Fungus Botrytis Cinerea Research Articles

The Gβ-like protein Bcgbl1 regulates development and pathogenicity of the gray mold Botrytis cinerea via modulating two MAP kinase signaling pathways.

The fungal Gβ-like protein has been reported to be involved in a variety of biological processes, such as mycelial growth, differentiation, conidiation, stress responses and infection. However, molecular mechanisms of the Gβ-like protein in regulating fungal development and pathogenicity are largely unknown. Here, we show that the Gβ-like protein gene Bcgbl1 in the gray mold fungus Botrytis cinerea plays a pivotal role in development and pathogenicity by regulating the mitogen-activated protein (MAP) kinases signaling pathways. The Bcgbl1 deletion mutants were defective in mycelial growth, sclerotial formation, conidiation, macroconidial morphogenesis, plant adhesion, and formation of infection cushions and appressorium-like structures, resulting in a complete loss of pathogenicity. Bcgbl1 interacted with BcSte50, the adapter protein of the cascade of MAP kinase (MAPK). Bcgbl1 mutants had reduced phosphorylation levels of two MAPKs, namely Bmp1 and Bmp3, thereby reducing infection. However, deletion of Bcgbl1 did not affect the intracellular cAMP level, and exogenous cAMP could not restore the defects. Moreover, Bcgbl1 mutants exhibited defects in cell wall integrity and oxidative stress tolerance. Transcriptional profiling revealed that Bcgbl1 plays a global role in regulation of gene expression upon hydrophobic surface induction. We further uncovered that three target genes encoding the hydrophobic surface binding proteins (HsbAs) contributed to the adhesion and virulence of B. cinerea. Overall, these findings suggest that Bcgbl1 had multiple functions and provided new insights for deciphering the Bcgbl1-mediated network for regulating development and pathogenicity of B. cinerea.

Genetic Diversity of Botrytis Cinerea Which Caused Gray Mold Disease in Strawberry and Some Other Vegetable Plants

The study aimed to isolate and identification the fungus Botrytis cinerea that caused gray mold disease, depending on its morphological and molecular characterizations. The results of isolation on PDA showed that 75 pure isolates were obtained from The pathogenic fungus B. cinerea is distributed as follows: Strawberry (45) isolates, eggplant (11) isolates, squash (3) isolates, cucumber (3) isolates, pepper (9) isolates, and tomato (4) isolates. DNA was extracted from 17 isolates of pathogenic fungus B. cinerea, the results of electrophoresis on 2% agarose gel, which included 17 isolates distributed in crops (strawberry 11 isolates, eggplant 4 isolates, squash and tomato one isolate each) was detected at 550 base pair(bp) of all the isolates using ITS1 and ITS4 primers. The results of detection and investigation of genetic variation of pathogenic Fungi isolates were clarified by determining the degree of kinship and drawing a phylogenetic tree An evolutionary and relationship tree was drawn using Snap Gene Viewer, When performing Allayment analysis of the isolates, the results showed that the isolates bearing the symbols (S3,S2,S1) isolated from strawberry fruits were identical to the SMGM003 strain registered in South Korea with a percentage of 100%, and isolates (S6,S5,S4) isolated from strawberry fruits are identical to the strain WMG recorded in South Korea, and isolates (S10,S9,S8) isolated from strawberry fruits are identical to the strain CIM13704 registered in China, and isolates (S11) isolated from strawberry fruits.

Vegetation Indices for Early Grey Mould Detection in Lettuce Grown under Different Lighting Conditions.

