Cinerea Decay Research Articles

Current insights into the biocontrol and biotechnological approaches for postharvest disease management of Botrytis cinerea

Postharvest decay in fruits and vegetables caused by fungal pathogens such as Botrytis cinerea leads to substantial economic losses. The decay caused by B. cinerea can be mitigated through the application of synthetic chemicals. However, due to its toxic residual effects on human health and environment stimulated the researchers to explore alternate effective and safe methods for the postharvest B. cinerea disease management. This article explains the current understanding of B. cinerea pathogenesis and the identification of antagonists used in the management of postharvest B. cinerea decay. This article also explains the mechanism of postharvest biocontrol agents (BCAs) and bioactive compounds derived from microorganisms and other plant resources with a particular focus on current advancements in molecular genomics such as (genetic engineering, transgenes and RNAi technology), omics and nanotechnology. Moreover, encapsulation of BCAs with nanoparticles increases their efficiency by delivering the BCAs to a specific host in a controlled and effective manner, with the aim of combating B. cinerea. Advanced molecular genetics allows for the identification and characterization of genes responsible for producing antifungal compounds produced by BCAs, which can be used to engineer strains with increased production of these compounds, making them more effective in controlling fungal diseases. Similarly, crops can be modified genetically which can show more resistance against the B. cinerea. However, more research will be needed to find the novel antimicrobial compounds derived from BCAs and estimation of developing beneficial microbial consortia for postharvest disease management, as well as genetic approaches, such as the use of CRISPR/Cas9 technology.

Enhancing strawberry quality and resistance to Botrytis cinerea using calcareous seaweed-derived Ca2+/carrageenan extracts

The dilute HCl pretreatment of the calcareous red alga, Liagora viscida, either at room temperature or 100 °C, produced Ca2+/carrageenan-containing extracts. Dipping strawberries in these extracts for 10 s demonstrated their ability to maintain various quality and nutritional traits during cold storage. The weight loss of the fruits after 7 days at 4 °C was reduced to 2.48–2.63 % in the treatments, compared to 3.26 % in the control. The treatments were effective in retaining the contents of vitamin C, titratable acidity, and phenolics, compared to marked reductions in the control. Additionally, the levels of anthocyanins, flavonoids, and the total antioxidant capacity were enhanced during cold storage. The treated fruits also showed higher chitinase activities, while the activities of cellulase, polygalacturonase, and pectin methylesterase (PME) showed remarkable reductions. The application of the extract derived at 100 °C reduced the decay caused by Botrytis cinerea decay to 34 % and 63.26 % after 3 and 4 days of infection, respectively, compared to 55.09–97 % in the untreated control. This reduction was concomitant with higher anthocyanins, flavonoids, and chitinase, and lower cellulase and PME in this treatment. The levels of malondialdehyde indicated less stressed fruits during both cold storage and fungal infection. Overall, the treatments promoted systemic resistance in the fruits, enhancing their ability to defend against pathogens. These results suggest the promising utilization of calcareous macroalgae as a sustainable biomass for developing a cost-effective and eco-friendly preservative to extend the shelf-life of strawberries during cold storage and enhance their resistance to pathogens.

Improving Biogenic Amines and Combating Botrytis cinerea Decay in ‘Golden Delicious’ Apples With Post-Harvest Essential Oil Treatments

Improving Biogenic Amines and Combating Botrytis cinerea Decay in ‘Golden Delicious’ Apples With Post-Harvest Essential Oil Treatments

Hot water treatment in combination with silicate salts dipping for controlling apple gray mold caused by Botrytis cinerea Pers.:Fr.

BackgroundGray mold is the most prevalent postharvest disease of apple fruits in Egypt. In this study, five isolates of Botrytis cinerea were isolated from apple fruits that had postharvest decay symptoms. Investigations were made into the pathogenicity tests of these isolates as well as the molecular identification of the most virulent isolate. A study was done in vitro to see how B. cinerea's mycelial growth and conidial germination would be affected by hot water treatments (HWT) at temperatures of 25, 50, 52, 54, or 56 °C for 10, 20, 30, or 40 s as well as silicate salts (SS), specifically potassium silicate and sodium silicate at 0.0, 2.0, 4.0, and 6.0%. The effectiveness of hot water treatment and silicate salts dipping (SSD), both separately and together, for preventing B. cinerea infection and preserving the natural qualities of apple fruits was investigated in vivo.ResultsPathogenicity tests on apples (Anna cv.) revealed that B. cinerea isolate (Bc-1) was found to be the most virulent. This isolate was identified as belonging to the fungus B. cinerea through molecular testing using internal transcribed spacer (ITS) sequencing and phylogenetic analyses, and it has since been added to Gene Bank with the accession number ON1498639.1. The lethal temperature for B. cinerea mycelial growth and spore germination in vitro was 54 °C/30 s and 54 °C/10 s, respectively. At a 6.0%, the SS, specifically potassium silicate and sodium silicate, completely prevented pathogen growth. When applied separately, HWT (60 °C/30 s) and SSD (6.0%/1 min) significantly reduced B. cinerea decay of apple fruits stored at 20 ± 2 °C for 15 days. In terms of control efficacy, the HWT (60 °C/30 s) and SSD (6.0%/1 min) combination performed better.ConclusionsWhen apple fruits are stored at 20 ± 2 °C for 15 days, the combination of HWT (60 °C/30 s) and SSD (6.0%/1 min) may be an efficient way to control the gray mold disease. The amount of total soluble solids (TSS) in apple fruits was unaffected by these treatments, but they significantly lessened fruit weight loss after 40 days of storage at 20 ± 2 °C.

