Comparative Analyses of Four Chemicals Used to Control Black Mold Disease in Tomato and Its Effects on Defense Signaling Pathways, Productivity and Quality Traits

A review of the interaction mechanisms between jasmonic acid (JA) and various plant hormones, as well as the core regulatory role of MYC2

Jasmonic acid (JA), as a defensive plant hormone, can synergistically or antagonistically interact with common hormones such as gibberellin (GA), abscisic acid (ABA), indole-3-acetic hormone acid (IAA), and ethylene (ETH) during the plant growth process, as well as interact with hormones such as melatonin (MT), brassinolide (BR), and resveratrol to regulate plant growth and development processes such as metabolite synthesis, pest and disease defense, and organ growth. The core regulatory factor MYC2 of JA mainly mediates the signal transduction pathways of these hormone interactions by interacting with other genes or regulating transcription. This article reviews the mechanism of cross-talk between JA and hormones such as ABA, GA, and salicylic acid (SA), and discusses the role of MYC2 in hormone interactions.

A comprehensive review of integrated management strategies for damping-off disease in chili

Damping-off disease in chili (Capsicum annum L.) cultivation is a significant global issue, severely affecting seeds, seedlings, and young plants, regardless of the location of cultivation, whether in greenhouses or open fields. Despite chili being a widely popular vegetable used in various cuisines globally, farmers face challenges in meeting the growing demand due to the extensive damage caused by this disease, ranging from 20 to 85%. The shelf life and quality of mature pods are also severely affected. Damping-off disease is mainly caused by soil-borne fungus from the Pythium species, with additional contributions from Phytophthora, Fusarium, and Rhizoctonia species. These pathogens' adaptability to diverse environmental conditions and resistance to synthetic fungicides make controlling damping-off on a commercial scale challenging. However, integrated disease management has shown promising results as a remedial approach. In this review, we discuss the current state of chili diseases, the nature of the pathogens causing damping-off, the epidemiology of the disease, and various control mechanisms. In this review, we broadly discuss the current state of chili diseases, the nature of the pathogens causing damping-off, the epidemiology of the disease, and various control mechanisms. Furthermore, we highlight the importance and efficacy of integrated disease management techniques, along with future prospects in unexplored areas, such as host-pathogen interaction and sustainable disease control measures. The information in this review aims to assist chili growers in understanding the epidemiology and management of damping-off in chili cultivation.

MdBT2 regulates nitrogen-mediated cuticular wax biosynthesis via a MdMYB106-MdCER2L1 signalling pathway in apple

Cuticular waxes play important roles in plant development and the interaction between plants and their environment. Researches on wax biosynthetic pathways have been reported in several plant species. Also, wax formation is closely related to environmental condition. However, the regulatory mechanism between wax and environmental factors, especially essential mineral elements, is less studied. Here we found that nitrogen (N) played a negative role in the regulation of wax synthesis in apple. We therefore analysed wax content, composition and crystals in BTB-TAZ domain protein 2 (MdBT2) overexpressing and antisense transgenic apple seedlings and found that MdBT2 could downregulate wax biosynthesis. Furthermore, R2R3-MYB transcription factor 16-like protein (MdMYB106) interacted with MdBT2, and MdBT2 mediated its ubiquitination and degradation through the 26S proteasome pathway. Finally, HXXXD-type acyl-transferase ECERIFERUM 2-like1 (MdCER2L1) was confirmed as a downstream target gene of MdMYB106. Our findings reveal an N-mediated apple wax biosynthesis pathway and lay a foundation for further study of the environmental factors associated with wax regulatory networks in apple.

Nanoparticles-Based Delivery Systems for Salicylic Acid as Plant Growth Stimulator and Stress Alleviation