Early detection of pathogenic fungi in controlled environment areas can prevent major food production losses. Grey mould caused by Botrytis cinerea is often detected as an infection on lettuce. This paper explores the use of vegetation indices for early detection and monitoring of grey mould on lettuce under different lighting conditions in controlled environment chambers. The aim was focused on the potential of using vegetation indices for the early detection of grey mould and on evaluating their changes during disease development in lettuce grown under different lighting conditions. The experiment took place in controlled environment chambers, where day/night temperatures were 21 ± 2/17 ± 2 °C, a 16 h photoperiod was established, and relative humidity was 70 ± 10% under different lighting conditions: high-pressure sodium (HPS) and light-emitting diode (LED) lamps. Lettuces were inoculated by 7-day-old fungus Botrytis cinerea isolate at the BBCH 21. As a control, non-inoculated lettuces were grown under HPS and LEDs (non-inoculated). Then, the following were evaluated: Anthocyanin Reflectance Index 2 (ARI2); Carotenoid Reflectance Index 2 (CRI2); Structure Intensive Pigment Index (SIPI); Flavanol Reflectance Index (FRI); Greenness (G); Greenness 2 (G2); Redness (R); Blue (B); Blue Green Index 2 (BGI2); Browning Index 2 (BRI2); Lichtenthaler Index 1 (LIC1); Pigment Specific Simple Ratio (PSSRa and PSSRb); Gitelson and Merzlyak (GM1 and GM2); Zarco Tejada-Miller Index (ZMI); Normalized Difference Vegetation Index (NDVI); Simple Ratio (SR); Red-Eye Vegetation Stress Index (RVSI); Photochemical Reflectance Index (PRI); Photochemical Reflectance Index 515 (PRI515); Water Band Index (WBI); specific disease index for individual study (fD); Healthy Index (HI); Plant Senescence Reflectance (PSRI); Vogelmann Red Edge Index (VREI1); Red Edge Normalized Difference Vegetation Index (RENDVI); and Modified Red Edge Simple Ratio (MRESRI). Our results showed that the PSRI and fD vegetation indices significantly detected grey mould on lettuce grown under both lighting systems (HPS and LEDs) the day after inoculation. The results conclusively affirmed that NDVI, PSRI, HI, fD, WBI, RVSI, PRI, PRI515, CRI2, SIPI, chlorophyll index PSSRb, and coloration index B were identified as the best indicators for Botrytis cinerea infection on green-leaf lettuce (Lactuca sativa L. cv Little Gem) at the early stage of inoculated lettuce's antioxidative response against grey mould with a significant increase in chlorophyll indices.

Novel Zinc/Silver Ions-Loaded Alginate/Chitosan Microparticles Antifungal Activity against Botrytis cinerea.

Addressing the growing need for environmentally friendly fungicides in agriculture, this study explored the potential of biopolymer microparticles loaded with metal ions as a novel approach to combat fungal pathogens. Novel alginate microspheres and chitosan/alginate microcapsules loaded with zinc or with zinc and silver ions were prepared and characterized (microparticle size, morphology, topography, encapsulation efficiency, loading capacity, and swelling behavior). Investigation of molecular interactions in microparticles using FTIR-ATR spectroscopy exhibited complex interactions between all constituents. Fitting to the simple Korsmeyer-Peppas empirical model revealed the rate-controlling mechanism of metal ions release from microparticles is Fickian diffusion. Lower values of the release constant k imply a slower release rate of Zn2+ or Ag+ ions from microcapsules compared to that of microspheres. The antimicrobial potential of the new formulations against the fungus Botrytis cinerea was evaluated. When subjected to tests against the fungus, microspheres exhibited superior antifungal activity especially those loaded with both zinc and silver ions, reducing fungal growth up to 98.9% and altering the hyphal structures. Due to the slower release of metal ions, the microcapsule formulations seem suitable for plant protection throughout the growing season. The results showed the potential of these novel microparticles as powerful fungicides in agriculture.

The apocarotenoid β-ionone regulates the transcriptome of Arabidopsis thaliana and increases its resistance against Botrytis cinerea.

