Salt Stress Highlights the Relevance of Genotype × Genotype Interaction in the Nitrogen-Fixing Symbiosis between <i>Sinorhizobium meliloti</i> and Alfalfa
Agnese Bellabarba,
Francesca Decorosi,
Camilla Fagorzi,
Amina El Hadj Mimoune,
Arianna Buccioni,
Margherita Santoni,
Gaio Cesare Pacini,
Abdelkader Bekki,
Khalid Azim,
Majida Hafidi,
Marco Mazzoncini,
Alessio Mengoni,
Francesco Pini,
Carlo Viti
Affiliations
Agnese Bellabarba
Department of Agricultural, Food, Environmental and Forestry Sciences (DAGRI), University of Florence, I-50144 Florence, Italy
Francesca Decorosi
Department of Agricultural, Food, Environmental and Forestry Sciences (DAGRI), University of Florence, I-50144 Florence, Italy
Camilla Fagorzi
Department of Biology, University of Florence, I-50019 Florence, Italy
Amina El Hadj Mimoune
Laboratory of Rhizobia Biotechnology and Plant Breeding, University Oran1, Es Senia 31000, Algeria
Arianna Buccioni
Department of Agricultural, Food, Environmental and Forestry Sciences (DAGRI), University of Florence, I-50144 Florence, Italy
Margherita Santoni
Department of Agricultural, Food, Environmental and Forestry Sciences (DAGRI), University of Florence, I-50144 Florence, Italy
Gaio Cesare Pacini
Department of Agricultural, Food, Environmental and Forestry Sciences (DAGRI), University of Florence, I-50144 Florence, Italy
Abdelkader Bekki
Laboratory of Rhizobia Biotechnology and Plant Breeding, University Oran1, Es Senia 31000, Algeria
Khalid Azim
National Institute of Agricultural Research (INRA), Regional Center of Agadir, Inzegane Principale, Agadir CP 80350, Morocco
Majida Hafidi
Department of Biology, Faculty of Science, Moulay Ismail University, Meknés BP 11201, Morocco
Marco Mazzoncini
Centro di Ricerche Agro-Ambientali “Enrico Avanzi” (CiRAA), University of Pisa, I-57100 Pisa, Italy
Alessio Mengoni
Department of Biology, University of Florence, I-50019 Florence, Italy
Francesco Pini
Department of Biosciences, Biotechnology and Environment (DBBA), University of Bari—Aldo Moro, I-70125 Bari, Italy
Carlo Viti
Department of Agricultural, Food, Environmental and Forestry Sciences (DAGRI), University of Florence, I-50144 Florence, Italy
Sustainable-forage production is globally increasing, especially in marginal areas where the edaphic conditions for plant growth are not optimal. Soil salinization influences the symbiotic interaction between alfalfa and rhizobia. The efficiency of different symbiotic pairs (Sinorhizobium meliloti—Medicago sativa) was evaluated in relation to NaCl application (100 mM) on two different alfalfa cultivars (Marina and Etrusca) and 21 S. meliloti strains isolated in Algeria. At 100 mM NaCl, it was observed that there was a higher variability of plant dry weight compared to the control. The strains able to improve plant growth at 100 mM NaCl were different and specific for each alfalfa cultivar, highlighting that (symbiont) G × (host) G interaction is magnified under stressed (saline) conditions (E). Three strains were then identified as candidate inoculants for M. sativa cv Marina and used for an in-field experiment with induced stress (no irrigation), together with S. meliloti GR4 (a highly competitive strain). In-field experiments, showed a high variability, and a significant difference of plant biomass was observed only for those inoculated with S. meliloti GR4. Obtained results suggest that multiple traits should be considered for inoculant-strain selection, and for an efficient translation from lab to field, it requires extensive comprehension of the mechanisms driving G × G × E interaction.
