The most serious problems for cultivated grapes are pathogenic microorganisms, which reduce the yield and quality of fruit. One of the most widespread disease of grapes is \"gray mold\", caused by the fungus Botrytis cinerea. Some strains of Bacillus, such as Bacillus halotolerans, Bacillus amyloliquefaciens, and Bacillus velezensis, are known to be active against major post-harvest plant rots. In this study, we showed that the endophytic bacteria B. velezensis strain AMR25 isolated from the leaves of wild grapes Vitis amurensis Rupr. exhibited antimicrobial activity against grape pathogens, including B. cinerea. The genome of B. velezensis AMR25 has one circular chromosome with a length of 3,909,646 bp. with 3689 open reading frames. Genomic analysis identified ten gene clusters involved in the nonribosomal synthesis of polyketides (macrolactin, bacillene, and difficidin), lipopeptides (surfactin, fengycin, and bacillizin), and bacteriocins (difficidin). Also, the genome under study contains a number of genes involved in root colonization, biofilm formation, and biosynthesis of phytohormones. Thus, the endophytic bacteria B. velezensis strain AMR25 shows great promise in developing innovative biological products for enhancing plant resistance against various pathogens.

This study examined the potential use of three bacterial strains-Paraburkholderia sp. strain CRV74, Pseudomonas sp. strain CRV21, and Acinetobacter sp. strain CRV19-as biocontrol agents of Botrytis cinerea in grapevine. These strains were selected for their ability to inhibit B. cinerea growth in vitro and used in field conditions for the control of grey mould symptoms in \'Glera\' grapes. To this end, after inoculating these microorganisms onto plants sprayed with B. cinerea spores, the final yield, the physicochemical characteristics of the must, disease incidence, and the possible influence on the expression of plant-defence proteins were evaluated. Strain CRV21 resulted as being the most effective in combating grey mould (-20% of disease incidence). Although yield was not affected, significantly different values of total soluble solids content was observed. Additionally, a significant up-regulation of the genes PR-1, PR-5, β-1,3-glucanase, and class III chitinase was observed. These findings highlight the potential application of strains with anti-botrytis activity as sustainable alternatives to chemical defence for the control of this pathogen.

Sophora flavescens, a traditional Chinese herb, produces a wide range of secondary metabolites with a broad spectrum of biological activities. In this study, we isolated six isopentenyl flavonoids (1-6) from the roots of S. flavescens and evaluated their activities against phytopathogenic fungi. In vitro activities showed that kurarinone and sophoraflavanone G displayed broad spectrum and superior activities, among which sophoraflavanone G displayed excellent activity against tested fungi, with EC50 values ranging from 4.76 to 13.94 μg/mL. Notably, kurarinone was easily purified and showed potential activity against Rhizoctonia solani, Botrytis cinerea, and Fusarium graminearum with EC50 values of 16.12, 16.55, and 16.99 μg/mL, respectively. Consequently, we initially investigated the mechanism of kurarinone against B. cinerea. It was found that kurarinone disrupted cell wall components, impaired cell membrane integrity, increased cell membrane permeability, and affected cellular energy metabolism, thereby exerting its effect against B. cinerea. Therefore, kurarinone is expected to be a potential candidate for the development of plant fungicides.

Methionine (Met) can inhibit plant diseases caused by phytopathogens. However, the effect of Met on gray mold resulted from Botrytis cinerea in tomato is still unclear. This study showed 5 mM Met alleviated disease development of gray mold, enhanced chitinase (CHI) and β-1, 3-glucanase (GNS) activities and the expression of SlCHI, SlGNS, SlPR1 and SlNPR1 in tomatoes, rather than inhibited the growth of B. cinerea directly. Moreover, ethylene biosynthesis and signal transduction before pathogen inoculating were induced by 5 mM Met. Interestingly, Met reduced the nitrosylation levels of ACS4 and ACO6, enhanced the activities of nitric oxide synthase, nitrite reductase (NR) and S-nitrosoglutathione reductase (GSNOR) and the expression of SlNR and SlGSNOR. Tomatoes treated with aminoethoxyvinylglycine and carboxy-PTIO exhibited lower resistance to B. cinerea. These results indicate 5 mM Met promoted ethylene biosynthesis and signal transduction to facilitate NO synthesis and metabolism, enhancing the resistance of tomatoes to B. cinerea.