Carotenoids are isoprenoid pigments indispensable for photosynthesis. Moreover, they are the precursor of apocarotenoids, which include the phytohormones abscisic acid (ABA) and strigolactones (SLs) as well as retrograde signaling molecules and growth regulators, such as β-cyclocitral and zaxinone. Here, we show that the application of the volatile apocarotenoid β-ionone (β-I) to Arabidopsis plants at micromolar concentrations caused a global reprogramming of gene expression, affecting thousands of transcripts involved in stress tolerance, growth, hormone metabolism, pathogen defense, and photosynthesis. This transcriptional reprogramming changes, along with induced changes in the level of the phytohormones ABA, jasmonic acid, and salicylic acid, led to enhanced Arabidopsis resistance to the widespread necrotrophic fungus Botrytis cinerea (B.c.) that causes the gray mold disease in many crop species and spoilage of harvested fruits. Pre-treatment of tobacco and tomato plants with β-I followed by inoculation with B.c. confirmed the effect of β-I in increasing the resistance to this pathogen in crop plants. Moreover, we observed reduced susceptibility to B.c. in fruits of transgenic tomato plants overexpressing LYCOPENE β-CYCLASE, which contains elevated levels of endogenous β-I, providing a further evidence for its effect on B.c. infestation. Our work unraveled β-I as a further carotenoid-derived regulatory metabolite and indicates the possibility of establishing this natural volatile as an environmentally friendly bio-fungicide to control B.c.

GREEN BIOCHEMICAL PROTECTION OF POSTHARVEST TABLE GRAPES AGAINST GRAY MOLD (BOTRYTIS CINEREA) USING 7S PROTEINS

The 7S globulins (seed storage glycoprotein) isolated from soybean and chickpea seeds have the antifungal potential against the pathogenic fungus (Botrytis cinerea) causing gray mold in grapes assessing table grapes in vitro or postharvest by comparing with synthetic fungicide, Switch 62.5 WG. Conventional microbiological procedures estimated the in-vitro antifungal potential of the 7S globulins, such as linear growth curves and scanning electron microscopy (SEM). Soybean-7S significantly inhibited the in-vitro growth of Botrytis cinerea by about 64.44%, 66.64%, and 76.67% when applied at 50, 100, and 200 μg/mL, respectively, followed by chickpea 7S with growth reduction of 52.22%, 54.44%, and 66.67%, respectively. The synthetic fungicide (Switch 62.5 WG) induced higher growth inhibition extents (83.33% and 86.66%) when applied at 50 and 200 μg/mL, respectively. The 7S-exposed B. cinerea displayed swollen hyphae compared with the control under scanning electron microscope examination. The 7S derived from soybean and chickpea inhibited gray mold development in table grapes when applied at 200 and 400 μg/mL for 30 days after infection with B. cinerea. The maintained disease severity was also minimal (40% and 25% for soybean-7S and chickpea-7S, respectively). An increased level of treatment (400 μg/mL) highly reduced the disease severity to only 7.5% after 30 days of storage at cold conditions for both proteins. The 7S globulin from legume seeds can be an alternative to synthetic fungicides for controlling B. cinerea as a postharvest treatment. Developing these legume proteins as natural fungicides could also progress for the safe control of various plant pathogens, causing drastic crop losses.

Multifunctional carbon dots reinforced gelatin-based coating film for strawberry preservation

The development of safe, non-toxic, multifunctional nano preserved materials with excellent performance has become a hot research topic. Multifunctional Sophora Japonica extract (95% rutin)-derived carbon dots (R-CDs) were prepared by hydrothermal method. The π-π conjugation structure of R-CDs enabled them UV broadband absorption properties. The excellent antioxidant properties of R-CDs were attributed to the presence of the sp2 carbon in core and a large number of hydroxyl groups at the edges, and their degradation rate of potassium permanganate and scavenging activity of superoxide anion radical were better than that of ascorbic acid. The presence of CO bond may be the site for the generation of reactive oxygen species (ROS) and thus they could kill Staphylococcus aureus (S. aureus), Bacillus subtilis (B. subtilis) and Listeria monocytogenes (L. monocytogenes) at a concentration of 2 mg/mL and inhibited the growth of fungi (Botrytis cinerea). Then R-CDs were uniformly dispersed in gelatin-based solution, and the as-prepared films had smooth surface, good hydrophilicity, strong mechanical properties and good biocompatibility. With the increase of R-CDs addition, the tensile strength increased and then decreased, and the elongation at break rose to 358%. The film inherited the broadband UV absorption, antioxidant and antibacterial properties of R-CDs. The storage period of strawberries was prolonged after coating. The variety and abundance of microorganisms on the surface of strawberries was reduced and the growth of harmful bacteria was inhibited. This work provides more possibilities for the application of nanomaterials in fruit preservation.