Ozone washing decreases strawberry susceptibility to Botrytis cinerea while maintaining antioxidant, optical and sensory quality

This work aimed to evaluate the effect of ozone washing (maximum concentration 3.5 mgL-1- 5 and 15 min) on Botrytis cinerea decay, physicochemical parameters, bioactive compounds, in vitro and in vivo antioxidant activity, and sensory properties of strawberries cv. Albion throughout refrigerated storage at 5 ± 1 °C. A 5 min long ozonation delayed the onset of B. cinerea infection by 4 days, and significantly reduced its incidence as storage progressed (~17 % lesser than in control at day 8), without impairing physicochemical parameters or sensory quality. This treatment did not affect the antioxidant activity of strawberry extracts neither in in vitro (ORAC and ABTS assays) or in vivo assays using Caenorhabditis elegans as a model organism. Higher ozone doses did not achieve greater reduction of B. cinerea decay throughout the storage period. This study demonstrated that exposing strawberries to a 5 min long aqueous ozone treatment could extend their storability at 5 °C.

Fungicide Efficacy Against Botrytis cinerea at Different Positions on Grape Shoots

Fungicide efficacy at different positions on grape shoots was determined on vinelets inoculated with Botrytis cinerea. To ensure proper fungicide coverage, vinelets (table grape cultivar Dauphine, wine grape cultivar Merlot noir), prepared from cuttings, were sprayed in a spray chamber at the recommended dosages with iprodione, pyrimethanil, cyprodinil/fludioxonil and fenhexamid. Vinelets for the control treatment were left unsprayed. After 24 h the vinelets were dusted with dry, airborne conidia in a settling ower to reduce the sporadic occurrence of the pathogen on shoots and incubated for 24 h at high relative humidity (±93 % ) to promote infection. Fungicide efficacy was determined by observing intact vinelets for symptom expression at nodes, internodes, leaf blades, petioles and inflorescences, and by determining surface colonisation (shoots left unsterile) and penetration (surfacedisinfested shoots) by isolation studies. Symptoms of B. cinerea decay did not develop on sprayed and unsprayed vinelets that were kept in dry chambers during the 2-week observation period. The pathogen, however, developed from the isolated parts. On the unsprayed vinelets for both cultivars B. cinerea incidences recorded on two media and the two sterility regimes were significantly higher on leaf blades than on the petioles, shoot pieces and inflorescences. The isolation studies showed that the different fungicides were highly and nearly equally efficient in reducing superficial B. cinerea and latent infection at the various positions. In the case of leaf blades B. cinerea incidence was significantly reduced by each fungicide on both cultivars. This was not the case for the other parts, which yielded B. cinerea at low incidences under the two sterility regimes. The study showed that the fungicides used in this study, if applied properly to shoots at the pre-bloom stage, should effectively reduce the amount of B. cinerea in leaves and completely prevent the infection of nodes, internodes and inflorescences.

Epidemiology of Botrytis cinerea on Grape: Wound Infection by Dry, Airborne Conidia

