Green Mold Research Articles

First Report of Penicillium oxalicum Causing Leaf Blight on Maize in China.

In August 2022, two-month-old maize plants (Zea mays cv. 'Zihei'; "Chinese purple corn") exhibited irregular lesions on leaves and leaf blight symptoms (Figure 1). Although the lesions were yellow at the early infection stages, they turned brown during the pathogen advancement and culminated in leaf blight. Nearly 60% of plants from a non-commercial maize field (0.2 ha) in south-eastern Jiangsu (Nantong municipality, China; 120.54º E, 31.58º N) exhibited brown lesions, and about 4% of the diseased plants showed advanced leaf blight symptoms. The disease resulted in approximately a 9% yield loss compared to previous years when no disease symptoms were observed. Thirty small leaf pieces, approximately 0.3 cm2 in size and showing disease symptoms, were surface sterilized in 1.5% NaOCl for 1 min and washed twice with sterile ddH2O. The pathogen was cultured on PDA medium in the dark at 25 ºC, with grayish colonies observed after 5 days. Morphological analysis showed the presence of round/oval conidia (8.81 ± 0.50 μm diameter; n = 86) and branched conidiophores, which was consistent with the morphology of Penicillium spp. (Visagie et al. 2014). Nine representative isolates were obtained from different leaf pieces via single spore isolation, and the internal transcribed spacer (ITS), β-tubulin (TUB2) and calmodulin (CMD) genes were amplified using ITS1/ITS4, BT2a/BT2b and CMD5/CMD6 primers, respectively. The obtained ITS (OP954496-OP954497 and OP942428-OP942434), TUB2 (OP966781-OP966784 and OQ025045-OQ025049) and CMD (OQ078664-OQ078672) sequences were submitted in GenBank. Two isolates belonged to the P. citrinum species, while seven of the isolates belonged to the P. oxalicum species. A blast search revealed that the obtained P. citrinum ITS and CMD sequences had 99.39% and 100% homology to the ex-type strain P. citrinum NRRL 1841; GenBank numbers: AF033422 and GU944638 (Peterson & Horn 2009). Additionally, the obtained P. oxalicum ITS and CMD sequences had 99.82-100% and 94.64-95.49% homology to the ex-type strain P. oxalicum NRRL 787; GenBank numbers: AF033438 and KF296367 (Visagie et al. 2015). A molecular phylogenetic tree was constructed using MEGA7 to confirm the identity of the pathogen (Figure 2). To confirm pathogenicity, 3-week-old healthy 'Zihei' plants were used. The leaves were sprayed with aqueous solutions (sterilized ddH2O) that contained 1 × 106 spores/mL of each isolate. For the control experiment, sterilized ddH2O was used. After 5 days in a growth chamber at 25 ºC and 70% relative humidity, yellow lesions were observed. The number of lesions was higher when inoculating with P. oxalicum than when inoculating with P. citrinum. This result, together with the higher occurrence of P. oxalicum isolates, suggests that P. oxalicum is the main species causing the disease symptoms. The pathogen was recovered from the infected plants, and its identity was confirmed by ITS sequencing and morphological analysis. As far as we know, this is the first report of P. citrinum and P. oxalicum causing maize leaf blight worldwide. These species have previously been associated with maize kernels, as a source of mycotoxins posing relevant hazards to human health (Keller et al. 2013; Yang et al. 2020). P. citrinum was recently identified as the causal agent of green mold on Dictyophora rubrovalvata in China (Qin et al. 2022), while P. oxalicum was reported to cause citrus rot, pineapple leaf spot, and blue mold on Gastrodia elata, Astralagus membranaceus and muskmelon (Tang et al. 2020; Wu et al. 2022; Zheng et al. 2022). China is one of the world's largest producers of maize, harvesting more than 171 million tons in 2021. This report will help to better understand the pathogens that affect China's maize production.

