Colletotrichum Musae Research Articles

In vitro bioassays of some plant extracts against Banana anthracnose caused by Colletotrichum musae

Anthracnose of banana caused by Colletotrichum musae is an invasive disease, which is difficult to control in the export process. Plant extracts used to control plant diseases are gradually becoming substitutes for traditional fungicides because they are safe for the human body and environmentally friendly. The study was conducted to record the prevalence of banana anthracnose in two locations and to determine the best medium for the growth of C. musae and botanical extracts for managing the fungus under in-vitro conditions. Six media viz., Ripen banana peels media (RBPM), Unripen banana peels media (URBPM), Ripen banana flash fruit media (RBFFM), Unripen banana flash fruit media (URBFFM), Banana leaf media (BLM) and Potato dextrose agar media (PDA), four botanical extracts including Garlic (GC), Mint (MT), Eucalyptus (EC) and Neem seed (NS) at 2, 4 and 6% concentrations were tested against the fungus and the control (CL) remain untreated. Potato dextrose agar media (PDA) was used as a standard semi-synthetic growth media. The prevailing frequency of the disease was high in the investigation area. The maximum linear mycelial growth of the C. musae was recorded on PDA (85 mm) followed by URBFFM (40 mm), RBFFM (26 mm) whereas the lowest mycelial growth was recorded on BLM (20 mm) and URBPM (8 mm). In-vitro experiments showed that PDA was the best medium for the mycelial growth of C. musae. Moreover, tested botanical extracts showed high variation in reducing the colony growth of the fungus. EC was found most effective in reducing the colony growth of the fungus followed by NS, GC and MT. These results suggest that all the botanical extracts may be potentially useful for controlling anthracnose of bananas, EC extract can be effectively used for the field experiment. Keywords: Botanical extracts, Efficacy, Growth media, Incidence, Prevalence

Properties of beeswax antifungal coatings obtained by high‐pressure homogenisation and their application for preserving bananas during storage

SummaryBananas are tropical fruits that are perishable and susceptible to fungal diseases, mainly caused by Colletotrichum musae. Antimicrobial emulsion‐based coating materials have been used extensively to inhibit the growth of these fungi and extend the shelf life of bananas. Targeted emulsion‐based film functionalities offer excellent mechanical, physicochemical and barrier properties and limit fungal growth kinetics. Antifungal compounds, such as essential oils or phenolic compounds, are added to emulsion‐based (wax/biopolymer) coatings to enhance their antimicrobial properties. This study set out to formulate a beeswax‐based emulsion for banana coatings using high‐pressure homogenisation (HPH) and hydrophilic food‐grade/organic coating materials. The particle size distribution, stability and mechanical properties of the film‐forming emulsions, water vapour and the oxygen permeabilities of the resulting coating were investigated. The most promising sucrose emulsions were tested as coatings on banana fruits to assess their efficacy against moisture and firmness loss during storage. Adding thymol (0.5% w/w) to the sucrose emulsions further enhanced the inhibition of Colletotrichum musae growth to its barest minimum of <20%. Emulsion stability was clearly enhanced using HPH while the best inhibition was obtained with a 20% diluted sucrose emulsion containing 0.5% thymol, with or without HPH.

Biosurfactant-Producing Bacillus velezensis PW192 as an Anti-Fungal Biocontrol Agent against Colletotrichum gloeosporioides and Colletotrichum musae.

In this study, plant-root-associated Bacillus species were evaluated as antifungal biocontrol agents by analyzing the production of surface bioactive molecules known as lipopeptide biosurfactants. This study aimed to isolate and characterize antifungal biosurfactant-producing Bacillus bacterium. Bacillus velezensis PW192 was isolated from the rhizosphere of Lagerstroemia macrocarpa var macrocarpa and identified based on phylogenetic analysis of the 16S rRNA gene. The biosurfactant was excreted to cultured supernatant and exhibited emulsification power up to 60% and a decrease in surface tension from 72 in distilled water to 21 mN/m. The surface tension properties were stable in a broad range of pH from 6 to 10, in high temperatures up to 100 °C, and in salinities with a NaCl concentration up to 12% (w/v). Starting from 0.5 mg of acid, precipitated crude biosurfactant exhibited antifungal activity toward Anthracnose, caused by the phytopathogens Colletotrichum gloeosporioides and C. musae. The chemical structures of the biosurfactant were structurally characterized as lipopeptides fengycin A and fengycin B. The stability of the biosurfactant, as well as the antifungal properties of B. velezensis PW192, can potentially make them useful as agricultural biocontrol agents, as well as in other biotechnological applications.

