Mojtaba Lotfi; Mohammad Farsi; Amin Mirshamsi Kakhki; Javad Janpoor
Abstract
Introduction: Because of their high protein and mineral contents and low fat, calories and cholesterol, edible mushrooms such as Agaricus bisporus are an important part of the people diet in many countries, but in Iran, the yield of this mushroom is less than the average of yield in the world. Phase ...
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Introduction: Because of their high protein and mineral contents and low fat, calories and cholesterol, edible mushrooms such as Agaricus bisporus are an important part of the people diet in many countries, but in Iran, the yield of this mushroom is less than the average of yield in the world. Phase change from the vegetative to the reproductive stage and fruit body initiation of this mushroom depends on special physical, chemical and microbial properties of casing layer. Phase change is initiated by decreasing oftemperature and CO2 concentration and presence of some bacteria (such as Pseudomonas putida) in the casing layer. It is believed that P. putida may cause this process and increase the yield of A. bisporus by siderophore and hormone-like compounds secretion, decreasing the level of ethylene via ACC deaminase activity and dissolution of insoluble phosphate. The objective of this work was to identify P. putida isolates as growthpromoting bacteria isolated from A.bisporus casing soil and to evaluate their effect on mushroom yield.
Materials and Methods: In this study, 81 individual bacterial isolates were collected by screening the casing layer of 6 edible mushroom farms. Luria Bertani (LB) medium supplemented with sodium lauroyl sarcosine (SLS) and trimethoprim were used for isolation of Pseudomonas bacteria by plating serial dilutions of each soil sample. Finally, using species-specific primers, 33 isolates that identified as P. putida were selected and were used toinoculate
A. bisporuscasing layer. Inoculations were performed in a completely-randomized design with two replicates. The harvesting began when buttons were fully-grown (but not yet open), and the number of mushrooms and fresh (wet) weight of them were recorded after harvesting of each flush. In the next experiment IAA and siderophore production ability, ACC deaminase production capacity and ability of dissolving of insoluble phosphate in isolates and the correlation between these factors and number and fresh weight of mushroom were evaluated. Analysis of the data was carried out using JMP 8. Means were compared using Tukey’s test at p≤0.05.
Results and Discussion: The results of this study showed that the best stage for collecting P. putida is pinning, because the maximum number of identifiedP. putidawas recorded at this stage.Field experiment showed that different isolates have a significant effect on fresh weight and the number of mushrooms per kg compost compared to control (p≤0.05), so that the highest fresh weight observed in treatment of P27 and P13 isolates with 361.63 and 342.8 gr/kg compost respectively and the highest number of mushroom observed in treatment of P18 and P24 isolates with 21 and 20.83 mushroom per kg of compost,respectively. Interestingly, in this study, some isolates showed negative or no effect on mushroom yield which could be due to the interaction between bacteria and A. bisporus strain and/or complex conditions of casing layer. Other results showed that there is a positive and significant correlation between IAA production ability in P. putidaand fresh weight (r=0.58) and the number of mushrooms (r=0.50) in A. bisporus.Whereas there was no significant correlation between other factors and fresh weight and the number of mushrooms. IAA through promotion of cell elongation and differentiation increased mushroom growth and protein.This hormone is one of the needs of A.bisporus mushroom and it is very effective in growth and caused an increase in mushroom yield compared to other growth promoting factors.
Conclusions: In the present study, with the aim of investigation of the effect of P. putida on the yield of
A. bisporus and determining the most effective factor in this process, collectedisolatesinoculated to A. bisporuscasing layer and growth promoting factors in these isolates were evaluated. Results showed that the best stage for collecting P. putida is pinning. These bacteria havesignificant effects on fresh weight and the number of mushrooms.There is not significant correlation between other factors and fresh weight and the number of mushrooms. Based on the results, it could be said that the use of growth promoting bacteria in edible mushroom culturing could be resulted anincrease in mushroom yield and could be beneficial in production of healthy food. Finally, it could be said that P. putida isolates P27 and P13 may have the potential to act as a potential bio-fertilizer.
Rasoul Rahmanipoor; Reza Sadrabadi Haghighi; Javad Janpoor
Abstract
Introduction: Today, due to increasing world population, food needs to be provided from different ways. The white button mushroom has also become an important constituent of a healthy diet. Their nutritional value relies on relatively high protein, minerals, vitamins, essential amino acids content and ...