Enhancing the antioxidant and antifungal properties of polyphenols through encapsulation in β-lactoglobulin nanoparticles using emulsification-evaporation technique

Numerous studies have demonstrated the potential of banana blossom polyphenols as antioxidants and antifungal agents. However, their application in the food field is extremely limited due to their vulnerability to environmental conditions. This study aims to increase the stability of banana blossom polyphenols and explore their potential in food preservation, particularly against fungal infections. To achieve this, β-lactoglobulin@ferulic acid-quercetin-vanillic acid nanoparticles (N-β-LG@FA-QT-VA) with a particle size of 74.5–80.7 nm were successfully obtained using β-lactoglobulin (β-LG) as the encapsulating material, combined with protein heating modification and emulsification-evaporation techniques. The encapsulation process resulted in a significant increase in antioxidant activity, with an improvement of 42.3% over the free polyphenols. Furthermore, N-β-LG@FA-QT-VA nanoparticles displayed significantly higher antifungal activity and fruit preservation abilities compared to β-LG and FA-QT-VA mixtures. They effectively inhibited the germination and expansion of Penicillium digitatum, a common fruit pathogen. Applying this knowledge, these nanoparticles were tested on orange fruits inoculated with P. digitatum. A successful delay in green mold infection and decay was observed, demonstrating the potential of N-β-LG@FA-QT-VA nanoparticles as a natural alternative to synthetic fungicides, all while maintaining fruit quality.

Utilizing of the Statistical Analysis for Evaluation of the Properties of Green Sand Mould

Utilizing of the Statistical Analysis for Evaluation of the Properties of Green Sand Mould

Biological control of green and blue molds on postharvest lemon by lactic acid bacteria

Postharvest green and blue molds caused mainly by Penicillium digitatum and P. italicum conduce to economic losses in citrus production. Here, the potential antifungal activity of four lactobacilli strains was assessed against local isolates of these fungi to control postharvest diseases on lemons. Inhibitory activity of L. paraplantarum CRL 1905, L. fermentum CRL 973, L. casei CRL 1110 and L. reuteri CRL1101 strains was assayed by the culture overlay method. Also, inhibition of conidial germination by cell-free supernatants (CFS) obtained from 24 and 48 h-cultures of these lactobacilli strains (CFS24 and CFS48, respectively) was tested by microtiter assay. CRL 1905 showed the strongest fungicidal activity and was selected for further studies. When the antifungal compound/s produced by CRL 1905 strain were investigated, it was observed that the ability of CFS24 to inhibit conidial germination was lost after pH neutralization, inferring an acidic nature of the metabolite/s. Finally, to detect whether CFS24 had a potential application to control of Penicillium rot on lemons, a fruit decay test was performed. It was demonstrated that ten-fold concentrated CFS24 was able to decrease the disease incidence by ∼ 80 %. In conclusion, the use of extracellular components derived from CRL 1905 with antifungal activity could be an eco-friendly alternative to control postharvest decays of lemon.

Quantifying the ultraviolet-induced fluorescence intensity in green mould lesions of diverse citrus varieties: Towards automated detection of citrus decay in postharvest

Citrus fungal infections developing during fruit storage and transportation can cause significant economic losses after harvest. The most important is caused by the fungus Penicillium digitatum, which infects the fruit through rind wounds and causes a rot lesion. The symptoms of decay are difficult to notice by the human eye in the initial stages of decay development because the colour of the lesion is very similar to that of the healthy rind. One method to detect this disease early is to illuminate the fruit with ultraviolet (UV) light since the disease causes visible fluorescence. Manual inspection exposes the workers to UV light, which is dangerous for their skin and eyes. An alternative is to use artificial vision systems. But not all varieties show the same level of fluorescence, and even some do not produce this phenomenon, making it challenging to create effective automatic detection systems based on image analysis. This work has studied and determined the fluorescence level of 104 varieties of oranges and mandarins using hyperspectral and colour imaging. The samples were inoculated with spores of the P. digitatum in controlled conditions. Images were captured exposing the fruit under UV light (380 nm) using a colour camera and a hyperspectral imaging system. The fluorescence level of each variety was measured using three colour coordinates and the hyperspectral images. Best correlations between the spectral and the colour-based systems were achieved using the green (G) colour coordinate of the RGB colour space (R2 =0.85). Navel and common oranges emit the most fluorescence, while 16 varieties (mostly blood oranges and other mandarins) have very low or undetectable fluorescence.

