doi:10.1038/nindia.2018.72 Published online 17 June 2018
Researchers have synsthesised a plant-oil-based nanoemulsion that inhibits the growth of a specific bacterium that infects soybean plants1. This nanoemulsion also increases the overall growth of soybean plants, offering an eco-friendly way to enhance crop yields by combating bacterial disease.
Synthetic chemicals are widely used to protect crops against deadly diseases. Such chemicals, however, pollute soil, water and air. They gradually accumulate in plants and aquatic animals such as fish and eventually end up in humans, unleashing harmful effects.
In search of a biocompatible material, scientists from Maharana Pratap University of Agriculture and Technology in Udaipur, Rajasthan, Chaudhary Charan Singh Haryana Agricultural University in Hisar, Haryana, and Washington University in the United States, led by Vinod Saharan, prepared the nanoemulsion using thymol, an essential plant oil component; saponin, a plant-derived surfactant; and water.
They then tested the nanoemulsion’s efficiency in killing Xanthomonas axonopodis pv. Glycine, a bacterium that causes bacterial pustule disease in soybean. This disease begins with the formation of small, pale-green spots that gradually expand and merge to form large spots on soybean leaves, leading to severe disease.
Spraying nanoemulsion on disease-affected plant leaves significantly reduced disease severity. The nanoemulsion contains tiny droplets that contribute to the nanoemulsion’s antibacterial property.
Besides killing the bacteria, the nanoemulsion induced the secretion of plant defence enzymes that protect the plants against the bacterial infection. Nanoemulsion treatment also considerably increased plant height, root length, number of pods and seed weight.
1. Kumari, S. et al. Thymol nanoemulsion exhibits potential antibacterial activity against bacterial pustule disease and growth promotory effect on soybean. Sci. Rep. 8, 6650 (2018)