Characterization and Expression of Phospholipase D Putatively Involved in Colletotrichummusae Disease Development of Postharvest Banana Fruit

Phospholipase D (PLD) in plants plays an important role in growth, development, and stress response. The effect of hexanal on PLD in banana fruit responding to Colletotrichum musae infection remains poorly understood. In this study, four putative PLD genes, named as MaPLD1, MaPLD2, MaPLD3, and MaPLD4 were identified from banana fruit. The four MaPLDs can be classified into three of the seven known PLD families according to sequence characterization. Their deduced amino acid sequences displayed homology of PLDs from other plant species. Furthermore, the specific expression analysis of PLD genes in banana fruit in response to infection in C. musae was studied and the response relationship between PLD family members and banana fruit under anthracnose stress was clarified. Changes in both the activity of PLD and PLC, and the connection between hexanal and phospholipases in the banana fruit C. musae infection were compared. The results showed that the incidence of disease in banana inoculated with C. musae was dramatically increased after 6 days of storage, the activation of PLD and PLC in infected anthracnose fruit before disease development, and that this activation was inhibited by hexanal treatment, which suggested that both enzymes play a protective role in banana fruit to cope with C. musae infection and the participation of hexanal in their regulation. Of the four MaPLD genes, the anthracnose had a stronger effect on MaPLD1 and MaPLD4. These data demonstrated that hexanal treatment could enhance fruit disease resistance to C. musae, and that PLD could take part in the disease defensive system of harvested banana fruit to C. musae by modulating the metabolism of cell membrane lipids, and thus suppress disease development in C. musae -inoculated banana during storage.

First Report of Crown Rot of Banana Caused by Fusarium proliferatum in Georgia, U.S.A.

Crown rot is one of the most damaging disease of banana fruit characterized by rot and necrosis of crown tissues. In severe cases, the disease can spread to the pedicel and banana pulp. Crown rot can be infected by several common fungi, including Lasiodiplodia theobromae, Musicillium theobromae, Colletotrichum musae, and a complex of Fusarium spp. and lead to softening and blackening of tissues (Lassois et al., 2010; Kamel et al., 2016; Triest et al., 2016; Snowdon, 1990). In November 2020, typical crown rot of banana fruits (cv. Pisang Awak, belonging to the tetraploid AABB genome) were observed from UGA Banana Research 12 Plots, Tifton, GA, with incidence rates of 15%. Initial symptoms appeared in the infected crown of green banana fruits. As the infection progressed, the crown tissues became blackened and softened, followed by an internal development of infection affecting the peduncle and the fruit, triggered early ripening of bananas. At last, the development of necrosis on the pedicels and fruits appeared and caused the fingers to fall off. To identify the pathogen, tissue pieces (~0.25 cm2) from the infected crown and pedicles were surface-sterilized in a 10% bleach solution for 1 min, followed by 30 s in 70% EtOH. The disinfected tissues were rinsed in sterile water 3 times and cultured on potato dextrose agar (PDA) amended with 50 µg/ml streptomycin at 25°C in the dark for 5-10 days. Isolates of the pathogen were purified using the single-spore isolation method (Leslie and Summerell 2006). Colonies on PDA produced fluffy aerial mycelium and developed an intense purple pigment when viewed from the underside. A range of colony pigmentation and growth rates were observed among the isolates. The microconidia were ovoid, hyaline, or ellipse in shape. The morphological features of the isolates were identified as Fusarium proliferatum (Leslie and Summerell, 2006). To further identify the isolates, genomic DNA was extracted from a representative isolate. And the internal transcribed spacer (ITS) region, the partial elongation factor (TEF1-α) gene and the β-tubulin gene (TUB2)were amplified and sequenced using the primers ITS1/ITS4 (Yin et al. 2012), EF-1 /EF-2 (O'Donnell et al. 1998) and B-tub1 /B-tub2 (O'Donnell and Cigelnik, 1997), respectively. The amplicons were sequenced and deposited in NCBI (accessions no. MZ292989, MZ293071 for ITS: MZ346602, MZ346603 for TEF1-α and MZ346600 and MZ346601 for B-tub). The ITS, TEF1-α, and B-tub sequences of the isolates showed 100% sequence similarity with Fusarium proliferatum isolates (accessions no. MT560212, LS42312, and LT575130, respectively) using BLASTn in Genbank. For pathogenicity testing, three whole bunched bananas sterilized with 10% bleach solutions and washed by sterilized water, were cut into 5 bananas per brunch. The cut surface of the banana crown was inoculated with conidial suspension (1.0 × 107 cfu/ml) of the pathogen with pipette tips. Equal number of bananas were treated with sterilized water in the same volume as a control. All bananas were sealed in a plastic bag and incubated at 25°C. After 7 days post inoculation, all inoculated bananas showed initial crown rot symptoms while no symptoms were observed on the control bananas. The fungus was re-isolated from the symptomatic tissues of infected bananas and confirmed to be genetically identical to F. proliferatum of the original inoculated strains according to morphological characteristics and molecular identification, fulfilling Koch's postulates. To the best of our knowledge, this is the first report of F. proliferatum causing crown rot on bananas in Georgia, USA.

