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Hu J, Liu C, Du Z, Guo F, Song D, Wang N, Wei Z, Jiang J, Cao Z, Shi C, Zhang S, Zhu C, Chen P, Larkin RM, Lin Z, Xu Q, Ye J, Deng X, Bosch M, Franklin‐Tong VE, Chai L. Transposable elements cause the loss of self-incompatibility in citrus. PLANT BIOTECHNOLOGY JOURNAL 2024; 22:1113-1131. [PMID: 38038155 PMCID: PMC11022811 DOI: 10.1111/pbi.14250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2023] [Revised: 10/25/2023] [Accepted: 11/11/2023] [Indexed: 12/02/2023]
Abstract
Self-incompatibility (SI) is a widespread prezygotic mechanism for flowering plants to avoid inbreeding depression and promote genetic diversity. Citrus has an S-RNase-based SI system, which was frequently lost during evolution. We previously identified a single nucleotide mutation in Sm-RNase, which is responsible for the loss of SI in mandarin and its hybrids. However, little is known about other mechanisms responsible for conversion of SI to self-compatibility (SC) and we identify a completely different mechanism widely utilized by citrus. Here, we found a 786-bp miniature inverted-repeat transposable element (MITE) insertion in the promoter region of the FhiS2-RNase in Fortunella hindsii Swingle (a model plant for citrus gene function), which does not contain the Sm-RNase allele but are still SC. We demonstrate that this MITE plays a pivotal role in the loss of SI in citrus, providing evidence that this MITE insertion prevents expression of the S-RNase; moreover, transgenic experiments show that deletion of this 786-bp MITE insertion recovers the expression of FhiS2-RNase and restores SI. This study identifies the first evidence for a role for MITEs at the S-locus affecting the SI phenotype. A family-wide survey of the S-locus revealed that MITE insertions occur frequently adjacent to S-RNase alleles in different citrus genera, but only certain MITEs appear to be responsible for the loss of SI. Our study provides evidence that insertion of MITEs into a promoter region can alter a breeding strategy and suggests that this phenomenon may be broadly responsible for SC in species with the S-RNase system.
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Affiliation(s)
- Jianbing Hu
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, College of Horticulture and Forestry SciencesHuazhong Agricultural UniversityWuhanP. R. China
- Hubei Hongshan LaboratoryWuhanP. R. China
| | - Chenchen Liu
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, College of Horticulture and Forestry SciencesHuazhong Agricultural UniversityWuhanP. R. China
- Hubei Hongshan LaboratoryWuhanP. R. China
| | - Zezhen Du
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, College of Horticulture and Forestry SciencesHuazhong Agricultural UniversityWuhanP. R. China
- Hubei Hongshan LaboratoryWuhanP. R. China
| | - Furong Guo
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, College of Horticulture and Forestry SciencesHuazhong Agricultural UniversityWuhanP. R. China
| | - Dan Song
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, College of Horticulture and Forestry SciencesHuazhong Agricultural UniversityWuhanP. R. China
| | - Nan Wang
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, College of Horticulture and Forestry SciencesHuazhong Agricultural UniversityWuhanP. R. China
| | - Zhuangmin Wei
- Guangxi Subtropical Crops Research InstituteNanningP. R. China
| | - Jingdong Jiang
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, College of Horticulture and Forestry SciencesHuazhong Agricultural UniversityWuhanP. R. China
| | - Zonghong Cao
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, College of Horticulture and Forestry SciencesHuazhong Agricultural UniversityWuhanP. R. China
| | - Chunmei Shi
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, College of Horticulture and Forestry SciencesHuazhong Agricultural UniversityWuhanP. R. China
| | - Siqi Zhang
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, College of Horticulture and Forestry SciencesHuazhong Agricultural UniversityWuhanP. R. China
| | - Chenqiao Zhu
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, College of Horticulture and Forestry SciencesHuazhong Agricultural UniversityWuhanP. R. China
| | - Peng Chen
- Horticultural Institute, Hunan Academy of Agricultural SciencesChangshaChina
| | - Robert M. Larkin
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, College of Horticulture and Forestry SciencesHuazhong Agricultural UniversityWuhanP. R. China
- Hubei Hongshan LaboratoryWuhanP. R. China
| | - Zongcheng Lin
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, College of Horticulture and Forestry SciencesHuazhong Agricultural UniversityWuhanP. R. China
- Hubei Hongshan LaboratoryWuhanP. R. China
| | - Qiang Xu
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, College of Horticulture and Forestry SciencesHuazhong Agricultural UniversityWuhanP. R. China
- Hubei Hongshan LaboratoryWuhanP. R. China
| | - Junli Ye
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, College of Horticulture and Forestry SciencesHuazhong Agricultural UniversityWuhanP. R. China
| | - Xiuxin Deng
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, College of Horticulture and Forestry SciencesHuazhong Agricultural UniversityWuhanP. R. China
- Hubei Hongshan LaboratoryWuhanP. R. China
| | - Maurice Bosch
- Institute of Biological, Environmental and Rural Sciences (IBERS)Aberystwyth UniversityAberystwythUK
| | | | - Lijun Chai
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, College of Horticulture and Forestry SciencesHuazhong Agricultural UniversityWuhanP. R. China
- Hubei Hongshan LaboratoryWuhanP. R. China
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Wang Y, Wang J, Yan Z, Hou J, Wan L, Yang Y, Liu Y, Yi J, Guo P, Han D. Structural investigation of pathogenic RFC1 AAGGG pentanucleotide repeats reveals a role of G-quadruplex in dysregulated gene expression in CANVAS. Nucleic Acids Res 2024; 52:2698-2710. [PMID: 38266156 PMCID: PMC10954463 DOI: 10.1093/nar/gkae032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 01/04/2024] [Accepted: 01/08/2024] [Indexed: 01/26/2024] Open
Abstract
An expansion of AAGGG pentanucleotide repeats in the replication factor C subunit 1 (RFC1) gene is the genetic cause of cerebellar ataxia, neuropathy, and vestibular areflexia syndrome (CANVAS), and it also links to several other neurodegenerative diseases including the Parkinson's disease. However, the pathogenic mechanism of RFC1 AAGGG repeat expansion remains enigmatic. Here, we report that the pathogenic RFC1 AAGGG repeats form DNA and RNA parallel G-quadruplex (G4) structures that play a role in impairing biological processes. We determine the first high-resolution nuclear magnetic resonance (NMR) structure of a bimolecular parallel G4 formed by d(AAGGG)2AA and reveal how AAGGG repeats fold into a higher-order structure composed of three G-tetrad layers, and further demonstrate the formation of intramolecular G4s in longer DNA and RNA repeats. The pathogenic AAGGG repeats, but not the nonpathogenic AAAAG repeats, form G4 structures to stall DNA replication and reduce gene expression via impairing the translation process in a repeat-length-dependent manner. Our results provide an unprecedented structural basis for understanding the pathogenic mechanism of AAGGG repeat expansion associated with CANVAS. In addition, the high-resolution structures resolved in this study will facilitate rational design of small-molecule ligands and helicases targeting G4s formed by AAGGG repeats for therapeutic interventions.
