Progress 10/01/02 to 09/30/07
Outputs
OUTPUTS: Approximately 40% of the resources of this project were allocated to genetic research. Non-genetic resources research (e.g. cultural, physiological, pest management and engineering research) accounted for the remainder of the commitment. We have demonstrated that it is possible to obtain reasonably high yields of brown Agaricus bisporus on non-composted substrate (NCS) and mixtures of NCS/"spent" mushroom compost (SMC) following the additions of either organic or inorganic supplements at spawning or at casing. For shiitake, we determined that ground wheat straw could replace a portion of the oak sawdust used in shiitake production substrate formulae. Based on relative feed value (RFV), we predicted that spent shiitake substrate from wheat straw-amended substrate would be a good as corn silage (RFV=133) and better than alfalfa (RFV=100%, harvested at full bloom) for ruminant feed. We also showed that L-ergothioneine (ERGO), a powerful antioxidant, might be a stress metabolite
in A. bisporus because it increased in basidiomata with flush in the crop cycle. Also, by breaking up the mycelial network in the compost before casing or by the use of drier compost, the ERGO content increased. In pathology-related studies, we evaluated identified resistance in strains of Pleurotus eryngii to bacterial blotch (Pseudomonas tolaasii). Additional research was carried out with the purpose of providing Agaric mushroom growers with safe and effective disease management alternatives that would serve to increase environmental compliance, improve worker safety, and enhance the wholesomeness of the end product. Here, biorational fungicides were evaluated for activity against the two major fungal maladies on A. bisporus, Trichoderma green mold and Verticillium dry bubble. Of the various biofungicides screened, a certified organic bacterial formulation (Bacillus sp.) effectively controlled Trichoderma green mold disease caused by the highly pathogenic genotype, Trichoderma
aggressivum f. aggressivum (Ta2). Treating the spawn with the bacterial biofungicide provided complete control under high disease pressures (74-83% crop loss in the non-treated control) and without overt toxicity to A. bisporus. Continuing studies with this biocontrol product will focus on optimizing its rate as a spawn treatment, more fully evaluating its possible toxic side effects, and determining its efficacy as a supplement treatment. None of the biorational products evaluated in this investigation was effective for Verticillium dry bubble disease. In other pathology studies, the efficacy of the fungicide, imazalil sulfate, was evaluated for the control of green mold disease caused by Ta2 on A. bisporus. The results of a series full-scale cropping trials indicated that highly effective control of green mold can be achieved by treating each the spawn (1600 units) and the supplement (909 kg) with 0.45 kg imazalil sulfate. This fungicide also was effective in controlling Ta2 in the
casing layer though aqueous applications during crop management.
PARTICIPANTS: Project co-leaders included Daniel J. Royse and C. Peter Romaine, professors of plant pathology. Interdepartmental collaborators included: Robert B. Beelman, professor of food science and Paul Heinemann and Paul N. Walker, professors of agricultural and biological engineering. External collaborators included Jose E. Sanchez, professor, El Colegio de la Frontera Sur, Tapachula, Mexico. There were five graduate students associated with the project as follows: Dr. Patrick Collopy, Dr. Delphina Mamiro and Ms. Alma Rodriguez Estrada from plant pathology, Dr. N. Joy Dubost from the department of food science and Mr. Mark Bechara from agricultural and biological engineering. Dr. Carl Schlagnhaufer participated as a research associate from plant pathology. In addition to the Penn State Agricultural Experiment Station, funding for the project was provided by The Penn State Mushroom Industry Endowment, Penn State Mushroom Industry Farmer-Based Applied Research Program, USDA - NE
IPM Center - Critical and Emerging Issues program, Ford Foundation, and Nutricore North East, Inc.
TARGET AUDIENCES: Our work targeted the mushroom community consisting of growers, suppliers and merchandisers. Our education programs were delivered via conferences, farm visits, telephone, email, the Mushroom News and scientific publications.