Sunlight-Mediated Green Synthesis of Silver Nanoparticles Using the Berries of Ribes rubrum (Red Currants): Characterisation and Evaluation of Their Antifungal and Antibacterial Activities.

Plants are a treasure trove of several important phytochemicals that are endowed with therapeutic and medicinal properties. Ribes rubrum L. (red currants) are seasonal berries that are widely consumed for their nutritional value and are known for their health benefits. Red currants are a rich source of secondary metabolites such as polyphenols, tocopherols, phenolic acids, ascorbic acid, and flavonoids. In this study, sunlight-mediated synthesis of silver nanoparticles (AgNPs) was successfully accomplished within 9 min after adding the silver nitrate solution to the aqueous extract of red currant. The synthesised AgNPs were characterised with UV–Vis, transmission electron microscopy (TEM), dynamic light scattering (DLS), Fourier transform infrared spectrum (FTIR), and energy-dispersive X-ray spectrum (EDX). The efficacy of aqueous extracts of red currants and AgNPs in controlling the growth of some pathogenic fungi and bacteria was also investigated. The UV–visible (UV–Vis) spectrum displayed an absorption peak at 435 nm, which corresponded to the surface plasmon band. The strong silver signal on the EDX spectrum at 3 keV, authenticated the formation of AgNPs. The several peaks on the FTIR spectrum of the aqueous extract of red currant and the nanoparticles indicated the presence of some important functional groups such as amines, carbonyl compounds, and phenols that are vital in facilitating the process of capping and bioreduction, besides conferring stability to nanoparticles. The TEM microphotographs showed that the nanoparticles were well dispersed, roughly spherical, and the size of the nanoparticles ranged from 8 to 59 nm. The red currant silver nanoparticles were highly potent in inhibiting the growth and proliferation of some fungal and bacterial test isolates, especially Alternaria alternata, Colletotrichum musae, and Trichoderma harzianum. Based on the robust antifungal and antibacterial activity demonstrated in this study, red currant nanoparticles can be investigated as potential replacements for synthetic fungicides and antibiotics.

Efficacy and potential mechanism of hinokitiol against postharvest anthracnose of banana caused by Colletotrichum musae

Anthracnose caused by Colletotrichum musae is a devastating post-harvest disease on bananas, and it leads to serious economic losses. Exploring environmentally friendly natural compounds to manage anthracnose in fruit has been attracting more attention. In the current study, the effect of hinokitiol against C. musae and on banana quality was investigated. Our results showed that hinokitiol exhibited promising antifungal activities both in vitro and in vivo. Importantly, it effectively delayed banana ripening by maintaining weight, color, firmness, and TSS content, and it dramatically reduced the release of ethylene, the respiration rate, and the expression of genes involved in releasing ethylene. Moreover, the activities of defense-related enzymes including SOD, POD, and APX were enhanced by hinokitiol. The mechanism of hinokitiol against C. musae may be attributed to the destruction on the integrity of the plasma membrane, which leads to the leakage of cellular constituents and eventually the cell death of C. musae. Taken together, this study provided substantial evidence that hinokitiol had great potential to be developed as a natural antifungal agent against C. musae, prolonging the storage period of postharvest bananas.