PdGpaA controls the growth and virulence of Penicillium digitatum by regulating cell wall reorganization, energy metabolism, and CDWEs production

Penicillium digitatum could infect citrus and cause devastating green mold disease. One of the essential parts of the G protein is the Gα subunit, which is essential to signal transduction in filamentous fungi but has not been reported in P. digitatum. In this study, PdGpaA was identified as a homolog of Gα in P. digitatum, and deletion of the PdGpaA gene significantly accelerated early-stage spore germination and inhibited late-stage hyphal growth and conidiophore formation. The ΔPdGpaA strain showed faster growth in sodium dodecyl sulfate (SDS) and calcofluor white (CFW) but more sensitivity to Congo red (CR). We predicted that cell wall integrity had been compromised due to cell wall rearrangement. Moreover, the increased quantity of septa and the reorganization of cell walls were confirmed by CFW staining and quantitative real-time PCR analysis. Deletion of the PdGpaA gene increased intracellular reactive oxygen species (ROS)and mitochondrial deterioration, which obstruct the TCA cycle and hinder energy metabolism. A pathogenicity test revealed that the lesion diameter was decreased by 90.62 % in the ΔPdGpaA strain, probably as the result of a decline in the activity of pectinase and cellulase. In addition, the ΔPdGpaA strain was more sensitive to prochloraz, KCl and H2O2. In conclusion, this study provides multiple functions for the PdGpaA gene, which might have broad application space and prospects in the control of citrus green mold.

Effect of Epiphytic Bacteria from Citrus against Green Mold Post-Harvest Diseases of Citrus

This study investigates the potential of epiphytic bacteria isolated from citrus fruits to control green mold post-harvest disease caused by Penicillium digitatum in Thompson Navel sweet oranges in the north of Iran. Twenty-three epiphytic bacteria were isolated and screened in vitro against P. digitatum, and 13 isolates with antagonistic activity were selected for further studies. Isolates B15 (Bacillus sp.), P17 (Pseudomonas sp.), and S13 (Streptomyces sp.) exhibited the most effective inhibitory effects on P. digitatum in vitro and in vivo. Among these, B15 showed the highest percentage of mycelium growth reduction and was further identified as B. cereus by 16S rRNA sequence analysis. Metabolic analysis of Bacillus sp. isolate B15 extract revealed the presence of the inhibiting antifungal substance Iturin A. The result showed that the application of epiphytic B. cereus decreased the percentage of green mold post-harvest diseases in orange fruit. This indicates their potential as an environmentally friendly alternative to chemical post-harvest control of orange diseases caused by P. digitatum.

Postharvest control of green and blue molds on Mexican lime fruit caused by Penicillium species using Thymus vulgaris essential oil and carboxy methyl cellulose

Postharvest control of green and blue molds on Mexican lime fruit caused by Penicillium species using Thymus vulgaris essential oil and carboxy methyl cellulose

Genome-wide discovery of Pichia galeiformis-secreted proteins and their induction of green mold resistance in citrus fruit

Microbe-secreted proteins could alter plant defense systems, but yeast-secreted proteins and their impact on plant disease resistance remains uninvestigated. As our team had previously found that Pichia galeiformis (P. galeiformis) induced citrus green mold resistance, the purpose of this study was to identify its secreted proteins and their role in disease resistance. The genome of P. galeiformis was completely sequenced, and 4386 putative protein-coding genes were identified. The crude culture of P. galeiformis contained 1443 proteins. Among these proteins, 55 were identified as secreted proteins with an N-terminal signal peptide and lacking transmembrane structural domain. Overexpression of secreted proteins 2-gene0581, 22-gene0896, 23-gene0290, 12-gene3564, 9-gene0639, and 15-gene0649 significantly reduced citrus fruit disease incidence and lesion diameter. And the best effect was achieved by 15-gene0649 treatment. Notably, P. galeiformis 15-gene0649, which was named PgSCP, encoded a novel protein. The purified protein PgSCP demonstrated considerable ability to prevent green mold caused by Penicillium digitatum in citrus. This study presented here confirms that yeast could increase citrus green mold resistance through secreted proteins. Those secreted proteins offer a fresh insight for controlling postharvest disease in citrus fruit as well as a new commercialization and application method for antagonistic yeast.