This study describes the infection of fresh wounds on berries exposed to freshly deposited airborne Botrytis cinerea conidia, and on berries carrying previously deposited conidia and germlings (latent infections). Grapes at bunch closure and at the mature (harvest) stage, as well as mature, cold-stored grapes, were used. The grapes were dusted with dry conidia in a settling tower. The inocula were subjected to conditions commonly encountered by the pathogen in grape bunches: dry conidia on dry berries under dry conditions, dry conidia on dry berries under high relative humidity, and dry conidia exposed to a film of water on the berry surface. The mean number of wounds that yielded B. cinerea decay 14 days after inoculation was calculated. Fluorescence microscopy revealed that conidia occurred evenly as single cells on the grape berry surface and seldom landed at the wound periphery. They remained dormant on dry berries, but germinated freely on the unbroken skin and at the wound periphery on moist and wet berries. In the case of berries inoculated at bunch closure and harvest stages, wounds were not infected by conidia deposited on berries four days prior to wounding. This finding indicated that, following adhesion and the first stages of growth, the pathogen did not survive for extended periods on surfaces of immature and mature grape berries. Freshly deposited dry conidia were needed to infect the wounds. The freshly deposited conidia furthermore needed free water, and not high humidity or wound exudates, to infect the fresh wounds. Proportions of wounds infected were extremely low. According to these findings, this mode of infection should not contribute to a gradual build-up of secondary inoculum and to B. cinerea epiphytotics in the vineyard. The previously and freshly deposited conidia both infected wounds made on cold-stored mature berries. Of the two inocula, freshly deposited conidia were more successful in causing wound infection. Therefore, in the event of wounding, postharvest decay would be caused primarily by conidia occurring on the grape berry surface, and not by mycelia in the berry skin.

Long-Term Storage Quality of Table Grapes as Influenced by Pre-Harvest Yeast Applications and Post-Harvest Use of Controlled Atmosphere

The effects of pre-harvest applications of antagonistic yeast and controlled atmosphere storage treatments on inhibiting Botrytis cinerea decay and maintaining the quality of table grapes were compared to identify a treatment that could replace the use of sulphur dioxide (SO2) during post-harvest handling. Treatments for this study included pre-harvest application of antagonistic yeasts Cryptococcus albidus (Yieldplus®), Cryptococcus sp. (LF) and Candida pelliculosa (R951) on table grapes (cvs. ‘Barlinka’, ‘Dauphine’, ‘Red Globe’, ‘Sunred Seedless’ and ‘Thompson Seedless’) from 2001 to 2003. Grapes were stored under regular (air), controlled atmosphere (CA, O2 + CO2) and SO2 conditions at -0.5°C and subsequent storage at a 15°C to simulate shelf-life conditions. Results of this study showed that Botrytis decay levels did not develop rapidly due to low temperatures (-0.5°C vs 15°C), shorter storage periods (4 vs 8 weeks or 0 vs 7 vs 14 days), and CA treatment effects. The CA gas mixtures maintained commercially important low levels (less than 1%) of B. cinerea decay during the cold storage period at -0.5°C. However, during shelf-life storage at 15°C these low levels of decay could only be maintained by some of the SO2 treatments. A necessary commercial requirement is to maintain low decay levels for longer at higher shelf-life temperatures, for which this study cannot conclusively recommend a CA and/or antagonistic yeast treatment as an alternative to SO2. However, pre-harvest applications of the yeast and CA limited the general quality deterioration of the grapes at -0.5°C and 15°C compared to SO2 treatments. Inclusion of macro- or micro-perforated polyethylene packaging liners in combination with CA and pre-harvest yeast treatments did not show obvious negative effects on quality parameters in this study. Discovery and selection of yeast strains that survive under low temperatures and CA conditions would make suitable candidates for continued control of decay development on the fruit surface during shelf-life storage periods.

Biocontrol Ability and Action Mechanism of Starmerella bacillaris (Synonym Candida zemplinina) Isolated from Wine Musts against Gray Mold Disease Agent Botrytis cinerea on Grape and Their Effects on Alcoholic Fermentation.

Gray mold is one of the most important diseases of grapevine in temperate climates. This plant pathogen affects plant growth and reduces wine quality. The use of yeasts as biocontrol agents to apply in the vineyard have been investigated in recent years as an alternative to agrochemicals. In this work, fermenting musts obtained from overripe grape berries, therefore more susceptible to infection by fungal pathogens such as Botrytis cinerea, were considered for the selection of yeasts carrying antifungal activity. Thirty-six isolates were identified as Starmerella bacillaris, a species recently proven to be of enological interest. Among them 14 different strains were studied and antifungal activity against B. cinerea was demonstrated, for the first time, to be present in S. bacillaris species. The production of volatile organic compounds (VOCs), tested in vitro, was found to be the main responsible of S. bacillaris antifungal effects. All the strains were able to reduce B. cinerea decay on wounded grape berries artificially inoculated with gray mold. The colonization level of wound was very high reaching, after 5 days, a concentration of 106 cells per ml of grape juice obtained after berry crushing. At this cell concentration S. bacillaris strains were used to ferment synthetic and natural musts. The sequential yeast inoculation, performed by adding S. cerevisiae 48 h after S. bacillaris, was needed to complete sugar consumption and determined a significant increase in glicerol content and a reduction of ethanol and acetic acid concentrations. The high wound colonization ability, found in this work, together with the propensity to colonize grape berry and the interesting enological traits possessed by the selected S. bacillaris strains allow the use of this yeast as biocontrol agent on vine and grape berries with possible positive effects on must fermentation, although the presence of S. cerevisiae is needed to complete the fermentation process. This work introduces new possibilities in wine yeast selection programs in order to identify innovative wine yeasts that are simultaneously antifungal agents in vineyards and alternative wine starters for grape must fermentation and open new perspective to a more integrated strategy for increasing wine quality.

