Trichoderma-Induced Resistance to Botrytis cinerea in Solanum Species: A Meta-Analysis

With the idea of summarizing the outcomes of studies focusing on the resistance induced by Trichoderma spp. against Botrytis cinerea in tomato, the present paper shows, for the first time, results of a meta-analysis performed on studies published from 2010 to 2021 concerning the cross-talk occurring in the tomato–Trichoderma-B. cinerea system. Starting from an initial set of 40 papers, the analysis was performed on 15 works and included nine parameters, as a result of a stringent selection mainly based on the availability of more than one article including the same indicator. The resulting work not only emphasizes the beneficial effects of Trichoderma in the control of grey mold in tomato leaves (reduction in disease intensity, severity and incidence and modulation of resistance genes in the host), but carefully drives the readers to reply to two questions: (i) What are the overall effects of Trichoderma on B. cinerea infection in tomato? (ii) Do the main effects of Trichoderma differ based on the tomato species, Trichoderma species, amount, type and duration of treatment? At the same time, this meta-analysis highlights some weak points of the available literature and should be seen as an invitation to improve future works to better the conceptualization and measure.

Sodium valproate is effective against Botrytis cinerea infection of tomato by enhancing histone H3 acetylation-directed gene transcription and triggering tomato fruits immune response

Botrytis cinerea causes grey mold resulting in enormous financial loss. Fungicide resistance of B. cinerea has become a serious issue in food safety and agricultural environmental protection. Sodium valproate (SV) has been used in clinical trials, thus it is excellent candidate for fungicide development considering its safety. However, the antifungal activity remains unclear. SV was effective against B. cinerea by enhancing acetylation of histone H3, including H3K9ac, H3K14ac, and H3K56ac. A transcriptomics analysis revealed that the expression of 1,557 genes changed significantly in response to SV. A pathway enrichment analysis identified 16 significant GO terms, in which molecular functions were mainly involved. In addition, the expression levels of 13 genes involved in B. cinerea virulence and 5 genes involved in tomato immune response were altered by the SV treatment. These results indicate that SV inhibits B. cinerea by enhancing acetylation of histone H3 and modifying gene transcription. Thus, SV is an effective, safe potential antifungal agent for control of both pre- and post-harvest losses caused by B. cinerea.

Biosafe Management of Botrytis Grey Mold of Strawberry Fruit by Novel Bioagents

Recently, there have been urgent economic and scientific demands to decrease the use of chemical fungicides during the treatment of phytopathogens, due to their human health and environmental impacts. This study explored the biocontrol efficacy of novel and eco-friendly preen (uropygial) oil and endophytic Bacillus safensis in managing postharvest Botrytis grey mold in strawberry fruit. The preen oil (25 μL/mL) showed high antifungal activity against B. cinerea Str5 in terms of the reduction in the fungal radial growth (41.3%) and the fungal colony-forming units (28.6%) compared to the control. A new strain of Bacillus safensis B3 had a good potential to produce chitinase enzymes (3.69 ± 0.31 U/mL), hydrolytic lipase (10.65 ± 0.51 U/mL), and protease enzymes (13.28 ± 0.65 U/mL), which are responsible for the hydrolysis of the B. cinerea Str5 cell wall and, consequently, restrict fungal growth. The in vivo experiment on strawberry fruit showed that preen (uropygial) oil reduced the disease severity by 87.25%, while the endophytic bacteria B. safensis B3 reduced it by 86.52%. This study reports the efficiency of individually applied bioagents in the control of phytopathogenic fungi for the first time and, consequently, encourages their application as a new and innovative strategy for prospective agricultural technology and food safety.

Evaluation of Pseudomonas fluorescens Strains, Fungicides and Non-conventional Chemicals Against Botyrotinia ricini Causing Grey Mold Disease in Castor

A study was made to evaluate the efficacy of Pseudomonas fluorescens strains, fungicides and non-conventional chemicals against Botryotinia ricini, causing grey mold disease in castor, under in vitro conditions. Among the 40 strains isolated from rhizosphere soil samples of different crops across the State of Telangana, India, only eight strains inhibited the growth of B. ricini under dual culture technique, of which strains Pf 21 (90.56%), Pf 23 (88.89%), Pf 34 (86.11%) and Pf 36 (84.17%) were the most effective. Among the seven chemicals (four fungicides and three non-conventional chemicals) tested for their efficacy, carbendazim followed by propiconazole had significant antagonistic effect against B. ricini. Exposure of healthy castor capsules to B. ricini and P. fluorescens for different time periods revealed that strains Pf 34 and Pf 36 were effective in completely inhibiting the growth of B. ricini and hence these two strains have been identified as effective biocontrol agents, on par with carbendazim, which offer scope for sustainable and integrated disease management of grey mold disease in castor.