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Affiliation(s)
- Yang Wang
- School of Materials Science and Engineering, Tianjin University, Tianjin 300350, China
- Zhejiang Cancer Hospital, Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences, Hangzhou, Zhejiang 310022, China
| | - Junyan Wang
- Zhejiang Cancer Hospital, Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences, Hangzhou, Zhejiang 310022, China
| | - Zhenzhen Yan
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, Guangdong 510006, China
| | - Jianing Hou
- Institute of Molecular Medicine (IMM) Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
| | - Liqi Wan
- Zhejiang Cancer Hospital, Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences, Hangzhou, Zhejiang 310022, China
| | - Yingquan Yang
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, Guangdong 510006, China
| | - Yu Liu
- Zhejiang Cancer Hospital, Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences, Hangzhou, Zhejiang 310022, China
| | - Jie Yi
- Zhejiang Cancer Hospital, Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences, Hangzhou, Zhejiang 310022, China
| | - Pei Guo
- Zhejiang Cancer Hospital, Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences, Hangzhou, Zhejiang 310022, China
| | - Da Han
- Zhejiang Cancer Hospital, Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences, Hangzhou, Zhejiang 310022, China
- Institute of Molecular Medicine (IMM) Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China
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Hiraoka Y, Ferrante SP, Wu GA, Federici CT, Roose ML. Development and Assessment of SNP Genotyping Arrays for Citrus and Its Close Relatives. PLANTS (BASEL, SWITZERLAND) 2024; 13:691. [PMID: 38475537 DOI: 10.3390/plants13050691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 02/13/2024] [Accepted: 02/22/2024] [Indexed: 03/14/2024]
Abstract
Rapid advancements in technologies provide various tools to analyze fruit crop genomes to better understand genetic diversity and relationships and aid in breeding. Genome-wide single nucleotide polymorphism (SNP) genotyping arrays offer highly multiplexed assays at a relatively low cost per data point. We report the development and validation of 1.4M SNP Axiom® Citrus HD Genotyping Array (Citrus 15AX 1 and Citrus 15AX 2) and 58K SNP Axiom® Citrus Genotyping Arrays for Citrus and close relatives. SNPs represented were chosen from a citrus variant discovery panel consisting of 41 diverse whole-genome re-sequenced accessions of Citrus and close relatives, including eight progenitor citrus species. SNPs chosen mainly target putative genic regions of the genome and are accurately called in both Citrus and its closely related genera while providing good coverage of the nuclear and chloroplast genomes. Reproducibility of the arrays was nearly 100%, with a large majority of the SNPs classified as the most stringent class of markers, "PolyHighResolution" (PHR) polymorphisms. Concordance between SNP calls in sequence data and array data average 98%. Phylogenies generated with array data were similar to those with comparable sequence data and little affected by 3 to 5% genotyping error. Both arrays are publicly available.
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Affiliation(s)
- Yoko Hiraoka
- Department of Botany and Plant Sciences, University of California, Riverside, CA 92521, USA
| | - Sergio Pietro Ferrante
- Department of Botany and Plant Sciences, University of California, Riverside, CA 92521, USA
| | - Guohong Albert Wu
- US Department of Energy Joint Genome Institute, Walnut Creek, CA 94598, USA
| | - Claire T Federici
- Department of Botany and Plant Sciences, University of California, Riverside, CA 92521, USA
| | - Mikeal L Roose
- Department of Botany and Plant Sciences, University of California, Riverside, CA 92521, USA
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Fu MK, He YN, Yang XY, Tang X, Wang M, Dai WS. Genome-wide identification of the GRF family in sweet orange (Citrus sinensis) and functional analysis of the CsGRF04 in response to multiple abiotic stresses. BMC Genomics 2024; 25:37. [PMID: 38184538 PMCID: PMC10770916 DOI: 10.1186/s12864-023-09952-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Accepted: 12/28/2023] [Indexed: 01/08/2024] Open
Abstract
BACKGROUND Citrus is one of the most valuable fruits worldwide and an economic pillar industry in southern China. Nevertheless, it frequently suffers from undesirable environmental stresses during the growth cycle, which severely restricts the growth, development and yield of citrus. In plants, the growth-regulating factor (GRF) family of transcription factors (TF) is extensively distributed and plays an vital part in plant growth and development, hormone response, as well as stress adaptation. However, the systematic identification and functional analysis of GRF TFs in citrus have not been reported. RESULTS Here, a genome-wide identification of GRF TFs was performed in Citrus sinensis, 9 members of CsGRFs were systematically identified and discovered to be scattered throughout 5 chromosomes. Subsequently, physical and chemical properties, phylogenetic relationships, structural characteristics, gene duplication events, collinearity and cis-elements of promoter were elaborately analyzed. In particular, the expression patterns of the CsGRF genes in response to multiple phytohormone and abiotic stress treatments were investigated. Predicated on this result, CsGRF04, which exhibited the most differential expression pattern under multiple phytohormone and abiotic stress treatments was screened out. Virus-induced gene silencing (VIGS) technology was utilized to obtain gene silenced plants for CsGRF04 successfully. After the three stress treatments of high salinity, low temperature and drought, the CsGRF04-VIGS lines showed significantly reduced resistance to high salinity and low temperature stresses, but extremely increased resistance to drought stress. CONCLUSIONS Taken together, our findings systematically analyzed the genomic characterization of GRF family in Citrus sinensis, and excavated a CsGRF04 with potential functions under multiple abiotic stresses. Our study lay a foundation for further study on the function of CsGRFs in abiotic stress and hormone signaling response.