Frass from yellow mealworm (Tenebrio molitor) as plant fertilizer and defense priming agent

World population growth requires the development of a sustainable agriculture that allows feeding all the inhabitants of the planet, while reducing the use of agrochemicals. Currently, the insect farming industry for food and feed production is developing exponentially throughout the world; also producing insect frass with a potential utilization within agriculture and greenhouse industry. In the case of the yellow mealworm (Tenebrio molitor), few studies have been developed so far on the use of frass as a fertilizer, and there are none on its ability to activate plant defenses. By applying 2% sterilized mealworm frass to tomato we found a significant increase in its growth, demonstrating that the microbiota might not play a key role in its fertilizing capacity. In addition, the application of frass to sunflowers under different situations of nutritional deficit allowed us to determine what specific nutrients this fertilizer may be providing to the plant, finding a possible deficiency in the supply of N, but with sufficient amounts of P, K, Ca, and S. With respect to the induction of defenses, mealworm insect frass did not induce local root defenses in a root callose deposition assay in Arabidopsis thaliana under our experimental conditions. However, it activated systemic defenses in Arabidopsis thaliana by inducing defense genes in the absence of pathogen, further enhanced by infection with the necrotrophic fungus Botrytis cinerea. Therefore, mealworm frass could be a good fertilizer resource and plant defense inducer to support development of sustainable agriculture.

MICROCHEMICAL TECHNIQUES ON BOTRYTIS CINEREA: CONTRIBUTION TO IDENTIFICATION OF PRIMARY AND SECONDARY METABOLITES

Histochemical techniques comprise several staining methods in microscopy for investigation of chemical groups or pathologies regarding tissues in plants and fungi and have been widely used for detection of groups of substances. Thereby, our work demonstrates the application of histochemical techniques recognized for detection of secondary metabolites in plants to detect substances in the fungus Botrytis cinerea. Our findings are compatible with previous reports on metabolites identified in B. cinerea, and show proteins stored in vesicular structures (0.3-0.9µm), accumulated in small groups inside of developed mycelia, and in large quantity in spores (0.2-0.7µm). Alkaloids were only detected in mycelium containing spores, not influenced by their size. Terpenoids were detected in spores, and with lighter color for mycelia vesicles. However, in younger mycelium we verified terpenoids in storage structures in the mycelia segments, demonstrating higher quantity in early development. The presence of neutral polysaccharides and terpenoids was observed around the mycelia containing younger spores and, in some storage, structures close to the spores. Our results corroborate reports on the presence of substances of the secondary metabolism in B. cinerea and could be utilized in other species of fungi to screen substances of pharmacological and nutraceutical interest.

Detection and prediction of Botrytis cinerea infection levels in wine grapes using volatile analysis.

Infection of grape berries (Vitis vinifera) by the fungus Botrytis cinerea (grey mould) frequently occurs in vineyards, resulting in off-flavours and other odours in wine and potential yield losses. In this study, volatile profiles of four naturally infected grape cultivars, and laboratory-infected grapes were analysed to identify potential markers for B. cinerea infection. Selected volatile organic compounds (VOCs) were highly correlated with two independent measures of B. cinerea infection levels, demonstrating that ergosterol measurements provide accurate quantification of lab-inoculated samples, while B. cinerea antigen detection is more suitable for naturally infected grapes. Excellent predictive models of infection level were confirmed (Q2Y of 0.784-0.959) using selected VOCs. A time course experiment confirmed that selected VOCs 1,5-dimethyltetralin, 1,5-dimethylnaphthalene, phenylethyl alcohol and 3-octanol are good markers for B. cinerea quantification and 2-octen-1-ol could be considered as an early marker of the infection.