Blueberry is an important perennial fruit crop with expanding consumption and production worldwide. Consumer demand for blueberries has grown due to the desirable flavor and numerous health benefits, and fresh market production in the U.S. has risen in turn. U.S. imports have also increased to satisfy year-round consumer demand for fresh blueberries. Pre- and post-harvest fruit diseases such as anthracnose (caused by Colletotrichum spp.) and botrytis fruit rot (caused by Botrytis spp.) have a significant impact on fruit quality and consumer acceptance. These are also among the most difficult diseases to control in the blueberry cropping system. These latent pathogens can cause significant losses both in the field, and especially during transport and marketplace storage. Although both diseases result in rotted fruit, the biology and infection strategies of the causal pathogens are very different, and the management strategies differ. Innovations for management, such as improved molecular detection assays for fungicide resistance, postharvest imaging, breeding resistant cultivars, and biopesticides have been developed for improved fruit quality. Development and integration of new strategies is critical for the long-term success of the blueberry industry.

The complexity of the interaction between the necrotrophic pathogen Botrytis cinerea and grape berries (Vitis vinifera spp.) can result in the formation of either the preferred noble rot (NR) or the loss-making grey rot (GR), depending on the prevailing climatic conditions. In this study, we focus on the functional gene set of V. vinifera by performing multidimensional scaling followed by differential expression and enrichment analyses. The aim of this study is to identify the differences in gene expression between grape berries in the phases of grey rot, noble rot, and developing rot (DR, in its early stages) phases. The grapevine transcriptome at the NR phase was found to exhibit significant differences from that at the DR and GR stages, which displayed strong similarities. Similarly, several plant defence-related pathways, including plant-pathogen interactions as hypersensitive plant responses were found to be enriched. The results of the analyses identified a potential plant stress response pathway (SGT1 activated hypersensitive response) that was found to be upregulated in the GR berry but downregulated in the NR berry. The study revealed a decrease in defence-related in V. vinifera genes during the NR stages, with a high degree of variability in functions, particularly in enriched pathways. This indicates that the plant is not actively defending itself against Botrytis cinerea, which is otherwise present on its surface with high biomass. This discrepancy underscores the notion that during the NR phase, the grapevine and the pathogenic fungi interact in a state of equilibrium. Conversely the initial stages of botrytis infection manifest as a virulent fungus-plant interaction, irrespective of whether the outcome is grey or noble rot.

Rhamnolipids (RLs) and Fengycins (FGs) are biosurfactants with very promising antifungal properties proposed to reduce the use of synthetic pesticides in crops. They are amphiphilic molecules, both known to target the plasma membrane. They act differently on Botrytis cinerea and Sclerotinia sclerotiorum, two close Sclerotiniaceae phytopathogenic fungi. RLs are more efficient at permeabilizing S. sclerotiorum, and FGs are more efficient at permeabilizing B. cinerea mycelial cells. To study the link between the lipid membrane composition and the activity of RLs and FGs, we analyzed the lipid profiles of B. cinerea and S. sclerotiorum. We determined that unsaturated or saturated C18 and saturated C16 fatty acids are predominant in both fungi. We also showed that phosphatidylethanolamine (PE), phosphatidic acid (PA), and phosphatidylcholine (PC) are the main phospholipids (in this order) in both fungi, with more PA and less PC in S. sclerotiorum. The results were used to build biomimetic lipid membrane models of B. cinerea and S. sclerotiorum for all-atom molecular dynamic simulations and solid-state NMR experiments to more deeply study the interactions between RLs or FGs with different compositions of lipid bilayers. Distinctive effects are exerted by both compounds. RLs completely insert in all the studied model membranes with a fluidification effect. FGs tend to form aggregates out of the bilayer and insert individually more easily into the models representative of B. cinerea than those of S. sclerotiorum, with a higher fluidification effect. These results provide new insights into the lipid composition of closely related fungi and its impact on the mode of action of very promising membranotropic antifungal molecules for agricultural applications.