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Affiliation(s)
- Ming-Kang Fu
- College of Life Sciences, Gannan Normal University, National Navel Orange Engineering Research Center, Ganzhou, 341000, Jiangxi, China
| | - Ying-Na He
- College of Life Sciences, Gannan Normal University, National Navel Orange Engineering Research Center, Ganzhou, 341000, Jiangxi, China
| | - Xiao-Yue Yang
- College of Life Sciences, Gannan Normal University, National Navel Orange Engineering Research Center, Ganzhou, 341000, Jiangxi, China
| | - Xi Tang
- College of Life Sciences, Gannan Normal University, National Navel Orange Engineering Research Center, Ganzhou, 341000, Jiangxi, China
| | - Min Wang
- College of Life Sciences, Gannan Normal University, National Navel Orange Engineering Research Center, Ganzhou, 341000, Jiangxi, China
| | - Wen-Shan Dai
- College of Life Sciences, Gannan Normal University, National Navel Orange Engineering Research Center, Ganzhou, 341000, Jiangxi, China.
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5
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Jia HH, Xu YT, Yin ZJ, Qing M, Xie KD, Guo WW, Wu XM. Genome-wide identification of the C2H2-Zinc finger gene family and functional validation of CsZFP7 in citrus nucellar embryogenesis. PLANT REPRODUCTION 2023; 36:287-300. [PMID: 37247027 DOI: 10.1007/s00497-023-00470-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 05/15/2023] [Indexed: 05/30/2023]
Abstract
KEY MESSAGE Genome-wide identification of C2H2-ZF gene family in the poly- and mono-embryonic citrus species and validation of the positive role of CsZFP7 in sporophytic apomixis. The C2H2 zinc finger (C2H2-ZF) gene family is involved in plant vegetative and reproductive development. Although a large number of C2H2 zinc-finger proteins (C2H2-ZFPs) have been well characterized in some horticultural plants, little is known about the C2H2-ZFPs and their function in citrus. In this work, we performed a genome-wide sequence analysis and identified 97 and 101 putative C2H2-ZF gene family members in the genomes of sweet orange (C. sinensis, poly-embryonic) and pummelo (C. grandis, mono-embryonic), respectively. Phylogenetic analysis categorized citrus C2H2-ZF gene family into four clades, and their possible functions were inferred. According to the numerous regulatory elements on promoter, citrus C2H2-ZFPs can be divided into five different regulatory function types that indicate functional differentiation. RNA-seq data revealed 20 differentially expressed C2H2-ZF genes between poly-embryonic and mono-embryonic ovules at two stages of citrus nucellar embryogenesis, among them CsZFP52 specifically expressed in mono-embryonic pummelo ovules, while CsZFP7, 37, 44, 45, 67 and 68 specifically expressed in poly-embryonic sweet orange ovules. RT-qPCR further validated that CsZFP7 specifically expressed at higher levels in poly-embryonic ovules, and down-regulation of CsZFP7 in the poly-embryonic mini citrus (Fortunella hindsii) increased rate of mono-embryonic seeds compared with the wild type, indicating the regulatory potential of CsZFP7 in nucellar embryogenesis of citrus. This work provided a comprehensive analysis of C2H2-ZF gene family in citrus, including genome organization and gene structure, phylogenetic relationships, gene duplications, possible cis-elements on promoter regions and expression profiles, especially in the poly- and mono-embryogenic ovules, and suggested that CsZFP7 is involved in nucellar embryogenesis.
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Affiliation(s)
- Hui-Hui Jia
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, China
| | - Yuan-Tao Xu
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, China
| | - Zhu-Jun Yin
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, China
| | - Mei Qing
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, China
| | - Kai-Dong Xie
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, China
| | - Wen-Wu Guo
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, China
| | - Xiao-Meng Wu
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, China.
