The transfer of genetic material between stocks and scions of grafted plants has been extensively studied;however,the nature and frequency of the transferred material remain elusive.Here,we report a grafting system in...The transfer of genetic material between stocks and scions of grafted plants has been extensively studied;however,the nature and frequency of the transferred material remain elusive.Here,we report a grafting system involving woody goji as the stock and herbaceous tomato as the scion,which was developed using in vitro and in vivo approaches;the results confirmed horizontal transfer of multiple nuclear DNA fragments from donor goji cells to recipient tomato cells.Tomato tissues containing goji donor DNA fragments at or near the grafting junctions had a perennial-biased anatomical structure,from which roots or shoots were regenerated.Most of the fragments were plasmid-like extrachromosomal circular DNAs(eccDNAs)present in the regenerants derived from the cells and in their asexual offspring.Plants with transferred eccDNAs in regenerated roots or shoots(designated“Go-tomato”)were grown perennially and showed excellent agronomic performance.The present study provides new insights into the replication,expression,and potential function of eccDNAs in the pleiotropic traits of Go-tomato.Mobile eccDNAs offer evidence of stock-to-scion horizontal DNA transfer beyond chromosomes and organelles,thereby contributing to the molecular understanding of graft-induced genetic variation,evolution,and breeding.展开更多
The silk gland cells of silkworm are special cells which only replicate DNA in the nucleus without cell division throughout the larval stage. The extrachromosomal circular DNAs (eccDNAs) have not yet been reported in ...The silk gland cells of silkworm are special cells which only replicate DNA in the nucleus without cell division throughout the larval stage. The extrachromosomal circular DNAs (eccDNAs) have not yet been reported in the silk gland of silkworms. Herein, we have explored the characterization of eccDNAs in the posterior silk gland of silkworms. A total of 35 346 eccDNAs were identified with sizes ranging from 30 to 13 569 549 bp. Motif analysis revealed that dual direct repeats are flanking the 5′ and 3′ breaking points of eccDNA. The sequences exceeding 1 kb length in eccDNAs present palindromic sequence characteristics flanking the 5′ and 3′ breaking points of the eccDNA. These motifs might support possible models for eccDNA generation. Genomic annotation of the eccDNA population revealed that most eccDNAs (58.6%) were derived from intergenic regions, whereas full or partial genes were carried by 41.4% of eccDNAs. It was found that silk protein genes fib-H, fib-L, and P25, as well as the transcription factors SGF and sage, which play an important regulatory role in silk protein synthesis, could be carried by eccDNAs. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses showed that the genes carried by eccDNAs were mainly associated with the development and metabolism-related signaling pathways. Moreover, it was found that eccDNAfib-L could promote the transcription of fib-L gene. Overall, the results of the present study not only provide a novel perspective on the mechanism of silk gland development and silk protein synthesis but also complement previously reported genome-scale eccDNA data supporting that eccDNAs are common in eukaryotes.展开更多
基金supported by grants from the Zhejiang Provincial“Three Rural Nine Parties”Science and Technology Cooperation Plan Project(2022SNJF027).
文摘The transfer of genetic material between stocks and scions of grafted plants has been extensively studied;however,the nature and frequency of the transferred material remain elusive.Here,we report a grafting system involving woody goji as the stock and herbaceous tomato as the scion,which was developed using in vitro and in vivo approaches;the results confirmed horizontal transfer of multiple nuclear DNA fragments from donor goji cells to recipient tomato cells.Tomato tissues containing goji donor DNA fragments at or near the grafting junctions had a perennial-biased anatomical structure,from which roots or shoots were regenerated.Most of the fragments were plasmid-like extrachromosomal circular DNAs(eccDNAs)present in the regenerants derived from the cells and in their asexual offspring.Plants with transferred eccDNAs in regenerated roots or shoots(designated“Go-tomato”)were grown perennially and showed excellent agronomic performance.The present study provides new insights into the replication,expression,and potential function of eccDNAs in the pleiotropic traits of Go-tomato.Mobile eccDNAs offer evidence of stock-to-scion horizontal DNA transfer beyond chromosomes and organelles,thereby contributing to the molecular understanding of graft-induced genetic variation,evolution,and breeding.
基金funded by National Key R&D Program of China(2019YFA0905200)the Natural Science Founda-tion of the Jiangsu Higher Education Institutions ofChina(22KJB23003)+2 种基金the National Natural Science Foundation of China(31872424,31972620,and 32072792)China Postdoctoral Science Foundation(2019M661937)Priority Academic Program of Development of Jiangsu Higher Education Institutions.
文摘The silk gland cells of silkworm are special cells which only replicate DNA in the nucleus without cell division throughout the larval stage. The extrachromosomal circular DNAs (eccDNAs) have not yet been reported in the silk gland of silkworms. Herein, we have explored the characterization of eccDNAs in the posterior silk gland of silkworms. A total of 35 346 eccDNAs were identified with sizes ranging from 30 to 13 569 549 bp. Motif analysis revealed that dual direct repeats are flanking the 5′ and 3′ breaking points of eccDNA. The sequences exceeding 1 kb length in eccDNAs present palindromic sequence characteristics flanking the 5′ and 3′ breaking points of the eccDNA. These motifs might support possible models for eccDNA generation. Genomic annotation of the eccDNA population revealed that most eccDNAs (58.6%) were derived from intergenic regions, whereas full or partial genes were carried by 41.4% of eccDNAs. It was found that silk protein genes fib-H, fib-L, and P25, as well as the transcription factors SGF and sage, which play an important regulatory role in silk protein synthesis, could be carried by eccDNAs. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses showed that the genes carried by eccDNAs were mainly associated with the development and metabolism-related signaling pathways. Moreover, it was found that eccDNAfib-L could promote the transcription of fib-L gene. Overall, the results of the present study not only provide a novel perspective on the mechanism of silk gland development and silk protein synthesis but also complement previously reported genome-scale eccDNA data supporting that eccDNAs are common in eukaryotes.
