Papers by alejandro Perticari
Persistence and Competitiveness of Or191-Like Rhizobia and Sinorhizobium meliloti (Sme) Strains in an Acidic Soil of Argentina
Springer eBooks, 2000
Acid soils represent a severe constraint for alfalfa crop in Argentina and Uruguay. The nitrogen-... more Acid soils represent a severe constraint for alfalfa crop in Argentina and Uruguay. The nitrogen-fixing symbiosis established between S. meliloti and alfalfa becomes seriously altered in acid environments accounting for a significant reduction in the yield and persistence of cultures. In our laboratory we are investigating the basis of symbiosis development at low pH, and the mechanisms of acid tolerance in alfalfa nodulating rhizobia (ANR).
V Congreso Argentino de Microbiología Agrícola y Ambiental (Virtual). 15 al 17 septiembre de 2021, Sep 15, 2021
Resumen Se plantaron estacas apicales e internodales de dos variedades en tubetes de 400 cm 3 sob... more Resumen Se plantaron estacas apicales e internodales de dos variedades en tubetes de 400 cm 3 sobre una mezcla de turba y perlita (1:1), y un testigo con compost. Los PGPR evaluados fueron A. brasilense Az39, P. fluorescens ZME4 y P. putida LSR1. Las estacas se inocularon en forma de riego en la base del tallo con una dosis de 5 mL/planta. Luego de 15 días, se evaluó la longitud del brote, peso fresco y seco de los brotes y peso fresco y seco de la raíz. Si bien, en la parte aérea los efectos de la inoculación no fueron significativos, los tratamientos inoculados no se diferenciaron estadísticamente de los esquejes crecidos en compost, que fueron los que mayor crecimiento aéreo presentaron. El crecimiento radicular, en cambio, no se vio favorecido con el compost, en donde se pudo observar plantas con raíces más livianas y más débiles que aquellas inoculadas. Un buen sistema radicular, obtenido con algunos de los tratamientos con PGPR es imprescindible para lograr plantines viables.
Inoculation with Azospirillum brasilense is a useful tool in Eucalyptus globulus management
American-Eurasian Journal of Agricultural and Environmental Science, 2010
Queda hecho el depósito que marca la Ley 11.723 Todos los derechos reservados. Prohibida su repro... more Queda hecho el depósito que marca la Ley 11.723 Todos los derechos reservados. Prohibida su reproducción total o parcial, así como su traducción, almacenamiento y transmisión por cualquier medio, sin consentimiento previo, expreso y por escrito; de los depositarios legales de la obra. Impreso en Argentina.
Agrotecnia, 2017
Microorganismos promotores del crecimiento vegetal Efecto de la inoculación con diferentes cepas ... more Microorganismos promotores del crecimiento vegetal Efecto de la inoculación con diferentes cepas Ensifer meliloti sobre el rendimiento de forraje de Alfalfa.
The Journal of general and applied microbiology, Jan 25, 2016
Fluorescent Pseudomonas are ubiquitous soil bacteria that usually establish mutualistic associati... more Fluorescent Pseudomonas are ubiquitous soil bacteria that usually establish mutualistic associations with plants, promoting their growth and health by several mechanisms. This makes them interesting candidates for the development of crop bio-inoculants. In this work, we isolated phosphate-solubilizing fluorescent Pseudomonas from the rhizosphere and inner tissues of different plant species growing in red soil from Misiones, Argentina. Seven isolates displaying strong phosphate solubilization were selected for further studies. Molecular identification by rpoD genotyping indicated that they belong to different species within the P. fluorescens and P. putida phylogenetic groups. Screening for in vitro traits such as phosphate solubilization, growth regulators synthesis or degradation, motility and antagonism against phytopathogens or other bacteria, revealed a unique profile of characteristics for each strain. Their plant growth-promoting potential was assayed using lettuce as a model ...
