Plant protein-based self-assembling core–shell nanocarrier for effectively controlling plant viruses: Evidence for nanoparticle delivery behavior, plant growth promotion, and plant resistance induction

The excessive use of non-renewable formulations, low utilization efficiency, and eco-unfriendly behavior are serious disadvantages of traditional pesticide formulations. Herein, a scalable and sustainable biopolymer-based core–shell (CS) nanocarrier loaded with an anti-viral candidate agent, Bingqingxiao (BQX), was investigated for plant disease management. Preliminary BQX@PyPHEMA@SWP nanoparticles (BQX@PP@S NPs) were manufactured through the noncovalent self-assembly of pyridine-grafted poly (hydroxyethyl methacrylate) (PyPHEMA) and natural soy whey protein (SWP), and exhibited a stable spherical morphology with a diameter of approximately 130 nm. Notably, encapsulation of BQX into the NPs increased the ultra-violet (UV) resistance of the compound by 8.7-fold, and the nanocarrier PyPHEMA@SWP (PP@S) enhanced the BQX foliar surface wettability, resulting in a slow, urea-responsive release. In vivo studies revealed that the protective activity of BQX@PP@S NPs was 1.4-fold higher than that of BQX against tobacco mosaic virus (TMV), and the antiviral efficiency was further improved by stimulation with 0.2 M urea. Furthermore, foliar application of BQX@PP@S NPs activated host plant defense responses by upregulating the expression of salicylic acid (SA)- and abscisic acid (ABA)-related genes. Interestingly, the developed BQX@PP@S NPs act as plant nutrition to enhance the crop fresh and dry weight by 24.7% and 19.9%, respectively. Consequently, PP@S is a promising biocompatible carrier that can enhance the potency of various pesticides, synergistically improve plant disease resistance, and simultaneously act as a fertilizer for crop growth.