Specific Host-Responsive Associations Between Medicago truncatula Accessions and Sinorhizobium Strains

Abstract

Legume plants interact with rhizobia to form nitrogen-fixing root nodules. Legume-rhizobium interactions are specific and only compatible rhizobia and plant species will lead to nodule formation. Even within compatible interactions, the genotype of both the plant and the bacterial symbiont will impact on the efficiency of nodule functioning and nitrogen-fixation activity. The model legume Medicago truncatula forms nodules with several species of the Sinorhizobium genus. However, the efficiency of these bacterial strains is highly variable. In this study, we compared the symbiotic efficiency of Sinorhizobium meliloti strains Sm1021, 102F34, and FSM-MA, and Sinorhizobium medicae strain WSM419 on the two widely used M. truncatula accessions A17 and R108. The efficiency of the interactions was determined by multiple parameters. We found a high effectiveness of the FSM-MA strain with both M. truncatula accessions. In contrast, specific highly efficient interactions were obtained for the A17-WSM419 and R108-102F34 combinations. Remarkably, the widely used Sm1021 strain performed weakly on both hosts. We showed that Sm1021 efficiently induced nodule organogenesis but cannot fully activate the differentiation of the symbiotic nodule cells, explaining its weaker performance. These results will be informative for the selection of appropriate rhizobium strains in functional studies on symbiosis using these M. truncatula accessions, particularly for research focusing on late stages of the nodulation process.

Nodule-forming Sinorhizobium and arbuscular mycorrhizal fungi (AMF) improve the growth of Acacia farnesiana (Fabaceae): an alternative for the reforestation of the Cerro de la Estrella, Mexico

“…In contrast to the AMF, the rhizobia are more specific to the host they colonize (Kazmierczak et al 2017). However, no rhizobia specific for A. farnesiana were found in the CE soil.…”

“…The sequences acquired were compared with those in the GenBank database using the program BLAST (Camacho et al 2009). The 16S rRNA, recA, atpD and glnII gene sequences were aligned independently using CLUSTAL X software (Larkin et al 2007). The sequences of the recA, atpD and glnII genes were concatenated manually.…”

MtNIP5;1, A Novel Medicago Truncatula Boron Diffusion Facilitator Induced Under Deficiency

“…Plants grown under symbiotic conditions were inoculated with Sinorhizobium meliloti FSM-MA strain (60) without receiving any external input of N (-N). Non-inoculated plants were supplemented with 20 mM NH 4 NO 3 (+ N).…”

Medicago truncatula: Genetic and Genomic Resources

“…Jemalong and R108 differ in their responses to abiotic stresses such as drought, salt, and aluminum toxicity; sulfur and iron deficiencies (de Lorenzo et al., ; Gao, Li, Tian, Wang, & Zhang, ; Li, Wang, Tian, Wang, & Zhang, ; Luo et al., ); and tolerance to the fungal pathogen Macrophomina phaseolina (Gaige, Doerksen, & Shuain, ). A17 and R108 are also different in their capacity to establish symbiosis with different species and strains of Sinorhizobium (Kazmierczak et al., ; Salzer, Feddermann, Wiemken, Boller, & Staehelin, ). The genome of R108 is 17% smaller than that of A17 (Blondon, Marie, Brown, & Kondorosi, ).…”