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Castelar, Argentina

Iribarren M.J.,CONICET | Iribarren M.J.,National University of Lujan | Pascuan C.,CONICET | Pascuan C.,Institute Genetica Ewald A Favret | And 4 more authors.
FEMS Microbiology Letters

Phytophthora capsici is a virulent oomycete pathogen of many vegetable crops. Recently, it has been demonstrated that the recognition of the RXLR effector AVR3a1 of P. capsici (PcAVR3a1) triggers a hypersensitive response and plays a critical role in mediating non-host resistance. Here, we analyzed the occurrence of PcAVR3a1 in 57 isolates of P. capsici derived from globe squash, eggplant, tomato and bell pepper cocultivated in a small geographical area. The occurrence of PcAVR3a1 in environmental strains of P. capsici was confirmed by PCR in only 21 of these pathogen isolates. To understand the presence-absence pattern of PcAVR3a1 in environmental strains, the flanking region of this gene was sequenced. PcAVR3a1 was found within a genetic element that we named PcAVR3a1-GI (PcAVR3a1 genomic island). PcAVR3a1-GI was flanked by a 22-bp direct repeat, which is related to its site-specific recombination site. In addition to the PcAVR3a1 gene, PcAVR3a1-GI also encoded a phage integrase probably associated with the excision and integration of this mobile element. Exposure to plant induced the presence of an episomal circular intermediate of PcAVR3a1-GI, indicating that this mobile element is functional. Collectively, these findings provide evidence of PcAVR3a1 evolution via mobile elements in environmental strains of Phytophthora. © FEMS 2015. Source

Salerno J.C.,Institute Genetica Ewald A Favret | Kandus M.V.,Institute Genetica Ewald A Favret | Boggio Ronceros R.,Institute Genetica Ewald A Favret | Almorza D.,Institute Genetica Ewald A Favret
BAG - Journal of Basic and Applied Genetics

In order to increase the efficiency of hybrid seed production in maize, it is necessary to achieve a high grain yield to reduce production costs. This goal requires an expansion of the basic knowledge of the inheritance of traits to develop new breeding techniques. The balanced lethal systems allow the study of the relative contribution of different chromosomal segments to hybrid vigour due to the heterozigosity of certain chromosomal sectors while the rest of the genome becomes homozygous through continuous selfing. In this way, these segments can be transferred to inbred lines in order to increase grain yield or pollen production through the increase of tassel size. In the last fifteen years, the transference of heterotic segments that belong to three lines regulated by different balanced lethal systems (BLS) to S5 flint lines derived from two commercial hybrids, (ACA 2000 and Cóndor with closed pedigree) was carried out, with the aim of increasing grain yield or tassel size. The statistical analysis showed a significant increase in grain yield and tassel size in the S5 flint lines of both commercial hybrids, carrying three different heterotic segments of the BLS lines. Source

Landau A.,Institute Genetica Ewald A Favret | Lencina F.,Institute Genetica Ewald A Favret | Pacheco M.G.,Institute Genetica Ewald A Favret | Prina A.R.,Institute Genetica Ewald A Favret
Journal of Heredity

The barley chloroplast mutator (cpm) is an allele of a nuclear gene that when homozygous induces several types of cytoplasmically inherited chlorophyll deficiencies. In this work, a plastome Targeting Induced Local Lesions in Genomes (TILLING) strategy based on mismatch digestion was used on families that carried the cpm genotype through many generations. Extensive scanning of 33 plastome genes and a few intergenic regions was conducted. Numerous polymorphisms were detected on both genic and intergenic regions. The detected polymorphisms can be accounted for by at least 61 independent mutational events. The vast majority of the polymorphisms originated in substitutions and small indels (insertions/deletions) in microsatellites. The rpl23 and the rps16 genes were the most polymorphic. Interestingly, the variation observed in the rpl23 gene consisted of several combinations of 5 different one nucleotide polymorphisms. Besides, 4 large indels that have direct repeats at both ends were also observed, which appear to be originated from recombinational events. The cpm mutation spectrum suggests that the CPM gene product is probably involved in plastome mismatch repair. The numerous subtle molecular changes that were localized in a wide range of plastome sites show the cpm as a valuable source of plastome variability for plant research and/or plant breeding. Moreover, the cpm mutant appears to be an interesting experimental material for investigating the mechanisms responsible for maintaining the stability of plant organelle DNA. © The American Genetic Association. 2015. All rights reserved. Source

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