Impacts
Our work on production of A. bisporus on non-composted substrates could lead to commercial production of this species without the necessity to compost-an operation that often is associated with negative environmental consequences, including offensive odor generation and ground water contamination. We have shown that the relative feed value of spent shiitake substrate is relatively high. Growers may now consider using their spent substrate as ruminant feed rather than disposing of the substrate through land application or by sending it to landfills. We have determined practical cultural practices that can increase the level of ERGO produced mushrooms so this could result in valuable new opportunities for growers. Imazalil sulfate represents a viable replacement fungicide for thiophanate-methyl, that is now used throughout the mushroom industry to control green mold disease, but for which significant resistance has developed in the Ta2 population in southeastern
Pennsylvania. At the same time, a commercial bacterium-based biocontrol formulation was found to have promising efficacy in controlling Trichoderma green mold. Its longstanding proven safety, broad-spectrum mode of action, and OMRI status (organic certified) represent a major breakthrough in fungicide chemistry for mushrooms. This product has the potential to become the first of its kind, namely a durable, safe, and effective biological control agent for a major fungal pathogen on A. bisporus.
Publications
- Bechara, M.A., P. Heinemann, P. N. Walker, and C. P. Romaine. 2007. Non-composted grain-based substrate for mushroom production: an update. Mushroom News 55(8):4-10.
- Dubost, N. J., R. B. Beelman, and D. J. Royse. 2007. Influence of selected cultural factors and postharvest storage on ergothioneine content of common button mushrooms (Agaricus bisporus). Int. J. Med. Mushr. 9:163-176.
- Mamiro, D. P., D. J. Royse, and R. B. Beelman. 2007. Yield, size and mushroom solids content of Agaricus bisporus produced on non-composted and spent mushroom compost. World J. Microbiol. Biotechnol. 23:1289-1296.
- Rodriguez Estrada, A. E. and D. J. Royse. 2007. Yield, size and bacterial blotch resistance of Pleurotus eryngii grown on cottonseed hulls/oak sawdust supplemented with manganese, copper and whole ground soybean. Bioresource Technol. 98:1898-1906.
- Romaine, C. P., D. J. Royse, and C. Schlagnhaufer. 2007. Imazalil sulfate as an alternative spawn and supplement treatment for green mold disease. Mushroom News 55(4):4-7.
- Royse, D. J. and J. E. Sanchez. 2007. Ground wheat straw as a substitute for portions of oak wood chips used in shiitake (Lentinula edodes) substrate formulae. Bioresource Technol. 98:2137-2141.
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Progress 01/01/06 to 12/31/06
Outputs
L-ergothioneine, a naturally occurring antioxidant in mushrooms, was quantified in Agaricus bisporus, Grifola frondosa, Lentinula edodes, Pleurotus ostreatus, and P. eryngii by high-performance liquid chromatography and liquid chromatography-mass spectroscopy. Freeze dried mushroom powder was analyzed with two C18 columns in tandem utilizing an isocratic mobile phase consisting of an aqueous sodium phosphate buffer with 3% acetonitrile and 0.1% triethylamine. Ergothioneine was identified by matching the retention time and mass spectra of the authentic compound with the mushroom samples, while quantification was completed via absorbance at 254 nm. The ergothioneine content of the mushrooms ranged from 0.4-2.09 mg/g (dry wt). Within A. bisporus, the white variety contained the least ergothioneine (0.41 mg/g) while the portabellas (brown) contained the highest (0.68 mg/g). The specialty mushrooms ranged from a low of 1.72 mg/g for P. eryngii to a high of 2.09 mg/g
