Revealing the underlying mechanisms mediated by endophytic actinobacteria to enhance the rhizobia - chickpea (Cicer arietinum L.) symbiosis

Abstract Purpose The effects of endophytic actinobacterial strains, Microbispora sp. CP56, Actinomadura CP84B, Streptomyces spp. CP200B and CP21A, on the chickpea- Mesorhizobium symbiosis, were investigated in planta , with aim revealing underlying mechanisms action. Methods endophytes co-inoculated ciceri onto chickpea seedlings to study effect plant growth parameters, nodulation development grain yield. role exudates rhizobial was investigated, as root actinobacteria-colonized plants expression nod factors biofilm formation. Changes flavonoids bacterial N-fixation genes resulting from co-inoculation assessed using qPCR. Results Application endophytes, together M. showed promotion an increase nodule number weight. Enhanced accompanied by increases total nitrogen, larger weight a 2–3-fold Factors associated this tripartite symbiosis are growth, earlier formation, increased secondary up-regulated related flavonoid synthesis nif genes. In addition, roots colonised actinobacteria nodulation-related biological processes - chemotaxis, formation gene expression. Conclusion These positively affect many aspects Similar improvements recorded growing potted field soils, shows potential enhance production field.