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Introduction: Today, due to increasing world population, food needs to be provided from different ways. The white button mushroom has also become an important constituent of a healthy diet. Their nutritional value relies on relatively high protein, minerals, vitamins, essential amino acids content and low calories. Mushroom mycelia growth and mushroom development are not only related to genetic factors but also depends on environmental, chemical, and microbiological conditions. Casing soil can protect the compost against desiccation, supporting the mushroom against pests and diseases and providing sporophores development and development and growth of mushroom by gas exchange. Casing layer provides an environmental change in which the mushroom shifts from a vegetative stage to a reproductive one due to microorganisms in the casing soil. Casing soil bacteria influence productivity, product quality and uniformity. Physical and chemical properties of a good casing should be high porosity and water holding capacity (WHC), pH range from 7.2 to8.2, low content of soluble inorganic and organic nutrients and free of disease and pests. Many materials, alone or in combination, have been used as casing both commercially and experimentally, although only a few have been shown to be practical application. Peat is generally regarded as the most suitable casing. Because of its unique water holding and structural properties, it is widely accepted as ideal for the purposes of casing. Peats has a neutral pH and because of it contains organic matter and granular structure can stay porous even after a consecutive irrigation, hold moisture, allows appropriate gaseous exchanges and supports microbial population to release hormone-like substances which are very likely involved in stimulating the initiation of fruit bodies. Peat and limestone commonly used as a casing soil, however problems associated with its use, especially viability, depletion of reserves and alteration of ecosystems, have led to the search for alternative materials.
Materials and Methods: In order to investigate the effect of different compositions of casing soil on the white button mushroom (Agaricus bisporus Longe) cultivation, an experiment was carried out in laboratory of mushroom research, Department of Industrial Fungi Biotechnology, Iranian Academic Center for Education, Culture and Research (ACECR- Khorasan Razavi), in 2015. The experiment was conducted in a completely randomized design with 8 treatments and 3 replications. The treatments were including peat soil (100%), peat soil (60%) + vermicompost (40%), peat soil (60%) + cocopeat (40%), peat soil (60%) + activated carbon (40%), peat soil (60%) + spent mushroom compost (40%), peat soil (60%) + vermicompost (30%) + activated carbon (10%), peat soil (60%) + cocopeat (30%) + activated carbon (10%), peat soil (60%) + spent mushroom compost (30%) + activated carbon(10%). The treatments were applied on the compost block (40 × 60 × 20 cm sizes), that inoculated with the mushroom spawn, commercial line A15. The investigated characteristics including mushrooms yield, mean of mushroom weight, number of mushrooms per square meter, mean of stipe length, mean of cape diameter, which was measured in each harvest flash, separately. The traits were measured three times from casing to first harvest flash and harvest period.
Results and Discussion: The results showed that the longest duration between casing to first flashing belonged to peat soil (60%) + spent mushroom compost (40%). The lowest duration belonged to peat soil (60%) + cocopeat(40%), peat soil (60%) + activated carbon (40%) and peat soil (60%) + cocopeat (30%) + activated carbon (10%). Treatments with the lowest duration between casing to first harvest flash, produced the most yield. The results also revealed that casing soils treatments contained cocopeat(40%) and cocopeat(30%) + active carbon(10%) had the highest yield, fruit number, fruiting period and shortest duration from casing to first harvest flash as a good characteristic, although the mean of mushrooms weight and diameter of cape were lower than other treatments that it affect on marketing quality. Two treatments including spent mushroom compost (40%) and spent mushroom compost (30%) + active carbon(10%), had the lowest yield, fruit number, fruiting duration, the longest duration between casing to first harvest flash as an unfavorable characteristic, although these treatments had the highest mean weight and cape diameter. Overall, the results showed that spent mushroom compost utilization as casing soil is not economically cost-effective.
Javad Janpoor; Mohammad Farsi; Fatemeh Gholizade; Hamid Reza Pourianfar; Sharareh Rezaeian
Abstract
Introduction: King oyster mushroom (Pleurotus eryngii) belongs to Basidiomycota division, Agaricomycetes class and Pleurotaceae family. This mushroom generally grows on wood wastes of Apiaceae family. The Pleurotus eryngii is found in pastures, meadows, gardens and seldom in grassy forest clearings and ...