ergothioneine for Lentinula edodes. The results of this study suggest that differences in strains, along with growing conditions, can affect the level of ergothioneine produced in the mushrooms. Experiments also were conducted to determine if Pleurotus cornucopiae and Grifola frondosa could be enriched with selenium by addition of sodium selenite to the growth substrate. Basidiomata were harvested from the treated substrates and analyzed for selenium content. Selenium increased in basidiomata of both mushrooms in direct response to levels added to the substrate, but greater uptake of selenium occurred with P. cornucopiae compared to G. frondosa. To evaluate the effect of non-composted substrate (NCS) and spent mushroom compost (SMC) as media for A. bisporus production, five substrate mixtures of NCS and SMC as well as spawn carriers and strains were evaluated for their effects on yield and mushroom solids content. The substrates included NCS, 75/25 NCS/SMC, 50/50 NCS/SMC, 25/75
NCS/SMC and Phase II compost (control). The substrates were spawned with either brown or white strains on various spawn carriers including millet, casing inoculum (CI), 50/50 CI/millet or NCS. Substrate mixtures of NCS/SMC produced mushroom yields comparable to non-supplemented Phase II compost. A substrate mixture of 50/50 NCS/SMC and spawn carrier NCS produced the highest yield (12.8 kg/m2) of all substrates, followed by a mixture of 75/25 NCS/SMC. The highest mushroom dry weight (7.1% solids) was obtained from the brown strain produced on 50/50 NCS/SMC. Similarly, non-composted substrates comprised of mixtures of cereal grain spawn and commercial delayed-release nutrient supplements generated mushroom yields on average of 5.3 kg/m2.
Impacts
We have shown that various species of edible mushrooms could be a viable and economical source of ergothioneine in the diet. This could provide new opportunities for mushroom growers, since mushrooms can serve as an excellent source of ergothioneine and provide yet another reason to incorporate mushrooms into the human diet. We also demonstrated that both P. cornucopiae and G. frondosa could be predictably enriched with selenium to become excellent dietary sources of selenium that could improve their potential as functional foods. The organic selenium compounds that are present may be transferred to extracts that are used for dietary supplements or medicinal purposes that could create new uses for these products. Our work on production of A. bisporus on non-composted substrates could lead to commercial production of this species without the necessity to compost-an operation that often is associated with negative environmental consequences, including offensive odor
generation and ground water contamination. We have identified gene elements that enable the expression of recombinant genes in the fruiting body of A. bisporus. These genetic elements now permit the exploration of transgenic resistance to La France virus disease. Imazalil sulfate represents a viable replacement fungicide for thiophanate-methyl, which is now used throughout the industry to control green mold disease, but for which significant resistance has developed in the Ta2 population in the major mushroom growing region in southeastern Pennsylvania.
Publications
- Bechara, M.A., Heinemann, P., Walker, P.N., and Romaine, C.P. 2006. Non-composted grain-based substrates for mushroom production (Agaricus bisporus). Trans. ASABE 49:819-824.
- Bechara, M. A., Heinemann, P., Walker, P.N., and Romaine, C.P. 2006. Agaricus bisporus mushroom cultivation in hydroponic systems. Trans. ASABE 49: 825-832.
- Beelman, R. B. and Royse, D.J. 2006. Selenium enrichment of Pleurotus cornucopiae (Paulet) Rolland and Grifola frondosa (Dicks.:Fr.) S. F. Gray mushrooms. International J. Medicinal Mushrooms 8:77-84.
- Dubost, N. J., Beelman, R.B., Peterson, D. and Royse, D.J. 2006. Identification and quantification of ergothioneine in cultivated mushrooms by liquid chromatography-mass spectroscopy. International J. Medicinal Mushrooms 8:215-222.
- Mamiro, D. P. 2006. Non-composted and spent mushroom substrates for production of Agaricus bisporus. Ph.D. Thesis. The Pennsylvania State University, University Park, PA. pp. 1-100.
- Rodriguez Estrada, A. E. and Royse, D.J. 2006. Bacterial blotch of the king oyster mushroom: effects of strain and substrate supplementation on disease severity. Mushroom News 54(2):14-21.
- Romaine, C. P. and Schlagnhaufer, C. 2006. Mushroom (Agaricus bisporus). In: Agrobacterium Protocols. K. Wang (ed.). Methods in Molecular Biology 344. Humana Press Inc. Vol. 2, pp. 453-463.