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6
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Huang Y, He J, Xu Y, Zheng W, Wang S, Chen P, Zeng B, Yang S, Jiang X, Liu Z, Wang L, Wang X, Liu S, Lu Z, Liu Z, Yu H, Yue J, Gao J, Zhou X, Long C, Zeng X, Guo YJ, Zhang WF, Xie Z, Li C, Ma Z, Jiao W, Zhang F, Larkin RM, Krueger RR, Smith MW, Ming R, Deng X, Xu Q. Pangenome analysis provides insight into the evolution of the orange subfamily and a key gene for citric acid accumulation in citrus fruits. Nat Genet 2023; 55:1964-1975. [PMID: 37783780 DOI: 10.1038/s41588-023-01516-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 08/28/2023] [Indexed: 10/04/2023]
Abstract
The orange subfamily (Aurantioideae) contains several Citrus species cultivated worldwide, such as sweet orange and lemon. The origin of Citrus species has long been debated and less is known about the Aurantioideae. Here, we compiled the genome sequences of 314 accessions, de novo assembled the genomes of 12 species and constructed a graph-based pangenome for Aurantioideae. Our analysis indicates that the ancient Indian Plate is the ancestral area for Citrus-related genera and that South Central China is the primary center of origin of the Citrus genus. We found substantial variations in the sequence and expression of the PH4 gene in Citrus relative to Citrus-related genera. Gene editing and biochemical experiments demonstrate a central role for PH4 in the accumulation of citric acid in citrus fruits. This study provides insights into the origin and evolution of the orange subfamily and a regulatory mechanism underpinning the evolution of fruit taste.
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Affiliation(s)
- Yue Huang
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan, People's Republic of China
- Hubei Hongshan Laboratory, Wuhan, People's Republic of China
| | - Jiaxian He
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan, People's Republic of China
| | - Yuantao Xu
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan, People's Republic of China
- Hubei Hongshan Laboratory, Wuhan, People's Republic of China
| | - Weikang Zheng
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan, People's Republic of China
| | - Shaohua Wang
- Institute of Tropical and Subtropical Cash Crops, Yunnan Academy of Agricultural Sciences, Yunnan, People's Republic of China
| | - Peng Chen
- Horticulture Institute, Hunan Academy of Agricultural Sciences, Changsha, People's Republic of China
| | - Bin Zeng
- Horticulture Institute, Hunan Academy of Agricultural Sciences, Changsha, People's Republic of China
| | - Shuizhi Yang
- Horticulture Institute, Hunan Academy of Agricultural Sciences, Changsha, People's Republic of China
| | - Xiaolin Jiang
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan, People's Republic of China
| | - Zishuang Liu
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan, People's Republic of China
| | - Lun Wang
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan, People's Republic of China
| | - Xia Wang
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan, People's Republic of China
| | - Shengjun Liu
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan, People's Republic of China
| | - Zhihao Lu
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan, People's Republic of China
| | - Ziang Liu
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan, People's Republic of China
| | - Huiwen Yu
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan, People's Republic of China
| | - Jianqiang Yue
- Institute of Tropical and Subtropical Cash Crops, Yunnan Academy of Agricultural Sciences, Yunnan, People's Republic of China
| | - Junyan Gao
- Institute of Tropical and Subtropical Cash Crops, Yunnan Academy of Agricultural Sciences, Yunnan, People's Republic of China
| | - Xianyan Zhou
- Institute of Tropical and Subtropical Cash Crops, Yunnan Academy of Agricultural Sciences, Yunnan, People's Republic of China
| | - Chunrui Long
- Institute of Tropical and Subtropical Cash Crops, Yunnan Academy of Agricultural Sciences, Yunnan, People's Republic of China
| | - Xiuli Zeng
- Qinghai-Tibet Plateau Fruit Trees Scientific Observation Test Station, Ministry of Agriculture and Rural Affairs, Lhasa, People's Republic of China
| | - Yong-Jie Guo
- Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, People's Republic of China
- University of the Chinese Academy of Sciences, Beijing, People's Republic of China
| | - Wen-Fu Zhang
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, People's Republic of China
| | - Zongzhou Xie
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan, People's Republic of China
| | - Chunlong Li
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan, People's Republic of China
| | - Zhaocheng Ma
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan, People's Republic of China
| | - Wenbiao Jiao
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan, People's Republic of China
| | - Fei Zhang
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan, People's Republic of China
| | - Robert M Larkin
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan, People's Republic of China
| | - Robert R Krueger
- United States Department of Agriculture-Agricultural Research Service National Clonal Germplasm Repository for Citrus and Dates, Riverside, CA, USA
| | - Malcolm W Smith
- Department of Agriculture and Fisheries, Bundaberg, Queensland, Australia
| | - Ray Ming
- Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Xiuxin Deng
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan, People's Republic of China
| | - Qiang Xu
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan, People's Republic of China.
- Hubei Hongshan Laboratory, Wuhan, People's Republic of China.
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7
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Wang M, Qin YY, Wei NN, Xue HY, Dai WS. Highly efficient Agrobacterium rhizogenes-mediated hairy root transformation in citrus seeds and its application in gene functional analysis. FRONTIERS IN PLANT SCIENCE 2023; 14:1293374. [PMID: 38023879 PMCID: PMC10644275 DOI: 10.3389/fpls.2023.1293374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 10/19/2023] [Indexed: 12/01/2023]
Abstract
Highly efficient genetic transformation technology is beneficial for plant gene functional research and molecular improvement breeding. However, the most commonly used Agrobacterium tumefaciens-mediated genetic transformation technology is time-consuming and recalcitrant for some woody plants such as citrus, hampering the high-throughput functional analysis of citrus genes. Thus, we dedicated to develop a rapid, simple, and highly efficient hairy root transformation system induced by Agrobacterium rhizogenes to analyze citrus gene function. In this report, a rapid, universal, and highly efficient hairy root transformation system in citrus seeds was described. Only 15 days were required for the entire workflow and the system was applicable for various citrus genotypes, with a maximum transformation frequency of 96.1%. After optimization, the transformation frequency of Citrus sinensis, which shows the lowest transformation frequency of 52.3% among four citrus genotypes initially, was increased to 71.4% successfully. To test the applicability of the hairy roots transformation system for gene functional analysis of citrus genes, we evaluated the subcellular localization, gene overexpression and gene editing in transformed hairy roots. Compared with the traditional transient transformation system performed in tobacco leaves, the transgenic citrus hairy roots displayed a more clear and specific subcellular fluorescence localization. Transcript levels of genes were significantly increased in overexpressing transgenic citrus hairy roots as compared with wild-type (WT). Additionally, hairy root transformation system in citrus seeds was successful in obtaining transformants with knocked out targets, indicating that the Agrobacterium rhizogenes-mediated transformation enables the CRISPR/Cas9-mediated gene editing. In summary, we established a highly efficient genetic transformation technology with non-tissue-culture in citrus that can be used for functional analysis such as protein subcellular localization, gene overexpression and gene editing. Since the material used for genetic transformation are roots protruding out of citrus seeds, the process of planting seedlings prior to transformation of conventional tissue culture or non-tissue-culture was eliminated, and the experimental time was greatly reduced. We anticipate that this genetic transformation technology will be a valuable tool for routine research of citrus genes in the future.
