Encephalartos villosus and Vigna unguiculata L. (Walp) shared symbionts contribute to V. unguiculata plant nutrition and growth in nutrient-deficient ecosystems

Abstract

Abstract Cycads are ancient plants that establish symbiotic associations with plant growth-promoting (PGP) microbes. These ancient associations are rarely contrasted with more recent associations involving PGP microbes and legumes. This study investigated if V. unguiculata growing in Encephalartos villosus acidic, and nutrient-deficient rhizosphere and surrounding soils may share similar symbionts. In addition, the biomass accumulation and plant nutrition in V. unguiculata growing in these soils was investigated. Vigna unguiculata seeds were grown in E. villosus rhizosphere and surrounding soils for 45 days. Thereafter, growth characteristics and plant nutrition were calculated. Vigna unguiculata plants grown in E. villosus rhizosphere and surrounding soils were nodulated by Paenibacillus, Bacillus, Peribacillus, Brevibacillus, Alkalihalobacillus, and Lysinibacillus species that were also identified in E. villosus coralloid roots. There were no significant differences in the total plant biomass, however, V. unguiculata plants in rhizosphere and surrounding soils invested more resources in belowground biomass. The findings of this study show that V. unguiculata and E. villosus growing in similar soil conditions may share the same symbionts promoting plant nutrient assimilation and growth.