Peptide analogs of a Trichoderma peptaibol effectively control downy mildew in the vineyard.

Plasmopara viticola, the agent of grapevine downy mildew, causes enormous economic damage and its control is primarily based on synthetic fungicides. The European Union (EU) policies promote reducing reliance on synthetic plant protection products. Biocontrol agents (BCA) such as Trichoderma constitute a resource for the development of biopesticides. Trichoderma species produce secondary metabolites such as peptaibols, whose poor water solubility hampers their practical use as agrochemicals. To identify new bio-inspired molecules effective against P. viticola, some water-soluble peptide analogs of the peptaibol trichogin were synthesized. In grapevine leaf disk assays, various peptides at 50 µM completely prevented P. viticola infection after zoosporangia inoculation. Microscopic observations carried out with one of the most effective peptides showed that it causes membrane lysis and cytoplasm granulation of both zoosporangia and zoospores. Among the effective peptides, 4r was selected for a two-year field trial experiment. In the vineyard, the peptide administered at 100 µM (equivalent to 129.3 g/ha) overall reduced significantly disease incidence and severity on both leaves and bunches, allowing protection levels similar to those obtained with a cupric fungicide. In the second-year trial, reduced dosages were also tested, and results indicated that even by reducing the peptide concentration by 50 or 75%, a significant decrease in the disease level was obtained at the end of the trial. The peptide did not show any phytotoxic effect. Previously, peptide 4r had been demonstrated to be active against other fungal pathogens, including the grapevine fungus Botrytis cinerea. Thus, this peptide may be a candidate for broad-spectrum fungicide whose biological properties deserve further investigation.

The Bcvic1 and Bcvic2 vegetative incompatibility genes in Botrytis cinerea encode proteins with domain architectures involved in allorecognition in other filamentous fungi

Vegetative incompatibility is a fungal allorecognition system characterised by the inability of genetically distinct conspecific fungal strains to form a viable heterokaryon and is controlled by multiple polymorphic loci termed vic (vegetative incompatibility) or het (heterokaryon incompatibility). We have genetically identified and characterised the first vic locus in the economically important, plant-pathogenic, necrotrophic fungus Botrytis cinerea. A bulked segregant approach coupled with whole genome Illumina sequencing of near-isogenic lines of B. cinerea was used to map a vic locus to a 60-kb region of the genome. Within that locus, we identified two adjacent, highly polymorphic open reading frames, Bcvic1 and Bcvic2, which encode predicted proteins that contain domain architectures implicated in vegetative incompatibility in other filamentous fungi. Bcvic1 encodes a predicted protein containing a putative serine esterase domain, a NACHT family of NTPases domain, and several Ankyrin repeats. Bcvic2 encodes a putative syntaxin protein containing a SNARE domain; such proteins typically function in vesicular transport. Deletion of Bcvic1 and Bcvic2 individually had no effect on vegetative incompatibility. However, deletion of the region containing both Bcvic1 and Bcvic2 resulted in mutant lines that were severely restricted in growth and showed loss of vegetative incompatibility. Complementation of these mutants by ectopic expression restored the growth and vegetative incompatibility phenotype, indicating that Bcvic1 and Bcvic2 are controlling vegetative incompatibility at this vic locus.

The N-Terminal Region of the BcWCL1 Photoreceptor Is Necessary for Self-Dimerization and Transcriptional Activation upon Light Stimulation in Yeast.

