd1 and RPi-ber, introgressed from the wild tuber-bearing potato species Solanum microdontum and S. berthaultii were combined in a diploid S. tuberosum population. Individual genotypes from this population were classified after four groups, carrying no Rpi-gene, with only RPi-mcd1, with only RPi-ber, and a group with the pyramided RPi-mcd1 and RPi-ber by means of tightly linked molecular markers. The levels of resistance between the groups were compared in a field experiment in 2007. The group with RPi-mcd1 showed a significant delay to reach 50% infection of the leaf area of 3Â days. The group with RPi-ber showed a delay of 3Â weeks. The resistance level in the pyramid group suggested an additive effect of RPi-mcd1 with RPi-ber. This suggests that potato breeding can benefit from combining individual Rpi-genes, irrespective of the weak effect of RPi-mcd1 or the strong effect of RPi-ber
Identification and characterization of cichlid TAAR genes and comparison with other teleost TAAR repertoires
Azo Complexes of Osmium(II): Preparation and Reactivity of Organic Azide and Hydrazine Derivatives
The genomic substrate for adaptive radiation in African cichlid fish
Cichlid fishes are famous for large, diverse and replicated adaptive radiations in the Great Lakes of East Africa. To understand the molecular mechanisms underlying cichlid phenotypic diversity, we sequenced the genomes and transcriptomes of five lineages of African cichlids: the Nile tilapia (Oreochromis niloticus), an ancestral lineage with low diversity; and four members of the East African lineage: Neolamprologus brichardi/pulcher (older radiation, Lake Tanganyika), Metriaclima zebra (recent radiation, Lake Malawi), Pundamilia nyererei (very recent radiation, Lake Victoria), and Astatotilapia burtoni (riverine species around Lake Tanganyika). We found an excess of gene duplications in the East African lineage compared to tilapia and other teleosts, an abundance of non-coding element divergence, accelerated coding sequence evolution, expression divergence associated with transposable element insertions, and regulation by novel microRNAs. In addition, we analysed sequence data from sixty individuals representing six closely related species from Lake Victoria, and show genome-wide diversifying selection on coding and regulatory variants, some of which were recruited from ancient polymorphisms. We conclude that a number of molecular mechanisms shaped East African cichlid genomes, and that amassing of standing variation during periods of relaxed purifying selection may have been important in facilitating subsequent evolutionary diversification
Challenges of genomic data generation for non-model complex species
International audienc
Challenges of genomic data generation for non-model complex species
International audienc
Etude de la plasticité de la plante aquatique invasive [i]Ludwigia grandiflora[/i] en milieu terrestre
Session 1 : Scénarios et Potentiel InvasifNational audienc
Preparation of an insoluble polymer-supported Mn (III) porphyrin and its use as a new alkene epoxidation and alkane hydroxylation catalyst
Genomic relationships among diploid and polyploid species of the genus Ludwigia L. section Jussiaea using a combination of molecular cytogenetic, morphological, and crossing investigations
International audienceThe genus Ludwigia L. section Jussiaea is composed of a polyploid species complex with 2x, 4x, 6x and 10x ploidy levels, suggesting possible hybrid origins. The aim of the present study is to understand the genomic relationships among diploid and polyploid species in the section Jussiaea. Morphological and cytogenetic observations, controlled crosses, genomic in situ hybridization (GISH), and flow cytometry were used to characterize species, ploidy levels, ploidy patterns, and genomic composition across taxa. Genome sizes obtained were in agreement with the diploid, tetraploid, hexaploid, and decaploid ploidy levels. Results of GISH showed that progenitors of Ludwigia stolonifera (4x) were Ludwigia peploides subsp.montevidensis (2x) and Ludwigia helminthorrhiza (2x), which also participated for one part (2x) to the Ludwigia ascendens genome (4x). Ludwigia grandiflora subsp. hexapetala (10x) resulted from the hybridization between L. stolonifera (4x) and Ludwigia grandiflora subsp.grandiflora (6x). One progenitor of L. grandiflora subsp. grandiflora was identified as L. peploides (2x). Our results suggest the existence of several processes of hybridization, leading to polyploidy, and possibly allopolyploidy, in the section Jussiaea due to the diversity of ploidy levels. The success of GISH opens up the potential for future studies to identify other missing progenitors in Ludwigia L. as well as other taxa
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