Infection of grapevines with the grey mold pathogen Botrytis cinerea results in severe problems for winemakers worldwide. Browning of wine is caused by the laccase-mediated oxidation of polyphenols. In the last decades, Botrytis management has become increasingly difficult due to the rising number of resistances and the genetic variety of Botrytis strains. During the search for sustainable fungicides, polyphenols showed great potential to inhibit fungal growth. The present study revealed two important aspects regarding the effects of grape-specific polyphenols and their polymerized oxidation products on Botrytis wild strains. On the one hand, laccase-mediated oxidized polyphenols, which resemble the products found in infected grapes, showed the same potential for inhibition of growth and laccase activity, but differed from their native forms. On the other hand, the impact of phenolic compounds on mycelial growth is not correlated to the effect on laccase activity. Instead, mycelial growth and relative specific laccase activity appear to be modulated independently. All phenolic compounds showed not only inhibitory but also inductive effects on fungal growth and/or laccase activity, an observation which is reported for the first time. The simultaneous inhibition of growth and laccase activity demonstrated may serve as a basis for the development of a natural botryticide. Yet, the results showed considerable differences between genetically distinguishable strains, impeding the use of a specific phenolic compound against the genetic variety of wild strains. The present findings might have important implications for future understanding of Botrytis cinerea infections and sustainable Botrytis management including the role of polyphenols.

In this work, liposomes loaded with the fungicide, Fludioxonil (FLUD), for the containment of fungal diseases in agriculture were developed. Three types of vesicles with different compositions were compared: (I) plain vesicles, composed of soy phosphatidylcholine and cholesterol; (II) PEG-coated vesicles, with an additional polyethylene glycol coating; and (III) cationic vesicles, containing didodecyldimethylammonium bromide. Nanometric-sized vesicles were obtained both by the micelle-to-vesicle transition method and by the extrusion technique, and encapsulation efficiency, drug loading content, and Zeta potential were determined for all the samples. The extruded and PEGylated liposomes were the most stable over time and together with the cationic ones showed a significant prolonged FLUD release capacity. The liposomes\' biological activity was evaluated on conidial germination, germ tube elongation and colony radial growth of the ascomycete Botrytis cinerea, a phytopathogenic fungus affecting worldwide many important agricultural crops in the field as well as in the postharvest phase. The extruded and PEGylated liposomes showed greater effectiveness in inhibiting germ tube elongation and colony radial growth of the fungal pathogen, even at 0.01 µg·mL-1, the lowest concentration assessed.

BACKGROUND: Growing concerns about sustainability have driven the search for eco-friendly pest management solutions. Combining natural and synthetic compounds within controlled release systems is a promising strategy. This study investigated the co-encapsulation of the natural compound citral (Cit) and the synthetic antifungal cyproconazole (CPZ) using two water-based nanocarriers: solid lipid nanoparticles (SLNs) and chitosan nanoparticles (CSNPs).
RESULTS: Both CSNPs and SLNs loaded with Cit + CPZ displayed superior antifungal activity against Botrytis cinerea compared to free compounds. Notably, CSNPs with a 2:1 Cit:CPZ ratio exhibited the highest efficacy, achieving a minimum inhibitory concentration (MIC100) of < 1.56 μg mL-1, lower than the 12.5 μg mL-1 of non-encapsulated compounds. This formulation significantly reduced the required synthetic CPZ while maintaining efficacy, highlighting its potential for environmentally friendly pest control.
CONCLUSIONS: The successful co-encapsulation of Cit + CPZ within CSNPs, particularly at a 2:1 ratio, demonstrates a promising approach for developing effective and sustainable antifungal formulations against B. cinerea. © 2024 Society of Chemical Industry.