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Affiliation(s)
| | | | | | | | - Wen-Shan Dai
- China-USA Citrus Huanglongbing Joint Laboratory, National Navel Orange Engineering Research Center, College of Life Sciences, Gannan Normal University, Ganzhou, Jiangxi, China
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Jabeen S, Saif R, Haq R, Hayat A, Naz S. Whole-genome sequencing and variant discovery of Citrus reticulata "Kinnow" from Pakistan. Funct Integr Genomics 2023; 23:227. [PMID: 37422603 DOI: 10.1007/s10142-023-01153-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 06/20/2023] [Accepted: 06/21/2023] [Indexed: 07/10/2023]
Abstract
Citrus is a source of nutritional and medicinal advantages, cultivated worldwide with major groups of sweet oranges, mandarins, grapefruits, kumquats, lemons and limes. Pakistan produces all major citrus groups with mandarin (Citrus reticulata) being the prominent group that includes local commercial cultivars Feutral's Early, Dancy, Honey, and Kinnow. The present study designed to understand the genetic architecture of this unique variety of Citrus reticulata 'Kinnow.' The whole-genome resequencing and variant calling was performed to map the genomic variability that might be responsible for its particular characteristics like taste, seedlessness, juice content, thickness of peel, and shelf-life. A total of 139,436,350 raw sequence reads were generated with 20.9 Gb data in Fastq format having 98% effectiveness and 0.2% base call error rate. Overall, 3,503,033 SNPs, 176,949 MNPs, 323,287 INS, and 333,083 DEL were identified using the GATK4 variant calling pipeline against Citrus clementina. Furthermore, g:Profiler was applied for annotating the newly found variants, harbor genes/transcripts and their involved pathways. A total of 73,864 transcripts harbors 4,336,352 variants, most of the observed variants were predicted in non-coding regions and 1009 transcripts were found well annotated by different databases. Out of total aforementioned transcripts, 588 involved in biological processes, 234 in molecular functions and 167 transcripts in cellular components. In a nutshell, 18,153 high impact variants and 216 genic variants found in the current study, which may be used after its functional validation for marker-assisted breeding programs of "Kinnow" to propagate its valued traits for the improvement of contemporary citrus varieties in the region.
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Affiliation(s)
- Sadia Jabeen
- Department of Biotechnology, Lahore College for Women University, Lahore, Pakistan
| | - Rashid Saif
- Department of Biotechnology, Qarshi University, Lahore, Pakistan
- Decode Genomics, Punjab University Employees Housing Scheme, Lahore, Pakistan
| | - Rukhama Haq
- Department of Biotechnology, Lahore College for Women University, Lahore, Pakistan
| | - Akbar Hayat
- Citrus Research Institute, Sargodha, Pakistan
| | - Shagufta Naz
- Department of Biotechnology, Lahore College for Women University, Lahore, Pakistan.
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9
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Flint-Garcia S, Feldmann MJ, Dempewolf H, Morrell PL, Ross-Ibarra J. Diamonds in the not-so-rough: Wild relative diversity hidden in crop genomes. PLoS Biol 2023; 21:e3002235. [PMID: 37440605 PMCID: PMC10368281 DOI: 10.1371/journal.pbio.3002235] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 07/25/2023] [Indexed: 07/15/2023] Open
Abstract
Crop production is becoming an increasing challenge as the global population grows and the climate changes. Modern cultivated crop species are selected for productivity under optimal growth environments and have often lost genetic variants that could allow them to adapt to diverse, and now rapidly changing, environments. These genetic variants are often present in their closest wild relatives, but so are less desirable traits. How to preserve and effectively utilize the rich genetic resources that crop wild relatives offer while avoiding detrimental variants and maladaptive genetic contributions is a central challenge for ongoing crop improvement. This Essay explores this challenge and potential paths that could lead to a solution.