- Royse, D. J. 2006. Germplasm enhancement, culture developments and disease management for Agaricus bisporus and Lentinula edodes in North America. In Proceedings of the International Symposium on Mushroom Science, September 20-22. Akita Prefectural University, Shimoshinjo-Nakano, Akita, Japan. Pages 39-48.
- Shen, Q. and Royse, D.J. 2006. Diversity of Grifola frondosa (maitake) in Asia & Eastern North America. Mushroom News 54(2):6-13.
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Progress 01/01/05 to 12/31/05
Outputs
Phytase is used commercially to maximize phytic acid degradation and to increase mineral and amino acid availability in animal and human nutrition. To determine phytase content in edible mushrooms, basidiomata of Agaricus bisporus and three specialty mushrooms (Grifola frondosa, Lentinula edodes, and Pleurotus cornucopiae) and spent mushroom substrate (SMS) were surveyed. Enzyme activity ranged from 0.046 to 0.074 U/g tissue for four A. bisporus types (closed and open whites, and closed and open browns) grown at The Pennsylvania State Universitys Mushroom Test Demonstration Facility (MTDF). The addition of various nutrient supplements to Phase II mushroom substrate did not alter phytase activity in A. bisporus. Portabella mushrooms (open brown) obtained from a commercial farm had significantly higher levels of phytase activity (0.211 U/g tissue) compared to A. bisporus grown at the MTDF. Of the specialty mushrooms surveyed, maitake (G. frondosa) had 20% higher phytase
activity (0.287 U/g tissue) than commercial portabella mushrooms. The yellow oyster mushroom (P. cornucopiae) ranked second in level of phytase activity (0.213 U/g tissue). Shiitake (L. edodes) contained the least amount of phytase in basidiomata (0.107 U/g tissue). Post-crop steam-treatment (60 degrees C, 24 hr) of SMS reduced phytase activity from 0.074 U/g to 0.018 U/g. Phytase was purified from commercially grown portabella basidiomata 314-fold with an estimated molecular weight of 531 kDa by gel filtration chromatography. The optimum pH for activity was 5.5, but appreciable phytase activity was observed over the range of pH 5.0-8.0. Purified A. bisporus phytase was inactivated following a 10-min incubation at 60C. Bacterial blotch, caused by Pseudomonas tolaasii, is a serious disease of the king oyster mushroom (Pleurotus eryngii). To evaluate factors influencing severity of bacterial blotch, live bacteria and bacterial toxin (tolassin) were applied to basidiomata of two mushroom
strains produced on substrates supplemented with various levels of ground soybean. Disease severity was higher when live bacteria were used compared to toxin. Mushroom strain was the most important variable contributing to disease severity followed by increased ground soybean content in the substrate.
Impacts
Phytase isolated from A. bisporus dies not appear to be a good candidate for direct use in the human diet due to the inactivation of the enzyme at the low pH levels encountered in human gastric fluid. However, the utilization of this enzyme to reduce phytic acid in vitro should be further explored. Growers attempting to maximize the yield and quality of the king oyster mushroom should select the most resistant germplasm and exercise caution when supplementing substrates with high levels (>8% dry wt) of ground soybean. Resistant germplasm and moderate levels of nitrogen in the substrate should help to maximize mushroom yield and quality and minimize the potential threat of blotch epidemics on their farms.
Publications
- Collopy, P. D. and Royse, D. J. 2004. Characterization of phytase activity from cultivated edible mushrooms and their production substrates. J. Agr. Food Chem. 52:7518-7524.
- Royse, D. J. and Shen, Q. 2005. Shiitake bag cultivation in the U.S. In: Gush, R. (Ed.) Mushroom Growers Handbook 2: Shiitake Cultivation. MushWorld, Seoul, Korea. Pp 106-108..
