Ethylene Renders Silver Nanoparticles Stress Tolerance in Rice Seedlings by Regulating Endogenous Nitric Oxide Accumulation

Synergy of plant growth promoting rhizobacteria and silicon in regulation of AgNPs induced stress of rice seedlings

Silver Nanoparticles (AgNPs), as an emerging pollutant, have been receiving significant attention as they deepen the concern regarding the issue of food security. Silicon (Si) and plant growth-promoting rhizobacteria (PGPR) are likely to serve as a sustainable approach to ameliorating abiotic stress and improving plant growth through various mechanisms. The present study aims to evaluate the synergistic effect of Si and PGPRs on growth, physiological, and molecular response in rice seedlings (Oryza sativa) under AgNPs stress. Data suggested that under AgNPs exposure, the root and shoot growth, photosynthetic pigments, antioxidant enzymes (CAT and APX), expression of antioxidant genes (OsAPX and OsGR), silicon transporter (OsLsi2), and auxin hormone-related genes (OsPIN10 and OsYUCCA1) were significantly decreased which accompanied with the overproduction of reactive oxygen species (ROS), nitric oxide (NO) and might be due to higher accumulation of Ag in plant cells. Interestingly, the addition of Si along with the AgNPs enhances the level of ROS generation, thus oxidative stress, which causes severe damage in all the above-tested parameters. On the other hand, application of PGPR alone and along with Si reduced the toxic effect of AgNPs through the improvement of growth, biochemical, and gene regulation (OsAPX and OsGR, OsPIN10 and OsYUCCA1). However, the addition of L-NAME along with PGPR and silicon drastically lowered the AgNPs induced toxicity through lowering the oxidative stress and maintained the overall growth of rice seedlings, which suggests the role of endogenous NO in Si and PGPRs mediated management of AgNPs toxicity in rice seedlings.

Encapsulated nanopesticides application in plant protection: Quo vadis?

The increased global food insecurity due to the growing population can be addressed with precision and sustainable agricultural practices. To tackle the issues regarding food insecurity, farmers used different agrochemicals that improved plant growth and protection. Among these agrochemicals, synthetic pesticides used for plant protection in the agricultural field have various disadvantages. Conventional applications of synthetic pesticides have drawbacks such as rapid degradation, poor solubility, and non-target effects, as well as increased pesticide runoff that pollutes the environment. Nanotechnology has evolved as a potential solution to increase agricultural productivity through the development of different nanoforms of agrochemicals such as nanopesticides, nano-fabricated fertilizers, nanocapsules, nanospheres, nanogels, nanofibers, nanomicelles, and nano-based growth promoters. Encapsulation of these pesticides inside the nanomaterials has provided good biocompatibility over conventional application by inhibiting the early degradation of active ingredients (AI), increasing the uptake and adhesion of pesticides, improving the stability, solubility, and permeability of the pesticides, and decreasing the environmental impacts due to the pesticide runoff. In this review, different nanoforms of encapsulated pesticides and their smart delivery systems; nanocarriers in RNA interference (RNAi) based pesticides; environmental fate, practical implications, management of nanopesticides; and future perspectives are discussed.