Biogenic Silver Nanoparticles From Rice Seed Endophytes Enhance Growth and Suppress Major Rice Phytopathogens.

Area of Science:

• Agricultural Science
• Nanotechnology
• Microbiology

Background:

• Rice diseases like bacterial blight and fungal blast cause significant global yield losses.
• Conventional pesticides and fertilizers pose environmental risks.
• Nanoparticles offer a safer alternative for agriculture, promoting plant growth and disease control.

Purpose of the Study:

• To synthesize biogenic silver nanoparticles (AgNPs) using a rice-seed endophytic bacterium.
• To evaluate the efficacy of AgNPs in enhancing rice growth and managing key rice pathogens.
• To investigate the uptake and effects of AgNPs on rice plant physiology and immunity.

Main Methods:

• Synthesis of AgNPs using endophytic bacteria and characterization via electron microscopy and X-ray spectroscopy.
• Controlled experiments to assess AgNP impact on rice seed germination and seedling growth.
• In vitro and in vivo assays to determine antimicrobial activity against Xanthomonas oryzae and Magnaporthe oryzae.
• Analysis of AgNP uptake and translocation in rice plants and gene expression profiling of immunity-related genes.

Main Results:

• Spherical AgNPs (10-20 nm) were successfully synthesized and confirmed by spectroscopy.
• AgNPs significantly enhanced rice seed germination and seedling growth by up to 50%.
• AgNPs demonstrated potent antimicrobial activity against bacterial and fungal rice pathogens.
• AgNPs were absorbed by rice roots and translocated to shoots, influencing immunity gene expression (e.g., OsWRKY31 upregulation).

Conclusions:

• Biogenic AgNPs synthesized from rice endophytic bacteria are effective plant growth promoters.
• AgNPs provide a dual benefit of enhancing crop yield and controlling major rice diseases.
• These AgNPs represent a promising, environmentally friendly alternative to synthetic agrochemicals for sustainable agriculture.