- Rodriguez-Estrada, A. E. and Royse, D. J. 2005. Cultivation of Pleurotus eryngii in bottles. Mushroom News 53(2):10-19. 9
- Romaine, C. P., Royse, D. J. and Schlagnhaufer, C. 2005. Superpathogenic Trichoderma resistant to Topsin M found in Pennsylvania and Delaware. Mushroom News 53(10):6-9. 10
- Rodriguez-Estrada, A. E. 2005. Influence of substrate composition and mushroom strains on productivity and susceptibility of Plerutous eryngii to bacterial blotch disease. M.S. Thesis. The Pennsylvania State University, University Park, PA. Pg. 1-98.
- Royse, D. J., Shen, Q. and McGarvey, C. 2005. Consumption and production of recently domesticated edible fungi in the United States with a projection of their potential. In: Tan et al. (eds.) Proceedings of The 5th International Conference on Mushroom Biology and Mushroom Products, April 8-12, 2005, Shanghai, China. Acta Edulis Fungi Vol. 12 (Supplement). Pp. 331-337.
- Mamiro, D. P. and Royse, D. J. 2005. Laboratory efficacy of selected fungicides and Rhododendron catawbiense leaf extracts on growth of Verticillium fungicola. In: Tan et al. (eds.) Proceedings of The 5th International Conference on Mushroom Biology and Mushroom Products, April 8-12, 2005, Shanghai, China. Acta Edulis Fungi Vol. 12 (Supplement). Pp. 390-396.
- Rodriguez-Estrada, A. and Royse, D. J. 2005. Determination of Pseudomonas tolaasii threshold concentrations required to produce symptoms of bacterial blotch disease of Pleurotus eryngii. In: Tan et al. (eds.) Proceedings of The 5th International Conference on Mushroom Biology and Mushroom Products, April 8-12, 2005, Shanghai, China. Acta Edulis Fungi Vol. 12 (Supplement). Pp. 379-382.
- Beelman, R. B. and Royse, D. J. 2005. Evaluation of OryktaTM as a source of micronutrients to improve yield and quality of Agaricus bisporus mushrooms. In: Tan et al. (eds.) Proceedings of The 5th International Conference on Mushroom Biology and Mushroom Products, April 8-12, 2005, Shanghai, China. Acta Edulis Fungi Vol. 12 (Supplement). Pp. 277-281.
- Garcia, B. S., Royse, D. J. and Sanchez, J. E. 2005. Vermicompost in substrate and casing formulas for the production of brown Agaricus bisporus. In: Tan et al. (eds.) Proceedings of The 5th International Conference on Mushroom Biology and Mushroom Products, April 8-12, 2005, Shanghai, China. Acta Edulis Fungi Vol. 12 (Supplement). Pp. 243-248.
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Progress 01/01/04 to 12/31/04
Outputs
Phylogenetic analyses of 62 isolates of 42 Agaricus and related secotioid species (A. inapertus, Gyrophragmium dunalii and Longula texensis) were conducted based on sequence data of the internal transcribed spacers (ITS) and partial large subunit (LSU) of ribosomal DNA. Bayesian, maximum likelihood and maximum parsimony analyses were used to reveal evolutionary groups within the genus Agaricus, while molecular clock analyses were carried out to obtain more information about the divergence times during the evolution of Agaricus within the Basidiomycota. Six major distinct clades were found within the genus with varying levels of support. These monophyletic groups suggested interspecific relationships both confirming and challenging previous morphological sections in several cases. Our results show that most morphological features likely have evolved in apparently similar ways multiple times independently during evolution, and that the secotioid A. inapertus,