Control of Green and Blue Molds of Citrus Fruits Using some Biocontrol Agents under Egyptian Conditions

Control of Green and Blue Molds of Citrus Fruits Using some Biocontrol Agents under Egyptian Conditions

Yeast biocontrol against green mold in pear orange postharvest

The objective of this study was to evaluate the efficiency of the enzyme β-1, 3-glucanase and the mechanisms of action produced by yeasts in the biological control ofgreen mold in post-harvest oranges of the pear variety. The Fully Casualized Delineation(FCD) was used. The results were submitted to analysis of variance (ANOVA), in triplicate,compared with Tukey's test at a 5% probability level (p < 0.05), using the statisticalsoftware Sisvar. It was found that the killer activity was observed in 85.7% of the yeastsevaluated. The yeast Candida peltata URM4681 showed better production of β-1.3-glucanase, between 1.071 and 5.422 µg mL -1 . A factorial delineation 2 3 was used in amedium composed of yeast extract, soybean extract and meat extract to increaseenzymatic production, reaching an increase of 4.351 times comparing the assay of lowerand higher activity. The in situ assays showed a reduction in the number of infected fruitstreated with the enzymatic extract, being on average 78.5% when compared with thecontrol treatment (distilled water). As for sporulation, the enzymatic extract, which had anaverage of 8.4 spores, did not differ statistically from the IMZ and TBZ fungicides, both in apreventive and curative manner. Regarding the severity of the disease, it was noted thatthe fruits treated with enzymatic extract, had an average damage of 7.57 %, also notdiffering statistically from fungicides, both preventive and curative. Our studies suggestthat C. peltata URM4681, makes this a good candidate for biocontrol against green mold.

γ-Cyclodextrin encapsulated thymol for citrus preservation and its possible mechanism against Penicillium digitatum

The volatility of essential oils greatly limits their industrial applications. Here, we successfully prepared γ-cyclodextrin (γ-CD) inclusion compounds (γ-CDTL) containing thymol (TL) for the control of green mold caused by Penicillium digitatum (P. digitatum) in citrus fruit. In vitro experiment showed that the minimum fungicidal concentration (MFC) of γ-CDTL against the hyphae growth of P. digitatum was 2.0 g/L, and 8 × MFC treatment significantly reduced the occurrence of green mold in citrus fruit and had no adverse effect on fruit quality in vivo test compared to prochloraz. Scanning electron microscopy (SEM), x-ray diffraction (XRD), fourier transform-infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), physical properties and sustained release properties were also performed, results indicated that the hydrogen bonds between TL and γ-CD were the basis for the formation of γ-CDTL. We further investigated the inhibition mechanism of γ-CDTL. SEM and TEM experiments showed that γ-CDTL treatment caused severe damage to the hyphal morphology and cells in 30 min and disrupted the permeability of P. digitatum mycelial cell walls by increasing the chitinase activity, thus accelerating the leakage of intracellular lysates. However, the integrity of the cell membrane was obviously damaged only after 60 min of treatment. In conclusion, we prepared a novel inclusion complex γ-CDTL with obvious antifungal effects and preliminarily elucidated its inclusion mechanism and antifungal mechanism. γ-CDTL might be a potent alternative to chemical fungicides for controlling the postharvest decay of citrus.

Application of Lactobacillus spp. for the biological management of green mold (Penicillium digitatum) on sweet orange fruit under in vitro and storehouse conditions

ABSTRACT This study aimed to investigate the use of probiotic lactic acid bacteria including Lactobacillus brevis, L. plantarum, L. helveticus and L. delbrueckii from dairy products against Penicillium digitatum (green mold) on sweet orange fruit. Antifungal activity of Lactobacillus spp. was first assayed using bacterial cells through the overlay method against 105 spore/mL suspension of P. digitatum. Also, P. digitatum growth inhibition was measured in the PDA medium containing 15 and 30% cell-free supernatant (CFS) of Lactobacillus spp. Antifungal activity of Lactobacillus spp. was evaluated under storehouse conditions by treating wounded fruits with 108/mL cell suspension (CS) and 30% CFS of Lactobacillus spp., which then infected with 105/mL spore suspension of P. digitatum. The CS and CFS of L. plantarum had the best antifungal activity under both in vitro and in vivo conditions followed by L. helveticus, L. delbrueckii and L. brevis. L. plantarum. The 15 and 30% L. plantarum CFS were able to inhibit the growth of P. digitatum by 30.31%, 76.82% and 97.6% respectively, under in vitro conditions. Also, L. plantarum CS and 30% CFS reduced the growth of the P. digitatum on the fruit by 92.77 and 98.9% respectively, under storehouse conditions. The total content of all sugars of treated fruits with Lactobacillus spp., CS and CFS showed significant difference compared to untreated fruits. Therefore, the present study highlights the successful application of biological fungicides based on secondary compounds of Lactobacillus spp. due to greater stability of metabolites than bacterial cells in the environment.

