Endophytic Streptomyces extend the vase life of Gerbera jamesonii L. by modulating antioxidant system and suppressing bacterial growth

Gerbera flowers are the best-selling cut flowers worldwide owing to their attractive appearance. Nevertheless, one significant challenge for gerbera flowers is their relatively short vase life. Commercially, synthetic chemicals are used to prolong the vase life of flowers; however, they are not environmentally friendly, posing sustainability concerns. Therefore, we used different concentrations of the biocontrol spore suspension of Streptomyces exfoliatus FT05W and evaluated their effect on vase life, bacterial population, and different morphology and physiological indices of gerbera cut flowers, with the objective of determining the optimal concentration for maximum efficiency. The results revealed that all spore suspensions of S. exfoliatus FT05W (1 × 106 CFU mL) significantly extended vase life and were 4 days longer than the control. S. exfoliatus FT05W treatment also increased bottle life extension days, blossom diameter, and fresh weight, and maintained water balance. In addition, it decreased malondialdehyde (MDA) levels and relative electrolyte leakage (REL), leading to decreased oxidative stress. S. exfoliatus FT05W significantly increased antioxidant enzymes, including superoxide dismutase (SOD) activity, catalase (CAT) activity, peroxidase (POD) activity, soluble sugar (SS), and soluble protein (SP), compared to the control. Furthermore, it can effectively inhibit bacterial proliferation, resulting in a decline in colonies and a significant delay in the flower ageing process. The beneficial impacts of S. exfoliatus FT05W were most pronounced at a concentration of 1 × 106 CFU/mL. The findings of this research suggest that S. exfoliatus FT05W has great potential as a bio-fertiliser for cut flowers, as it is capable of addressing the challenges associated with flower cultivation.