Influence of cadmium on the symbiotic interaction established between peanut (Arachis hypogaea L.) and sensitive or tolerant bradyrhizobial strains.
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.
Departamento de Ciencias Naturales, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Ruta 36 Km 601, 5800 Río Cuarto, Córdoba, Argentina. Electronic address: ebianucci@exa.unrc.edu.ar.
Eliana
E
Bianucci
Ana
A
Furlan
Jesica
J
Rivadeneira
Juan
J
Sobrino-Plata
Ramón O
RO
Carpena-Ruiz
María del Carmen
Mdel C
Tordable
Adriana
A
Fabra
Luis E
LE
Hernández
Stella
S
Castro
D010367:Arachis / Q000187:drug effects / Q000378:metabolism / Q000382:microbiology*; D020369:Bradyrhizobium / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D002104:Cadmium / Q000633:toxicity*; D004785:Environmental Pollutants / Q000633:toxicity; D006861:Hydrogen Peroxide / Q000378:metabolism; D015227:Lipid Peroxidation; D018384:Oxidative Stress; D018517:Plant Roots / Q000033:anatomy & histology / Q000187:drug effects / Q000382:microbiology; D017382:Reactive Oxygen Species / Q000378:metabolism; D012988:Soil Microbiology; D013559:Symbiosis / Q000187:drug effects
D004785:Environmental Pollutants; D017382:Reactive Oxygen Species; D002104:Cadmium; D006861:Hydrogen Peroxide
Cadmium accumulation; Oxidative stress; Peanut-Bradyrhizobium sp. symbiosis