Abstract:

Phenylalanine ammonia-lyase (PAL) is an important plant enzyme in pathogen defense. The purpose of this work was to analyze the phylogenetic relationships of a partial PAL gene sequence from Arachis hypogaea L. (peanut) cv. Tegua (designated AhPAL), a PAL sequence from cultivar JL24 and PAL sequences from other legumes and non-legumes plants. In addition, changes in the AhPAL transcript abundance related to induced systemic resistance (ISR) were also evaluated. AhPAL sequence shows high level of similarity with PAL genes and proteins from several plant species, including legumes and non-legumes. Quantification of relative transcript abundance indicated that AhPAL could be involved in the A. hypogaea cv. Tegua response towards the phytopathogen Sclerotium rolfsii.

Author affiliation: Tonelli, Maria Laura. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Ibañez, Fernando Julio. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Taurian, Tania. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Argüello, J.. Worcester Polytechnic Institute; Estados Unidos

Author affiliation: Fabra, Adriana Isidora. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Abstract:

This study analyses the effect of inoculation of native phosphate solubilizing bacteria on peanut (Arachis hypogaea L.) growth and phosphorus acquisition. Peanut plants were inoculated individually with 18 native phosphate solubilizing bacteria in microcosm studies using a low content P soil from the producing area. Survival of inoculated bacteria in soil at the end of the experiment was determined by streaking serial dilutions of dry soil samples and subsequent rep-fingering analysis of the colonies. The ability of peanut plants to increase P levels without bacteria was determined in hydroponic culture. The results obtained indicated that inoculation of native phosphate solubilizing bacteria on peanut seedlings led to an increase in at least one of the plant growth parameters analyzed. The beneficial effect of bacteria inoculation was mainly observed in aerial organs of peanut plants. Inoculation of Serratia sp. J260, Enterobacter sp. J33, Acinetobacter sp. L176, Enterococcus sp. L185, Enterococcus sp. L191 and Bacillus sp. L55 on peanut plants led to an increase in plant or soil P content. Plant assay in hydroponic conditions indicated that peanut plants growing with tricalcium phosphate were able to release soluble P into the growth medium reaching values similar to those of plants growing with available P. The beneficial effects of the bacteria analyzed in this study and their ability to survive encourage us to consider them for the production of a potential P-bioinoculant for peanut crops.

Author affiliation: Anzuay, María Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; Argentina

Author affiliation: Ludueña, Liliana Mercedes. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; Argentina

Author affiliation: Angelini, Jorge Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; Argentina

Author affiliation: Fabra, Adriana Isidora. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; Argentina

Author affiliation: Taurian, Tania. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; Argentina

Abstract:

The mineral phosphate-solubilizing phenotype in bacteria is attributed predominantly to secretion of gluconic acid produced by oxidation of glucose by the glucose dehydrogenase enzyme and its cofactor, pyrroloquinoline quinone. This study analyzes pqqE gene expression and pqq promoter activity in the native phosphate-solubilizing bacterium Serratia sp S119 growing under P-limitation, and in the presence of root exudates obtained from peanut plants, also growing under P-limitation. Results indicated that Serratia sp. S119 contains a pqq operon composed of six genes (pqqA,B,C,D,E,F) and two promoters, one upstream of pqqA and other between pqqA and pqqB. PqqE gene expression and pqq promoter activity increased under P-limiting growth conditions and not under N-deficient conditions. In the plant–bacteria interaction assay, the activity of the bacterial pqq promoter region varied depending on the concentration and type of root exudates and on the bacterial growth phase. Root exudates from peanut plants growing under P-available and P-limiting conditions showed differences in their composition. It is concluded from this study that the response of Serratia sp. S119 to phosphorus limitation involves an increase in expression of pqq genes, and that molecules exuded by peanut roots modify expression of these phosphate-solubilizing bacterial genes during plant–bacteria interactions.

