[6][14] However, P. digitatum has also been isolated from other food sources. Mold reproduces and spreads via microscopic spores, thousands of which can fit onto a surface the size of a postage stamp. [1] Reports have been made concerning fungicides thiabendazole, benomyl, imazalil, sodium-o-phenylphenate as well as fungistatic agent, biphenyl, with no prior treatment required in the case of biphenyl. According to the USDA, soft fruits and vegetables with high moisture content, such as an orange, can be contaminated below the surface. [2], Infection with green mould at 25 °C (77 °F) can last 3 to 5 days with the rate of conidial production per infected fruit being as high as 1–2 billion conidia. 116 0 obj [1][2] In nature, it is often found alongside the fruits it infects, making species within the genus Citrus its main ecosystem. The minimum water activity required for growth at 25 °C (77 °F) is 0.90, at 37 °C (99 °F) is 0.95 and at 5 °C (41 °F) is 0.99. [1][13] The conidiophore is usually an asymmetrical, delicate structure with smooth, thin walls. BACKGROUND Fungal decay is a prevalent condition that mainly occurs during transportation of products to consumers (from harvest to consumption) and adversely affects postharvest operations and sales of citrus fruit. [15] Production of mycotoxins or secondary metabolites by P. digitatum has not been observed although this species has been shown to be toxic to both shrimp and chicken embryos. Previously, we have observed that citral dose-dependently inhibited the mycelial growth of P. digitatum, with the minimum inhibitory concentration (MIC) of 1.78 mg/mL, but the underlying molecular mechanism is barely understood. [19] This presence is suggested to be due to the intake of contaminated fruits and/or breathing air contaminated with extracellular polysaccharide. [14] During the reproductive stages of its life cycle, P. digitatum reproduces asexually via the production of asexual spores or conidia. [3] Being a wound pathogen, fruit injuries are required for successful fruit infections, with much of these injuries occurring due to improper handling throughout the harvesting process. [3] Post-harvest chemical treatment usually consists of washes conducted at 40–50 °C (104–122 °F), containing detergents, weak alkalines and fungicides. [15] The production observed in shake cultures can be inhibited by actinomycin D and cycloheximide and modulated by inorganic phosphate. [1] Latex agglutination detects Aspergillus and Penicillium species in foods by attaching antibodies specific for the extracellular polysaccharide of P. digitatum to 0.8 μm latex beads. Background. [22] In Australia, guazatine is commonly used although this treatment is restricted to the domestic market. No, you only see part of the mold on the surface of food — gray fur on forgotten bologna, fuzzy green dots on bread, white dust on Cheddar, coin-size velvety circles on fruits, and furry growth on the surface of jellies. [1] The media used are Czapek Yeast Extract Agar (at 5, 25 and 37 °C), Malt Extract Agar (at 25 °C) and 25% Glycerol Nitrate Agar (at 25 °C). Previously, we have observed that citral dose-dependently inhibited the mycelial growth of P. digitatum, with the minimum inhibitory concentration (MIC) of 1.78 mg/mL, but the underlying molecular mechanism is barely understood. [1] Molecular methods can also aid with identification. However, P. digitatum can also be cultivated in the laboratory setting. [1][2] The mechanism of P. digitatum resistance to imazalil is suggested to lie in the over-expression of the sterol 14α-demethylase (CYP51) protein caused by a 199 base-pair insertion into the promoter region of the CYP51 gene and/or by duplications of the CYP51 gene. [17][18] Spores, proteolytic enzymes and glycoproteins are amongst the components commonly reported as allergens in humans and animal models. Foot rot is common in citrus and leaves gummy lesions that will leave bark looking slimy and waterlogged. [3][7] As temperature at time of infection decreases, the delay of initial symptom onset increases. The most common postharvest fungal disease affecting citrus fruit worldwide is green mold, which is caused by Penicillium digitatum and accounts for up to 60–80% of the total fungal decay during fruit storage (Wuryatmo et al., 2014, Zheng et al., 2015). RIVKA BARKAI-GOLAN, in Postharvest Diseases of Fruits and Vegetables, 2001. [1] On 25% Glycerol Nitrate Agar at 25 °C, colony growth is planar yet develops into a think gel with colony size diameter ranging from 6–12 mm. xڭZY��~�_��TqS#�8xy_��XobW9�̓�v�8$F�C�Z����O7�A�䱓��` 4����h��D��/��~�H �n�P�Y&�7ioN��ʫ��_m�&M�Xś4��D%����Ë0�y�-��Ѿrø�7���{�O�{���E�9~�βT�R��+K��8��N�0Uj�]��o�^|�ȓM�L6��P2J7@j�yWm�o�}m^����|-#�i�+�!u��V�LR���Nc�r+�(���}q�7�@�Oƴ��]�T���*x|kJ�2���}і�'�[d��Xhb���Yþۙ�.