Genotype-Specific Responses of Anthyllis vulneraria to Lead and Manganese Stress Mediated by Rhizobacterial Symbiosis

Legume–rhizobia symbiosis plays an important role in plant responses to stressful environments, including soils contaminated with heavy metals. Anthyllis vulneraria, a widespread wild legume, exhibits genotype-dependent variation in metal tolerance and accumulation. The objective of this study was to compare responses of three A. vulneraria genotypes to Pb and Mn stress and to test the hypothesis that tolerance is influenced by rhizobial inoculation with a specific strain. Plants were cultivated under partially controlled conditions with or without inoculation and subjected to Pb or Mn stress. Growth, nodulation, tissue water content, photochemical performance, and metal accumulation were assessed. Both metals negatively affected plant growth and physiological performance; however, responses were genotype-dependent and modified by inoculation. Genotype AV1 showed consistently positive responses, AV2 moderate responses particularly under Mn stress, and AV3 limited effects. Metal accumulation patterns suggested genotype-dependent differences, with AV2 showing higher accumulation in roots and lower Mn concentrations, while AV1 and AV3 showed higher Pb concentration in older leaves under inoculated conditions. Overall, the results suggest that plant responses in A. vulneraria may depend on specific genotype–rhizobia–metal combinations, but these findings are based on a limited number of genotypes and a single inoculum and should be interpreted cautiously with respect to phytoremediation applications.