Gyrophragmium dunalii and Longula texensis evolved from Agaricus species in Clade I. A new name Agaricus aridicola Geml, Geiser et Royse, and a new combination Agaricus texensis (Berk. et Curt.) Geml, Geiser et Royse are suggested to replace the names Gyrophragmium dunalii and Longula texensis, respectively. Molecular clock estimates for minimal age of separation of the genus Agaricus from its closest relatives were 32.63 +/- 8.06 and 15.45 +/- 3.82 Ma, respectively, using calibrations based on other molecular clock studies on fungi and fossil data. However, Agaricus likely diverged much earlier (73.30 +/- 18.12 Ma), as suggested by the estimate based on the most robust calibration. To find a cost effective alternative substrate, Pleurotus cornucopiae 608 (yellow basidiomata) was grown on: 1) chopped, pasteurized switch grass (Panicum virgatum, 99%) with 1% ground limestone and 2) a mixture of pasteurized cottonseed hulls (75% dry wt), 24% chopped wheat straw, and 1% ground limestone
(all ingredients wt/wt). The substrates were spawned at various levels (2.5%, 3.75% or 5% wet wt, crop I) and nonsupplemented or supplemented with commercial delayed release nutrient (Campbell's S-41) at various levels (0%, 1.5%, 3%, 4.5%, 6%, 7.5% and 9% dry wt, crop II). Maximum yield (weight of fresh mushrooms harvested at maturity) was obtained on cottonseed hull/wheat straw substrate at a 3.75-5% spawn level and 6% S-41 supplement. On switch grass substrate, increasing spawn levels and supplement levels stimulated yields in a linear fashion. However, maximum yields were only 46% or less for those of similar treatments on cottonseed hull/wheat straw substrate. Yields were three times higher on switch grass that was harvested after the grass had senesced (winter; beige color) compared to material that was harvested when the grass was green (summer; time of flowering). Additional physical processing of the material, such as milling, may improve yield potential of this material.
Impacts
A better understanding of the phylogenetic relationships of species of Agaricus may help the selection and breeding of commercial lines and help to improve commercial cultivation of these mushrooms as well as the clarification of the systematics of this diverse genus. Cost-effective production of oyster mushrooms depends on the reliability, availability and cost of substrate ingredients. Based on yield and net cost, it does not appear that switch grass is an economically viable alternative for growers currently using cottonseed hulls/wheat straw substrates.
Publications
- Shen, Q., Tan, Q. and Royse, D.J. 2004. Growing Lentinula edodes and other mushrooms in China--a low input technology alternative. Revista Mexicana de Micologia 18:15-20.
- Romaine, C.P., Keil, C.B., Rinker, D.L. and Royse, D.J. (eds.). 2004. Science and Cultivation of Edible and Medicinal Fungi. Mushroom Science, Vol. 16. The Pennsylvania State University Press, University Park, Pennsylvania, U.S.A. 733 pp.
- Beelman, R.B., Royse, D.J. and Chikthimmah, N. 2004. Bioactive components in Agaricus bisporus (J. Lge) Imbach of nutritional, medicinal, or biological importance. IN Science and Cultivation of Edible and Medicinal Fungi. Mushroom Science, Vol. 16. Romaine, C. P., C. B. Keil, D. L. Rinker and D. J. Royse, eds. The Pennsylvania State University Press, University Park, Pennsylvania. pp. 1-16.
- Royse, D.J., Ohga, S. and Sanchez-Vasquez, J.E. 2004. Yield, mushroom size and time to production of Pleurotus cornuucopiae (oyster mushroom) grown on switch grass substrate spawned and supplemented at various rates. Bioresource Technol. 91:85-91.
- Geml, J., Geiser, D.M. and Royse, D.J. 2004. Molecular evolution of Agaricus species based on ITS and LSU rDNA sequences. Mycological Progress 3:157-176.
- Coutino, F., Jimenez, L., Sanchez, J.E. and Royse, D.J. 2004. Digitaria decambens grass substrate prepared by alkaline immersion for culture of Pleurotus spp. IN Science and Cultivation of Edible and Medicinal Fungi. Mushroom Science, Vol. 16. Romaine, C. P., C. B. Keil, D. L. Rinker and D. J. Royse, eds. The Pennsylvania State University Press, University Park, Pennsylvania, U.S.A. pp. 267-271.
