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Wen Y, Qin Y, Shao B, Li J, Ma C, Liu Y, Yang B, Jin X. The extremely reduced, diverged and reconfigured plastomes of the largest mycoheterotrophic orchid lineage. BMC PLANT BIOLOGY 2022; 22:448. [PMID: 36123622 PMCID: PMC9487142 DOI: 10.1186/s12870-022-03836-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 09/09/2022] [Indexed: 06/01/2023]
Abstract
BACKGROUND Plastomes of heterotrophic plants have been greatly altered in structure and gene content, owing to the relaxation of selection on photosynthesis-related genes. The orchid tribe Gastrodieae is the largest and probably the oldest mycoheterotrophic clade of the extant family Orchidaceae. To characterize plastome evolution across members of this key important mycoheterotrophic lineage, we sequenced and analyzed the plastomes of eleven Gastrodieae members, including representative species of two genera, as well as members of the sister group Nervilieae. RESULTS The plastomes of Gastrodieae members contain 20 protein-coding, four rRNA and five tRNA genes. Evolutionary analysis indicated that all rrn genes were transferred laterally and together, forming an rrn block in the plastomes of Gastrodieae. The plastome GC content of Gastrodia species ranged from 23.10% (G. flexistyla) to 25.79% (G. javanica). The plastome of Didymoplexis pallens contains two copies each of ycf1 and ycf2. The synonymous and nonsynonymous substitution rates were very high in the plastomes of Gastrodieae among mycoheterotrophic species in Orchidaceae and varied between genes. CONCLUSIONS The plastomes of Gastrodieae are greatly reduced and characterized by low GC content, rrn block formation, lineage-specific reconfiguration and gene content, which might be positively selected. Overall, the plastomes of Gastrodieae not only serve as an excellent model for illustrating the evolution of plastomes but also provide new insights into plastome evolution in parasitic plants.
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Affiliation(s)
- Yingying Wen
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- School of Life Sciences, Nanchang University, Nanchang, 330031, China
| | - Ying Qin
- Guangxi Zhuang Autonomous Region and Chinese Academy of Sciences, Guangxi Institute of Botany, Guilin, 541006, Guangxi, China
| | - Bingyi Shao
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Jianwu Li
- Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun Township, Mengla County, Yunnan, 666303, China
| | - Chongbo Ma
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Yan Liu
- Guangxi Zhuang Autonomous Region and Chinese Academy of Sciences, Guangxi Institute of Botany, Guilin, 541006, Guangxi, China.
| | - Boyun Yang
- School of Life Sciences, Nanchang University, Nanchang, 330031, China.
| | - Xiaohua Jin
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.
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Bolaños-Villegas P, Chen FC. Advances and Perspectives for Polyploidy Breeding in Orchids. PLANTS 2022; 11:plants11111421. [PMID: 35684197 PMCID: PMC9183072 DOI: 10.3390/plants11111421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 03/11/2022] [Accepted: 03/17/2022] [Indexed: 11/16/2022]
Abstract
The orchid market is a dynamic horticultural business in which novelty and beauty command high prices. The two main interests are the development of flowers, from the miniature to the large and showy, and their fragrance. Overall organ size might be modified by doubling the chromosome number, which can be accomplished by careful study of meiotic chromosome disjunction in hybrids or species. Meiosis is the process in which diploid (2n) pollen mother cells recombine their DNA sequences and then undergo two rounds of division to give rise to four haploid (n) cells. Thus, by interfering in chromosome segregation, one can induce the development of diploid recombinant cells, called unreduced gametes. These unreduced gametes may be used for breeding polyploid progenies with enhanced fertility and large flower size. This review provides an overview of developments in orchid polyploidy breeding placed in the large context of meiotic chromosome segregation in the model plants Arabidopsis thaliana and Brassica napus to facilitate molecular translational research and horticultural innovation.
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Affiliation(s)
- Pablo Bolaños-Villegas
- Fabio Baudrit Agricultural Research Station, University of Costa Rica, La Garita District, Alajuela 20101, Costa Rica
- Lankester Botanical Garden, University of Costa Rica, Dulce Nombre District, Cartago 30109, Costa Rica
- Faculty of Food and Agricultural Sciences, Rodrigo Facio Campus, School of Agronomy, University of Costa Rica, Montes de Oca County, San Jose 11503, Costa Rica
- Correspondence:
| | - Fure-Chyi Chen
- General Research Service Center, National Pingtung University of Science and Technology, #1 Shuefu Road, Neipu township, Pingtung 91201, Taiwan;
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Ullah I, Ansari HA, Verry IM, Hussain SW, Ellison NW, McManus MT, Williams WM. Introgression of Trifolium ambiguum Into Allotetraploid White Clover ( Trifolium repens) Using the Ancestral Parent Trifolium occidentale as a Bridging Species. FRONTIERS IN PLANT SCIENCE 2022; 13:858714. [PMID: 35371143 PMCID: PMC8971954 DOI: 10.3389/fpls.2022.858714] [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: 01/20/2022] [Accepted: 02/16/2022] [Indexed: 06/14/2023]
Abstract
White clover (Trifolium repens) is an allotetraploid pasture legume widely used in moist temperate climates, but its vulnerability to drought, grazing pressure and pests has restricted its wider use. A related species, Caucasian clover (Trifolium ambiguum), is a potential source of resistances to drought, cold, grazing pressure and pests that could potentially be transferred to white clover by interspecific hybridization. Although direct hybridization has been achieved with difficulty, the hybrids have not been easy to backcross for introgression breeding and no interspecific chromosome recombination has been demonstrated. The present work shows that interspecific recombination can be achieved by using Trifolium occidentale, one of the ancestral parents of T. repens, as a bridging species and that large white clover breeding populations carrying recombinant chromosomes can be generated. A 4x hybrid between T. ambiguum and T. occidentale was crossed with T. repens and then backcrossed for two generations. Five backcross hybrid plants with phenotypes appearing to combine traits from the parent species were selected for FISH-GISH analyses. Recombinant chromosome segments from T. ambiguum were found in all five plants, suggesting that recombination frequencies were significant and sufficient for introgression breeding. Despite early chromosome imbalances, the backcross populations were fertile and produced large numbers of seeds. These hybrids represent a major new resource for the breeding of novel resilient forms of white clover.
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Affiliation(s)
- Ihsan Ullah
- AgResearch (Grasslands Research Centre), Palmerston North, New Zealand
- College of Sciences, Massey University, Palmerston North, New Zealand
| | - Helal A. Ansari
- AgResearch (Grasslands Research Centre), Palmerston North, New Zealand
| | - Isabelle M. Verry
- AgResearch (Grasslands Research Centre), Palmerston North, New Zealand
| | | | - Nick W. Ellison
- AgResearch (Grasslands Research Centre), Palmerston North, New Zealand
| | | | - Warren M. Williams
- AgResearch (Grasslands Research Centre), Palmerston North, New Zealand
- College of Sciences, Massey University, Palmerston North, New Zealand
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