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Affiliation(s)
- Sherry Flint-Garcia
- Plant Genetics Research Unit, United States Department of Agriculture, Agricultural Research Service, Columbia, Missouri, United States of America
| | - Mitchell J. Feldmann
- Department of Plant Sciences, University of California, Davis, California, United States of America
| | | | - Peter L. Morrell
- Department of Agronomy and Plant Genetics, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Jeffrey Ross-Ibarra
- Department of Evolution and Ecology, Center for Population Biology, and Genome Center, University of California, Davis, California, United States of America
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10
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Session AM, Rokhsar DS. Transposon signatures of allopolyploid genome evolution. Nat Commun 2023; 14:3180. [PMID: 37263993 DOI: 10.1038/s41467-023-38560-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 05/08/2023] [Indexed: 06/03/2023] Open
Abstract
Hybridization brings together chromosome sets from two or more distinct progenitor species. Genome duplication associated with hybridization, or allopolyploidy, allows these chromosome sets to persist as distinct subgenomes during subsequent meioses. Here, we present a general method for identifying the subgenomes of a polyploid based on shared ancestry as revealed by the genomic distribution of repetitive elements that were active in the progenitors. This subgenome-enriched transposable element signal is intrinsic to the polyploid, allowing broader applicability than other approaches that depend on the availability of sequenced diploid relatives. We develop the statistical basis of the method, demonstrate its applicability in the well-studied cases of tobacco, cotton, and Brassica napus, and apply it to several cases: allotetraploid cyprinids, allohexaploid false flax, and allooctoploid strawberry. These analyses provide insight into the origins of these polyploids, revise the subgenome identities of strawberry, and provide perspective on subgenome dominance in higher polyploids.
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Affiliation(s)
- Adam M Session
- Department of Molecular and Cell, University of California, Berkeley, CA, 94720, USA.
- US Department of Energy Joint Genome Institute, 1 Cyclotron Road, Berkeley, CA, 94720, USA.
- Department of Biological Sciences, Binghamton University, Binghamton, NY, 13902, USA.
| | - Daniel S Rokhsar
- Department of Molecular and Cell, University of California, Berkeley, CA, 94720, USA
- US Department of Energy Joint Genome Institute, 1 Cyclotron Road, Berkeley, CA, 94720, USA
- Molecular Genetics Unit, Okinawa Institute for Science and Technology Graduate University, Okinawa, Japan
- Chan Zuckerberg BioHub, San Francisco, CA, USA
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11
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Liu DD, Wang DR, Yang XY, Zhao CH, Li SH, Sha GL, Zhang RF, Ge HJ, Tong XS, You CX. Apomictic Malus plants exhibit abnormal pollen development. FRONTIERS IN PLANT SCIENCE 2023; 14:1065032. [PMID: 36890893 PMCID: PMC9986266 DOI: 10.3389/fpls.2023.1065032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Accepted: 01/30/2023] [Indexed: 06/18/2023]
Abstract
Apomixis is the asexual reproduction through seeds that leads to the production of genetically uniform progeny. It has become an important tool in plant breeding because it facilitates the retention of genotypes with desirable traits and allows seeds to be obtained directly from mother plants. Apomixis is rare in most economically important crops, but it occurs in some Malus species. Here, the apomictic characteristics of Malus were examined using four apomictic and two sexually reproducing Malus plants. Results from transcriptome analysis showed that plant hormone signal transduction was the main factor affecting apomictic reproductive development. Four of the apomictic Malus plants examined were triploid, and pollen was either absent or present in very low densities in the stamen. Variation in the presence of pollen was associated with variation in the apomictic percentage; specifically, pollen was absent in the stamens of tea crabapple plants with the highest apomictic percentage. Furthermore, pollen mother cells failed to progress normally into meiosis and pollen mitosis, a trait mostly observed in apomictic Malus plants. The expression levels of meiosis-related genes were upregulated in apomictic plants. Our findings indicate that our simple method of detecting pollen abortion could be used to identify apple plants that are capable of apomictic reproduction.
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Affiliation(s)
- Dan-Dan Liu
- College of Agriculture, Yunnan University, Kunming, Yunnan, China
| | - Da-Ru Wang
- National Key Laboratory of Crop Biology, National Research Center for Apple Engineering and Technology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, Shandong, China
| | - Xuan-Yu Yang
- College of Agriculture, Yunnan University, Kunming, Yunnan, China
| | - Chang-Hui Zhao
- College of Agriculture, Yunnan University, Kunming, Yunnan, China
| | - Shao-Hua Li
- College of Agriculture, Yunnan University, Kunming, Yunnan, China
| | - Guang-Li Sha
- Qingdao Academy of Agricultural Sciences, Qingdao, Shandong, China
| | - Rui-Fen Zhang
- Qingdao Academy of Agricultural Sciences, Qingdao, Shandong, China
| | - Hong-Juan Ge
- Qingdao Academy of Agricultural Sciences, Qingdao, Shandong, China
| | - Xian-Song Tong
- Fu-ning Popularizing Agricultural Techniques Center, Fu-ning, Yunnan, China
| | - Chun-Xiang You
- National Key Laboratory of Crop Biology, National Research Center for Apple Engineering and Technology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, Shandong, China
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12
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Li J, Wan L, Wang Y, Chen Y, Lee HK, Lam SL, Guo P. Solution Nuclear Magnetic Resonance Structures of ATTTT and ATTTC Pentanucleotide Repeats Associated with SCA37 and FAMEs. ACS Chem Neurosci 2023; 14:289-299. [PMID: 36580663 DOI: 10.1021/acschemneuro.2c00593] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Expansions of ATTTT and ATTTC pentanucleotide repeats in the human genome are recently found to be associated with at least seven neurodegenerative diseases, including spinocerebellar ataxia type 37 (SCA37) and familial adult myoclonic epilepsy (FAME) types 1, 2, 3, 4, 6, and 7. The formation of non-B DNA structures during some biological processes is thought as a causative factor for repeat expansions. Yet, the structural basis for these pyrimidine-rich ATTTT and ATTTC repeat expansions remains elusive. In this study, we investigated the solution structures of ATTTT and ATTTC repeats using nuclear magnetic resonance spectroscopy. Here, we reveal that ATTTT and ATTTC repeats can form a highly compact minidumbbell structure at the 5'-end using their first two repeats. The high-resolution structure of two ATTTT repeats was determined, showing a regular TTTTA pentaloop and a quasi TTTT/A pentaloop. Furthermore, the minidumbbell structure could escape from proofreading by the Klenow fragment of DNA polymerase I when it was located at five or more base pairs away from the priming site, leading to a small-scale repeat expansion. Results of this work improve our understanding of ATTTT and ATTTC repeat expansions in SCA37 and FAMEs, and provide high-resolution structural information for rational drug design.
