Miguel A. Caviedes

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A bacterial strain, designated PW21(T), was isolated from root nodules of Prosopis farcta in Tunisia. Phylogenetic analysis based on 16S rRNA gene sequences placed the isolate into the genus Paenibacillus, with its closest relatives being Paenibacillus glycanilyticus DS-1(T) and Paenibacillus castaneae Ch-32(T) with identity values of 96.9 %. DNA-DNA(More)
While the biology of nitrogen-fixing root nodules has been extensively studied, little is known about the evolutionary events that predisposed legume plants to form symbiosis with rhizobia. We have studied the presence and the expression of two pectic gene families in Medicago, polygalacturonases (PGs) and pectin methyl esterases (PMEs) during the early(More)
Arsenic (As) reduces legume nodulation by affecting the first stages of the symbiotic interaction, which causes a 90% decrease in rhizobial infections. In this paper, we examine molecular mechanisms underlying this toxic effect, using the model system Medicago sativa-Sinorhizobium. In the presence and absence of As, the expression patterns of seven nodulin(More)
Diversity of 50 bacterial isolates recovered from root nodules of Prosopis farcta grown in different arid soils in Tunisia, was investigated. Characterization of isolates was assessed using a polyphasic approach including phenotypic characteristics, 16S rRNA gene PCR–RFLP and sequencing, nodA gene sequencing and MLSA. It was found that most of isolates are(More)
MsPG3 is a Medicago sativa polygalacturonase gene isolated in our laboratory, its expression during nodule development is associated with the presence of Sinorhizobium meliloti. By RT-PCR and in situhybridization studies we showed the early induction of MsPG3 expression after inoculation of M. sativaplants with the microsymbiont, suggesting a role for MsPG3(More)
Spartina maritima is an ecosystem engineer that has shown to be useful for phytoremediation purposes. A glasshouse experiment using soil from a metal-contaminated estuary was designed to investigate the effect of a native bacterial consortium, isolated from S. maritima rizhosphere and selected owing to their plant growth promoting properties and(More)
Plasmid R68.45 was used to promote conjugal transfer of chromosomal markers in Rhizobium trifolii RS55. Analysis of two-factor and three-factor crosses among R. trifolii strains enabled construction of a circular linkage map of the R. trifolii chromosome, containing 17 nutritional and resistance markers.
Tip growth is a specialized type of polar growth where new cell wall is deposited in a localized region of the cell, the growing tip. These cells show a characteristic zonation, with a high accumulation of secretory vesicles containing cell wall components at the tip, followed by an organelle-enriched zone. MsPG3 is a Medicago sativa polygalacturonase gene(More)
Rhizobium-Legume symbiosis is an attractive biological process that has been studied for decades because of its importance in agriculture. However, this system has undergone extensive study and although many of the major factors underpinning the process have been discovered using traditional methods, much remains to be discovered. Here we present an(More)
Spartina maritima is a native endangered heavy metal rhizoaccumulator cordgrass naturally growing in southwest coasts of Spain, where is used as a biotool to rehabilitate degraded salt marshes. Fifteen bacterial strains were isolated from the rhizosphere of S. maritima growing in the estuary of the Tinto River, one of the most polluted areas in the world. A(More)