Tibetan weedy barleys reside at the edges of qingke(hulless barley)fields in Tibet(Xizang).The spikes of these weedy barleys contain or lack a brittle rachis,with either two-or six-rowed spikes and either hulled or hu...Tibetan weedy barleys reside at the edges of qingke(hulless barley)fields in Tibet(Xizang).The spikes of these weedy barleys contain or lack a brittle rachis,with either two-or six-rowed spikes and either hulled or hulless grains at maturity.Although the brittle rachis trait of Tibetan weedy barleys is similar to that of wild barley(Hordeum vulgare ssp.spontaneum Thell.),these plants share genetic similarity with domesticated barley.The origin of Tibetan weedy barleys continues to be debated.Here,we show that most Tibetan weedy barleys originated from cross-pollinated hybridization of domesticated barleys,followed by hybrid self-pollination and recombination between Non-brittle rachis 1(btr1)and 2(btr2).We discovered the specific genetic ancestry of these weedy barleys in South Asian accessions.Tibetan weedy barleys exhibit lower genetic diversity than wild and Chinese landraces/cultivars and share a close relationship with qingke,genetically differing from typical eastern and western barley populations.We classified Tibetan weedy barleys into two groups,brittle rachis(BR)and non-brittle rachis(NBR);these traits align with the haplotypes of the btr1 and btr2 genes.Whereas wild barleys carry haplotype combinations of Btr1 and Btr2,each showing lower proportions in a population,the recombinant haplotype BTR2H8+BTR1H24 is predominant in the BR group.Haplotype block analysis based on whole-genome sequencing revealed two recombination breakpoints,which are present in 80.6%and 16.8%of BR acces-sions according to marker-assisted analysis.Hybridization events between wild and domesticated barley were rarely detected.Thesefindings support the notion that Tibetan weedy barleys originated via recom-bination between Btr1 and Btr2 in domesticated barley.展开更多
Induced mutations are important for genetic research and breeding.Mutations induced by physical or chemical mutagenesis are usually heterozygous during the early generations.However,mutations must be fixed prior to ph...Induced mutations are important for genetic research and breeding.Mutations induced by physical or chemical mutagenesis are usually heterozygous during the early generations.However,mutations must be fixed prior to phenotyping or field trials,which requires additional rounds of self-pollination.Microspore culture is an effective method to produce double-haploid(DH)plants that are fixed homozygotes.In this study,we conducted ethyl methanesulfonate(EMS)-induced mutagenesis of microspore cultures of barley(Hordeum vulgare)cultivar‘Hua30’and landrace‘HTX’.The EMS concentrations were negatively correlated with the efficiency of callus induction and the frequency of mutant plant regeneration.The two genotypes showed different regeneration efficiencies.The phenotypic variation of the regenerated M1 plants and the presence of genome-wide nucleotide mutations,revealed by whole-genome sequencing,highlight the utility of EMS-induced mutagenesis of isolated microspore cultures for developing DH mutants.Genome-wide analysis of the mutation frequency in the regenerated plants revealed that a considerable proportion of mutations resulted from microspore culture(somaclonal variation)rather than EMS-induced mutagenesis.In addition to producing a population of 1972 homozygous mutant lines that are available for future field trials,this study lays the foundation for optimizing the regeneration efficiency of DH plants and the richness of mutations(mainly by fine-tuning the mutagen dosage).展开更多
Barley is a diploid species with a genome smaller than those of other members of the Triticeae tribe,making it an attractive model for genetic studies in Triticeae crops.The recent development of barley genomics has c...Barley is a diploid species with a genome smaller than those of other members of the Triticeae tribe,making it an attractive model for genetic studies in Triticeae crops.The recent development of barley genomics has created a need for a high-throughput platform to identify genetically uniform mutants for gene function investigations.In this study,we report an ethyl methanesulfonate(EMS)-mutagenized population consisting of 8525M_(3) lines in the barley landrace“Hatiexi”(HTX),which we complement with a high-quality de novo assembly of a reference genome for this genotype.The mutation rate within the