Bacillus altitudinis‐Stabilized Multifarious Copper Nanoparticles Prevent Bacterial Fruit Blotch in Watermelon (Citrullus lanatus L.): Direct Pathogen Inhibition, In Planta Particles Accumulation, and Host Stomatal Immunity Modulation

Abstract

The nano‐enabled crop protecting agents have been emerging as a cost‐effective, eco‐friendly, and sustainable alternative to conventional chemical pesticides. Here, the antibacterial activity and disease‐suppressive potential of biogenic copper nanoparticles (bio‐CuNPs) against bacterial fruit blotch (BFB), caused by Acidovorax citrulli (Ac), in watermelon (Citrullus lanatus L.) is discussed. CuNPs are extracellularly biosynthesized using a locally isolated bacterial strain Bacillus altitudinis WM‐2/2, and have spherical shapes of 29.11–78.56 nm. Various metabolites, such as alcoholic compounds, carboxylic acids, alkenes, aromatic amines, and halo compounds, stabilize bio‐CuNPs. Foliar application of bio‐CuNPs increases the Cu accumulation in shoots/roots (66%/27%), and promotes the growth performance of watermelon plants by improving fresh/dry weight (36%/39%), through triggering various imperative physiological and biochemical processes. Importantly, bio‐CuNPs at 100 µg mL−1 significantly suppress watermelon BFB through balancing reactive oxygen species system, improving photosynthesis capacity, and modulating stomatal immunity. Bio‐CuNPs show obvious antibacterial activity against Ac by inducing oxidative stress, biofilm inhibition, and cellular integrity disruption. These findings demonstrate that bio‐CuNPs can suppress watermelon BFB through direct antibacterial activity and induction of active immune response in watermelon plants, and highlight the value of this approach as a powerful tool to increase agricultural production and alleviate food insecurity.

Graphene–Cu Nanocomposites Induce Tolerance against Fusarium oxysporum, Increase Antioxidant Activity, and Decrease Stress in Tomato Plants

“…These results suggest that the use of CNMs could be a viable option to control diseases such as F. oxysporum in tomato crops. Foliar application of bio-CuNP enhanced copper accumulation in plants, promoting growth and photosynthesis of watermelons, and suppressed bacterial spots on watermelons caused by Acidovorax citrull by activating an immune response in plants [ 40 ].…”

Development of copper nanoparticles and their prospective uses as antioxidants, antimicrobials, anticancer agents in the pharmaceutical sector

“…Numerous chronic illnesses have been linked to oxidative stress, brought on by an imbalance between the generation of reactive oxygen species (ROS) and cellular antioxidant defense systems. CuNPs' antioxidant ability can reduce oxidative stress by scavenging ROS and defending cells from damage [8], [9]. CuNPs produced utilizing fungus have recently been shown to have considerable antioxidant activity, making them potential candidates for the creation of new medicinal treatments [10].…”

Dexterous green synthesis of Cu2O nanoparticles: An amenable catalyst for aqueous click reaction, antiproliferative, and wound healing applications

“…34 Besides, current research on copper oxide NPs elicit that they have extremely promising and potent roles in the field of drug delivery, 35 bio imaging, 36 cancer treatment, 37 fluorescent biological labels, 38 wound healing, 39 tissue engineering, 40 and bio detection of pathogens. 41 Copper oxide NPs have been used in various clinical trials illustrating efficacy in the treatment of wounds alongside other biomedical concerns as well as addressing the use of nanomedicine to be a valuable option for developing new antimicrobial agents due to their innate potential, antimicrobial, and fungicidal properties. [42][43][44] Food that is effective, nutraceutical, and fortified not merely enhances the nutrition yet additionally aids overall immune building and prevention of illness.…”