Effect of preharvest spraying Cryptococcus laurentii on postharvest decay and quality of strawberry

Application of a suspension (log 8.0/ml) of Cryptococcus laurentii prior to harvest led to a reduction in Botrytis cinerea decay of strawberries stored at 4 or 20°C, for 12 or 4days, respectively. The frequency of spraying antagonist significantly influenced disease incidence in strawberry fruit. The best inhibition of disease was achieved when fruit sprayed C. laurentii with three applications that began 6days prior to harvest, and the incidence of gray mold and natural decay treated with this method was 21% and 11%, compared with 88% and 62% in the control after storage at 20°C for 4days. A similar result occurred in the treated fruit after storage at 4°C for 12days. Dilation plate counts on Rose Bengal agar and scanning electron microscopy results showed that three applications with C. laurentii at 6, 3 and 0days before harvest improved its ability to colonize the epidermis of strawberry fruit in the greenhouse and during storage compared to single application. In addition, antagonistic yeast spraying before harvest could reduce the weight loss, delay the decrease of the firmness and ascorbic acid, but had no significant effect on the contents of soluble solids, titratable acidity and fruit surface color. These results suggested that preharvest spraying with C. laurentii might be a promising alternative to fungicide application for decay control of strawberry.

Yeast biocontrol of fungal spoilage of pears stored at low temperature

To reduce the use of fungicides, biological control with yeasts has been proposed in postharvest pears. Most studies of antagonists selection have been carried out at room temperature. However, in regions like North Patagonia where fruits are stored at -1/0 °C during 5-7 months the selection of potential antagonist agents must be carried out at low temperature. In this study, 75 yeast cultures were isolated from healthy pears from two Patagonian cold-storage packinghouses. Aureobasidium pullulans, Cryptococcus albidus, Cryptococcus difluens, Pichia membranifaciens, Pichia philogaea, Rhodotorula mucilaginosa and Saccharomyces cerevisiae yeast species were identified. Additionally, 13 indigenous isolates of Penicillium expansum and 10 isolates of Botrytis cinerea were obtained from diseased pears, characterized by aggressiveness and tested for sensitivity to postharvest fungicides. The yeasts were pre-selected for their ability to grow at low temperature. In a first biocontrol assay using the most aggressive and the most sensitive isolate of each pathogen, two epiphytic isolates of A. pullulans and R. mucilaginosa were the most promising isolates to be used as biocontrol agents. They reduced the decay incidence by P. expansum to 33% and the lesion diameter in 88% after 60 days of incubation in cold. Foreign commercial yeast used as a reference in assays, only reduced 30% of lesion diameter in the same conditions. Yeasts were not able to reduce the incidence of B. cinerea decay. The control activity of the best two yeasts was compared with the control caused by the fungicides in a second bioassay, obtaining higher levels of protection against P. expansum by the yeasts. These two regional yeasts isolates could be promising tools for the future development of commercial products for biological control.

Improved Control of Postharvest Decay of Pears by the Combination of Candida sake (CPA-1) and Ammonium Molybdate

ABSTRACT The potential enhancement of Candida sake (CPA-1) by ammonium molybdate to control blue and gray mold caused by Penicillium expansum and Botrytis cinerea, respectively, on Blanquilla pears was investigated. In laboratory trials, improved control of blue and gray molds was obtained with the application of ammonium molybdate (1, 5, 10, and 15 mM) alone or in combination with C. sake at 2 x 10(6) or 2 x 10(7) CFU ml(-1) on Blanquilla pears stored at 20 degrees C. In semicommercial trials at 1 degrees C for 5 months, the efficacy of C. sake at 2 x 10(6) CFU ml(-1) on reducing P. expansum and B. cinerea decay was enhanced more than 88% with the addition of ammonium molybdate 5 mM in the 1999-2000 season. In two seasons, the performance C. sake at 2 x 10(6) CFU ml(-1) plus ammonium molybdate was similar to or greater than that of C. sake at 2 x 10(7) CFU ml(-1). Similar control of blue mold was obtained on pears stored under low oxygen conditions. The preharvest application of ammonium molybdate did not reduce postharvest blue mold decay. The population of C. sake on pear wounds significantly decreased in the presence of ammonium molybdate 1 and 5 mM at 20 and 1 degrees C.