First Report of Green Mold Disease Caused by Penicillium ochrochloron on Medicinal Plant Pseudostellaria heterophylla in China.

Pseudostellaria heterophylla is one of the Chinese herbal medicines with high medicinal and economic values. From 2019 to 2021, postharvest green mold disease was observed with an incidence of 2~5% on the tuberous roots of the harvested P. heterophylla at eight locations in Zherong county, Fujian Province, China. The symptoms were as follows: white mycelial growth on the tuberous roots surface initially, then green mold layers forming, and the tuberous roots decaying finally. To identify the causal agent, a total of 20 symptomatic tuberous roots were collected. Small pieces (5 mm×5 mm) were treated by surface disinfestion with 75% ethanol and 1% NaOCl, then rinsed 3 times with sterile distilled water. These treated pieces were transferred onto potato dextrose agar (PDA) and incubated at 25°C in the dark for 7 days. Twenty pure cultures were obtained by single-spore isolation method. Colonies on PDA medium initially appeared as white mycelium that developed grayish-green conidia with white margins. Mycelium was septate and colorless. Conidiophores were predominantly monoverticillate, occasionally biverticillate. Stipes was long and slender. Phialides were ampulliform to almost cylindrical with collula, 11.25 (7.80-23.50) µm long (n=50). Conidia were smooth walled and pale green, with globose to ellipsoidal shape, 2.75 (2.37-3.27)× 2.47 (2.18-3.13) µm (n=50). Based on these morphological characteristics, the isolates matched the description of the genus Penicillium. Genomic DNAs from two representative isolates (FJAT-32578 and FJAT-32579) were extracted with a fungal genomic DNA extraction kit. The rDNA ITS region and partial β-tubulin gene (BenA) were amplified using the primers ITS1/ITS4 (White et al. 1990) and Bt2a/Bt2b (Glass and Donaldson 1995), respectively. The sequences of isolate FJAT-32578 and FJAT-32579 were deposited in GenBank (ITS, OM920986 and OM920987; BenA, OM953825 and OM953826). All sequences showed above 99% similarity to P. ochrochloron type strain CBS357.48 (ITS, NR111509; BenA, GU981672). In multilocus phylogenetic analysis (ITS + BenA), the two isolates from this study clustered together with other strains of P. ochrochloron with 100% bootstrap support. The two isolates were thus identified as P. ochrochloron based on both morphological and molecular characteristics. Pathogenicity tests were conducted in triplicate by inoculating the aseptic wounds with 10 µl of conidial suspension (1×106 conidia/ml) of the two isolates in the each healthy tuberous root (cv. Zheshen No.1). The experiment was conducted twice. All the inoculated tuberous roots were placed in sterilized Petri dishes with moistened filter paper, and incubated at 25 ± 2 °C. Fifteen days after inoculation, all inoculated tuberous roots demonstrated the same symptoms as those observed in the field conditions. The re-isolated fungi from the artificially infected tuberous roots were confirmed as P. ochrochloron using the method described above, while the control tuberous roots treated with sterile water did not develop symptoms, fulfilling Koch's postulates. To our knowledge, this is the first report of P. ochrochloron causing green mold disease on P. heterophylla in China, which would be a potentially new threat to the medicinal plant.

Overcoming lemon postharvest molds caused by Penicillium spp. multiresistant isolates by the application of potassium sorbate in aqueous and wax treatments.

