This work demonstrates the development of room-temperature curable and durable anti-soiling coating using fluorine functionalized mesoporous silica (F-SiO2) and silicone resin-based hydrophobic coatings. The use of silicone resin with a catalyst enabled room-temperature curing of the coating and enhanced its mechanical properties. The coating prepared from mesoporous silica and F-SiO2 exhibited contact angles of 102 degrees and 122 degrees, indicating a significant improvement in the wettability of F-SiO2-based coatings. Additionally, the transmittance values were 93 % and 94 %, respectively, which are comparable to those of bare PV cover glass. A soiling study of the fabricated coating was conducted in an outdoor environment for over one month. The results confirmed that the F-SiO2-based hydrophobic coatings showed a minimal transmittance loss compared to non-coated PV cover glass. The durability of the F-SiO2-based coating was confirmed by mechanical properties like adhesive strength (1.86 MPa) and hardness (4H). The photo-conversion efficiency of the F-SiO2 coated PV module was measured in an indoor soiling environment using wind cleaning action. It was observed that the module regained its photoconversion efficiency after only one minute of wind cleaning. These results indicate that the prepared coatings have a significant potential for practical application in PV industry.
Phytophthora infestans-induced potato late blight is considered the cancer of the potato crop. In this work, mesoporous silica nanoparticles (MSNs) with ultrahigh specific surface area (786.28 m(2)/g) were synthesized, which significantly inhibited P. infestans compared with some commercial fungicides. Moreover, MSNs inhibited the growth and reproductive of P. infestans processes, including germination, sporangia infection, and zoospore release. MSNs targeted key biological pathways and induced a stress response in the P. infestans, leading to reactive oxygen species (center dot O2-, center dot OH, and O-1(2)) production and structural damage of sporangia. Pot experiments showed that MSNs are translocated from leaves to roots of potato plants, enhancing physiological and biochemical processes, alleviating drought stress, improving resistance to pathogens, and exhibiting soil microbe-friendly. This study systematically reveals the mechanism of MSNs to weaken the reproduction process of P. infestans and confirm the safety and feasibility of MSNs as a green and sustainable fungicide.
In agriculture, soil-borne fungal pathogens, especially Fusarium oxysporum strains, are posing a serious threat to efforts to achieve global food security. In the search for safer agrochemicals, silica nanoparticles (SiO2NPs) have recently been proposed as a new tool to alleviate pathogen damage including Fusarium wilt. Hollow mesoporous silica nanoparticles (HMSNs), a unique class of SiO2NPs, have been widely accepted as desirable carriers for pesticides. However, their roles in enhancing disease resistance in plants and the specific mechanism remain unknown. In this study, three sizes of HMSNs (19, 96, and 406 nm as HMSNs-19, HMSNs-96, and HMSNs-406, respectively) were synthesized and characterized to determine their effects on seed germination, seedling growth, and Fusarium oxysporum f. sp. phaseoli (FOP) suppression. The three HMSNs exhibited no side effects on cowpea seed germination and seedling growth at concentrations ranging from 100 to 1500 mg/L. The inhibitory effects of the three HMSNs on FOP mycelial growth were very weak, showing inhibition ratios of less than 20% even at 2000 mg/L. Foliar application of HMSNs, however, was demonstrated to reduce the FOP severity in cowpea roots in a size- and concentration-dependent manner. The three HMSNs at a low concentration of 100 mg/L, as well as HMSNs-19 at a high concentration of 1000 mg/L, were observed to have little effect on alleviating the disease incidence. HMSNs-406 were most effective at a concentration of 1000 mg/L, showing an up to 40.00% decline in the disease severity with significant growth-promoting effects on cowpea plants. Moreover, foliar application of HMSNs-406 (1000 mg/L) increased the salicylic acid (SA) content in cowpea roots by 4.3-fold, as well as the expression levels of SA marker genes of PR-1 (by 1.97-fold) and PR-5 (by 9.38-fold), and its receptor gene of NPR-1 (by 1.62-fold), as compared with the FOP infected control plants. Meanwhile, another resistance-related gene of PAL was also upregulated by 8.54-fold. Three defense-responsive enzymes of POD, PAL, and PPO were also involved in the HMSNs-enhanced disease resistance in cowpea roots, with varying degrees of reduction in activity. These results provide substantial evidence that HMSNs exert their Fusarium wilt suppression in cowpea plants by activating SA-dependent SAR (systemic acquired resistance) responses rather than directly suppressing FOP growth. Overall, for the first time, our results indicate a new role of HMSNs as a potent resistance inducer to serve as a low-cost, highly efficient, safe and sustainable alternative for plant disease protection.