Biologically Active Volatile Organic Compounds (VOCs) Produced by Rhizospheric Actinobacteria Strains Inhibit the Growth of the Phytopathogen Colletotrichum musae

The antifungal potential of volatile organic compounds (VOCs) produced by actinobacterial strains Streptomyces sp. (ACTB-77) and Amycolatopsis sp. (ACTB-290) from the rhizosphere of Caatinga plants against Colletotrichum musae was investigated. VOCs produced by these microorganisms (axenic and co-culture) were investigated using headspace-solid phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS). Although no exclusive VOC peaks were observed in the co-culture with ACTB-77, the same experiment involving ACTB-290 yielded five new peaks, including two identified alcohols, suggested as bioreductive products of the corresponding ketones by the fungus. Statistical analysis revealed that co-culture ACTB-77/C. musae has a closer similarity to the fungus than to the actinobacteria, while the co‑culture ACTB-290/C. musae showed closer similarity to the actinobacteria. These confirmed the more pronounced antifungal activity of the ACTB-290 strain, as observed in the fungus growth inhibition experiments. The antifungal activity of ACTB-290 was associated to its sulfur-containing metabolites, while linalool was suggested as responsible for the ACTB-77 activity.

Antagonistic activity of bacteria from wild honey against Colletotrichum musae, and testing of wild honey as biopesticide spray to control banana anthracnose

Anthracnose is a foliar and fruit disease caused by Colletotrichum spp. affecting a wide range of crops. Infection occurs early followed by quiescence in fruits, such as in banana, where chemical-based pesticides are used as a dependable fungal control for many years. There is an increasing need for a safe control and as implicated in the Organic Agriculture Act of 2010 (RA 10068) in the Philippines. This scenario drove the use of alternative pest control such as the use of biologicals and natural products. In this study, seven bacteria were isolated from wild honey, produced by Apis mellifera, wherein four (BC2, BC3, BC6 and BC7) were found to be an effective antagonist against Colletotrichum musae in in vitro conditions. These bacteria were identified to belong to the genus Lactobacillus spp. (BC2, BC3, BC7) and Bacillus spp. (BC6) based on sugar utilization tests, morphological and cultural growth in PDPA. For the in vivo test, different dilutions of wild honey were used and it was found out that lower concentrations were effective as biopesticide spray to prevent anthracnose infection. Lastly, we report herewith the first isolation of bacteria with biological control potential from wild honey, and to apply the raw or natural product as biopesticide in postharvest fruits.

Effectiveness Test of Trichoderma harzianum on The Development of Anthracnose Disease (Colletotrichum musae) of Ambon Banana

The decrease in the quality of bananas can be caused by the attack of the pathogen Colletotrichum musae which causes anthracnose disease. The use of the antagonist fungus Trichoderma harzianum can be relied upon to control this disease. This study aimed to obtain a more effective level of T. harzianum spore density to suppress the development of anthracnose disease in Ambon bananas. The treatment tested was T. harzianum with five levels of spore density, namely 105, 106, 107,108, and 109 spore/mL, designed using a completely randomized design with five replications. The variables observed were the incubation period and the intensity of the disease. The results showed that the spore density of 109 was effective in suppressing the development of anthracnose disease by inhibiting the incubation period to 3.85 days and suppressing the intensity of the disease to 41.4%.Keywords: Banana, Trichoderma harzianum, Anthracnose, Colletotrichum musae

New Xanthones with Antiagricultural Fungal Pathogen Activities from the Endophytic Fungus Diaporthe goulteri L17

Six new xanthone dimers, diaporxanthones A-F (1-6), and an unusual xanthone monomer diaporxanthone G (7), in addition to seven known analogues (8-14), were isolated and identified from endophytic Diaporthe goulteri L17 harbored in the fruits of the salt-tolerant plant Vitex trifolia. The chemical structures of these metabolites were elucidated on the basis of nuclear magnetic resonance, high-resolution electrospray ionization mass spectrometry, and reported data in the literature. Their absolute configurations were established by single-crystal X-ray diffraction analysis together with time-dependent density functional theory electronic circular dichroism calculations. Among these compounds, compounds 1 and 6 exhibited moderate antifungal activities against Nectria sp. and Colletotrichum musae and compound 4 showed significant cytotoxicity against all selected five cancer cell lines.

