RESUMO
Due to its adsorption with aluminum and iron hydroxides, phosphorus viability is low in acidic soils; thus, the aim of this study was to isolate and identify bacteria from the rhizosphere of four legumes growing in acidic soils of the Cumbaza Sub-basin, San Martín, Peru, as well as to characterize their ability to solubilize aluminum phosphate and iron phosphate. The isolation process was conducted on TSA medium and the isolates were classified based on their origin and morphocolonial characteristics, with the bacillary shape being the most frequent, followed by cocci. To assess the solubilization of aluminum and iron phosphates, the liquid medium GELP was employed. Sixteen strains were selected, among which three stood out for their effectiveness in solubilizing AlPO4 (Sfcv-098-02, 22.65 mg L-1; Sfc-093-04, 26.50 mg L-1; and Sfcv-041-01-2, 55.98 mg L-1) and one for its ability to solubilize FePO4 (Sfcr-043-02, 32.61 mg L-1). These four strains were molecularly characterized, being identified as Enterobacter sp., Pseudomonas sp., and Staphylococcus sp. Additionally, a decrease in pH was observed in the reactions, with values ranging from 5.23 to 3.29, which enhanced the phosphate of solubilization. This suggests that the selected bacteria could be used to improve phosphorus availability in agricultural soils.
RESUMO
Burkholderia glumae causes bacterial leaf blight in rice, and its global spread has been exacerbated by climate change. To understand the genetic diversity and virulence of B. glumae strains isolated from rice cultivars in Perú, 47 isolates were obtained from infected rice fields, all belonging to B. glumae, and confirmed by recA and toxB sequences. The BOX-PCR typing group has 38 genomic profiles, and these turn into seven variable number tandem repeats (VNTR) haplotypes. There was no correlation between clustering and geographical origin. Nineteen strains were selected for phenotypic characterization and virulence, using both the maceration level of the onion bulb proxy and inoculation of seeds of two rice cultivars. Several strains produced pigments other than toxoflavin, which correlated with onion bulb maceration. In terms of virulence at the seed level, all strains produced inhibition at the root and coleoptile level, but the severity of symptoms varied significantly between strains, revealing significant differences in pathogenicity. There is no correlation between maceration and virulence scores, probably reflecting different virulence mechanisms depending on the host infection stage. This is the first study to evaluate the VNTR diversity and virulence of Peruvian strains of B. glumae in two commercial cultivars.
Assuntos
Burkholderia , Variação Genética , Oryza , Doenças das Plantas , Oryza/microbiologia , Burkholderia/genética , Burkholderia/patogenicidade , Burkholderia/isolamento & purificação , Doenças das Plantas/microbiologia , Virulência/genética , Filogenia , Repetições MinissatélitesRESUMO
The aim of the present study was to isolate, select and characterize endophytic bacteria in rice inhibiting Burkholderia glumae THT as well as to characterize the genetic diversity and virulence factors in strains of B. glumae and Burkholderia gladioli of rice. Rice plants were collected in 4 departments from the northern region of Peru, isolating endophytic bacteria, after tissue sterilization, at 30°C (48h) in Trypticase Soy Agar (TSA), evaluating the antimicrobial activity against B. glumae THT, production of siderophores, resistance of toxoflavine and partial sequencing of the 16S rRNA gene. Furthermore, B. glumae and B. gladioli were isolated in selective medium (pH 4.5) at 41°C/72h. Molecular identification was performed using BOX-PCR and sequencing of the 16S rRNA gene, in addition to the production of extracellular enzymes, motility tests and sensitivity/resistance to bactericides. One hundred and eighty nine (189) endophytic bacteria were isolated, and only 9 strains showed antimicrobial activity against B. glumae THT, highlighting Burkholderia vietnamiensis TUR04-01, B. vietnamiensis TUR04-03 and Bacillus aryabhattai AMH12-02. The strains produced siderophores and at least 55.5% were resistant to toxoflavin. Additionally, 17 strains were grouped into 9 BOX-PCR profiles, where 16 had similarity with B. glumae LMG2196T (100%) and 1 with B. gladioli NBRC 13700T (99.86%). High diversity was found according to geographical origin and virulence factors. In conclusion, strains of the genus Bacillus and Burkholderia are potential biocontrol agents against B. glumae.
Assuntos
Anti-Infecciosos , Burkholderia , Oryza , Bacillus , Burkholderia/genética , RNA Ribossômico 16S/genética , VirulênciaRESUMO
Aunque es detectado generalmente en seres humanos, los microorganismos identificados como Blastocystis han sido aislados de un amplio rango de hospedadores, tales como primates, cerdos, ganado, aves, anfibios y menos frecuentemente roedores e insectos.En el presente trabajo, se describe la detección de Blastocystis sp. en bivalvos del género Donax de la costa norteña peruana. Este hallazgo amplía el espectro de hospedadores para este enteropatógeno y abre la posibilidad de considerar la posible transmisión de Blastocystis en el hombre a partir de moluscos marinos.
Although commonly detected in humans, microorganisms identified as Blastocystis have also been isolated from a wide range of animals, such as primates, pigs, cattle, birds, amphibians and, less frequently, rodents and insects. In the present paper, we describe the detection of Blastocystis sp. in bivalve mollusks of the genus Donax from the Peruvian northern coast. This finding extends the host range of this pathogen, opening the possibility of Blastocytis transmission to human beings by marine mollusks.