The BcWCL1 protein is a blue-light photoreceptor from the fungus Botrytis cinerea. This protein has a central role in B. cinerea circadian regulation and is an ortholog to WC-1 from Neurospora crassa. The BcWCL1 and WC-1 proteins have similar protein domains, including a LOV (Light Oxygen Voltage) domain for light sensing, two PAS (Per Arnt Sim) domains for protein-protein interaction, and a DNA binding domain from the GATA family. Recently, the blue-light response of BcWCL1 was demonstrated in a version without PAS domains (BcWCL1PAS∆). Here, we demonstrated that BcWCL1PAS∆ is capable of self-dimerization through its N-terminal region upon blue-light stimulation. Interestingly, we observed that BcWCL1PAS∆ enables transcriptional activation as a single component in yeast. By using chimeric transcription factors and the luciferase reporter gene, we assessed the transcriptional activity of different fragments of the N-terminal and C-terminal regions of BcWCL1PAS∆, identifying a functional transcriptional activation domain (AD) in the N-terminal region that belongs to the 9aaTAD family. Finally, we determined that the transcriptional activation levels of BcWCL1PAS∆ AD are comparable to those obtained with commonly used ADs in eukaryotic cells (Gal4 and p65). In conclusion, the BcWCL1PAS∆ protein self-dimerized and activated transcription in a blue-light-dependent fashion, opening future applications of this photoreceptor in yeast optogenetics.

Fabrication and characterization of Plumula nelumbinis extract loaded gelatin/zein films (PNE@GZF) to prolong strawberries shelf-life

The encapsulation of natural-derived antimicrobial materials within packaging films is a promising strategy for food preservation. Nevertheless, such materials often exhibit inadequate inhibitory capabilities against both bacteria and fungi. In this work, an extract (phenol alkaloids) obtained from the green embryos of lotus seeds (Plumula nelumbinis, PNE) was encapsulated into the gelatin/zein films (GZFs), which was designed to extend the shelf-life of strawberries. The GZFs varied with different zein ratios (1%, 5%, and 9%) were fabricated by the solvent casting method. GZF5, which containted 5%wt. zein, was selected as the optimal film matrix for loading PNE at various concentration (0.8, 1.6, 3.2 mg/mL), due to its desired transparency, highest water contact angle of 77.30 ± 3.52°, minimized water evaporation rate of 9.50 ± 1.99%, and favorable oxygen barrier properties of 0.92 ± 0.06 cc/m·24 h atm. Notably, the loaded PNE demonstrated the ability to inhibit the growth of gram-positive bacteria (Staphylococcus aureus), gram-negative bacteria (Escherichia coli) and various fungi (Botrytis cinerea, Aspergillus Alternaria and Aspergillus terreus) even at a concentration as low as 1.6 mg/mL. Furthermore, PNE exhibited robust antioxidant activity at 0.8 mg/mL. As a result, the strawberries coated with PNE0.8@GZF5 (0.8 mg/mL PNE) exhibited complete preservation, when challenged with 1 × 106 CFU of Botrytis cinerea. This study highlights the potential of PNE-incorporated edible film as an innovative and practical packaging material for effective postharvest microbial control.

Arabidopsis subtilases promote defense-related pectin methylesterase activity and robust immune responses to botrytis infection

Plants involve a fine modulation of pectin methylesterase (PME) activity against microbes. PME activity can promote the cell wall stiffening and the production of damage signals able to induce defense responses and plant resistance to pathogens. However, the molecular mechanisms underlying PME activation during disease remain largely unknown. In this study, we explored the role of subtilases (SBTs) as PME activators in Arabidopsis immunity. By using biochemical and reverse genetic approaches, we found that the expression of SBT3.3 and SBT3.5 influences the induction of defense-related PME activity and resistance to the fungus Botrytis cinerea. Arabidopsis sbt3.3 and sbt3.5 knockout mutants showed decreased induction of PME activity and increased susceptibility to the fungus. SBT3.3 expression was stimulated by oligogalacturonides. Overexpression of SBT3.3 overactivated PME activity during fungal infection and enhanced resistance to B. cinerea. A negative correlation was observed between SBT3.3 expression and cell wall methyl ester content in the genotypes analyzed after B. cinerea infection. Increased expression of defense-related genes, including PAD3, CYP81F2 and WAK2, was also revealed in SBT3.3 overexpressing lines. We also demonstrated that SBT3.3 and pro-PME17 are both secreted into the cell wall using distinct protein secretion pathways and different kinetics. Our results propose SBT3.3 and SBT3.5 as modulators of PME activity in Arabidopsis against Botrytis to promptly boost immunity limiting the growth-defense trade-off.

