Synthesis of Silver Nanoparticle Composites Using Calliblepharis fimbriata Aqueous Extract, Phytochemical Stimulation, and Controlling Bacterial Blight Disease in Rice

In this study, the biosynthesized silver nanoparticle composites (AgNPCs) obtained from the polysaccharide extract of the red alga Calliblepharis fimbriata were used to control the infection of Xanthomonas oryzae pv. oryzae bacteria causing blight disease in rice. The effect of AgNPCs was evaluated based on seed germination, growth parameters, and photosynthetic pigments of the Oryzae sativa. The formation of AgNPCs was monitored by UV-visible spectrophotometer and characterized by using XRD, SEM, EDAX, and TEM analysis. The synthesized AgNPCs appear spherical in shape, and the size was measured in the range of 25-30 nm. Further, the aqueous extract of seaweed derived AgNPCs was characterized using FTIR, 1D and 2D H-1 NMR, and GC-MS analysis. Among the different treatments, a AgNPCs concentration of 50 mu g/mL was found to show a stimulatory effect in seed germination and its related growth parameters over control and untreated seeds. In this study, AgNPCs controlled the bacterial colonization and also enhanced the biochemical characteristics of infected rice plants. Later, EDAX analysis showed that infected and uninfected rice seedlings treated with 50 mu g/mL of AgNPCs were free of Ag particles but increased amount of nutrients like P, K C, S, Mg, and Cl in plants. However, reduction in the Ca and Fe ion concentrations was not below the level of untreated plants. This study concluded that AgNPCs of red alga C. fimbriata have growth stimulation as well as pesticidal properties to control bacterial blight in rice without compromising host growth, a potential substrate for nanopesticide production.

Automated summary

The biosynthesized silver nanoparticle composites (AgNPCs) obtained from red alga Calliblepharis fimbriata polysaccharide extract were used to control Xanthomonas oryzae pv. oryzae infection in rice plants. AgNPCs showed stimulating effect on seed germination and growth parameters, controlled bacterial colonization, and enhanced biochemical characteristics of infected rice plants without compromising host growth. This study concluded that AgNPCs have potential as nanopesticides for controlling bacterial blight in rice.