Isolation and identification of endophytic actinobacteria from Iris persica and Echium amoenum plants and investigation of their effects on germination and growth of wheat plant

Plant biotechnology helps to develop different types of new products with increased resistance to disease, greater tolerance to drought and salt stress, and better nutritional value. The interaction of plants and microorganisms will play a significant role to achieve this purpose. The aims of this study were to isolate endophyte Actinobacteria strains of some medicinal plants and the investigation of their bioactive potential. 15 Actinobacteria strains were selectively isolated from Persian iris and Echium amoenum plants, and then their belonging to Actinobacteria phylum was confirmed using an Actinobacteria-specific primer pair. The antioxidant activity of the crude extract obtained from the isolated strains was investigated based on DPPH method. Investigating the antioxidant activity of the crude extract showed that at a concentration of 100 mu g/mL, the two strains EG1 and EG2 had 71% and 78% antioxidant activity, respectively. According to the phylogeny studies, it was determined that two strains belonged to the Streptomyces genus. The effect of supernatant achieved from selected endophytic strain on 35-day wheat plants showed that the supernatant considerably promotes root and shoot growth and chlorophyll content under salinity stress (150 mM NaCl). In general, it can be concluded strains that live symbiotically with medicinal plants are rich sources of bioactive compounds. Therefore, identification of the bioactive compounds in the extract of isolated Actinobacteria from medicinal plants and further studies on their metabolism are suggested.

Automated summary

Plant biotechnology has facilitated the development of new products with enhanced disease resistance, drought and salt stress tolerance, and nutritional value. This study aimed to isolate endophytic Actinobacteria strains from medicinal plants and evaluate their bioactive potential. Fifteen Actinobacteria strains were isolated from Persian iris and Echium amoenum plants, which showed antioxidant activity. Phylogenetic analysis revealed that two strains belonged to the Streptomyces genus. Furthermore, the supernatant of a selected endophytic strain promoted root and shoot growth and increased chlorophyll content in wheat plants under salinity stress. Overall, symbiotic strains with medicinal plants are valuable sources of bioactive compounds.