�ᑺ�����Oc�Ӿ5}�8�y�[އ��T�ɏ/S�M���bo��<6 �Tرq�Y�Qa"X��6I��_���/0*��.���x�連����f��rᐮ���4 [1] The resulting colonial morphology on these media (described in Growth and Morphology above) allows for identification of P. digitatum. /Length 3985 Typically, strains are grown for one week on three chemically defined media under varying temperature conditions. [1][13] Each conidium is haploid and bears only one nucleus. [1] These include hazelnuts, pistachio nuts, kola nuts, black olives, rice, maize and meats. [3] The centre of the mycelial mass eventually turns olive as conidial production begins. [1] The back of the plate is described as pale or olive. It does not harm the tree, and you can wash it off the fruit. %���� [1][25][26], Penicillium digitatum can be identified in the laboratory using a variety of methods. >> Removing Green Mold. [3][7] Conidia often reside within soil but can also be found in the air of contaminated storage spaces. [1] GRAS substances such as sodium bicarbonate, sodium carbonate and ethanol, have displayed an ability to control P. digitatum by decreasing germination rate. Green Mold Post Harvest. Green-mold decay of citrus fruit de- velops at a rate proportional to the tem- perature of the rind. [1][23] During fruit decay, this species has been observed to make citric acid and gluconic acid and sequester ammonium ions into its cytoplasm. [2] This end result is commonly used to distinguish P. digitatum infections from those of P. italicum which produce a blue-green mould and ultimately render the fruit slimy. %PDF-1.5 Leaves, fruit and sometimes branches have a black, moldy appearance. [1] In comparison to other detection assays, the latex agglutionation assay exceeds the detection limit of the Enzyme-linked immunosorbent assay (ELISA) and is as effective in detecting Aspergillus and Pencillium species as the ergosterol production assay. [15] In addition, aminoethoxyvinyl glycine and methoxyvinyl glycine have been shown to inhibit both shake and static cultures. [7] Transmission can occur mechanically or via conidial dispersal in water or air to fruit surfaces. [1][23] In addition, P. digitatum has also been observed to modify plant defense mechanisms, such as phenylalanine ammonia lyase activity, in the citrus fruits it infects. [1] On Creatine Sucrose Agar at 25 °C, colony size diameter ranges from 4 to 10 mm. [16], Species within the genus Penicillium do not generally cause disease in humans. Decay fungi such as Alternaria rot or blue and green mold often invade wounded fruit. For example, P. digitatum has been observed to cause infection in unwounded fruits through mechanical transmission although a higher infection dose was required in such instances. [7][22] After infection at 24 °C, rapid growth ensues with active infection taking place within 48 hours and initial symptom onset occurring within 3 days. [1], "Penicillium digitatum. digitatum. Penicillium digitatum (/ˌpɛnɪˈsɪlɪəm/digitatum/) is a mesophilic fungus found in the soil of citrus-producing areas. The effective dose (ED 50) concentrations to inhibit the germination of P. digitatum spores of sodium carbonate (SC), potassium carbonate, sodium bicarbonate (SBC), ammonium bicarbonate, and potassium bicarbonate were 5.0, 6.2, 14.1, 16.4, and 33.4 mM, respectively. Green mold caused by Penicillium digitatumis the most damaging postharvest diseases of citrus fruit. [1] In terms of the export market, Generally recognized as safe (GRAS) substances are currently being explored as alternatives. [18] Within this context, members of Penicillium have been associated with a variety of immunological manifestations such as Type 1 allergic responses, hypersensitivity pneumonitis (Type 3 responses), and immediate and delayed asthma. [1][4][5]In nature, this necrotrophic wound pathogen grows in filaments and reproduces asexually through the production of conidiophores.