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Wu T, Ma T, Xu T, Pan L, Zhang Y, Li Y, Ning D. The De Novo Genome Assembly of Olea europaea subsp. cuspidate, a Widely Distributed Olive Close Relative. Front Genet 2022; 13:868540. [PMID: 36092936 PMCID: PMC9454953 DOI: 10.3389/fgene.2022.868540] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 05/09/2022] [Indexed: 11/13/2022] Open
Abstract
The olive complex, comprising six subspecies, is a valuable plant for global trade, human health, and food safety. However, only one subspecies (Olea europaea subsp. europaea, OE) and its wild relative (Olea europaea subsp. europaea var. sylvestris, OS) have genomic references, hindering our understanding of the evolution of this species. Using a hybrid approach by incorporating Illumina, MGI, Nanopore, and Hi-C technologies, we obtained a 1.20-Gb genome assembly for the olive subspecies, Olea europaea subsp. cuspidate (OC), with contig and scaffold N50 values of 5.33 and 50.46 Mb, respectively. A total of 43,511 protein-coding genes were predicted from the genome. Interestingly, we observed a large region (37.5 Mb) of “gene-desert” also called “LTR-hotspot” on chromosome 17. The gene origination analyses revealed a substantial outburst (19.5%) of gene transposition events in the common ancestor of olive subspecies, suggesting the importance of olive speciation in shaping the new gene evolution of OC subspecies. The divergence time between OC and the last common ancestor of OE and OS was estimated to be 4.39 Mya (95% CI: 2.58–6.23 Mya). The pathways of positively selected genes of OC are related to the metabolism of cofactors and vitamins, indicating the potential medical and economic values of OC for further research and utilization. In summary, we constructed the de novo genome assembly and protein-coding gene pool for Olea europaea subsp. cuspidate (OC) in this study, which may facilitate breeding applications of improved olive varieties from this widely distributed olive close relative.
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Affiliation(s)
| | | | | | | | | | - Yongjie Li
- *Correspondence: Yongjie Li, ; Delu Ning,
| | - Delu Ning
- *Correspondence: Yongjie Li, ; Delu Ning,
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Huang Y, Chen J, Dong C, Sosa D, Xia S, Ouyang Y, Fan C, Li D, Mortola E, Long M, Bergelson J. Species-specific partial gene duplication in Arabidopsis thaliana evolved novel phenotypic effects on morphological traits under strong positive selection. THE PLANT CELL 2022; 34:802-817. [PMID: 34875081 PMCID: PMC8824575 DOI: 10.1093/plcell/koab291] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 11/25/2021] [Indexed: 05/04/2023]
Abstract
Gene duplication is increasingly recognized as an important mechanism for the origination of new genes, as revealed by comparative genomic analysis. However, how new duplicate genes contribute to phenotypic evolution remains largely unknown, especially in plants. Here, we identified the new gene EXOV, derived from a partial gene duplication of its parental gene EXOVL in Arabidopsis thaliana. EXOV is a species-specific gene that originated within the last 3.5 million years and shows strong signals of positive selection. Unexpectedly, RNA-sequencing analyses revealed that, despite its young age, EXOV has acquired many novel direct and indirect interactions in which the parental gene does not engage. This observation is consistent with the high, selection-driven substitution rate of its encoded protein, in contrast to the slowly evolving EXOVL, suggesting an important role for EXOV in phenotypic evolution. We observed significant differentiation of morphological changes for all phenotypes assessed in genome-edited and T-DNA insertional single mutants and in double T-DNA insertion mutants in EXOV and EXOVL. We discovered a substantial divergence of phenotypic effects by principal component analyses, suggesting neofunctionalization of the new gene. These results reveal a young gene that plays critical roles in biological processes that underlie morphological evolution in A. thaliana.
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Affiliation(s)
- Yuan Huang
- School of Life Sciences, Yunnan Normal University, Kunming, Yunnan, China
- Department of Ecology and Evolution, The University of Chicago, Chicago, Illinois, USA
| | - Jiahui Chen
- Department of Ecology and Evolution, The University of Chicago, Chicago, Illinois, USA
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Chuan Dong
- Department of Ecology and Evolution, The University of Chicago, Chicago, Illinois, USA
| | - Dylan Sosa
- Department of Ecology and Evolution, The University of Chicago, Chicago, Illinois, USA
| | - Shengqian Xia
- Department of Ecology and Evolution, The University of Chicago, Chicago, Illinois, USA
| | - Yidan Ouyang
- National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, China
| | - Chuanzhu Fan
- Department of Biological Sciences, Wayne State University, Detroit, Michigan, USA
| | - Dezhu Li
- CAS Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Emily Mortola
- Department of Ecology and Evolution, The University of Chicago, Chicago, Illinois, USA
| | - Manyuan Long
- Department of Ecology and Evolution, The University of Chicago, Chicago, Illinois, USA
| | - Joy Bergelson
- Department of Ecology and Evolution, The University of Chicago, Chicago, Illinois, USA
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