The Effect of Zinc Oxide, Copper, and Silver Nanoparticles Synthesized by the Green Method for Controlling Strawberry Gray Mold Fungus, B. Cinerea Pers

Gray mold disease, caused by the fungus Botrytis cinerea, causes heavy losses in strawberries. The use of chemical fungicides due to the dangers for humans and the environment has caused attention to reduce their consumption and use biological methods. In this research, the effects of zinc oxide, copper, and silver nanoparticles have been synthesized from an aqueous extract of cloves, and the probiotic bacteria Lactobacillus casei by the green method was investigated on the gray mold disease of strawberries. The results showed that concentrations of 10% of zinc oxide nanoparticles synthesized from aqueous extract of cloves can completely control this pathogen on the culture medium and the fruit. Zinc and silver nanoparticles produced by Lactobacillus casei prevented 93.7% and 81% of fungal growth in the culture medium, respectively. Other treatments did not show a good inhibitory effect on the fungus. All treatments were able to prevent 100% to 50% of fungal growth after 96 hours on strawberries. The investigation of the storage characteristics showed the positive effect of the examined nanoparticles on reducing the rate of change of the physicochemical characteristics of the strawberry fruit tissue. Apparent decay was significantly reduced and samples treated with nanoparticles scored higher in sensory evaluation compared to control. Also, investigating the toxicity of nanoparticles in this experiment on the HepG2 cell line showed that Compared to the control, copper and zinc nanoparticles did not have significant toxicity on cells, but silver nanoparticles led to 25% cell death. This research provides promising results in the field of using nanoparticles for pre-harvest and post-harvest control of plant diseases.

Serine peptidases and increased amounts of soluble proteins contribute to heat priming of the plant pathogenic fungus Botrytis cinerea.

Botrytis cinerea causes gray mold disease in leading crop plants. The disease develops only at cool temperatures, but the fungus remains viable in warm climates and can survive periods of extreme heat. We discovered a strong heat priming effect in which the exposure of B. cinerea to moderately high temperatures greatly improves its ability to cope with subsequent, potentially lethal temperature conditions. We showed that priming promotes protein solubility during heat stress and discovered a group of priming-induced serine-type peptidases. Several lines of evidence, including transcriptomics, proteomics, pharmacology, and mutagenesis data, link these peptidases to the B. cinerea priming response, highlighting their important roles in regulating priming-mediated heat adaptation. By imposing a series of sub-lethal temperature pulses that subverted the priming effect, we managed to eliminate the fungus and prevent disease development, demonstrating the potential for developing temperature-based plant protection methods by targeting the fungal heat priming response. IMPORTANCE Priming is a general and important stress adaptation mechanism. Our work highlights the importance of priming in fungal heat adaptation, reveals novel regulators and aspects of heat adaptation mechanisms, and demonstrates the potential of affecting microorganisms, including pathogens through manipulations of the heat adaptation response.

Evaluation of the Rhodotorula glutinis in Controlling the Gray Rot Disease Caused by the Pathogenic Fungus Botrytis cinerea Pre and Post Strawberry Harvesting