Antifungal activity of wild bergamot (Monarda fistulosa) essential oil against postharvest fungal pathogens of banana fruits

This study aimed to examine the antifungal activity of wild bergamot (Monarda fistulosa) essential oil on Colletotrichum musae and Lasiodiplodia theobromae, the causative organisms of anthracnose and crown-rot diseases of banana fruits, respectively. Chitin synthase is a promising target for antifungal compounds, since it is involved in synthesizing chitin, which forms a major proportion of the fungal cell wall. Disc volatilisation method was employed to assess the in vitro antifungal activity of the oil. The vapours of this essential oil at 4 μL per Petriplate exhibited 100% growth inhibition of both the fungal pathogens, and at 66.66 μLL−1 , it significantly (P <0.05) reduced the incidence and severity of anthracnose and crown-rot diseases in artificially wounded and infected fruits. The chemical composition of wild bergamot essential oil was determined by GC-MS technique and the components of the essential oil were docked against chitin synthase to determine the components responsible for antifungal activity. Chitin synthase was modelled by de novo approach due to non-availability of the 3D structure. The in silico techniques such as molecular docking and conceptual DFT revealed that the major components of the essential oil namely thymol, carvacrol and cinnamyl carbanilate manifested the best antifungal activity. This illustrates effective inhibition of the major postharvest diseases of banana by wild bergamot essential oil.

Antifungal Activity of an Endophytic Fungus Aspergillus versicolor DYSJ3 from Aphanamixis grandifolia Blume against Colletotrichum musae

An endophytic fungus strain DYSJ3 was isolated from a stem of Aphanamixis grandifolia Blume, which was identified as Aspergillus versicolor based on the morphological characteristics, internal transcribed spacer (ITS) and calmodulin gene sequences analyses. A. versicolor DYSJ3 exhibited strong antagonistic activity against Colletotrichum musae, C. gloeosporioides and Fusarium oxysporum f. sp. cubense with the inhibition rates of 61.9, 51.2 and 55.3% respectively. The antifungal metabolites mainly existed in the mycelium of A. versicolor DYSJ3, and its mycelial crude extract (CE) had broad-spectrum antifungal activities against plant pathogenic fungi. The CE had a good thermal stability, and the inhibition rate of 100 µg/mL CE against C. musae was above 70.0% after disposing at 120 °C for 1 h. Five secondary metabolites were isolated from the CE and identified as averufanin, ergosterol peroxide, versicolorin B, averythrin and sterigmatocystin. Activity evaluation showed versicolorin B exhibited inhibitory effects on the mycelial growth and conidial germination of C. musae, and sterigmatocystin had a weak inhibitory effect on the mycelial growth of C. musae.

Mycofumigation with the endophytic fungi Fusarium proliferatum (Matsushima) Nirenberg and Diaporthe sp. for the control of banana and mango anthracnose

Banana and mango are the top commodities in the Philippines that are traded worldwide however, fungal diseases such as anthracnose affect their yield and quality. Environmentally sound control strategies have been explored and one of these is mycofumigation using fungal endophytes. This alternative approach is understudied in the Philippines, hence, the study aimed to evaluate the mycofumigation potential of fungal endophytes collected from Mt. Makiling, Luzon, Philippines and their pathogenicity to banana and mango fruits. In vitro and in vivo mycofumigation assays were conducted with a completely randomized design layout with triplicates per treatment under laboratory conditions. The fungal endophytes used as mycofumigants, Diaporthe sp. and Fusarium proliferatum, were comparatively effective in controlling the anthracnose of banana and mango. The mycelial growth for in vitro assay of Colletotrichum musae and Colletotrichum gloeosporioides were significantly reduced compared to the control when exposed to volatile organic compounds produced by the fungal endophytes. In addition, the results of the in vivo mycofumigation assay against C. musae showed Diaporthe sp. had a significantly higher inhibition rate (93%) than F. proliferatum (67%) when grown on potato dextrose agar plates. The bioefficacy of the Diaporthe sp. and F. proliferatum was improved when grown on peanut and corn seed substrates with a reduction of banana and mango anthracnose severity ranging from 82 to 100%. Cultures grown on corn substrate performed better than those grown on peanut. Pathogenicity tests also revealed that these endophytic fungi did not cause disease in the banana or mango fruits indicating their potential as good biocontrol agents against C. musae and C. gloeosporioides.