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Affiliation(s)
- Jinxia Li
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong 999077, China
| | - Liqi Wan
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong 999077, China
| | - Yang Wang
- The Cancer Hospital of the University of Chinese Academy of Sciences (Zhejiang Cancer Hospital), Institute of Basic Medicine and Cancer (IBMC) Chinese Academy of Sciences, Hangzhou, Zhejiang 310022, China.,School of Biology and Biological Engineering, South China University of Technology, Guangzhou, Guangdong 510006, China
| | - Yawen Chen
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, Guangdong 510006, China
| | - Hung Kay Lee
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong 999077, China
| | - Sik Lok Lam
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong 999077, China
| | - Pei Guo
- The Cancer Hospital of the University of Chinese Academy of Sciences (Zhejiang Cancer Hospital), Institute of Basic Medicine and Cancer (IBMC) Chinese Academy of Sciences, Hangzhou, Zhejiang 310022, China
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Pan-mitogenomics reveals the genetic basis of cytonuclear conflicts in citrus hybridization, domestication, and diversification. Proc Natl Acad Sci U S A 2022; 119:e2206076119. [PMID: 36260744 PMCID: PMC9618123 DOI: 10.1073/pnas.2206076119] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Although interactions between the cytoplasmic and nuclear genomes occurred during diversification of many plants, the evolutionary conflicts due to cytonuclear interactions are poorly understood in crop breeding. Here, we constructed a pan-mitogenome and identified chimeric open reading frames (ORFs) generated by extensive structural variations (SVs). Meanwhile, short reads from 184 accessions of citrus species were combined to construct three variation maps for the nuclear, mitochondrial, and chloroplast genomes. The population genomic data showed discordant topologies between the cytoplasmic and nuclear genomes because of differences in mutation rates and levels of heteroplasmy from paternal leakage. An analysis of species-specific SVs indicated that mitochondrial heteroplasmy was common and that chloroplast heteroplasmy was undetectable. Interestingly, we found a prominent divergence in the mitogenomes and the highest genetic load in the, which may provide the basis for cytoplasmic male sterility (CMS) and thus influence the reshuffling of the cytoplasmic and nuclear genomes during hybridization. Using cytoplasmic replacement experiments, we identified a type of species-specific CMS in mandarin related to two chimeric mitochondrial genes. Our analyses indicate that cytoplasmic genomes from mandarin have rarely been maintained in hybrids and that paternal leakage produced very low levels of mitochondrial heteroplasmy in mandarin. A genome-wide association study (GWAS) provided evidence for three nuclear genes that encode pentatricopeptide repeat (PPR) proteins contributing to the cytonuclear interactions in the Citrus genus. Our study demonstrates the occurrence of evolutionary conflicts between cytoplasmic and nuclear genomes in citrus and has important implications for genetics and breeding.
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14
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Wang N, Song X, Ye J, Zhang S, Cao Z, Zhu C, Hu J, Zhou Y, Huang Y, Cao S, Liu Z, Wu X, Chai L, Guo W, Xu Q, Gaut BS, Koltunow AMG, Zhou Y, Deng X. Structural variation and parallel evolution of apomixis in citrus during domestication and diversification. Natl Sci Rev 2022; 9:nwac114. [PMID: 36415319 PMCID: PMC9671666 DOI: 10.1093/nsr/nwac114] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 05/26/2022] [Accepted: 05/27/2022] [Indexed: 09/02/2023] Open
Abstract
Apomixis, or asexual seed formation, is prevalent in Citrinae via a mechanism termed nucellar or adventitious embryony. Here, multiple embryos of a maternal genotype form directly from nucellar cells in the ovule and can outcompete the developing zygotic embryo as they utilize the sexually derived endosperm for growth. Whilst nucellar embryony enables the propagation of clonal plants of maternal genetic constitution, it is also a barrier to effective breeding through hybridization. To address the genetics and evolution of apomixis in Citrinae, a chromosome-level genome of the Hongkong kumquat (Fortunella hindsii) was assembled following a genome-wide variation map including structural variants (SVs) based on 234 Citrinae accessions. This map revealed that hybrid citrus cultivars shelter genome-wide deleterious mutations and SVs into heterozygous states free from recessive selection, which may explain the capability of nucellar embryony in most cultivars during Citrinae diversification. Analyses revealed that parallel evolution may explain the repeated origin of apomixis in different genera of Citrinae. Within Fortunella, we found that apomixis of some varieties originated via introgression. In apomictic Fortunella, the locus associated with apomixis contains the FhRWP gene, encoding an RWP-RK domain-containing protein previously shown to be required for nucellar embryogenesis in Citrus. We found the heterozygous SV in the FhRWP and CitRWP promoters from apomictic Citrus and Fortunella, due to either two or three miniature inverted transposon element (MITE) insertions. A transcription factor, FhARID, encoding an AT-rich interaction domain-containing protein binds to the MITEs in the promoter of apomictic varieties, which facilitates induction of nucellar embryogenesis. This study provides evolutionary genomic and molecular insights into apomixis in Citrinae and has potential ramifications for citrus breeding.
