ABSTRACT
It is unclear how VvLaeA functions in regulating the growth and development of Volvariella volvacea (Bull. ex. Fr.) Sing.. Firstly, bioinformatics analysis of VvLaeA was carried out in this study. Subsequently, the Vvgpd promoter and the open reading frame (ORF) fragment of VvlaeA were amplified and fused by polymerase chain reaction (PCR). The fusion fragment was cloned into the pK2 (bar) plasmid. The recombinant construct pK2(bar)-OEVvlaeA was transfected into Beauveria bassiana by Agrobacterium tumefaciens-mediated transformation. Finally, the growth and development of the transformants were examined. The results showed that VvLaeA shared a low homology with similar proteins in other fungi. Compared with the wild type, the colony diameter of the transformant was significantly increased. However, the pigment deposition, conidial yields and germination rates were significantly decreased. The overexpression strains were more sensitive to stresses than that of the wild type. Further studies showed the conidial cell wall properties of the transformants were altered, and the expressions of genes related to the conidial development were significantly down-regulated. Collectively, VvLaeA increased the growth rate of B. bassiana strains and negatively regulated the pigmentation and conidial development, which shed a light for the functional identification of straw mushroom genes.
Subject(s)
Beauveria/metabolism , Spores, Fungal , Growth and DevelopmentABSTRACT
Aim: Developing high yielding single spore isolates and hybrid strains of paddy straw mushroom (Volvariella volvacea) with superior nutritional composition of the fruiting bodies.Methodology: Two contrasting high yielding strains (DMRO-463 and DMRO-484) of V. volvacea previously released for higher fruiting body yield were used for isolation of single spore isolates (SSIs). The slow growing SSIs were used for developing the hybrid strains by mating on Malt Extract Agar Medium Petri dishes. Conversely, the fast growing SSIs and the developed hybrid strains were screened for downward mycelial growth on paddy straw filled in wide mouth test tubes. Based upon downward mycelial growth, only eight SSIs and ten hybrid strains with numerically higher downward mycelial growth compared to two parents' checks were further evaluated for fruiting body yield on composted cotton ginning mill waste substrate under indoor conditions. Results: In successive yield evaluation trials (one preliminary and three full scale), hybrid strains VvH-11, VvH-13 and VvH-18 gave fruiting body yield higher than the two parents. Out of these hybrids, the yield distribution at different height (selves) in growing room was consistent in hybrid VvH-13 in trial-2, while rest two hybrids and parents showed significantly lower yield in lowest self (30 cm above floor level). The fruiting body weight also showed similar trend. The fruiting bodies from the highest yielding hybrid VvH-11 exhibited highest level of crude fiber (2.07%) and ash (10.95%) contents, while the hybrid VvH-13 giving consistent yield across growing room exhibited higher level of crude fiber (2.00 %), vitamin C (52.35 mg 100 g-1) and vitamin D (1434.7 µg 100 g-1). The third hybrid VvH-18 was superior in crude fiber (1.74%), manganese (22.46 ppm), selenium (0.26 ppm) and vitamin C (43.13 mg 100 g-1). All three hybrids exhibited lower fat (1.54 to 1.86 %) content compared to parents (2.54 to 2.59 %). Interpretation: High yielding hybrid strains can be developed in paddy straw mushroom (V. volvacea) through mating of slow growing SSIs, and their screening involving downward mycelial growth on paddy straw and repetitive grow out trials.
ABSTRACT
Mosquito-borne diseases are a major public health issue, especially in tropical and subtropical regions. In this study, wecompared the efficacy of Volvariella volvacea (Bull. ex Fr.) mushroom, an edible, commercially available mushroomspecies grown in Thailand with octenol (1-octen-3-ol) as a standard substance to kill larvae and attract adult, includingAedes aegypti Linnaeus and Culex sitiens Wiedemann, mosquitoes. Five concentrations of extract, including 120,12, 1.2, 0.12, and 0.012 mg/l were selected to test the effectiveness of killing mosquito larvae. Three concentrationsof extract, including 100, 10, and 1 mg/l were selected to test the effectiveness of adult female mosquito attraction.The result of the comparison of the larvicidal efficacy between V. volvacea extract and octenol in each concentration,showed that there were differences in number of dead larvae in almost all the concentrations in testing with octenol(p < 0.05), while in the adult mosquito attraction bioassay, V. volvacea extract attracted the highest number of adultfemale A. aegypti and C. sitiens at the 10 mg/l concentration followed by 1 and 100 mg/l, as well as the effect ofoctenol. The statistical comparison found that the efficiency of attracting A. aegypti and C. sitiens mosquitoes in allthe concentrations of V. volvacea extract was different from octenol (p < 0.05).
ABSTRACT
A novel phytase with a molecular mass of 14 kDa was isolated from fresh fruiting bodies of the common edible mushroom Volvariella volvacea (Straw mushroom). The isolation procedure involved successive chromatography on DEAE-cellulose, CM-cellulose, Affi-gel blue gel, Q-Sepharose and Superdex-75. The enzyme was a monomeric protein and was unadsorbed on DEAE-cellulose, CM-cellulose and Affi-gel blue gel, but was adsorbed on Q-Sepharose. The enzyme was purified 51.6-fold from the crude extract with 25.9% yield. Its N-terminal amino acid sequence GEDNEHDTQA exhibited low homology to the other reported phytases. The optimal pH and temperature of the purified enzyme was 5 and 45oC, respectively. The enzyme was quite stable over the pH range of 3.0 to 9.0 with less than 30% change in its activity, suggesting that it can be used in a very wide pH range. The enzyme exhibited broad substrate selectivity towards various phosphorylated compounds, but lacked antifungal activity against tested plant pathogens.