The population growth tendency leads to an increase in demand for food products, and in particular, products obtained from the processing of plants. However, there are issues of biotic and abiotic stresses that can significantly reduce crop yields and escalate the food crisis. Therefore, in recent years, the development of new methods of plant protection became an important task. One of the most promising ways to protect plants is to treat them with various phytohormones. Salicylic acid (SA) is one of the regulators of systemic acquired resistance (SAR) signaling pathways. These mechanisms are able to protect plants from biotic and abiotic stresses by increasing the expression of genes that encode antioxidant enzymes. However, salicylic acid in high doses can act as an antagonist and have the negative rebound effect of inhibition of plant growth and development. To maintain optimal SA concentrations in the long term, it is necessary to develop systems for the delivery and slow release of SA in plants. The purpose of this review is to summarize and study methods of delivery and controlled release of SA in a plant. Various carriers-based nanoparticles (NPs) synthesized from both organic and inorganic compounds, their chemical structure, impacts on plants, advantages, and disadvantages are comprehensively discussed. The mechanisms of controlled release of SA and the effects of the use of the considered composites on the growth and development of plants are also described. The present review will be helpful to design or fabricate NPs and NPs-based delivery systems for salicylic acid-controlled release and better understating of the mechanism of SA-NPs interaction to alleviate stress on plants.

Nanobiotechnological Approaches to Enhance Drought Tolerance in Catharanthus roseus Plants Using Salicylic Acid in Bulk and Nanoform

Drought has a detrimental effect on crop production, affecting economically important plants’ growth rates and development. Catharanthus roseus is an important medicinal plant that produces many pharmacologically active compounds, some of which have significant antitumor activity. The effect of bulk salicylic acid (SA) and salicylic acid nanoparticles (SA-NPs) were evaluated on water-stressed Catharanthus roseus plants. The results showed that SA and SA-NPs alleviated the negative effects of drought in the treated plants by increasing their shoot and root weights, relative water content, leaf area index, chlorophyll content, and total alkaloids percentage. From the results, a low concentration (0.05 mM) of SA-NPs exerted positive effects on the treated plants, while the best results of the bulk SA were recorded after using the highest concentration (0.1 mM). Both treatments increased the expression level of WRKY1, WRKY2, WRKY40, LEA, and MYC2 genes, while the mRNA level of MPKK1 and MPK6 did not show a significant change. This study discussed the importance of SA-NPs in the induction of drought stress tolerance even when used in low concentrations, in contrast to bulk SA, which exerts significant results only at higher concentrations.

A Novel Bacillus safensis-Based Formulation along with Mycorrhiza Inoculation for Controlling Alternaria alternata and Simultaneously Improving Growth, Nutrient Uptake, and Steviol Glycosides in Stevia rebaudiana under Field Conditions

The excess use of chemicals by farmers in the agroecosystems degrades soil quality, disturbs soil ecology, and increases soil salinity and health hazards in humans. Stevia rebaudiana is an important medicinal and aromatic crop whose leaves contain steviol glycosides (SGs). The Bacillus safensis NAIMCC-B-02323 strain STJP from the rhizosphere of S. rebaudiana producing salicylic acid (16.80 µg/mL), chitinase (75.58 U/mL), β-1,3-glucanase (220.36 U/mL), and cellulase (170 U/mL) was taken as a plant growth-promoting rhizobacteria (PGPR). The cell-free supernatant (CFS) from strain STJP showed significant biocontrol activity against Alternaria alternata (80%), suggesting the protective role of extracellular metabolite(s) against phytopathogens. Paneer whey-based bioformulation (P-WBF) was developed to exploit B. safensis STJP to enhance the growth, nutrient uptake, soil properties, stevioside content, and SGs biosynthesis in S. rebaudiana under an A. alternata-infested field. The combined treatment of P-WBF and mycorrhiza (Glomus fasciculatum ABTEC) significantly enhanced plant growth parameters after 90 days, in comparison with control. The symbiotic action (P-WBF and mycorrhiza) displayed much better results in terms of chlorophyll a and b (improved by 132.85% and 39.80%, respectively), protein (by 278.75%), flavonoid (by 86.99%), carbohydrate (by 103.84%), antioxidant (by 75.11%), and stevioside (by 120.62%) contents in plants as compared to the untreated set. Further, the augmentation of potassium (by 132.39%), phosphorous (by 94.22%), and zinc (by 111.11%) uptake in plant tissues and soil was also observed by the application of P-WBF and mycorrhiza. The expression of UGT74G1 and UGT85C2 genes related to SG biosynthesis was upregulated (2.7- and 3.2-fold, respectively) in plants treated with P-WBF and mycorrhiza as further confirmed by the accumulation of SGs. The results suggest that the application of P-WBF and mycorrhiza not only provides an ecofriendly and sustainable solution to improve stevioside content in S. rebaudiana by a nutrient-linked mechanism but also paves the way to enhanced production of stevioside.