Plant and Soil, 2015
Aims This study aims to (i) asses the contribution of biological N fixation (%Ndfa) in the soybea... more Aims This study aims to (i) asses the contribution of biological N fixation (%Ndfa) in the soybean production area of Argentina, (ii) build a model for predicting %Ndfa using crop, soil, and meteorological variables, and (iii) estimate %Ndfa at the country level using values obtained in this study. Methods %Ndfa was assessed in paddocks and experimental plots located in an area 22-39°S and 56-66°W. %Ndfa was determined using the natural 15 N abundance method. A complete data set of soil and meteorological variables (n-47) was used to develop a model for predicting %Ndfa. Results A median value of %Ndfa in aboveground biomass of 60 % (interquartile range 46-71 %) was estimated. Larger %Ndfa values were observed in areas with high crops yields. When seed yield was above 3.7 Mg ha −1 , effective rainfall during fallow and mean temperature in the seed-filling period explained %Ndfa. Below 3.7 Mg ha −1 , soil phosphorus content, pH, and effective rainfall in the vegetative period explicated %Ndfa. Conclusions Soybean production systems in Argentina showed larger %Ndfa than reported values in literature that may affect global N balances. Identified soil and meteorological variables may be useful for predicting %Ndfa in future studies, taking into account their spatial variation in the soil-plant system.
Persistence and Competitiveness of Or191-Like Rhizobia and Sinorhizobium meliloti (Sme) Strains in an Acidic Soil of Argentina
Current Plant Science and Biotechnology in Agriculture, 2000
Acid soils represent a severe constraint for alfalfa crop in Argentina and Uruguay. The nitrogen-... more Acid soils represent a severe constraint for alfalfa crop in Argentina and Uruguay. The nitrogen-fixing symbiosis established between S. meliloti and alfalfa becomes seriously altered in acid environments accounting for a significant reduction in the yield and persistence of cultures. In our laboratory we are investigating the basis of symbiosis development at low pH, and the mechanisms of acid tolerance in alfalfa nodulating rhizobia (ANR).
Genome Sequence of Bradyrhizobium japonicum E109, One of the Most Agronomically Used Nitrogen-Fixing Rhizobacteria in Argentina
Genome announcements, Jan 19, 2015
We present here the complete genome sequence of Bradyrhizobium japonicum strain E109, one of the ... more We present here the complete genome sequence of Bradyrhizobium japonicum strain E109, one of the most used rhizobacteria for soybean inoculation in Argentina since the 1970s. The genome consists of a 9.22-Mbp single chromosome and contains several genes related to nitrogen fixation, phytohormone biosynthesis, and a rhizospheric lifestyle.
Complete Genome Sequence of the Model Rhizosphere Strain Azospirillum brasilense Az39, Successfully Applied in Agriculture
Genome Announcements, 2014
We present the complete genome sequence of Azospirillum brasilense Az39, isolated from wheat root... more We present the complete genome sequence of Azospirillum brasilense Az39, isolated from wheat roots in the central region of Argentina and used as inoculant in extensive and intensive agriculture during the last four decades. The genome consists of 7.39 Mb, distributed in six replicons: one chromosome, three chromids, and two plasmids.
The Scientific World Journal, 2013
The genetic diversity among 31 putativeAzotobacterisolates obtained from agricultural and non-agr... more The genetic diversity among 31 putativeAzotobacterisolates obtained from agricultural and non-agricultural soils was assessed using rep-PCR genomic fingerprinting and identified to species level by ARDRA and partial 16S rRNA gene sequence analysis. High diversity was found among the isolates, identified asA. chroococcum,A. salinestris, andA. armeniacus. Selected isolates were characterized on the basis of phytohormone biosynthesis, nitrogenase activity, siderophore production, and phosphate solubilization. Indole-3 acetic-acid (IAA), gibberellin (GA3) and zeatin (Z) biosynthesis, nitrogenase activity, and siderophore production were found in all evaluated strains, with variation among them, but no phosphate solubilization was detected. Phytohormones excreted to the culture medium ranged in the following concentrations: 2.2–18.2 μg IAA mL−1, 0.3–0.7 μg GA3 mL−1, and 0.5–1.2 μg Z mL−1. Seed inoculations with further selectedAzotobacterstrains and treatments with their cell-free cultur...