The effectiveness of the yeast Rhodotorula glutinis was evaluated in the field experiment for control of the gray rot disease on strawberry caused by the fungus Botrytis cinerea. The results showed that all treatments of R. glutinis yeast led to a significant superiority in inducing systemic strawberry resistance and an increase in vegetative, productivity and quality indicators of three strawberry cultivars, compared to the Prado fungicide treatment and the pathogenic fungus treatment only. Treatment of filtrate and yeast cells (R. glutinis - Cs +F with B. cinerea) achieved the highest activity of the enzymes that induce plant resistance, which included peroxidase, chitinase and β-glucanase, the enzymatic activity was 2.25, 2.31 and 1.62 units/ml for Albion cultivar, with significant superiority compared to other treatments. The treatment of (R. glutinis - Cs +F) in the presence of the pathogenic fungus recorded the highest vegetative parameters, which included plant height and shoot weight in Albion cultivar, reaching 27.33 cm and 14.66 g, respectively. All treatments of R. glutinis yeast led to a significant superiority in affecting the severity of infection for all studied strawberry cultivars under the infection conditions with the pathogenic fungus B. cinerea, the Albion cultivar achieved the highest decrease in the infection severity reached 17.37% in (R. glutinis - Cs +F with B. cinerea ), while it had the least effect on the severity of infection in the Festival cultivar, reached 95.28% in the treatment of the pathogenic fungus. The yield of strawberry fruits in Albion cultivar was superior compared to other cultivars, as the plant yield reached 68.92 g/plant in the treatment of (R. glutinis-Cs +F with B. cinerea), while the lowest yield was 16.69 g/plant in the Festival cultivar with the pathogenic fungus treatment only. The treatment of yeast filtrate and cells with B. cinerea achieved the lowest infection intensity, the highest hardness and the highest vitamin C content of strawberry fruits after 7 days of harvest, compared to the Prado fungicide treatment and the pathogenic fungus treatment only.

Transcriptomic and physiological shade avoidance responses in potato (Solanum tuberosum) plants.

Plants detect competitors in shaded environments by perceiving a reduction in photosynthetically active radiation (PAR) and the reduction between the red and far-red light (R:FR) ratio and blue photons. These light signals are detected by phytochromes and cryptochromes, which trigger shade avoidance responses such as shoot and petiole elongation and lead to increased susceptibility to pathogen attack. We studied morphological, anatomical, and photosynthesis differences in potato plants (Solanum tuberosum var. Spunta) exposed to sunlight or simulated shade in a greenhouse. We found that simulated shade strongly induced stem and internode elongation with a higher production of free auxin in stems and a lower production of tubers. The mesophyll thickness of the upper leaves of plants grown in simulated shade was lower, but the epidermis was wider compared with the leaves of plants cultivated in sunlight. In addition, the photosynthesis rate was lower in the upper leaves exposed to nonsaturated irradiances and higher in the basal leaves at saturated irradiances compared with control plants. RNA-seq analysis showed that 146 and 155 genes were up- and downregulated by shade, respectively. By quantitative reverse transcription polymerase chain reaction, we confirmed that FLOWERING LOCUS T (FT), WRKY-like, and PAR1b were induced, while FLAVONOL 4-SULFOTRANSFERASE was repressed under shade. In shaded plants, leaves and tubers were more susceptible to the necrotrophic fungus Botrytis cinerea attack. Overall, our work demonstrates configurational changes between growth and defense decisions in potato plants cultivated in simulated shade.

Expression of EPL1 from Trichoderma atroviride in Arabidopsis Confers Resistance to Bacterial and Fungal Pathogens.

During plant interaction with beneficial microorganisms, fungi secrete a battery of elicitors that trigger plant defenses against pathogenic microorganisms. Among the elicitor molecules secreted by Trichoderma are cerato-platanin proteins, such as EPL1, from Trichoderma atroviride. In this study, Arabidopsis thaliana plants that express the TaEPL1 gene were challenged with phytopathogens to evaluate whether expression of EPL1 confers increased resistance to the bacterial pathogen Pseudomonas syringae and the necrotrophic fungus Botrytis cinerea. Infection assays showed that Arabidopsis EPL1-2, EPL1-3, EPL1-4 expressing lines were more resistant to both pathogens in comparison to WT plants. After Pseudomonas syringae infection, there were reduced disease symptoms (e.g., small chlorotic spots) and low bacterial titers in the three 35S::TaEPL1 expression lines. Similarly; 35S::TaEPL1 expression lines were more resistant to Botrytis cinerea infection, showing smaller lesion size in comparison to WT. Interestingly, an increase in ROS levels was detected in 35S::TaEPL1 expression lines when compared to WT. A higher expression of SA- and JA-response genes occurred in the 35S::TaEPL1 lines, which could explain the resistance of these EPL1 expression lines to both pathogens. We propose that EPL1 is an excellent elicitor, which can be used to generate crops with improved resistance to broad-spectrum diseases.