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Introduction: King oyster mushroom (Pleurotus eryngii) belongs to Basidiomycota division, Agaricomycetes class and Pleurotaceae family. This mushroom generally grows on wood wastes of Apiaceae family. The Pleurotus eryngii is found in pastures, meadows, gardens and seldom in grassy forest clearings and hilly areas. The Pleurotus of the Umbellifers occupy an area in the Northern hemisphere between the 30 and 50º N. These species are mainly found in the subtropical regions of the Mediterranean, Central Europe, Russia, Ukraine, Central Asia and Iran. The P. eryngii sensulato is the only taxon within the genus, which grows in association with plants. P. eryngii has distinguishable characteristics such as coherent texture, unique form, favorable taste and high durability. Mushroom cultivation represents the only current economically viable biotechnology process for the conversion of waste plant residues from forests and agriculture. The species of these genera show much diversity in their adaptation the varying agro-climatic condition which makes more cultivated species than other mushrooms. Special ability of Pleurotus family is growing in lingocellulosic plant or agricultural wastes without needing to prepared compost and casing soil. Pleurotus is an efficient lignin- degrading mushroom and can grow and yield well on different types of lignocellulolosic materials. Type of substrates for mushroom growing depends on available plant or agricultural wastes. In Europe, wheat straw is used for mushroom growing; whereas in Asian South-East countries sawdust is more popular. Different materials for cultivating of P. eryngii have been suggested in different regions of the world; but a few studies have been done on suitability of various lignocellulosic affordable wastes for P. eryngii production in Iran. Therefore, the current study aims to evaluate effects of various locally available agro wastes on the growth characteristics of King oyster mushroom (P. eryngii).
Materials and Methods: Sawdust was utilized as the main substrate obtained from beech and populous trees (1:1). After being rinsed off in water and supplemented with calcium sulfate (3%) and calcium carbonate (3%), the substrate was filled in 20 × 40 cm polyethylene bags weighted to 800 grams. Sterilization was performed at 121 °C under pressure of 1.5 bars for two hours. A cultivated P. eryngii strain was then inoculated in the cooled material at a rate of 3% of dry/fresh substrate. The experiments were conducted based on a completely randomized design with five treatments and four replications, measuring mycelial growth (MG), number of fruiting bodies (NFB), mushroom weight, and biological efficiency (BE). AMG was measured in both test tubes and in petri plates in different pH levels (5.5, 7, and 8.5). Data were analyzed by JAMP 4.0, while graphs were drawn by Microsoft Excel 2007 and SigmaPlot 12.0 software.
Results and Discussion: The pH of 7 was found to be the best for obtaining maximal MG under all treatments after seven days. The highest amount of MG was obtained with substrate No. 1, while the least was observed in the culture of substrate No. 5. The substrates No. 1 and No. 5 generated the highest and lowest NFBs (p≤0.05). However, there was no significant difference (p≥0.05) in NFB between substrates No. 1 and 3 or between substrates No. 2, 4 and 5. The BE percentages obtained from experimental treatments No. 1, 2, 3, 4, and 5 were 64.81, 49.74, 59.22, 28.72, and 19.8, respectively. The comparison of means of different growth characteristics revealed that there was no significant difference between substrates No. 1 and 3 or between substrates No. 4 and 5 (p≥0.05).
Conclusion: In this time, only two species (Agaricus bisporus and P. ostreatus) are producing in Iran, whereas at least 10 species of edible mushrooms are cultivating in the world. King oyster mushroom has low cost of production and distinguishable characteristics. Therefore, this mushroom can be use as alternative for button mushroom (A. bisporus). Many kind of agricultural wastes are in use for mushroom cultivation. Understanding the effects of substrate materials on mushroom production will be very valuable. The average number of fruits and biological efficiency of treatment No.1 showed significant difference with other treatments. Hence, the treatment No. 1 could be used for commercial production of King oyster mushrooms in Iran. Growth rate of P. eryngii was very diverse, in respect to the determinate values of the environmental factors. On the basis of the average growth rate of the strains, we could conclude what are the optimum ecological values of the species, though these conclusions did not always coincide with the optimum values of the certain strains. However, more research needs to be done to obtain regular and homogeneous supply of this mushroom.
