Identification of protoplast fusion strain Fhhh by randomly amplified polymorphic DNA

Construction and Characterization of an Intergeneric Fusant That Degrades the Fungicides Chlorothalonil and Carbendazim

Bordetella sp. CTN-16 (GenBank FJ598326) can degrade chlorothalonil (CTN) but not carbendazim (MBC), and Microbacterium sp. MBC-3 (GenBank OK667229) can degrade MBC but not CTN. A functional strain BD2 was obtained by protoplast fusion of CTN-16 and MBC-3 to generate a fusant with improved degradation efficiency of CTN and MBC. Fusant-BD2 with eighth transfer on a medium containing CTN and two antibiotics was obtained. To identify and confirm the genetic relationship between parental strains and fusion strain BD2, scanning electron microscopy (SEM), random amplified polymorphic DNA (RAPD), and 16S ribosomal RNA (rRNA) gene sequences analysis were carried out. SEM analysis illustrated BD2 and its parents had some slight differences in the cell morphology. Fusant-BD2 not only possessed the same bands as parental strains but also had its specific bands analyzed through RAPD. The genetic similarity indices for BD2 and its parental strains CTN-16 and MBC-3 are 0.571 and 0.428, respectively. The degradation rates of CTN and MBC were 79.8% and 65.2% in the inorganic salt solution containing 50 mg·L−1 CTN and 50 mg·L−1 MBC, respectively, and the degradation efficiencies were better than the parental strains CTN-16 and MBC-3. This study provides a prospect for the application of fusion strain BD2 in bioremediation of CTN and MBC contaminated sites.

Interspecific hybridization between cultivated morels Morchella importuna and Morchella sextelata by PEG-induced double inactivated protoplast fusion

The commercial production of Morchella mushrooms calls for urgent breeding of excellent varieties or strains with appropriate tools, such as protoplast fusion. However, the protoplast fusion in morels has not been studied. In this paper, interspecific hybridization between cultivated morels of M. importuna and M. sextelata by PEG-induced protoplast fusion was conducted. Apart from functional complementation of double inactivated protoplasts, the fusants were characterized by cultural and cultivated characters and molecular markers of random amplified polymorphic DNA (RAPD). The results suggested that the hybrids and their parents showed significant difference in their inoculum recovery time, mycelial growth rate, yield of cultivation and total amino acid content of ascocarps. Moreover, positive barrage reactions were observed between parental strains as well as between each parent and a hybrid line. A dendrogram created on the basis of RAPD fingerprints exhibited three major clusters, in which morel hybrids showed intra-cluster variations, M. sextelata #6 formed an out group, while M. importuna #4 was phylogenetically closer to morel hybrids. All the results demonstrated that real fusants were obtained in our study. Protoplast fusion may provide an ideal alternative for new strain selection, and thus will promote the healthy development of morel industry.

Construction and analysis of an intergeneric fusion from Pigmentiphaga sp. strain AAP-1 and Pseudomonas sp. CTN-4 for degrading acetamiprid and chlorothalonil

Pseudomonas sp. CTN-4 degrades chlorothalonil (CTN) but not acetamiprid (AAP), and Pigmentiphaga sp. strain AAP-1 degrades AAP but not CTN. A functional strain, AC, was constructed through protoplast fusion of two parental strains (Pseudomonas sp. CTN-4 and Pigmentiphaga sp. strain AAP-1) in order to simultaneously improve the degradation efficiency of AAP and CTN. Fusant-AC with eight transfers on plates containing two antibiotics and CTN was obtained. For the purpose of identifying and confirming the genetic relationship between fusant-AC and its parents, randomly amplified polymorphic DNA (RAPD), scanning electron microscopy (SEM), and 16S ribosomal DNA (rDNA) analysis were performed. In toto, RAPD fingerprint analysis produced 194 clear bands with 9 primers, which not only had bands in common with strains CTN-4 and AAP-1, but also had its own novel fusant-specific bands. The genetic similarity indices between fusant-AC and parental strains CTN-4 and AAP-1 were 0.40 and 0.69, respectively. The result of SEM indicated that the cell morphology of fusant-AC differed from both its parents. The fusant strain AC possesses a strong capability for AAP and CTN degradation. At AAP concentration (50-300 mg L(-1)), the degradation was achieved within 5 h. At the initial dose of 50 and 100 mg L(-1) CTN, the percentages reached 96 and 91 % over a 36-h incubation period. The present study indicates that the protoplast-fusion technique may have possible applications in environmental pollution control.

Construction and analysis of an intergeneric fusant able to degrade bensulfuron-methyl and butachlor

Rhodococcus sp. BX2 degrades bensulfuron-methyl but not butachlor, and Acinetobacter sp. LYC-1 degrades butachlor but not bensulfuron-methyl. Functional strains were constructed through protoplast fusion of Rhodococcus sp. BX2 and Acinetobacter sp. LYC-1 to generate fusants with an improved ability to simultaneously degrade bensulfuron-methyl and butachlor. Initial identification and stability tests of the fusants were performed. Three fusants with eighth transfer on plates containing two antibiotics and two herbicides were obtained. F1 also grew well in an inorganic salt solution containing bensulfuron-methyl and butachlor. F1 was characterized by its parents' morphological and physio-biochemical features. F1 not only had bands in common with BX2 and LYC-1, but also had its own specific bands analyzed by Random Amplified Polymorphic DNA. The genetic similarity indices between F1 and BX2 and F1 and LYC-1 were 0.507 and 0.470, respectively. The percentages bensulfuron-methyl and butachlor degradation by F1 in an inorganic salt solution supplemented with 100 mg/L bensulfuron-methyl and 100 mg/L butachlor were 65.35 and 62.41 %, respectively, and the percentages in soil contaminated with 10 mg/kg bensulfuron-methyl and 10 mg/kg butachlor with an inoculum size of 5 % at 34 °C and at a pH of 7.5 after 35 days were 63.74 and 61.53 %, respectively. It was demonstrated that F1 could simultaneously degrade bensulfuron-methyl and butachlor.

Extracellular proteomic analysis for degradation of PAHs in source of drinking water with fusant strains

Extracellular proteomic expressions of two fusant strains were analyzed to observe their abilities to degrade polycyclic aromatic hydrocarbons (PAHs) in the source of drinking water from Yangtze River. The extracellular proteomes for the hybrid strains, Fhhh and Xhhh, and one of their parental strain Phanerochaete chrysosporium were measured by the two-dimensional electrophoresis and MS/MS. The similarity of proteome expression was 34.7% between Fhhh and P. chrysosporium and that was 28.6% between Xhhh and P. chrysosporium. PAHs degeneration performance for Fhhh, Xhhh and the native bacterium NJ2007 was studied by biological activated carbon reactor. The specific degradation rate of Fhhh for PAHs was 3.05 x 10(-5) day(-1) which was significantly higher than that of the NJ2007 and Xhhh (P < 0.05). The results indicate that the fusant strain could not express the same proteome as that of its parental strain but could degrade PAHs in the source water with higher efficiency.