Effect of Pseudomonas sp. P7014 on the growth of edible mushroom Pleurotus eryngii in bottle culture for commercial production

Addition of bacterial culture strain P7014 and its supernatant to the mushroom growing media resulted in mushroom mycelia run faster. Mycelial growth rate of Pleurotus eryngii was increased up to 1.6 fold and primordial formation was induced one day earlier. Moreover, it was supposed that addition of bacteria had beneficial applications for commercial mushroom production, which appreciably reduced total number of days for cultivation of about 5+/-2 days compared with uninoculated, which took 55+/-2 days.     

Use of molecular markers for differentiation of cultivated strains of oyster and button mushrooms

Analysis of commercial strains of two edible mushrooms, Pleurotus ostreatus and Agaricus bisporus, using PCR and isozyme electrophoresis techniques allowed us to differentiate groups of genetically similar and distant strains. Among the commercial strains of P. ostreatus, the level of genetic variation was higher suggesting a broader genetic basis employed in breeding of this mushroom. The cultivars and hybrids of, A. bisporus, showed a higher level of homology. The isozyme markers (nonspecific esterase, leucinaminopeptidase, and phosphoglucoisomerase) are recommended for identification of the commercial strains of edible mushrooms.     

平菇类食用菌对农作物秸秆生物降解转化饲料的研究进展

综述了近年来国内外利用平菇类食用菌降解农作物秸秆的有关研究进展情况,主要包括限制秸秆饲料化的主要因素及提高秸秆饲料利用率的途径,平菇类食用菌降解秸秆的优势及其降解秸秆转化饲料的效果。并就笔者课题组近年来的研究总结了利用平菇类食用菌降解农作物秸秆的制约因素,以加快其应用于实际生产中。     

60Co-γ辐照在秀珍菇中的应用研究

采用不同剂量的^60 Co-γ射线辐照秀珍菇进行贮藏保鲜试验,结果表明：常温下210辐照,并采用聚乙烯塑料袋分装,可以延长鲜菇的保鲜期约10天。通过对维生素C和氨基酸含量的测定试验表明：辐处理前后无明显变化。辐照灭菌与常规高温灭菌相比,秀珍菇鲜菇产量高于对照。菌丝在经辐照灭菌的培养料上生长快,污染率下降,而且出菇快。     

Development of sporeless/low sporing strains of Pleurotus through mutation

Summary The sporophores of Pleurotus are gymnocarpous and continuously release spores in the atmosphere causing respiratory allergies like hay fever and farmer’s lung disease among workers. The allergy is caused by the antigens present on the walls of the spores. Apart from this, during commercial production, these spores settle on the fruit bodies, germinate and form a velvety film which gives an unpleasant appearance to the mushrooms. The spores emitted may include new genotypes likely to attack wood or trees. Spore allergy is one of the most important limiting factors for the large scale cultivation of this species. Different approaches are being adopted at IIHR for the production of commercial sporeless/low-sporing strains of Pleurotus to alleviate the spore allergy problem. Attempts were made during the present investigation to produce sporeless or low-sporing mutants through u.v. mutation. Mutation of the mycelium did not yield the desired results. Mutation of the spores of Pleurotus sajor-caju yielded an extremely low-sporing mutant after 75 min exposure. The character has been found to be stable for more than 10 generations of subculturing.     

Differentiation between Commercial Strains of Oyster and Button Mushrooms Using Molecular Markers

Analysis of commercial strains of two edible mushrooms, Pleurotus ostreatus and Agaricus bisporus, using PCR and isozyme electrophoresis techniques allowed us to differentiate groups of genetically similar and distant strains. Among the commercial strains of P. ostreatus, the level of genetic variation was higher suggesting a broader genetic basis employed in breeding of this mushroom. The cultivars and hybrids of A. bisporusshowed a higher level of homology. The isozyme markers (nonspecific esterase, leucinaminopeptidase, and phosphoglucoisomerase) are recommended for identification of the commercial strains of edible mushrooms.     

Mapping of genomic regions (quantitative trait loci) controlling production and quality in industrial cultures of the edible basidiomycete Pleurotus ostreatus

Industrial production of the edible basidiomycete Pleurotus ostreatus (oyster mushroom) is based on a solid fermentation process in which a limited number of selected strains are used. Optimization of industrial mushroom production depends on improving the culture process and breeding new strains with higher yields and productivities. Traditionally, fungal breeding has been carried out by an empirical trial and error process. In this study, we used a different approach by mapping quantitative trait loci (QTLs) controlling culture production and quality within the framework of the genetic linkage map of P. ostreatus. Ten production traits and four quality traits were studied and mapped. The production QTLs identified explain nearly one-half of the production variation. More interestingly, a single QTL mapping to the highly polymorphic chromosome VII appears to be involved in control of all the productivity traits studied. Quality QTLs appear to be scattered across the genome and to have less effect on the variation of the corresponding traits. Moreover, some of the new hybrid strains constructed in the course of our experiments had production or quality values higher than those of the parents or other commercial strains. This approach opens the possibility of marker-assisted selection and breeding of new industrial strains of this fungus.     