- Royse, D.J., Beelman, R.B. and Weil, D.A. 2004. Manganese sulfate additions increase mushroom (Pleurotus cornucopiae) yield in delayed release nutrient-supplemented cottonseed hull/wheat straw substrate. IN Science and Cultivation of Edible and Medicinal Fungi. Mushroom Science, Vol. 16. Romaine, C. P., C. B. Keil, D. L. Rinker and D. J. Royse, eds. The Pennsylvania State University Press, University Park, Pennsylvania, U.S.A. pp. 359-364.
- Ohga, S., Cho, N.S., Li, Y. and Royse, D.J. 2004. Utilization of pulsed power to stimulate fruitification of edible mushrooms. IN Science and Cultivation of Edible and Medicinal Fungi. Mushroom Science, Vol. 16. Romaine, C. P., C. B. Keil, D. L. Rinker and D. J. Royse, eds. The Pennsylvania State University Press, University Park, Pennsylvania, U.S.A. pp. 343-351.
- Geml, J., Geiser, D.M. and Royse, D.J. 2004. Molecular phylogeny of Agaricus species. IN Science and Cultivation of Edible and Medicinal Fungi. Mushroom Science, Vol. 16. Romaine, C. P., C. B. Keil, D. L. Rinker and D. J. Royse, eds. The Pennsylvania State University Press, University Park, Pennsylvania, U.S.A. pp. 165-173.
- Beelman, R. B., D. J. Royse and N. Chikthimmah. 2004. Comparison of nutritional components between button, shiitake and oyster mushrooms. Mush. News 52(2):12-23.
- Royse, D. J. 2003. Fungi. 2004. IN Encyclopedia of Food and Culture. S. H. Katz, ed. Charles Scribner's Sons Reference Books, NY. Vol 2:84-90.
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Progress 01/01/03 to 12/31/03
Outputs
Synthetic substrate consisting of oak sawdust (50%), white millet (28%), winter rye (11%) and soft red wheat bran (11%) was non-supplemented or supplemented with 0.2%, 0.4% or 0.6% (dry wt basis) precipitated calcium carbonate [CaCO(3)]. Shiitake (Lentinula edodes) was grown in two crops to determine the effect of three CaCO(3) levels on mushroom yield and size. Yields and biological efficiencies (averages for two crops) from substrates non-supplemented with CaCO(3) were lower by 14.1%, 18.4% and 24.9% compared to treatments supplemented with 0.2%, 0.4% and 0.6% CaCO(3), respectively. Mushroom size (weight) was larger with non-supplemented substrate (16.8 g) compared to substrate supplemented with 0.6% CaCO(3) (15.1 g). However, mushroom production was more consistent from crop to crop when 0.6% CaCO(3) was added to substrate. Since the early 1990s, the epidemic of green mold on the cultivated mushroom Agaricus bisporus in North America has been caused by Trichoderma
aggressivum f. aggressivum. The findings of earlier research suggested that the microevolutionary emergence of T. aggressivum f. aggressivum coincided wit the onset of the epidemic. Determining the disease susceptibility of mushroom strains grown widely before the epidemic manifested tested this hypothesis further. The results of the complementary methods of analysis, that entailed a grain protection assay and cropping trials, established that two pre-epidemic strains were more susceptible to green mold than three post-epidemic strains being cultivated at the time of the epidemic. Thus, if T. aggressivum f. aggressivum had been present within cultivated mushrooms prior to the epidemic, it should have been detected. It still appears to be true that T. aggressivum f. aggressivum emerged during he 1990s in a manner that remains unclear. The nutritional value of A. bisporus mushrooms compares favorably with L. edodes and Pleurotus spp. This is especially true of brown strains of A.
bisporus that are harvested fully mature with open caps (marketed in the U.S. as portabellas) as is done with shiitake and oyster. This is primarily a result of higher fiber and solids content in portabellas that makes them comparable to shiitake and oyster. On the other hand, A. bisporus are significantly better sources of riboflavin and important minerals potassium, selenium, and copper and comparable as sources of protein and important vitamins--thiamin, niacin and folate.
