Nannochloropsis oceanica promises to be an industrial-level producer of polyunsaturated fatty acids.In this study,the fastest and slowest growing N.oceanica mutants were selected through N-methyl-N'-nitro-N-nitros...Nannochloropsis oceanica promises to be an industrial-level producer of polyunsaturated fatty acids.In this study,the fastest and slowest growing N.oceanica mutants were selected through N-methyl-N'-nitro-N-nitrosoguanidine mutation,and two mutant strains and the wild type(WT) subjected to transcriptome profiling.It was found that the OD_(680) reads at stationary growth phase of both WT and its mutants were proportional to their cell density,thus indicating their division rate and growth speed during culture.This chemical mutation was effective for improving growth performance,and the fast strain divided faster by upregulating the expression of genes functioning in the cell cycle and downregulating genes involved in synthesis of amino acids,fatty acids,and sugars as well as the construction of ribosome and photosynthetic machinery.However,the relationship among the effected genes responsible for cell cycle,metabolism of fatty and amino acids,and construction of ribosome and photosynthetic machinery remained unclear.Further genetic studies are required for clarifying the genetic/metabolic networks underpinning the growth performance of N.oceanica.These findings demonstrated that this mutation strategy was effective for improving the growth performance of this species and explored a means of microalgal genetic improvement,particularly in species possessing a monoploid nucleus and asexual reproduction.展开更多
A cultured female half-smooth tongue sole(C ynoglossus semilaevis) was crossed with a wild male, yielding the fi rst fi lial generation of pseudo-testcrossing from which 200 fi sh were randomly selected to locate the ...A cultured female half-smooth tongue sole(C ynoglossus semilaevis) was crossed with a wild male, yielding the fi rst fi lial generation of pseudo-testcrossing from which 200 fi sh were randomly selected to locate the V ibrio anguillarum resistance trait in half-smooth tongue sole at its microsatellite linkage map. In total, 129 microsatellites were arrayed into 18 linkage groups, ≥4 each. The map reconstructed was 852.85 c M in length with an average spacing of 7.68 c M, covering 72.07% of that expected(1 183.35 cM). The V. anguillarum resistance trait was a composite rather than a unit trait, which was tentatively partitioned into Survival time in Hours After V. anguillarum Infection(SHAVI) and Immunity of V. A nguillarum Infection(IVAI). Above a logarithm of the odds(LOD) threshold of 2.5, 18 loci relative to SHAVI and 3 relative to IVAI were identifi ed. The 3 loci relative to IVAI explained 18.78%, 5.87% and 6.50% of the total phenotypic variation in immunity. The microsatellites bounding the 3 quantitative trait loci(QTLs) of IVAI may in future aid to the selection of V. anguillarum-immune half-smooth tongue sole varieties, and facilitate cloning the gene(s) controlling such immunity.展开更多
基金Supported by the National Natural Science Foundation of China(No.31270408)the National High Technology Research and Development Program of China(863 Program)(No.2014AA022001)
文摘Nannochloropsis oceanica promises to be an industrial-level producer of polyunsaturated fatty acids.In this study,the fastest and slowest growing N.oceanica mutants were selected through N-methyl-N'-nitro-N-nitrosoguanidine mutation,and two mutant strains and the wild type(WT) subjected to transcriptome profiling.It was found that the OD_(680) reads at stationary growth phase of both WT and its mutants were proportional to their cell density,thus indicating their division rate and growth speed during culture.This chemical mutation was effective for improving growth performance,and the fast strain divided faster by upregulating the expression of genes functioning in the cell cycle and downregulating genes involved in synthesis of amino acids,fatty acids,and sugars as well as the construction of ribosome and photosynthetic machinery.However,the relationship among the effected genes responsible for cell cycle,metabolism of fatty and amino acids,and construction of ribosome and photosynthetic machinery remained unclear.Further genetic studies are required for clarifying the genetic/metabolic networks underpinning the growth performance of N.oceanica.These findings demonstrated that this mutation strategy was effective for improving the growth performance of this species and explored a means of microalgal genetic improvement,particularly in species possessing a monoploid nucleus and asexual reproduction.
基金Supported by the National High Technology Research and Development Program of China(863 Program)(No.2012AA10A403)the Research Fund for the Doctoral Program of Higher Education of China(No.20110132110006)
文摘A cultured female half-smooth tongue sole(C ynoglossus semilaevis) was crossed with a wild male, yielding the fi rst fi lial generation of pseudo-testcrossing from which 200 fi sh were randomly selected to locate the V ibrio anguillarum resistance trait in half-smooth tongue sole at its microsatellite linkage map. In total, 129 microsatellites were arrayed into 18 linkage groups, ≥4 each. The map reconstructed was 852.85 c M in length with an average spacing of 7.68 c M, covering 72.07% of that expected(1 183.35 cM). The V. anguillarum resistance trait was a composite rather than a unit trait, which was tentatively partitioned into Survival time in Hours After V. anguillarum Infection(SHAVI) and Immunity of V. A nguillarum Infection(IVAI). Above a logarithm of the odds(LOD) threshold of 2.5, 18 loci relative to SHAVI and 3 relative to IVAI were identifi ed. The 3 loci relative to IVAI explained 18.78%, 5.87% and 6.50% of the total phenotypic variation in immunity. The microsatellites bounding the 3 quantitative trait loci(QTLs) of IVAI may in future aid to the selection of V. anguillarum-immune half-smooth tongue sole varieties, and facilitate cloning the gene(s) controlling such immunity.