population ranged from 1.51 to 4.09 mutations per megabase,depending on the treatment dosage of EMS and the mutation discrimination platform used for genotype analysis.We implemented a three-dimensional DNA pooling strategy combined with multiplexed amplicon sequencing to create a highly efficient and cost-effective TILLING(targeting induced locus lesion in genomes)platform in barley.Mutations were successfully identified from 72 mixed amplicons within a DNA pool containing 64 individual mutants and from 56 mixed amplicons within a pool containing 144 individuals.We discovered abundant allelic mutants for dozens of genes,including the barley Green Revolution contributor gene Brassinosteroid insensitive 1(BRI1).As a proof of concept,we rapidly determined the causal gene responsible for a chlorotic mutant by following the MutMap strategy,demonstrating the value of this resource to support forward and reverse genetic studies in barley.展开更多
Non-thermal plasma exhibits unique advan-tages in biomass conversion for the sustainable production of higher-value energy carriers.Different homogeneous catalysts are usually required for plasma-enabled biomass lique...Non-thermal plasma exhibits unique advan-tages in biomass conversion for the sustainable production of higher-value energy carriers.Different homogeneous catalysts are usually required for plasma-enabled biomass liquefaction to achieve time-and energy-efficient conver-sions.However,the effects of such catalysts on the plasma-assisted liquefaction process and of the plasma on those catalysts have not been thoroughly studied.In this study,an electrical discharge plasma is employed to promote the direct liquefaction of sawdust in a mixture of polyethylene glycol 200 and glycerol.Three commonly used chemicals,sulfuric acid,nitric acid and sodium p-toluene sulfate,were selected as catalysts.The effects of the type of catalyst and concentration on the liquefaction yield were examined;further,the roles of the catalysts in the plasma liquefaction process have been discussed.The results showed that the liquefaction yield attains a value of 90%within 5 min when 1%sulfuric acid was employed as the catalyst.Compared with the other catalysts,sulfuric acid presents the highest efficiency for the liquefaction of sawdust.It was observed that hydrogen ions from the catalyst were primarily responsible for the significant thermal effects on the liquefaction system and the generation of large quantities of active species;these effects directly con-tributed to a higher efficacy of the plasma-enabled liquefaction process.展开更多
文摘Tibetan weedy barleys reside at the edges of qingke(hulless barley)fields in Tibet(Xizang).The spikes of these weedy barleys contain or lack a brittle rachis,with either two-or six-rowed spikes and either hulled or hulless grains at maturity.Although the brittle rachis trait of Tibetan weedy barleys is similar to that of wild barley(Hordeum vulgare ssp.spontaneum Thell.),these plants share genetic similarity with domesticated barley.The origin of Tibetan weedy barleys continues to be debated.Here,we show that most Tibetan weedy barleys originated from cross-pollinated hybridization of domesticated barleys,followed by hybrid self-pollination and recombination between Non-brittle rachis 1(btr1)and 2(btr2).We discovered the specific genetic ancestry of these weedy barleys in South Asian accessions.Tibetan weedy barleys exhibit lower genetic diversity than wild and Chinese landraces/cultivars and share a close relationship with qingke,genetically differing from typical eastern and western barley populations.We classified Tibetan weedy barleys into two groups,brittle rachis(BR)and non-brittle rachis(NBR);these traits align with the haplotypes of the btr1 and btr2 genes.Whereas wild barleys carry haplotype combinations of Btr1 and Btr2,each showing lower proportions in a population,the recombinant haplotype BTR2H8+BTR1H24 is predominant in the BR group.Haplotype block analysis based on whole-genome sequencing revealed two recombination breakpoints,which are present in 80.6%and 16.8%of BR acces-sions according to marker-assisted analysis.Hybridization events between wild and domesticated barley were rarely detected.Thesefindings support the notion that Tibetan weedy barleys originated via recom-bination between Btr1 and Btr2 in domesticated barley.
基金The whole genome re-sequencing clean reads datasets were deposited in NCBI database with the accession ID“SAMN32366957”to“SAMN32366969”under the project ID“PRJNA915006”.