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Affiliation(s)
- Nan Wang
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Huazhong Agricultural University, Wuhan 430070, China
| | - Xietian Song
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Huazhong Agricultural University, Wuhan 430070, China
| | - Junli Ye
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Huazhong Agricultural University, Wuhan 430070, China
| | - Siqi Zhang
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Huazhong Agricultural University, Wuhan 430070, China
| | - Zhen Cao
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Huazhong Agricultural University, Wuhan 430070, China
| | - Chenqiao Zhu
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Huazhong Agricultural University, Wuhan 430070, China
| | - Jianbing Hu
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Huazhong Agricultural University, Wuhan 430070, China
| | - Yin Zhou
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Huazhong Agricultural University, Wuhan 430070, China
| | - Yue Huang
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Huazhong Agricultural University, Wuhan 430070, China
| | - Shuo Cao
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen 518124, China
| | - Zhongjie Liu
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen 518124, China
| | - Xiaomeng Wu
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Huazhong Agricultural University, Wuhan 430070, China
| | - Lijun Chai
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Huazhong Agricultural University, Wuhan 430070, China
| | - Wenwu Guo
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Huazhong Agricultural University, Wuhan 430070, China
| | - Qiang Xu
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Huazhong Agricultural University, Wuhan 430070, China
| | - Brandon S Gaut
- Department of Ecology and Evolutionary Biology, University of California Irvine, Irvine, CA 92697, USA
| | - Anna M G Koltunow
- Queensland Alliance for Agriculture and Food Innovation, University of Queensland, Brisbane 4072, Australia
| | - Yongfeng Zhou
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen 518124, China
| | - Xiuxin Deng
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Huazhong Agricultural University, Wuhan 430070, China
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Perez-Roman E, Borredá C, Tadeo FR, Talon M. Transcriptome analysis of the pulp of citrus fruitlets suggests that domestication enhanced growth processes and reduced chemical defenses increasing palatability. FRONTIERS IN PLANT SCIENCE 2022; 13:982683. [PMID: 36119632 PMCID: PMC9478336 DOI: 10.3389/fpls.2022.982683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 08/03/2022] [Indexed: 06/15/2023]
Abstract
To identify key traits brought about by citrus domestication, we have analyzed the transcriptomes of the pulp of developing fruitlets of inedible wild Ichang papeda (Citrus ichangensis), acidic Sun Chu Sha Kat mandarin (C. reticulata) and three palatable segregants of a cross between commercial Clementine (C. x clementina) and W. Murcott (C. x reticulata) mandarins, two pummelo/mandarin admixtures of worldwide distribution. RNA-seq comparison between the wild citrus and the ancestral sour mandarin identified 7267 differentially expressed genes, out of which 2342 were mapped to 117 KEGG pathways. From the remaining genes, a set of 2832 genes was functionally annotated and grouped into 45 user-defined categories. The data suggest that domestication promoted fundamental growth processes to the detriment of the production of chemical defenses, namely, alkaloids, terpenoids, phenylpropanoids, flavonoids, glucosinolates and cyanogenic glucosides. In the papeda, the generation of energy to support a more active secondary metabolism appears to be dependent upon upregulation of glycolysis, fatty acid degradation, Calvin cycle, oxidative phosphorylation, and ATP-citrate lyase and GABA pathways. In the acidic mandarin, downregulation of cytosolic citrate degradation was concomitant with vacuolar citrate accumulation. These changes affected nitrogen and carbon allocation in both species leading to major differences in organoleptic properties since the reduction of unpleasant secondary metabolites increases palatability while acidity reduces acceptability. The comparison between the segregants and the acidic mandarin identified 357 transcripts characterized by the occurrence in the three segregants of additional downregulation of secondary metabolites and basic structural cell wall components. The segregants also showed upregulation of genes involved in the synthesis of methyl anthranilate and furaneol, key substances of pleasant fruity aroma and flavor, and of sugar transporters relevant for sugar accumulation. Transcriptome and qPCR analysis in developing and ripe fruit of a set of genes previously associated with citric acid accumulation, demonstrated that lower acidity is linked to downregulation of these regulatory genes in the segregants. The results suggest that the transition of inedible papeda to sour mandarin implicated drastic gene expression reprograming of pivotal pathways of the primary and secondary metabolism, while palatable mandarins evolved through progressive refining of palatability properties, especially acidity.
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Combined Transcriptome and Metabolome Analyses Reveal Candidate Genes Involved in Tangor ( Citrus reticulata × Citrus sinensis) Fruit Development and Quality Formation. Int J Mol Sci 2022; 23:ijms23105457. [PMID: 35628266 PMCID: PMC9141862 DOI: 10.3390/ijms23105457] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 04/29/2022] [Accepted: 05/11/2022] [Indexed: 02/06/2023] Open
Abstract
Tangor, an important citrus type, is a hybrid of orange and mandarin and possesses their advantageous characteristics. Fruit quality is an important factor limiting the development of the citrus industry and highly depends on fruit development and ripening programs. However, fruit development and quality formation have not been completely explored in mandarin-orange hybrids. We sequenced the metabolome and transcriptome of three mandarin-orange hybrid cultivars at the early fruiting [90 days after full bloom (DAFB)], color change (180 DAFB), and ripening (270 DAFB) stages. Metabolome sequencing was performed to preliminarily identify the accumulation patterns of primary and secondary metabolites related to fruit quality and hormones regulating fruit development. Transcriptome analysis showed that many genes related to primary metabolism, secondary metabolism, cell wall metabolism, phytohormones, and transcriptional regulation were up-regulated in all three cultivars during fruit development and ripening. Additionally, multiple key genes were identified that may play a role in sucrose, citric acid and flavonoid accumulation, cell wall modification, and abscisic acid signaling, which may provide a valuable resource for future research on enhancement of fruit quality of hybrid citrus. Overall, this study provides new insights into the molecular basis of pulp growth and development regulation and fruit quality formation in mandarin-orange hybrids.
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