Response of lentil cultivars to Sclerotinia white mold and Botrytis grey mould infection under irrigated and dryland conditions

Diseases such as Sclerotinia white mold (SWM) caused by the fungus Sclerotinia sclerotiorum (Lib.) de Bary and Botrytis grey mold (BGM) caused by the fungus Botrytis cinerea Pers. may be limiting factors for lentil production in wetter areas of Alberta, Canada. Field trials were conducted at the Lethbridge Research and Development Centre from 2013-2015 to evaluate the response of lentil cultivars to SWM and BGM and yield impacts. Ten lentil cultivars from five market classes were evaluated under irrigated and dry land plots with two planting densities (120 plants m-2 and 160 plants m-2).Year and irrigation had the largest effect on disease incidence, with highest SWM incidence occurring under irrigation in 2013, followed by 2014 and 2015. Conversely, BGM incidence under irrigation was highest in 2015 and lowest in 2013, but levels were lower than SWM. Significantly (P <0.05) lower disease incidences were observed in dryland plots, which also produced higher yield than irrigated plots. Cultivars varied significantly in SWM incidence and yield under irrigated and dryland conditions, perhaps due to variable disease pressure, but there was no consistent trend in cultivar performance. BGM incidence was similar in cultivars, but differed among years. These findings indicate that SWM may be a limiting factor to lentil production in wetter areas, as the ten cultivars from five market classes tested were all highly susceptible to SWM.

The Efficacy of Nature-Friendly Chemicals Eugenol and Sodium Bicarbonate against Post-Harvest Botrytis cinerea in Two Pepper Cultivars

Grey mold, caused by Botrytis cinerea, is the most important pre-harvest and post-harvest disease of pepper. The disease leads to huge losses in quality and yield of pepper. Synthetic fungicides should not be used because of their harmful residues in the fruits postharvest. Hence, alternative chemicals have gained more importance for human health now-a-days. In this study, the postharvest effectiveness of eugenol and sodium bicarbonate (NaHCO3) to B. cinerea was determined on two pepper varieties, ‘Demre’ and ‘Charleston’ obtained from pepper fields in Çanakkale. In essay the Eugenol was used at dosages of 0.75 and 1.5%, while sodium bicarbonate was used at dosages of 0.5 and 1.0%. Pepper varieties ‘Demre’ and ‘Charleston’ showed significantly different sensitivities against grey mold disease (P < 0.01), and this case reflected also to the efficacies of alternative chemicals. During eight days of storage, Charleston was more sensitive to B. cinerea than ‘Demre’ peppers. NaHCO3 at high dosage (1.0%) completely inhibited the disease on ‘Charleston’ and ‘Demre’ peppers. The lower dose of NaHCO3 (i.e., 0.5%) was also highly effective in ‘Demre’ (providing 95% reduction in the disease) but its efficacy was a little lower for ‘Charleston’ variety (84%). Efficacy (83.7%) of eugenol at dosage of 1.5% to B. cinerea on 'Demre' was found to be like NaHCO3 at dosage 0.5% on ‘Charleston’ peppers. Alternative chemicals had no adverse effects on pepper varieties. It is concluded that both tested nature-friendly chemicals (Eugenol and sodium bicarbonate) could be used (postharvest) against to B. cinerea on peppers. © 2021 Friends Science Publishers

Screening of Lactic Acid Bacteria for the Bio-Control of Botrytis cinerea and the Potential of Lactiplantibacillus plantarum for Eco-Friendly Preservation of Fresh-Cut Kiwifruit

Botrytis cinerea, responsible for grey mold, represents the first biological cause of fruit and vegetable spoilage phenomena in post-harvest. Kiwifruit is a climacteric fruit particularly prone to this mold infestation during storage. Lactic acid bacteria (LAB) are food-grade bacteria that can synthesize several metabolites with antimicrobial activity and are, therefore, suggested as promising and eco-friendly resources for the bio-control of molds on fruits and vegetables. In this work, we propose the screening of a collection of 300 LAB previously isolated from traditional sourdoughs for their ability to counteract in vitro the growth of Botrytis cinerea CECT 20973. Only 2% of tested LAB strains belonging to Lactiplantibacillus plantarum species, exerted a strong antagonism against B. cinerea. The cell-free supernatants were partially characterized and results clearly indicated that high levels of lactic acid contributed to the antagonistic activity. PAN01 and UFG 121 cell-free supernatants were investigated as potential bio-control agents in a preliminary in vivo assay using freshly cut kiwifruits as a food model. The application of cell-free supernatants allowed to delay the growth of B. cinerea on artificially contaminated kiwifruits until two weeks. The antagonistic activity was greatly affected by the storage temperature (25 °C and 4 °C) selected for the processed fruits, suggesting the importance to include microbial-based solution in a broader framework of hurdle technologies.

Tetrandrine, a potent antifungal agent: inhibits mycelial growth and virulence of Botrytis cinerea

Tetrandrine (TET) is a potent calcium channel blocker used for the treatment of hypertension and inflammation. Currently, TET is predominantly used to treat a variety of human diseases, and there is little information regarding the use of TET against plant pathogens. In this study, we explored the antifungal activity of TET on a plant pathogen, Botrytis cinerea. We show that administration of low concentrations of TET effectively inhibited hyphal growth of fungus grown on potato dextrose agarose, and decreased the virulence of B. cinerea in tomato plants. Real-time PCR revealed that the expression of drug efflux pump related genes (alcohol dehydrogenase 1, multi-drug/pheromone exporter, pleiotropic drug resistance protein 1, and synaptic vesicle transporter) were down-regulated in the presence of TET. Finally, we show that TET acts synergistically with iprodione, resulting in increased inhibition of B. cinerea both in vitro and in vivo. These results indicate that TET might act as an effective antifungal agent in reducing grey mold disease.