Effect of Active Packaging Material Fortified with Clove Essential Oil on Fungal Growth and Post-Harvest Quality Changes in Table Grape during Cold Storage

Fungal growth in table grapes (Vitis vinifera cv. beauty seedless) is triggered by Botrytis cinerea, Penicillium sp., Aspergillus sp., and Rhizopus stolonifera during post-harvest storage. Due to the safety aspects, this research aimed to develop antifungal packaging embedded with essential oils (EOs) to alleviate the fungal decay of table grapes (TG). The various levels of EOs (0.5–5%, v/v) from clove, cinnamon, thyme, peppermint, lemon, bergamot, ginger, spearmint, and lemongrass were tested against Aspergillus sp. The results attained in radial growth, disk diffusion method, minimal inhibitory concentration, and minimal fungicidal concentration revealed that 1% clove essential oil (CEO) showed higher efficacy against Aspergillus sp. compared to the untreated control and other treatments. CEO at the 1% level exhibited a pleasant odor intensity in TG than the other EOs. The active polyvinyl alcohol (7% PVA) film with 1% CEO resulted in lower weight loss, disease severity, and TG berry drop than the control and other treated samples. Additionally, the acceptance score in the TG sample wrapped with a PVA film containing 1% CEO was augmented. Therefore, the PVA film with 1% CEO retarded the fungal growth and prolonged the shelf life of TG during storage of 21 days at 13 °C and 75% relative humidity (RH).

Quality Attributes and Storage of Tomato Fruits as Affected by an Eco-Friendly, Essential Oil-Based Product

The preservation of fresh produce quality is a major aim in the food industry since consumers demand safe and of high nutritional value products. In recent decades there has been a turn towards the use of eco-friendly, natural products (i.e., essential oils-EOs) in an attempt to reduce chemical-based sanitizing agents (i.e., chlorine and chlorine-based agents). The aim of this study was to evaluate the efficacy of an eco-friendly product (EP—based on rosemary and eucalyptus essential oils) and two different application methods (vapor and dipping) on the quality attributes of tomato fruits throughout storage at 11 °C and 90% relative humidity for 14 days. The results indicated that overall, the EP was able to maintain the quality of tomato fruits. Dipping application was found to affect less the quality attributes of tomato, such as titratable acidity, ripening index and antioxidant activity compared to the vapor application method. Vapor application of 0.4% EP increased fruit’s antioxidant activity, whereas tomatoes dipped in EP solution presented decreased damage index (hydrogen peroxide and lipid peroxidation levels), activating enzymes antioxidant capacity (catalases and peroxidases). Moreover, higher EP concentration (up to 0.8%) resulted in a less acceptable product compared to lower concentration (0.4%). Overall, the results from the present study suggest that the investigated EP can be used for the preservation of fresh produce instead of the current commercial sanitizing agent (chlorine); however, the method of application and conditions of application must be further assessed for every commodity tested.

The Application of a Plant Biostimulant Based on Seaweed and Yeast Extract Improved Tomato Fruit Development and Quality

Plant biostimulants are under investigation as innovative products to improve plant production and fruit quality, without resulting in environmental and food contaminations. Here, the effects of the application of Expando, a biostimulant based on seaweed and yeast extracts, on plant productivity, fruit ripening times, and fruit quality of Solanum lycopersicum var. Micro-Tom were evaluated. After biostimulant treatment, a two-week reduction of ripening times and a concomitant enhancement of the production percentage during the earliest ripening times, in terms of both fruit yield (+110%) and size (+85%), were observed. Concerning fruit quality, proximate analysis showed that tomatoes treated with the biostimulant had better nutritional composition compared to untreated samples, since both the quality of unsatured fatty acids (C16:3ω3: +328%; C18:2ω6: -23%) and micronutrients essential for human health (Fe: +14%; Cu: +21%; Zn: +24%) were increased. From a nutraceutical point of view, despite strong changes in bioactive compound profile not being observed, an increase of the antioxidant properties was recorded in fruits harvested by plants treated with the biostimulant (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS): +38%; 2,2-diphenyl-1-picrylhydrazyl (DPPH): +11%). In conclusion, the biostimulant application was able to reduce the ripening times and fruit size, while slightly increasing nutritional and nutraceutical values, leading to more marketable tomato fruits.