Discovery of zeylenone from Uvaria grandiflora as a potential botanical fungicide.

Botanical pesticides play an important role in organic agricultural practices and are widely used in integrated pest management (IPM). Uvaria grandiflora was mainly reported as traditional medicines and possessed antibacterial, antioxidant, and antiprotozoal activities. Therefore, important biological activities of U. grandiflora may suggest that they have the potential to be used as botanical pesticides. The extract of U. grandiflora exhibited broad-spectrum inhibitory activity toward phytopathogenic fungi and oomycetes, particularly against Colletotrichum musae and Phytophthora capsici, and its secondary metabolite zeylenone also displayed strong antifungal and anti-oomycete activities against phytopathogens. Particularly, half maximal effective concentration (EC50 ) values of zeylenone against Phytophthora capsici and C. musae were 6.98 and 3.37 μg mL-1 , showing better inhibitory effects than those of commercial fungicides (azoxystrobin and osthole). Additionally, the pot experiments showed that the extract of U. grandiflora could effectively control Pseudoperonospora cubensis, Phytophthora infestans, Phytophthora capsici and Podosphaera xanthii. In the field experiment, 5% microemulsion of U. grandiflora extract exhibited 79.72% efficacy against cucumber powdery mildew at 87.5g ha-1 on the 14th day after two sprayings, which was better than that of 21.5% trifloxystrobin and 21.5% fluopyram SC at 200.9g ha-1 . Surprisingly, 5% microemulsion of U. grandiflora extract could promote cucumber growth significantly. Furthermore, the action mechanism analysis indicated that zeylenone may damage the cytoderm and affect energy metabolism of Phytophthora capsici. It is the first time that the extract of U. grandiflora and zeylenone have been discovered leading to broad application prospects in the development as botanical fungicides. © 2021 Society of Chemical Industry.

Antifungal effects of Conyza bonariensis (L.) Cronquist essential oil against pathogenic Colletotrichum musae and its incorporation in gum Arabic coating to reduce anthracnose development in banana during storage.

This study evaluated the inhibitory effects on mycelial growth and damage on membrane integrity and enzymatic activity caused by Conyza bonariensis essential oil (CBEO) on distinct pathogenic Colletotrichum musae isolates, as well as the preventive and curative effects of coatings with gum Arabic (GA) and CBEO to reduce anthracnose development in banana during room temperature storage. The effects of GA-CBEO coatings on some physicochemical parameters of banana were investigated during room temperature storage. CBEO (0.4-1μlml-1 ) inhibited the mycelial growth of C. musae isolates in laboratory media. The exposure of C. musae conidia to CBEO (0.6μlml-1 ) for 3 and 5days resulted in high percentages of conidia with damaged cytoplasmic membrane and without enzymatic activity. Coatings with GA (0.1mgml-1 ) and CBEO (0.4-1μlml-1 ) reduced the anthracnose development in banana artificially contaminated with C. musae during storage. In most cases, the disease severity indexes found for GA-CBEO-coated banana were lower than or similar to those for banana treated with commercial fungicide. GA-CBEO-coated banana had reduced alterations in physicochemical parameters during storage, indicating more prolonged storability. The application of GA-CBEO coatings is effective to delay the anthracnose development in banana during storage, which should help to reduce the amount of fungicides used to control postharvest diseases in this fruit. This is the first study showing the efficacy of coatings formulated with GA and CBEO to delay the development of anthracnose in banana, as well as to decrease alterations in physicochemical parameters indicative of postharvest quality of this fruit during storage. In a practical point of view, GA-CBEO coatings could be innovative strategies to delay the anthracnose development and postharvest losses in banana.

