Multifunctional molybdenum disulfide-copper nanocomposite that enhances the antibacterial activity, promotes rice growth and induces rice resistance

Molybdenum disulfide sheets loaded with copper nanoparticles (MoS2-CuNPs) was prepared and its antibacterial activity against phytopathogen Xanthomonas oryzae pv. oryzae (Xoo) was investigated in vitro and in vivo for the first time. In a 2 h co-incubation, MoS2-CuNPs exhibited 19.2 times higher antibacterial activity against Xoo cells than a commercial copper bactericide (Kocide 3000). In the detached leaf experiment, the disease severity decreased from 86.25 % to 7.5 % in the MoS2-CuNPs treated rice leaves. The results further demonstrated that foliar application of MoS2-CuNPs could form a protective film and increase the density of trichome on the surface of rice leaves, finally prevent the infection of Xoo cells. This was probably due to the synergistic effect of MoS2-CuNPs. Additionally, foliar application of MoS2-CuNPs (4 - 32 mu g/ mL) increased obviously the content of Mo and chlorophyll (up 30.85 %), and then improved the growth of rice seedlings. Furthermore, the obtained MoS2-CuNPs could activate the activities of the antioxidant enzymes in rice, indicating higher resistance of rice under abiotic/biotic stresses. The multifunctional MoS2-CuNPs with superior antibacterial activity provided a promising alternative to the traditional antibacterial agents and had great potential in plant protection.