Biological control of postharvest pear diseases using a bacterium, Pantoea agglomerans CPA-2

Epiphytic microorganisms isolated from the fruits and leaf surfaces of apples and pears were screened for antagonistic activity against Penicillium expansum on pears. From 247 microorganisms tested for antagonistic properties against P. expansum, a bacterium strain identified as Pantoea agglomerans (CPA-2) was selected. This bacterium was very effective against Botrytis cinerea, P. expansum and Rhizopus stolonifer. Complete control at the three tested concentrations (2×10 7, 8×10 7 and 1×10 8 CFU ml −1) was obtained on wounded pears inoculated with 10 3, 10 4 and 10 5 conidia ml −1 of P. expansum and R. stolonifer. At 8×10 7 CFU ml −1, Pan. agglomerans reduced B. cinerea decay by more than 80% at the three concentrations of the pathogen. In over 3 years of experiments in semicommercial trials, Pan. agglomerans provided excellent control against B. cinerea and P. expansum under cold storage, either in air or in low oxygen atmospheres. Equal control was obtained with Pan. agglomerans at 8×10 7 CFU ml −1, as with the fungicide imazalil at commercial doses, against both pathogens. Pan. agglomerans grew well inside wounds on pears at both room and cold temperatures and under modified atmospheres. In contrast, it grew poorly on the surface of intact fruit.

Botrytis cinerea Decay in Apples Is Inhibited by Postharvest Heat and Calcium Treatments

`Golden Delicious' apples (Malus domestica Borkh.) were treated after harvest with heat (air at 38 °C for 4 days or 42 °C for 1 day) or 2% CaCl2 (w/v; applied as a dip or pressure-infiltrated) or a combination of the two and stored at 0 °C for ≤6 months. Decay caused by Botrytis cinerea Pers.:Fr. after inoculation to a depth of 2 mm with a conidial suspension virtually was eliminated in stored fruit heated at 38 °C, regardless of Ca treatment. Apples punctured to a depth of 0.5 mm (but not 2 mm) and inoculated with B. cinerea on removal from storage were almost completely protected from poststorage decay if they had previously been pressure-infiltrated with 2% CaCl2, regardless of the heat regime. Heating fruit at 42 °C and dipping in 2% CaCl2 were only partially effective in preventing decay from either pre- or poststorage inoculations. Fruit firmness was not related to resistance to decay.

Botrytis cinerea Decay in Apples is Inhibited by Postharvest Heat and Calcium Treatments

`Golden Delicious' apples (Malus domestica Borkh.) were treated postharvest with heat (38C/4 d or 42C/24 h) or 2% CaCl2 (applied as a dip or pressure-infiltrated) or a combination thereof and then stored. Decay caused by Botrytis cinerea was virtually eliminated in fruit heated at 38C after inoculation prior to storage, regardless of Ca treatment. Apples inoculated upon removal from storage were almost completely protected from decay if they had been previously pressure-infiltrated with Ca, regardless of heat regime. Heating at 42C or Ca dips were only partially effective in preventing decay. Pressure infiltration of Ca (regardless of heat regime) or heating at 38C (regardless of Ca treatment) resulted in firmer fruit (68 N) than Ca dips or heating at 42C (56 N), which were firmer than nontreated fruit (52 N).

Pre-harvest fungicide sprays and polyvinyl wraps to controlBotrytisrot and prolong the post-harvest storage life of strawberries

SummaryField sprays with iprodione, metameclan or captafol, applied once weekly during flowering and fruit development resulted in a significant reduction in Botrytis cinerea decay in cv Aliso strawberries during 10 days of storage at 2°C and a subsequent 2 days of shelf life (20°C) to simulate sea transport followed by marketing. Wrapping freshly harvested strawberries, harvested from unsprayed plots, in sealed PVC wraps permeabe to atmospheric gases, resulted in a considerable improvement in the keeping quality of the stored fruit, with better maintenance of fruit firmness, less weight loss, delayed drying of the calyx, and a significant reduction in the incidence of Botrytis decay. The improvement in the storability of the fruit coincided with the formation of a CO2-enriched atmosphere within the wraps. The PVC film responsible for the accumulation of the highest level of CO2 (10.5%) was the most effective in controlling Botrytis decay during storage. No off-flavours were detected in the fruit at this ...