New diphenyl ethers from a fungus Epicoccum sorghinum L28 and their antifungal activity against phytopathogens

The strategy “IEMAHC” (Induction of Endophyte Metabolism by Adding Host Components) was applied to the fermentation of the endophytic fungus Epicoccum sorghinum L28 from Myoporum bontioides by introducing guaiol, an ingredient of M. bontioides, into the cultivation medium, which resulted in the purification of nine new diphenyl ethers, epicoccethers A–I (1–9). Their structures were determined by overall spectroscopic analysis. HPLC-MS analysis revealed that compounds 5–7 were products generated by induction of guaiol. Compounds 6 and 7 are the first members containing an ester moiety formed by the natural long-chain fatty acid and the hydroxyl group in the phenylmethanol unit of the diphenyl ether class. The antifungal activities of compounds 1, 2, and 4–7 against Fusarium oxysporum were 1, 1, 2, 1, 2 and 4 times as high as those of the positive control triadimefon, respectively. Compounds 4 and 5 showed 1.6 times the antifungal activities of triadimefon towards Colletotrichum musae.

Potential of Trichoderma piluliferum as a biocontrol agent of Colletotrichum musae in banana fruits

Bananas are among the most widely consumed fruits in the world and are produced in large quantities in tropical and subtropical areas. These fruits are affected by several postharvest diseases, such as anthracnose caused by C. musae. This disease is generally managed by the application of chemical fungicides, however, biological control has been recommended as an alternative method. The main goal of this research was to evaluate the antagonistic capacity of T. piluliferum against C. musae using in vitro and in vivo tests. T. piluliferum grew on the hyphae of C. musae and occupied the entire surface of the medium. Volatile and nonvolatile metabolites produced by T. piluliferum inhibited the mycelial growth of C. musae by 62% and 20%, respectively. T. piluliferum secreted the cell-wall degrading enzymes chitinase, N-acetyl-β-d-glucosaminidase, β-1,3-glucanase as well as proteases after growth on C. musae biomass. These enzymes damaged the cell wall structures of C. musae resulting in swollen and vacuolated hyphae. The metabolites reduced damage caused by C. musae in banana fruits compared with the results obtained with the fungicide Imazalil. The data showed that the time of application of metabolites is an important factor to consider when developing a product to prevent postharvest diseases in banana fruits.

A New Sesquiterpene Derivative from the Mangrove Endophytic Fungus Trichoderma harzianum (Strain No. R1)

A new sesquiterpene derivative, ethyl hydroheptelidate (1), was isolated from the mangrove endophytic fungus Trichoderma harzianum R1. Its structure was elucidated by comprehensive spectroscopic analyses. This compound showed high antifungal activity against two plant pathogenic fungi, Fusarium oxysporum and Colletotrichum musae, and moderate to weak antibacterial activity against three types of avian pathogenic Escherichia coli: O8, O78, and O101.

Synergistic effect of Aloe gel (Aloe vera L.) and Lemon (Citrus Limon L.) peel extract edible coating on shelf life and quality of banana (Musa spp.)

Short shelf-life of banana at ambient temperature is major concern in tropical regions because the temperature elevates the ripening related changes such as tissue softening, senescence, spotting on peel, off-odour and fungal disease mainly anthracnose. Here, this work is focused to evaluate the potential effect of Aloe gel (AG), lemon peel extract (LPE) and their combinations as edible coating treatment on postharvest quality and shelf-life of banana during storage at 23 ± 1 °C. Effectiveness of coating on banana was assessed by performing variety of physiochemical parameters namely weight loss, decay, disease severity, pH, acidity, soluble solids, sugars and ascorbic acid. Moreover, the antifungal efficacy of lemon peel extract was examined on the most disastrous fungus Colletotrichum musae causing anthracnose in banana. The treated fruits showed reduction in the rate of weight loss and decay of the fruits during storage. The breakdown of organic acids and accumulation of soluble solids were slower in bananas protected with edible coatings. Furthermore, the amount of ascorbic acid in banana was maintained in AG (50%) + LPE (15%) coated fruits during storage. Besides, the application of edible coating extends the banana shelf life up to 9 days with no disease incident. Thus, it indicates that the Aloe gel (AG) and lemon peel extract (LPE) constituted edible coating is an effective alternative to extend the shelf life and reduce the quality losses in banana rather than the use of hazardous fungicides and chemical preservatives.