Marzieh Nourashrafeddin; Mohammad Farsi; Farajollah Shahriari; Javad Janpoor
Abstract
Introduction: Edible white button mushroom (Agaricusbisporus) is the most common edible mushroom in Iran and the world. The yield of this mushroom is less than the average of yield in the world because of strain degeneration and using strains with low yield. Most of the current hybrids are either identical ...
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Introduction: Edible white button mushroom (Agaricusbisporus) is the most common edible mushroom in Iran and the world. The yield of this mushroom is less than the average of yield in the world because of strain degeneration and using strains with low yield. Most of the current hybrids are either identical or very similar to the first hybrids. Ongoing breeding programs are exploiting the variability in Agaricus germplasm to produce new varieties with better traits including higher yield and resistance to biotic and abiotic stresses. One of the breeding programs is F1 production from parental homokaryons crossing. These homokaryonsis were isolated among germinated basidiospores on the culture media. During the last decades, various molecular markers based on nucleic acid polymorphisms (such as Restriction Fragment Length Polymorphism, Random Amplification of Polymorphic DNA, Amplified fragment of Length Polymorphism, Inter Simple Sequence Repeat, Simple Sequence Repeat markers) have been used to differentiate homokaryons and heterokaryons. Microsatellites consist of short tandem repeat motifs distributed throughout the genome. Microsatellites are usually highly polymorphic due to a high degree of variation in the number of repeats among individuals. Microsatellite markers are multiallelic and co-dominant and thus tend to be more informative than other marker systems. Microsatellite markers have been widely developed in animals and plants and more recently in fungal species. The presence of microsatellites in the genome of A. bisporus was previously reported.
Materials and Methods: In this research, 160 germinated basidiospores were collected from commercially cultivated strain A15 and they were grown on compost extract agar (CEA). The mycelial growth rate of these160 isolates was evaluated at 25°C on CEA medium. 18 isolates with slow growing rate were selected from 160 isolates. In the next step, co-dominant SSR markers were used to homokaryons detection. Ten SSR primers showed polymorphism in parental control samples that were used to this experiment. The isolates were divided into two general homoallelic and heteroallelic groups and seven isolates from homoallellic group, which showed one-band pattern, characterized as putative homokaryon. Genetic similarity was calculated by NTSYSpc software version 2.02 e using UPGMA method. In the next step of experiment, the isolates (4 and 8) had minimum genetic similarity that was crossed to produce hybrid. In order to confirm the hybrid formation, PCR-SSR reaction with a primer (AbSSR 45) was performed.
Results and Discussions: Basidiospores were collected and allowed to germinate on CEA medium. Putative homokaryons were different in colony morphology and growth rate compared to the original heterokaryons. Mycelium samples showed different colony morphology including tomentose, apprised and strandy mycelium. Different growth rate can be affected by genetic factors in nucleus and mitoconderia. After four weeks, mycelium browning was appeared in liquid compost extract medium and created a disturbance in DNA extraction. To solve this problem, DNA was extracted from three-week old mycelium. Mycelium browning may cause by phenolic compounds produced by mycelium and enzymes that catalyze melanin biosynthesis reactions. Ten primers were used to homokaryon isolation. These primers were situated on the 9 linkage groups of 13 haploid chromosomes. Seven isolates were distinguished as putative homokaryon that showed one-band in all primers on the gel electrophoresis. The results of genetic similarity calculation showed that this index was variable between 0.17 to 0.67in 7 homokaryon isolates and the minimum genetic similarity (0.17) was observed between isolates 4 and 8. These two isolates were crossed and the result of this crossing was N1 hybrid. Also, other homokaryon isolates were crossed and mating incompatibility was observed in some of them. According to these observations, it is suggested that in future studies, in addition to genetic similarity, sexual incompatibility should also be considered. Hybrid N1 produced aerial mycelium and had higher growth rate in comparison to parental homokaryons and similar to heterokaryon control, had two-bands pattern. This two bands pattern indicates the presence of two non-sister nucleuse in each cells. Finally, the results showed that SSR marker can result to accurate detection of homokaryons.
Conclusions: The aim of the present study was screening homokaryon isolates of A.bisporus using SSR markers to obtain hybrid. Results showed that growth rate of homokaryon isolates were lower than the heterokaryons. Since, SSR markers were able to show high polymorphism in the isolates, thus it can be said that these markers are suitable to homokaryon screening. Final result of this study is N1 hybrid that can compare to commercially cultivated strains.