Influence of spawn rate and commercial delayed release nutrient levels on Pleurotus cornucopiae (oyster mushroom) yield, size, and time to production

Pleurotus cornucopiae 608 was grown on a mixture of pasteurized cottonseed hulls (75% dry wt). 24% chopped wheat straw, and 1% ground limestone. The substrate was spawned at various levels (1.25%, 2.5%, 3.75%, or 5% wet wt) and not supplemented or supplemented with commercial delayed release nutrient (Campbell's S-41) at various levels (0%, 3%, 6%, 9%, or 12%). Maximum yield (weight of fresh mushrooms harvested at maturity) was obtained at 3.75-5% spawn level and 6% S-41 supplement. As supplement levels exceeded 6%, yields declined significantly. There was a negative correlation (r=-0.81) between spawn rate and days to production. As the spawn rate increased, the number of days to production decreased. By using a spawn rate of 3.75% of the wet substrate wt, it was possible to reduce the time to production by a mean of 9.2 days compared with a spawn rate of 1.25%.     

Yellow Blotch of Pleurotus ostreatus

Yellow blotch disease of the oyster mushroom (Pleurotus ostreatus) was first observed in a commercial mushroom farm in California in 1983. The disease, caused by Pseudomonas agarici, is characterized by primordia, with yellow droplets on their surface, which become stunted, yellow to orange, and deformed as they mature.     

Studies on genus Pleurotus. VIII. Interaction between mycelial growth and yield

This project studies the relationship between mycelial growth rate and production of basidiomata of 19 Pleurotus strains. Firstly, monosporic cultures were isolated of five strains from the following species: Pleurotus djamor (3), Pleurotus ostreatus (1) and Pleurotus pulmonarius (1). These were self-crossed in order to obtain 25 infraspecific dikaryons from which their mycelial growth rate was estimated. The parent strains and the 14 fastest growing crosses were cultivated in the pilot plant on barley straw with the following data recorded: days of incubation, primordia initiation, number of harvests, biological efficiency (BE), production rates (PR) and size of the basidiomes. The BE's fluctuated between 16.8 to 75.6% and the PR's between 0.34 to 1.68%. Most of the basidiomata presented a pileus diameter of 5-15 cm. With the exception of one cross with P. djamor, no increase was observed in the productivity and size of the carphophores of the crosses with respect to the parent strains, suggesting that the rapid mycelial growth rate of the strains was not reflected in the development of the fruiting bodies.     

Bioconversion of agricultural lignocellulosic wastes through the cultivation of the edible mushrooms Agrocybe aegerita,Volvariella volvacea and Pleurotus spp.

Ten selected wild and commercial strains of Pleurotus ostreatus,Pleurotus eryngii,Pleurotus pulmonarius, Agrocybe aegerita andVolvariella volvacea were cultivated on three agricultural wastes, i.e. wheat straw (WS), cotton waste (CW) and peanut shells (PS). All species demonstrated significantly higher colonization rates on WS and CW than on PS. WS supported faster growth of A. aegerita and Pleurotus spp., whereas V. volvacea performed better on CW. Comparison of growth rates on composted and non-composted WS and CW substrates revealed that in the latter case faster colonization was achieved, particularly for Pleurotus spp. However, one commercial strain of V. volvacea presented higher growth rates when the composted CW medium was used. Furthermore, earliness in the fructification of P. ostreatus, P. pulmonarius and V. volvacea strains was promoted in CW substrates, while WS favoured earliness of P. eryngii and A. aegerita. Similarly, high sporophore yields were obtained by P. ostreatus and P. pulmonarius on both wastes, whereas WS enhanced yield and basidioma size of P. eryngii and A. aegerita strains and CW production of V. volvacea. The substrates cellulose:lignin ratios were found to be positively correlated to mycelial growth rates and to mushroom yield of P. ostreatus and P. pulmonarius; in addition, positive correlation was also detected for carbon:nitrogen ratio and mushroom yield in P. eryngii and A. aegerita and between cellulose content and mushroom yield for V. volvacea strains.     