Penicillium digitatum and Penicillium italicum are the main causal agents of postharvest diseases in lemon. Over the last decades, the appearance of isolates resistant to the main commercial fungicides has been considered one of the most serious problems for the citrus industry. In this work, potassium sorbate (KS) was evaluated as an alternative to chemical fungicides to control postharvest diseases caused by Penicillium isolates resistant to imazalil, thiabendazol, and pyrimethanil. In vitro assays showed that 1% KS inhibited conidia germination and mycelial growth of sensitive and resistant P. digitatum and P. italicum isolates, being this effect stronger at pH 5 than at pH 9. In curative treatments, the immersion of inoculated lemons in 1% KS aqueous solution for 30 s reduced green and blue molds incidences by around 80%. No wound protection effect was observed when wounded lemons were immersed in 3% salt solution before inoculation. Noteworthy, the inclusion of KS in a commercial wax coating effectively controlled green and blue molds, even in decays caused by fungicide resistance isolates. Together, results encourage the use of KS in lemon postharvest treatments to contribute to the management of resistant strains, which represent a major challenge in packinghouses worldwide. PRACTICAL APPLICATION: The use of KS in citrus postharvest treatments would help producers to reduce spoilage caused by Penicillium fungicide-resistant strains. The inclusion of this generally recognized as safe compound in wax coatings improves its persistence on the fruit surface, keeping product quality during long-term overseas transport. In sum, KS constitutes an affordable and eco-friendly option for controlling postharvest molds in lemon fruit.

Investigation of the efficiency of some fungicides and disinfectants applied in Agaricus bisporus cultivation

Pathogenic moulds (e.g., Trichoderma, Hypomyces, and Lecanicillium) cause huge problems in industrial scale production of Agaricus bisporus. It is important to choose the right control strategy, either chemical or biocontrol-based, to prevent substantial economic losses. The present study was carried out to reveal the in vitro efficacy of some fungicides and disinfectants against causative agents of wet bubble (Hypomyces perniciosus), dry bubble (Lecanicillium fungicola var. fungicola), cobweb disease (Hypomyces odoratus), and green mould (e.g., Trichoderma aggressivum f. aggressivum, T. aggressivum f. europaeum, T. harzianum), the four most devastating fungal infections in mushroom production. Prochloraz was efficient against Trichoderma and H. perniciosus isolates. Metrafenone did not cause complete inhibition for any of the isolates even at the highest concentration (5%) tested. In both cases Lecanicillium isolates displayed the lowest growth rate inhibition. Concerning the tested disinfectants, treatment with Sekusept Aktiv resulted in complete growth inhibition for all isolates in the concentration range of 1.25-5%. Terralin Protect, Disinflex and Formalin were also effective, except against the tested isolates of T. agressivum f. agressivum which proved to be the most resistant.

Molecular characterization of Trichoderma spp. isolates in mushroom‐growing farms in Turkey and their effects on Agaricus bisporus production

AbstractMushroom production is highly affected by green mould disease, which causes severe losses worldwide. This study aimed to characterize Trichoderma spp. isolates collected from Agaricus bisporus‐ and Pleurotus ostreatus‐growing facilities based on their molecular features and evaluate their aggressiveness in mushroom production in vitro and in vivo. Fifty‐six Trichoderma isolates from mushroom farms in Aegean and Marmara regions were analysed for molecular characteristics. In a phylogenetic tree constructed based on internal transcribed spacer (ITS) and tef1 sequences, they were classified into five groups, which included Trichoderma spp. such as T. aggressivum, T. europaeum, T. pleuroticola, T. virens, T. harzianum and T. afroharzianum. Phylogenetic analyses revealed that tef1 sequences could distinguish between T. aggressivum f. aggressivum and T. aggressivum f. europaeum more specifically. Consequently, tef1 sequence variation identified 15 T. aggressivum f. europaeum isolates compared with ITS sequence variation. In vitro conditions based on the dual‐culture tests of the mycelial growth of A. bisporus showed growth inhibition between 50% and 75% depending on the isolates. Two Trichoderma isolates with different ITS and tef1 sequences (3/9 and 7/5 isolates, respectively) and more lytic and mycoparasitic activities were analysed further to determine their effects on yield and mushroom quality parameters. Therefore, T. aggressivum f. aggressivum is not the only species that affects mushroom production, and T. aggressivum f. aggressivum and T. aggressivum f. europaeum isolates significantly (p < 0.05) inhibited A. bisporus growth in vitro and in vivo.

Citrus Green Mold Biocontrol by Novel Epiphytic Antagonist Combined with Safe Compounds Formulations

Citrus Green Mold Biocontrol by Novel Epiphytic Antagonist Combined with Safe Compounds Formulations

Easter in Milan.