Author affiliation: Ludueña, Liliana Mercedes. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales. Departamento de Ciencias Naturales. Cátedra de Biologia General; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina

Author affiliation: Anzuay, María Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales. Departamento de Ciencias Naturales. Cátedra de Biologia General; Argentina

Author affiliation: Magallanes Noguera, Cynthia Alejandra. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina

Author affiliation: Tonelli, Maria Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; Argentina

Author affiliation: Ibañez, Fernando Julio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales. Departamento de Ciencias Naturales. Cátedra de Biologia General; Argentina

Author affiliation: Angelini, Jorge Guillermo. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina

Author affiliation: Fabra, Adriana Isidora. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina

Author affiliation: McIntosh, Matthew. Universitat Marburg; Alemania

Author affiliation: Taurian, Tania. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales. Departamento de Ciencias Naturales. Cátedra de Biologia General; Argentina

Abstract:

In this study, attempts were made to analyze mechanisms involved in the bacterial phosphate-solubilizing ability of peanut isolates. Bacteria were taxonomically identified by analysis of 16S rDNA sequence. Levels of soluble P released by the isolates in unbuffered or buffered with Tris–HCl or MES NBRIP-BPB medium as well as the production of D-gluconic acid were determined in their culture. Presence of two of the genes encoding the cofactor PQQ of GDH enzyme was analyzed in the genome of this bacterial collection. 16S rDNA sequence analysis indicated that isolates belong to genera Serratia, Enterobacter, Pantoea, Acinetobacter, Bacillus and Enterococcus. All bacteria showed ability to solubilize tricalcium phosphate either in unbuffered or buffered medium. Nevertheless, addition of buffer solutions reduced levels of Pi liberated by the isolates. Although almost all isolates produced detectable amounts of D-gluconic acid, no correlation with levels of P soluble released were observed. The presence of pqqE and pqqC genes was detected only in Gram negative bacteria. It was concluded from this study that the mechanism involved in phosphate solubilization is organic acids production and, presence of pqq genes in all Gram negative bacteria analyzed encourages to confirm their role in bacterial phosphate solubilizing ability as well to identify genes involved in this PGP trait in Gram positive bacteria.

Author affiliation: Anzuay, María Soledad. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Frola, Ornella. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales; Argentina

Author affiliation: Angelini, Jorge Guillermo. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Ludueña, Liliana Mercedes. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Fabra, Adriana Isidora. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Taurian, Tania. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Abstract:

Heavy metals in soil are known to affect rhizobia–legume interaction reducing not only rhizobia viability, but also nitrogen fixation. In this work, we have compared the response of the symbiotic interaction established between the peanut (Arachis hypogaea L.) and a sensitive (Bradyrhizobium sp. SEMIA6144) or a tolerant (Bradyrhizobium sp. NLH25) strain to Cd under exposure to this metal. The addition of 10 μM Cd reduced nodulation and nitrogen content in both symbiotic associations, being the interaction established with the sensitive strain more affected than that with the tolerant one. Plants inoculated with the sensitive strain accumulated more Cd than those inoculated with the tolerant strain. Nodules showed an increase in reactive oxygen species (ROS) production when exposed to Cd. The histological structure of the nodules exposed to Cd revealed a deposit of unknown material on the cortex and a significant reduction in the infection zone diameter in both strains, and a greater number of uninfected cells in those nodules occupied by the sensitive strain. In conclusion, Cd negatively impacts on peanut–bradyrhizobia interaction, irrespective of the tolerance of the strains to this metal. However, the inoculation of peanut with Bradyrhizobium sp. NLH25 results in a better symbiotic interaction suggesting that the tolerance observed in this strain could limit Cd accumulation by the plant.