文摘Induced mutations are important for genetic research and breeding.Mutations induced by physical or chemical mutagenesis are usually heterozygous during the early generations.However,mutations must be fixed prior to phenotyping or field trials,which requires additional rounds of self-pollination.Microspore culture is an effective method to produce double-haploid(DH)plants that are fixed homozygotes.In this study,we conducted ethyl methanesulfonate(EMS)-induced mutagenesis of microspore cultures of barley(Hordeum vulgare)cultivar‘Hua30’and landrace‘HTX’.The EMS concentrations were negatively correlated with the efficiency of callus induction and the frequency of mutant plant regeneration.The two genotypes showed different regeneration efficiencies.The phenotypic variation of the regenerated M1 plants and the presence of genome-wide nucleotide mutations,revealed by whole-genome sequencing,highlight the utility of EMS-induced mutagenesis of isolated microspore cultures for developing DH mutants.Genome-wide analysis of the mutation frequency in the regenerated plants revealed that a considerable proportion of mutations resulted from microspore culture(somaclonal variation)rather than EMS-induced mutagenesis.In addition to producing a population of 1972 homozygous mutant lines that are available for future field trials,this study lays the foundation for optimizing the regeneration efficiency of DH plants and the richness of mutations(mainly by fine-tuning the mutagen dosage).
基金funded by grants from the National Key Research and Development Program of China(2018YFD1000702/2018YFD1000700)the Agricultural Science and Technology Innovation Program of the Chinese Academy of Agricultural Sciences(CAAS),China.
文摘Barley is a diploid species with a genome smaller than those of other members of the Triticeae tribe,making it an attractive model for genetic studies in Triticeae crops.The recent development of barley genomics has created a need for a high-throughput platform to identify genetically uniform mutants for gene function investigations.In this study,we report an ethyl methanesulfonate(EMS)-mutagenized population consisting of 8525M_(3) lines in the barley landrace“Hatiexi”(HTX),which we complement with a high-quality de novo assembly of a reference genome for this genotype.The mutation rate within the population ranged from 1.51 to 4.09 mutations per megabase,depending on the treatment dosage of EMS and the mutation discrimination platform used for genotype analysis.We implemented a three-dimensional DNA pooling strategy combined with multiplexed amplicon sequencing to create a highly efficient and cost-effective TILLING(targeting induced locus lesion in genomes)platform in barley.Mutations were successfully identified from 72 mixed amplicons within a DNA pool containing 64 individual mutants and from 56 mixed amplicons within a pool containing 144 individuals.We discovered abundant allelic mutants for dozens of genes,including the barley Green Revolution contributor gene Brassinosteroid insensitive 1(BRI1).As a proof of concept,we rapidly determined the causal gene responsible for a chlorotic mutant by following the MutMap strategy,demonstrating the value of this resource to support forward and reverse genetic studies in barley.
基金This work was supported by the Foundation of Key Laboratory of Biomass Chemical Engineering of Ministry of Education,China(Zhejiang University,No.2018BCE006)We are also grateful to the Australian Research Council for their partial support.
文摘Non-thermal plasma exhibits unique advan-tages in biomass conversion for the sustainable production of higher-value energy carriers.Different homogeneous catalysts are usually required for plasma-enabled biomass liquefaction to achieve time-and energy-efficient conver-sions.However,the effects of such catalysts on the plasma-assisted liquefaction process and of the plasma on those catalysts have not been thoroughly studied.In this study,an electrical discharge plasma is employed to promote the direct liquefaction of sawdust in a mixture of polyethylene glycol 200 and glycerol.Three commonly used chemicals,sulfuric acid,nitric acid and sodium p-toluene sulfate,were selected as catalysts.The effects of the type of catalyst and concentration on the liquefaction yield were examined;further,the roles of the catalysts in the plasma liquefaction process have been discussed.The results showed that the liquefaction yield attains a value of 90%within 5 min when 1%sulfuric acid was employed as the catalyst.Compared with the other catalysts,sulfuric acid presents the highest efficiency for the liquefaction of sawdust.It was observed that hydrogen ions from the catalyst were primarily responsible for the significant thermal effects on the liquefaction system and the generation of large quantities of active species;these effects directly con-tributed to a higher efficacy of the plasma-enabled liquefaction process.