Mapping of Genomic Regions (Quantitative Trait Loci) Controlling Production and Quality in Industrial Cultures of the Edible Basidiomycete Pleurotus ostreatus

Industrial production of the edible basidiomycete Pleurotus ostreatus (oyster mushroom) is based on a solid fermentation process in which a limited number of selected strains are used. Optimization of industrial mushroom production depends on improving the culture process and breeding new strains with higher yields and productivities. Traditionally, fungal breeding has been carried out by an empirical trial and error process. In this study, we used a different approach by mapping quantitative trait loci (QTLs) controlling culture production and quality within the framework of the genetic linkage map of P. ostreatus. Ten production traits and four quality traits were studied and mapped. The production QTLs identified explain nearly one-half of the production variation. More interestingly, a single QTL mapping to the highly polymorphic chromosome VII appears to be involved in control of all the productivity traits studied. Quality QTLs appear to be scattered across the genome and to have less effect on the variation of the corresponding traits. Moreover, some of the new hybrid strains constructed in the course of our experiments had production or quality values higher than those of the parents or other commercial strains. This approach opens the possibility of marker-assisted selection and breeding of new industrial strains of this fungus.     

Molecular tools for breeding basidiomycetes.

The industrial production of edible basidiomycetes is increasing every year as a response to the increasing public demand of them because of their nutritional properties. About a dozen of fungal species can be currently produced for food with sound industrial and economic bases. Notwithstanding, this production is threatened by biotic and abiotic factors that make it necessary to improve the fungal strains currently used in industry. Breeding of edible basidiomycetes, however, has been mainly empirical and slow since the genetic tools useful in the selection of the new genetic material to be introduced in the commercial strains have not been developed for these fungi as it was for other organisms. In this review we will discuss the main genetic factors that should be considered to develop breeding approaches and tools for higher basidiomycetes. These factors are (i) the genetic system controlling fungal mating; (ii) the genomic structure and organisation of these fungi; and (iii) the identification of genes involved in the control of quantitative traits. We will discuss the weight of these factors using the oyster mushroom Pleurotus ostreatus as a model organism for most of the edible fungi cultivated industrially.     

白腐菌液体和固体培养产生木质纤维素降解酶的比较研究

侧耳sp2(Pleurotus sp．2)和粗毛栓菌(Trametes gallica)是产木质纤维素降解酶能力强,且产酶较快的菌株。对其在液体培养基、固体培养基中产生木质纤维素降解酶能力和行为进行了比较分析和研究。结果表明,Pleurotus sp．2在低氮高碳高无机盐培养基中的锰过氧化物酶(Manganese peroxidases, MnPs)、木质素过氧化物酶(Lignin peroxidases．LiPs)、漆酶(laccases,Lacs)和半纤维素酶(Hemicellulases, Hcels)的活性最高。当该菌株培养在含有低氮无碳高无机盐液体培养基的麦草粉中时,MnPs和Lacs的活性峰值均出现在10d,而Hcels的活性在40d时达到峰值。Trametes gallica在高氮低碳高无机盐培养基中的Lacs和LiPs的活性最高,在低氮高碳高无机盐培养基中的MnPs和Hcels的活性最高。当该菌株培养在含有高氮无碳高无机盐和低氮无碳高无机盐液体培养基的麦草粉中时,MnPs存10d、Lacs和Hcels在40d、LiPs存50d,分别达到峰值。Pleurotus sp．2和Trametes gallica在液体培养基中具有很强的木质纤维素降解酶产生能力且产酶速度较快,在固体培养基中具有很强的降解麦秸生物质能力,但这两株菌在液体和固体培养基中,产木质纤维素降解酶的能力和行为都有较大的差异,相关性小。     

Influence of formaldehyde-treated soybean and commercial nutrient supplementation on mushroom (Pleurotus sajor-caju) yield and in-vitro dry matter digestibility of spent substrate

Summary Pleurotus sajor-caju 537 was grown on chopped, pasteurized wheat straw non-supplemented and supplemented with formaldehyde-treated soybean, commercial delayed-release nutrient (SpawnMate II SE) or vegetable oil. Yield was 2.1-fold higher for substrate supplemented (12% dry wt) with low-volume formaldehyde-treated soybean as compared to non-supplemented substrate. Mushroom yield from substrate supplemented with commercial nutrient was 1.7-fold higher than yield from non-supplemented substrate. As the supplement level increased, the mushroom yield response increased. The yield ranged from 3.56 kg/m² for non-supplemented substrate to 7.36 kg/m² for substrate supplemented (12% dry wt) with formaldehyde-treated soybean. The type of supplement affected in vitro dry matter digestibility (IVDMD) of spent substrate; commercial supplement resulted in higher IVDMD compared to formaldehyde-treated substrate. An opportunity exists for commercial development of a nutrient(s) specifically designed for Pleurotus cultivation.     

Laccase isoenzymes of Pleurotus eryngii: characterization, catalytic properties, and participation in activation of molecular oxygen and Mn2+ oxidation.