Analysis of Genomic Diversity Among Photosynthetic Stem-nodulating Rhizobial Strains from Northeast Argentina
Systematic and Applied Microbiology, 2002
The genomic diversity among photosynthetic rhizobia from northeast Argentina was assessed. Forty ... more The genomic diversity among photosynthetic rhizobia from northeast Argentina was assessed. Forty six isolates obtained from naturally occurring stem and root nodules of Aeschynomene rudis plants were analyzed by three molecular typing methods with different levels of taxonomic resolution: repetitive sequence-based PCR (rep-PCR) genomic fingerprinting with BOX and REP primers, amplified 16S rDNA restriction analysis (ARDRA), and 16S-23S rDNA intergenic spacer-restriction fragment length polymorphism (IGS-RFLP) analysis. The in vivo absorption spectra of membranes of strains were similar in the near infrared region with peaks at 870 and 800 nm revealing the presence of light harvesting complex I, bacteriochlorophyll-binding polypeptides (LHI-Bchl complex). After extraction with acetone-methanol the spectra differed in the visible part displaying peaks belonging to canthaxanthin or spirilloxanthin as the main carotenoid complement. The genotypic characterization by rep-PCR revealed a high level of genomic diversity among the isolates and almost all the photosynthetic ones have identical ARDRA patterns and fell into one cluster different from Bradyrhizobium japonicum and Bradyrhizobium elkanii. In the combined analysis of ARDRA and rep-PCR fingerprints, 7 clusters were found including most of the isolates. Five of those contained only photosynthetic isolates; all canthaxanthin-containing strains grouped in one cluster, most of the other photosynthetic isolates were grouped in a second large cluster, while the remaining three clusters contained a few strains. The other two clusters comprising reference strains of B. japonicum and B. elkanii, respectively. The IGS-RFLP analysis produced similar clustering for almost all the strains. The 16S rRNA gene sequence of one representative isolate was determined and the DNA sequence analysis confirmed the position of photosynthetic rhizobia in a distinct phylogenetic group within the Bradyrhizobium rDNA cluster.
Metarhizium anisopliae (Metschnikoff) Sorokin Promotes Growth and Has Endophytic Activity in Tomato Plants
Advances in Biological Research, 2011
Abstract: The present study aimed to evaluate the effect of the inoculation with Metarhizium anis... more Abstract: The present study aimed to evaluate the effect of the inoculation with Metarhizium anisopliae on the growth of tomato plants and to determine the endophytic activity of this fungus. The three isolates of M. anisopliae evaluated (Ma 8, Ma 10 and Ma 20) ...
Tropical Grasslands-Forrajes Tropicales, 2019
Keynote paper presented at the International Leucaena Conference, 1‒3 November 2018, Brisbane, Qu... more Keynote paper presented at the International Leucaena Conference, 1‒3 November 2018, Brisbane, Queensland, Australia.This review describes the history of research in Leucaena leucocephala (leucaena) feeding systems carried out by the National Institute of Agricultural Technology (INTA) over the last 5 decades and discusses the main limitations resulting in poor adoption in Argentina. Leucaena was introduced in the subtropical region of the north of the country in the late 1960s and early 1970s. Since then, INTA has conducted research to evaluate forage and animal productivity, leucaena accessions, rhizobial strains, contribution to soil carbon and total nitrogen and density effects on competition and other ecosystem interactions in silvopastoral systems. In spite of the convincing research results showing the excellent potential of leucaena to increase forage quality and animal production in suitable areas, there has been poor adoption of this forage tree legume on a broad scale.
FEMS Microbiology Letters, 2008
A Bradyrhizobium japonicum USDA 110-derived strain able to produce wider halos in soft-agar mediu... more A Bradyrhizobium japonicum USDA 110-derived strain able to produce wider halos in soft-agar medium than its parental strain was obtained by recurrent selection. It was more chemotactic than the wild type towards mannitol and three amino acids. When cultured in minimal medium with mannitol as a single carbon-source, it had one thick subpolar flagellum as the wild type, plus several other flagella that were thinner and sinusoidal. Root adsorption and infectivity in liquid media were 50-100% higher for the selected strain, but root colonization in water-unsaturated vermiculite was similar to the wild type. A field experiment was then carried out in a soil with a naturalized population of 1.8 Â 10 5 soybean-nodulating rhizobia g of soil À1. Bradyrhizobium japonicum strains were inoculated either on the soybean seeds or in the sowing furrows. Nodule occupation was doubled when the strains were inoculated in the sowing furrows with respect to seed inoculation (significant with P o 0.05). On comparing strains, nodule occupation with seed inoculation was 6% or 10% for the wild type or selected strains, respectively, without a statistically significant difference, while when inoculated in the sowing furrows, nodule occupation increased to 12% and 22%, respectively (differences significant with P o 0.05).