Impacts
Our work demonstrated that substrates containing up to 0.6% precipitated CaCO3 were more productive than substrates without CaCO3. This information will help growers increase productivity with minimal increase in production cost. Perhaps the most practical implications of our study on T. aggressivum f. aggressivum resistance, is the discovery of a positive correlation between the resistance of a mushroom strain based on crop loss analysis and the ability of the strain to protect the spawn substrate from colonization by the pathogen. Much more is known about the potential medicinal value of components found in L. edodes and Pleurotus spp. than in A. bisporus. However, recent evidence suggests that A. bisporus mushrooms also contain high levels of substances of possible medicinal importance such as tyrosinase, aromatase inhibitor(s) and immunomodulating and antitumor polysaccharides. This suggests that the medicinal value of A. bisporus warrants more intense study.
Publications
- Royse, D. J., and Sanchez-Vazquez, J. E. 2003. Influence of precipitated calcium carbonate [CaCO(3)] on shiitake (Lentinula edodes) yield and mushroom size. Bioresource Technol. 90:225-228.
- Beelman, R. B., Royse, D. J. and Chikthimmah. 2003. Bioactive components in Agaricus bisporus (J. Lge) Imbach (Agaricomycetideae) of nutritional, medicinal, and biological importance (Review). Internat. J. Med. Mush. 5:321-337.
- Chen, X., Ospina-Giraldo, M. D., Wilkinson, V., Royse, D. J. and Romaine, C. P. 2003. Resistance of pre- and post-epidemic strains of Agaricus bisporus to Trichoderma aggressivum f. aggressivum. Plant Dis. 87:1457-1461.
- Royse, D. J. 2003. Cultivation of oyster mushrooms. College of Agricultural Sciences, Pennsylvania State University, University Park, PA. 12 pp.
- Royse, D. J. and Romaine, C. P. 2003. Evaluation of fungicide applications on spawn for control of mushroom green mold, 2002. Fungicide and Nematicide Tests 58:V069.
- Royse, D. J. and Romaine, C. P. 2003. The effect of fungicides for control of Trichoderma green mold on mushrooms, 2002. Fungicide and Nematicide Tests 58:V075.
- Royse, D. J. and Romaine, C. P. 2003. Evaluation of fungicides for control of Trichoderma green mold, 2002. Fungicide and Nematicide Tests 58:V076.
- Royse, D. J. and Romaine, C. P. 2003. Spawn application of fungicides for control of Trichoderma green mold of mushrooms, 2002. Fungicide and Nematicide Tests 58:V068.
- Royse, D. J. and Romaine, C. P. 2003. Evaluation of microbes for control of Trichoderma green mold of mushrooms, 2002. Biological and Cultural Tests 18:V018.
- Royse, D. J. 2003. Moving toward improved Pleurotus quality. Mushroom News 51(2):6-12.
- Romaine, C. P., Royse, D. J. and Schlagnhaufer, C. 2003. An evaluation of disinfectants targeting pathogens of the button mushroom. Mushroom News 51(4):6-11.
- Sanchez, J. and Royse, D. J., eds. 2002. La Biologia y el Cultivo de Pleurotus spp. LIMUSA. 290p.
- Royse, D. J. and Sanchez, J. 2002. Importance of growing Pleurotus, production statistics worldwide and in some Spanish speaking countries. IN La Biologia y el Cultivo de Pleurotus spp. LIMUSA. Sanchez, J. and Royse, D. J., eds. pp. 17-26.
- Wilkinson, V. and Royse, D. J. 2002. A review of techniques for mushroom strain maintenance, emphasizing those that are well adapted for Pleurotus spp. IN La Biologia y el Cultivo de Pleurotus spp. LIMUSA. Sanchez, J. and Royse, D. J., eds. pp 125-139.
- Sanchez, J., and Royse. D.J. 2002. The cultivation of Pleurotus spp. IN La Biologia y el Cultivo de Pleurotus spp. LIMUSA. Sanchez, J. and Royse, D. J., eds. pp. 187-203.
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