I never imagined I'd be famous. People come from all over the world to see me. Yet my beginnings were humble. My mother, a buxom Milanese, was low in the pecking order. I was expected to follow the family tradition and cater for my embryonic relative. But I didn't get the chance to pursue that calling, for I was torn from my home at an early age and assigned to decorating duty.I was to help paint a dining room wall. The traditional method involved combining pigments with water and quickly applying the mix to fresh plaster before it dried. But my supervisor had no experience with this high-throughput fresco technique. His expertise was in painting dry surfaces like wood panels. He'd mix pigments with me or oil to produce bright paints that allowed for much greater freedom to adjust and correct, suiting his meticulous ways. But these tempera- or oil-based methods hadn't been tried out on murals. He decided to risk it and do the experiment. For good measure, he threw both me and oil into the mix.That's how I found myself clinging to a dry wall, 15 ft from the ground, my supervisor perched next to me on scaffolding. Friars came and went below, for the monastery dining room was still in use despite the renovations underway. Being so close to my supervisor, I could read his thoughts. He was planning to depict thirteen males (I only became aware that his species had females much later), taking supper at a long table. I was to contribute to blue mountains in a central window that backlit the scene.My supervisor was obsessed. Not only did he ceaselessly ponder the poses and composition of his mural; his mind overflowed with inventions of war machines, flying machines, architectural designs, theories of how mountains, rivers and living beings develop and function. He didn't trust accepted ideas but always made careful observations for himself, sketching what he saw and scribbling down notes in mirror script. His mission: look at the world with fresh eyes and find better ways of understanding, representing and improving it.I was three when they removed the scaffolding. Visitors came from far and wide to witness the revolutionary composition that lit the central figure, the dazzling combinations of red, green, yellow and ultramarine robes, the extraordinary interplay of contrasts, the lifelike expressive faces, plates of food and pleated tablecloth. My supervisor had achieved lasting fame, putting to rest accusations that he never completed his works.Fortunately, he didn't witness my decay, for he died in France 22 years later. It was around then that parts of me began to flake off. By my fifties I was in such a sorry state that the friars felt justified in cutting a door into the wall beneath me, amputating the central figure's feet and further loosening paint with blows from their pickaxes. When I reached 300, Napoleon's soldiers pelted me with bricks and used the room as a stable. Four years later there was a fifteen-day flood and I became covered in green mould. At 450, an RAF bomb blew the roof off and only tarpaulin protected me from the skies. A major restoration began 34 years later. They removed the grime, overpainting, waxes, varnishes, glues, shellacs and resins that had been used to preserve me. After 22 years of painstaking work, what little colour remained was said to be 20% supervisor, 80% restorer.I'm now 529. Visitors raise hand-held devices to capture my decayed state. What if my supervisor hadn't been so experimental? What if the spirit of his age had been to stick to the tried-and-tested rather than risk failure? Maybe they'd still be able to see his creation in its full glory. But then again, I wouldn't be here, and neither would those hand-held devices.

Extracts of Ulva lactuca Induce Responses against Penicillium digitatum on Oranges

Penicillium digitatum causes severe damage to postharvest and stored citrus fruits, making it necessary to seek acceptable solutions limiting environmental and sanitary impacts. The seaweed liquid extracts (SLEs) obtained from the green macroalgae Ulva lactuca have previously shown anti-fungal activities towards postharvest green mold due to P. digitatum. Moreover, treatment with aqueous and ethanolic extracts had an influence on disease incidence and lesion severity on wounded oranges “Valentia late”. Therefore, we studied the abilities of the U. lactuca extracts and chlorophyll a (as a standard) to activate defense mechanisms in oranges. The analyses showed modifications in the protein concentrations and activities of β-1,3-glucanase and peroxidase in orange tissues, with a maximum activity level reached at 72 h after treatments. It appears that the SLEs were able to fight P. digitatum infections in the absence of direct contact with the pathogen, reflecting that the induction of host resistance is also a probable mode of action. Ulva lactuca fractions are rich in chlorophyll a, polyphenols, organic acids and ulvans, which might be the key molecules involved in the defense mechanism of oranges’ albedo. The use of these natural substances could be an alternative way to control postharvest citrus rot.