Agronomy Journal, 2009
Th e issue of competition for nodulation has received much attention in studies on soybean [Glyci... more Th e issue of competition for nodulation has received much attention in studies on soybean [Glycine max (L.) Merr.] crops because native soil rhizobia oft en preclude nodulation of inoculated high-quality strains. In this work, soil placement and enhanced motility of Bradyrhizobium japonicum were investigated as strategies to improve the competitiveness of soybean inoculants applied in the presence of large populations of native (or indigenous) soybean-nodulating rhizobia. Th e fi rst strategy might allow for the enhanced distribution of inoculant rhizobia in the surface soil, compared with inoculant that is directly applied to soybean seed, while the second strategy is expected to enhance root colonization. Th e eff ects of soil placement and enhanced bacterial motility on percentage nodule occupation, grain yield, and grain N contents were examined during the 2004-2005 soybean season at three locations in Argentina, comprising soils classifi ed as entic hapludol, argillic pelludert, and typical argiudol. Th e experimental design was a randomized complete block design, and main eff ects and interactions were also analyzed with a factorial design. Strain LP 3008, previously selected for increased motility, was more eff ective than the commonly inoculated strain E 109. While E 109 occupied, on average, 13.2% of nodules with seed inoculation, LP 3008 occupied 28.2%. In comparison, in-furrow inoculation yielded 24.2 and 37.2% average nodule occupancies for E 109 and LP 3008, respectively. However, these gains in nodulation effi cacy lead to a modest, nonsignifi cant yield increase, and grain N content was unaff ected.
Biochemical Journal
An adenylate cyclase activity in Medicago sativa L. (alfalfa) roots was partially characterized. ... more An adenylate cyclase activity in Medicago sativa L. (alfalfa) roots was partially characterized. The enzyme activity remains in the supernatant fluid after centrifugation at 105,000 g and shows in crude extracts an apparent Mr of about 84,000. The enzyme is active with Mg2+ and Ca2+ as bivalent cations, and is inhibited by EGTA and by chlorpromazine. Calmodulin from bovine brain or spinach leaves activates this adenylate cyclase.
Soybean Rizobia Inoculation Has a Positive Contribution to Argentine Grain Production
In Argentina, the request of microbiological products that enhances crop nutrition and growth is ... more In Argentina, the request of microbiological products that enhances crop nutrition and growth is increasing. It is estimated that approximately 70% of the soybean crops are inoculated with rizobia providing not only better N nutrition but also greater grain yields. The objective of the study was to quantify the contribution of the present use of Bradyrhizobium japonicum on soybean production in soybean rotated lands. During the 2007/8 and 2008/9, 28 experimental sites were established comparing untreated control and seed inoculated treatments using a single experimental formulation the National Institute of Agricultural Technology (INTA) providing more than 105 units of rizobia forming colonies by soybean seed. In each location, the nodulation (number and dry weight) was evaluated at v4 and r5 growing stages, the shoot dry matter at r6 and grain production and yield components (single grain weight) at physiological maturity. The N derived from the biological N fixation process was a...
Biol Fert Soils, 2003
The acid tolerance of Sinorhizobium meliloti in culture media and in soils is considered a useful... more The acid tolerance of Sinorhizobium meliloti in culture media and in soils is considered a useful criteria to select for strains with improved survival in agricultural acidic soils. Using a glass tube system with gammairradiated soil at different pH values, we analysed the survival of two different alfalfa-nodulating rhizobia: S. meliloti (pH limit for growth 5.6-6.0) and the acid-tolerant Rhizobium sp. LPU83, closely related to the strain Rhizobium sp. Or191 (pH limit for growth below 5.0). Although the acid-tolerant rhizobia showed a slightly better survival during the first months in acid soil (pH=5.6), none of the strains could be detected 2 months after inoculation (bacterial counts were below 10 3 colonyforming units (cfu)/30 g of soil). The inclusion of two alfalfa plants/glass tube with soil, however, supported the persistence of both types of rhizobia at pH 5.6 for over 2 months with counts higher than 910 6 cfu/30 g of soil. Remarkably, in the presence of alfalfa the cell densities reached by S. meliloti were higher than those reached by strain LPU83, which started to decline 1 week after inoculation. Although more acid-sensitive in the culture medium than the Or191-like rhizobia, in the presence of the host plant the S. meliloti strains showed to be better adapted to the free-living condition, irrespective of the pH of the soil.
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Papers by alejandro Perticari