Two laccase isoenzymes produced by Pleurotus eryngii were purified to electrophoretic homogeneity (42- and 43-fold) with an overall yield of 56.3%. Laccases I and II from this fungus are monomeric glycoproteins with 7 and 1% carbohydrate content, molecular masses (by sodium dodecyl sulfate-polyacrylamide gel electrophoresis) of 65 and 61 kDa, and pIs of 4.1 and 4.2, respectively. The highest rate of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) oxidation for laccase I was reached at 65 degrees C and pH 4, and that for laccase II was reached at 55 degrees C and pH 3.5. Both isoenzymes are stable at high pH, retaining 60 to 70% activity after 24 h from pH 8 to 12. Their amino acid compositions and N-terminal sequences were determined, the latter strongly differing from those of laccases of other basidiomycetes. Antibodies against laccase I reacted with laccase II, as well as with laccases from Pleurotus ostreatus, Pleurotus pulmonarius, and Pleurotus floridanus. Different hydroxy- and methoxy-substituted phenols and aromatic amines were oxidized by the two laccase isoenzymes from P. eryngii, and the influence of the nature, number, and disposition of aromatic-ring substituents on kinetic constants is discussed. Although both isoenzymes presented similar substrate affinities, the maximum rates of reactions catalyzed by laccase I were higher than those of laccase II. In reactions with hydroquinones, semiquinones produced by laccase isoenzymes were in part converted into quinones via autoxidation. The superoxide anion radical produced in the latter reaction dismutated, producing hydrogen peroxide. In the presence of manganous ion, the superoxide union was reduced to hydrogen peroxide with the concomitant production of manganic ion. These results confirmed that laccase in the presence of hydroquinones can participate in the production of both reduced oxygen species and manganic ions.     

Identification of mating type loci and development of SCAR marker genetically linked to the B3 locus in Pleurotus eryngii

In order to estimate how diverse the mating types in Pleurotus eryngii from different regions are, pairings between monokaryons derived from inter- and intragroups were done. Sixteen and 15 alleles were identified at loci A and B from the 12 strains. In the P. eryngii KNR2312, widely used for commercial production, four mating loci, A3, A4, B3, and B4, were determined. Those loci, except A3, were found in 4 strains out of 12 strains. To improve breeding efficiency, especially in mating type determination, RAPD and BSA were performed to screen for a mating type specific marker. The SCAR marker 13- 2(2100) was developed based on the RAPD-derived sequence typing B3 locus. The sequence analysis of 13-2(2100) revealed that it contained a conserved domain, the STE3 superfamily, and consensus sequences like the TATA box and GC box. It seems likely that the SCAR marker region is a part of the pheromone receptor gene.     

Liquid chromatographic and electrophoretic characterisation of extracellular beta-glucosidase of Pleurotus ostreatus grown in organic waste

The production of beta-glucosidase by the ligninolytic fungus Pleurotus ostreatus has been studied in different culture media containing agro-industrial wastes. The enzyme is purified by anion-exchange chromatography, the molecular mass and isoelectric point of purified beta-glucosidase are measured by sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and isoelectric focusing and the stability and kinetic parameters of the enzyme assessed by spectrophotometry. It has been established that the retention time, molecular mass and isoelectric point of the enzyme depend on the composition of the culture media while the activity and stability of beta-glucosidases of different origin were very similar. The combined chromatographic and electrophoretic methods have proved to be suitable techniques for the purification and characterisation of the beta-glucosidases produced by the ligninolytic fungus Pleurotus ostreatus in different culture media.     

Improvement of yield of Pleurotus eryngii var. eryngii by substrate supplementation and use of a casing overlay

Improved yield and biological efficiency (BE) of Pleurotus eryngii var. eryngii were achieved by supplementation of substrate with a commercial delayed-release nutrient and use of a casing overlay. Yield increases of 14% were achieved from cased substrates that were supplemented at time of casing with delayed-release nutrient (Remo’s). Use of a casing layer enhanced yield by 141% over non-cased substrates. When casing and substrate supplementation were combined, yield increased 179% over non-cased/non-supplemented substrates. Mushrooms harvested from cased substrates were darker in color and solids contents were lower compared to non-cased substrates. An additional break of mushrooms was harvested from non-cased “spent” substrate by fragmenting and re-supplementing the substrate prior to the application of a casing overlay. Three production methods were compared for their effect on mushroom yield: “standard”, “casing” and “casing after first break”. Casing of the substrate before first break (“casing” production method) resulted in the highest yield and biological efficiency.     

新疆阿魏菇与杏鲍菇中氨基酸含量的分析研究

对新疆阿魏菇与杏鲍菇的氨基酸成分进行系统分析,结果显示新疆本地的阿魏菇和杏鲍菇中17种氨基酸含量丰富,种类齐全,阿魏菇中氨基酸总量为16.80%高于杏鲍菇中氨基酸总量(14.34%);两种菇中必需氨基酸含量(EAA)占总氨基酸含量的比例分别为34.72%和37.92%。新疆阿魏菇与杏鲍菇种富含人体必需的氨基酸,可作为饮食氨基酸来源的重要补充。