The Agrobacterium mediated transgenic rice ( Oryza saliva L.) population with inserts of maize transposon Activator/Dissociation (Ac/Ds) was investigated. DNA sequences flanking the T-DNA were analyzed with inverse PC...The Agrobacterium mediated transgenic rice ( Oryza saliva L.) population with inserts of maize transposon Activator/Dissociation (Ac/Ds) was investigated. DNA sequences flanking the T-DNA were analyzed with inverse PCR. Results showed that 65.4% of the T-DNA was integrated in different locations of rice genome, and some T-DNA flanking sequences were located on certain chromosomes. A number of T-DNA was found to have inserted into protein coding regions. In order to induce transposition of the inserted Ds elements, 354 crosses of Ac x Ds and Ds x Ac were constructed. The excision frequency of Ds element trans-activated by Ac transposase was 22.7% in the F-2 populations, and the transposition was confirmed with analyses of DNA sequences flanking the Ds elements. In addition to the transposition due to 'cut-paste' mechanism, Ds can replicate itself and integrate into a new locus, and inaccurate excisions were also found. A proportion of DNA segments flanking the Ds elements showed no homologies to sequences published in GenBank, of which two were registered under the accession numbers AF355153 and AF355770. The strategy of using transposon tagging for rice genomics study was discussed.展开更多
Sweet orange has one of the largest cultivar groups in Citrus,characterized by diverse horticultural traits developed through the selection of bud sports(somatic mutants).However,the role of transposable-element activ...Sweet orange has one of the largest cultivar groups in Citrus,characterized by diverse horticultural traits developed through the selection of bud sports(somatic mutants).However,the role of transposable-element activity in its diversification is largely unknown.Here,we comprehensively surveyed transposon activity in sweet orange genomes and identified six transposon families whose activity is increased up to 8974.2-fold in modern cultivars.These insertions serve as mutational markers,enabling the tagging of major sweet orange cultivar groups and distinguishing over 99%of sweet orange accessions.Moreover,they are significantly enriched in genes that affect plant development and hormone signaling.The widespread insertions of these hyperactive transposons enabled us to trace the lineage history of nearly all sweet orange cultivars,dating them to a common ancestor∼500 years ago,and to infer three major dispersal events.The activation of these transposons has resulted in significantly higher transposon activity in sweet orange compared to its parental species,revealing their unrecognized and crucial role in sweet orange breeding.展开更多
文摘The Agrobacterium mediated transgenic rice ( Oryza saliva L.) population with inserts of maize transposon Activator/Dissociation (Ac/Ds) was investigated. DNA sequences flanking the T-DNA were analyzed with inverse PCR. Results showed that 65.4% of the T-DNA was integrated in different locations of rice genome, and some T-DNA flanking sequences were located on certain chromosomes. A number of T-DNA was found to have inserted into protein coding regions. In order to induce transposition of the inserted Ds elements, 354 crosses of Ac x Ds and Ds x Ac were constructed. The excision frequency of Ds element trans-activated by Ac transposase was 22.7% in the F-2 populations, and the transposition was confirmed with analyses of DNA sequences flanking the Ds elements. In addition to the transposition due to 'cut-paste' mechanism, Ds can replicate itself and integrate into a new locus, and inaccurate excisions were also found. A proportion of DNA segments flanking the Ds elements showed no homologies to sequences published in GenBank, of which two were registered under the accession numbers AF355153 and AF355770. The strategy of using transposon tagging for rice genomics study was discussed.
基金supported in part by the US National Institute of Food and Agriculture(NIFA,grant number 2023-70029-41309)to F.L.,Y.D.,and F.G.G.the US National Science Foundation(NSF,grant numbers ABI1759856,MRI-2018069,and MTM2-2025541)to F.L.the Guangdong Provincial Special Fund for Modern Agriculture Industry Technology Innovation Teams(2024CXTD10)to Y.C.
文摘Sweet orange has one of the largest cultivar groups in Citrus,characterized by diverse horticultural traits developed through the selection of bud sports(somatic mutants).However,the role of transposable-element activity in its diversification is largely unknown.Here,we comprehensively surveyed transposon activity in sweet orange genomes and identified six transposon families whose activity is increased up to 8974.2-fold in modern cultivars.These insertions serve as mutational markers,enabling the tagging of major sweet orange cultivar groups and distinguishing over 99%of sweet orange accessions.Moreover,they are significantly enriched in genes that affect plant development and hormone signaling.The widespread insertions of these hyperactive transposons enabled us to trace the lineage history of nearly all sweet orange cultivars,dating them to a common ancestor∼500 years ago,and to infer three major dispersal events.The activation of these transposons has resulted in significantly higher transposon activity in sweet orange compared to its parental species,revealing their unrecognized and crucial role in sweet orange breeding.