Author affiliation: Bianucci, Eliana Carolina. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Furlan, Ana Laura. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Rivadeneira, Jesica. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales; Argentina

Author affiliation: Sobrino Plata, Juan. Universidad Autónoma de Madrid; España

Author affiliation: Carpena Ruiz, Ramón O.. Universidad Autónoma de Madrid; España

Author affiliation: Tordable, Maria del Carmen. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales; Argentina

Author affiliation: Fabra, Adriana Isidora. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Hernández, Luis E.. Universidad Autónoma de Madrid; España

Author affiliation: Castro, Stella Maris. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Abstract:

Plant-growth-promoting bacteria are often used to enhance crop yield and for biological control of phytopathogens. Bacillus sp. CHEP5 is a biocontrol agent that induces systemic resistance (ISR) in Arachis hypogaea L. (peanut) against Sclerotium rolfsii, the causal agent of root and stem wilt. In this work, the effect of the co-inoculation of Bacillus sp. CHEP5 and the peanut nodulating strain Bradyrhizobium sp. SEMIA 6144 was studied on induction of both systemic resistance and nodulation processes. Bradyrhizobium sp. SEMIA 6144 did not affect the ability of Bacillus sp. CHEP5 to protect peanut plants from S. rolfsii by ISR and the priming in challenged-plants, as evidenced by an increment in phenylalanine ammonia-lyase enzyme activity. Additionally, the capacity of Bradyrhizobium sp. SEMIA 6144 to induce nodule formation in pathogen-challenged plants was improved by the presence of Bacillus sp. CHEP5.

Author affiliation: Figueredo, María Soledad. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales. Departamento de Ciencias Naturales. Cátedra de Biologia General; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Tonelli, Maria Laura. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales. Departamento de Ciencias Naturales. Cátedra de Biologia General; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Taurian, Tania. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales. Departamento de Ciencias Naturales. Cátedra de Biologia General; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Angelini, Jorge Guillermo. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales. Departamento de Ciencias Naturales. Cátedra de Biologia General; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Ibañez, Fernando Julio. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales. Departamento de Ciencias Naturales. Cátedra de Biologia General; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Valetti, Lucio. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales. Departamento de Ciencias Naturales. Cátedra de Biologia General; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Muñoz, Vanina Laura. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales. Departamento de Ciencias Naturales. Cátedra de Biologia General; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Anzuay, María Soledad. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales. Departamento de Ciencias Naturales. Cátedra de Biologia General; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Ludueña, Liliana Mercedes. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales. Departamento de Ciencias Naturales. Cátedra de Biologia General; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Fabra, Adriana Isidora. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales. Departamento de Ciencias Naturales. Cátedra de Biologia General; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Abstract:

The term "Plant Growth Promoting Bacteria" or PGPB designates a diverse group of prokaryotic microorganisms that can increase plant growth by diverse mechanisms. Some PGPB are capable of colonizing root inner tissues and constitute endophytic populations. Incorporation of these microorganisms into agricultural practices may constitute a valid alternative to increase crop productivity in a sustainable and environmentally friendly production scheme, reducing the application of agrochemicals. In a previous work, we described the characterization of bacteria belonging to Pseudomonas, Enterobacter and Klebsiella obtained from surface sterilized peanut nodules. In addition, we showed that some of these isolates were able to promote several peanut growth and symbiotic parameters. Bounded to the results from this particular study, and considering their potential ability to interact with different plant species, in this work we assessed the effects of their inoculation in maize (Zea mays L.) under controlled conditions. Furthermore, we analyzed growth promotion in a simulated peanut-maize crop rotation system. Finally, we determined the plant growth promoting (PGP) properties present in the isolates. Results indicated that all bacteria are able to significantly promote maize and peanut growth, and that they also displayed plant growth promotion activity in maize growing in a peanut-maize crop rotation sequence. © 2014 Elsevier B.V.

Author affiliation: Ibañez, Fernando Julio. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales. Departamento de Ciencias Naturales. Cátedra de Biologia General; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Arroyo, María Eugenia. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales. Departamento de Ciencias Naturales. Cátedra de Biologia General; Argentina

Author affiliation: Angelini, Jorge Guillermo. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales. Departamento de Ciencias Naturales. Cátedra de Biologia General; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Tonelli, Maria Laura. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales. Departamento de Ciencias Naturales. Cátedra de Biologia General; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Muñoz, Vanina Laura. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales. Departamento de Ciencias Naturales. Cátedra de Biologia General; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Ludueña, Liliana Mercedes. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales. Departamento de Ciencias Naturales. Cátedra de Biologia General; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Valetti, Lucio. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales. Departamento de Ciencias Naturales. Cátedra de Biologia General; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Fabra, Adriana Isidora. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales. Departamento de Ciencias Naturales. Cátedra de Biologia General; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Abstract:

In this study, it was investigated the reactive oxygen species (ROS) production in peanut nodules at three peanut growth stages (R): R1 (flowering), R4 (full pod) and R6 (full seed). Analysis of ROS production showed that superoxide anion and hydrogen peroxide contents decreased while lipid peroxidation and protein oxidation remained unchanged throughout nodule development. Furthermore, it was found that the inside of formed nodules was 100% red at (R1), 54% at (R4) and 39% at (R6), respectively. The total soluble protein content decreased while leghemoglobin content remained unaltered at different growth stages. Thus, our findings suggest that ROS production is not involved in the peanut nodule senescence indicating that this process would not be accompanied by an oxidative burst. It is possible to suggest that the antioxidant system would play an important role in the protection of peanut nodules against ROS production.

Author affiliation: Carlier, Evelin. Universidad Nacional de Rio Cuarto; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Castro, Stella Maris. Universidad Nacional de Rio Cuarto; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Fabra, Adriana Isidora. Universidad Nacional de Rio Cuarto; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Abstract:

Aims: We evaluated whether reactive oxygen species (ROS) production and the plant antioxidant system are involved in the symbiotic interaction between bradyrhizobia and legumes infected by crack entry, without intracellular infection threads (IT) formation, such as Arachis hypogaea L. (peanut). The role of bradyrhizobial Nod factors (NF) in modulating the plants’ oxidative burst was also analysed. Methods and Results: Histochemical and quantitative procedures were used to detect ROS levels in inoculated and in NF-treated peanut roots. Increase in root H2O2 production was determined at 10 min postinoculation with Bradyrhizobium sp. SEMIA 6144 or after NF addition. ROS production was modulated by NF. From 15 to 30 min postinoculation, the compatibility of Bradyrhizobium sp.–peanut interaction depends mostly on the H2O2 detoxification via catalase. Conclusions: We demonstrated for the first time that the early events of the symbiotic interaction in legumes invaded by crack entry trigger an increase in ROS production (represented exclusively by a higher H2O2 content) in which NADPH-oxidase seems not to be involved. NF modulate this response by enhancing the plant antioxidant machinery, contributing to the creation of adequate conditions for symbiosis development. Significance and Impact of the Study: Our data provide new insights into the mechanism involves in the symbiotic interaction that establish legumes infected by crack entry and suggest that ROS response shows differences compared with legumes invaded by IT formation.

Author affiliation: Muñoz, Vanina Laura. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Ibañez, Fernando Julio. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Tordable, Maria del Carmen. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; Argentina

Author affiliation: Megías, M.. Universidad de Sevilla; España

Author affiliation: Fabra, Adriana Isidora. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Abstract:

Soybean is an economically very important crop throughout the word and particularly in Argentina. Soybean yield may be affected by many factors such as the lack of some essential nutrients or pathogens attack. In this work we demonstrated that the co-inoculation of the native biocontrol bacterium Bacillus sp. CHEP5 which induces resistance against Cercospora sojina in soybean and the nitrogen fixing strain Bradyrhizobium japonicum E109, was more effective in reducing frog leaf spot severity than the inoculation of the biocontrol agent alone. Probably, this is related with the increase in the ability to form biofilm when both bacteria are growing together. Furthermore, Bacillus sp. CHEP5 inoculation did not affect Bradyrhizobium japonicum E109 symbiotic behavior and flavonoids composition of root exudates in pathogen challenged plants. These results suggest that co-inoculation of plants with rhizobia and biocontrol agents could be a strategy to improve soybean production in a sustainable system.

Author affiliation: Tonelli, Maria Laura. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina

Author affiliation: Magallanes Noguera, Cynthia Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; Argentina

Author affiliation: Fabra, Adriana Isidora. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina