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Guan J, Zhu J, Liu H, Yang H, Zhong S, Chen W, Yi X, Chen C, Tan F, Shen J, Luo P. Arogenate dehydratase isoforms strategically deregulate phenylalanine biosynthesis in Akebia trifoliata. Int J Biol Macromol 2024; 271:132587. [PMID: 38788880 DOI: 10.1016/j.ijbiomac.2024.132587] [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: 11/10/2023] [Revised: 05/01/2024] [Accepted: 05/21/2024] [Indexed: 05/26/2024]
Abstract
Arogenate dehydratase (ADT) is key for phenylalanine (Phe) biosynthesis in plants. To examine ADT components and function in Akebia trifoliata, a representative of Ranunculaceae, we first identified eight ADTs (AktADT1-8, encoding sequences varying from 1032 to 1962 bp) in the A. trifoliata reference genome and five proteins (AktADT1, AktADT4, AktADT7, AktADT8 and AktADT8s) with moonlighting prephenate dehydratase (PDT) activity and Km values varying from 0.43 to 2.17 mM. Structurally, two basic residue combinations (Val314/Ala317 and Ala314/Val317) in the PAC domain are essential for the moonlighting PDT activity of ADTs. Functionally, AktADT4 and AktADT8 successfully restored the wild-type phenotype of pha2, a knockout mutant of Saccharomyces cerevisiae. In addition, AktADTs are ubiquitously expressed, but their expression levels are tissue specific, and the half maximal inhibitory concentration (IC50) of Phe for AktADTs ranged from 49.81 to 331.17 μM. Both AktADT4 and AktADT8 and AktADT8s localized to chloroplast stromules and the cytosol, respectively, while the remaining AktADTs localized to the chloroplast stroma. These findings suggest that various strategies exist for regulating Phe biosynthesis in A. trifoliata. This provides a reasonable explanation for the high Phe content and insights for further genetic improvement of the edible fruits of A. trifoliata.
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Affiliation(s)
- Ju Guan
- Key Laboratory of Plant Genetics and Breeding at Sichuan Agricultural University of Sichuan Province, Chengdu 611130, Sichuan, China; Cuisine Science Key Laboratory of Sichuan Province, Sichuan Tourism University, Chengdu 611130, China
| | - Jun Zhu
- Key Laboratory of Plant Genetics and Breeding at Sichuan Agricultural University of Sichuan Province, Chengdu 611130, Sichuan, China
| | - Hao Liu
- Key Laboratory of Plant Genetics and Breeding at Sichuan Agricultural University of Sichuan Province, Chengdu 611130, Sichuan, China
| | - Hao Yang
- Key Laboratory of Plant Genetics and Breeding at Sichuan Agricultural University of Sichuan Province, Chengdu 611130, Sichuan, China; Sichuan Akebia trifoliata Biotechnology Co., Ltd., Chengdu 611130, China
| | - Shengfu Zhong
- Key Laboratory of Plant Genetics and Breeding at Sichuan Agricultural University of Sichuan Province, Chengdu 611130, Sichuan, China
| | - Wei Chen
- Key Laboratory of Plant Genetics and Breeding at Sichuan Agricultural University of Sichuan Province, Chengdu 611130, Sichuan, China; Sichuan Akebia trifoliata Biotechnology Co., Ltd., Chengdu 611130, China
| | - Xiaoxiao Yi
- Key Laboratory of Plant Genetics and Breeding at Sichuan Agricultural University of Sichuan Province, Chengdu 611130, Sichuan, China
| | - Chen Chen
- Key Laboratory of Plant Genetics and Breeding at Sichuan Agricultural University of Sichuan Province, Chengdu 611130, Sichuan, China
| | - Feiquan Tan
- Key Laboratory of Plant Genetics and Breeding at Sichuan Agricultural University of Sichuan Province, Chengdu 611130, Sichuan, China
| | - Jinliang Shen
- Key Laboratory of Plant Genetics and Breeding at Sichuan Agricultural University of Sichuan Province, Chengdu 611130, Sichuan, China
| | - Peigao Luo
- Key Laboratory of Plant Genetics and Breeding at Sichuan Agricultural University of Sichuan Province, Chengdu 611130, Sichuan, China.
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Zhong S, Yang H, Guan J, Shen J, Ren T, Li Z, Tan F, Li Q, Luo P. Characterization of the MADS-Box Gene Family in Akebia trifoliata and Their Evolutionary Events in Angiosperms. Genes (Basel) 2022; 13:genes13101777. [PMID: 36292662 PMCID: PMC9601569 DOI: 10.3390/genes13101777] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 09/27/2022] [Accepted: 09/28/2022] [Indexed: 11/16/2022] Open
Abstract
As the largest clade of modern plants, flower plants have evolved a wide variety of flowers and fruits. MADS-box genes play key roles in regulating plant morphogenesis, while basal eudicots have an evolutionarily important position of acting as an evolutionary bridge between basal angiosperms and core eudicots. Akebia trifoliata is an important member of the basal eudicot group. To study the early evolution of angiosperms, we identified and characterized the MADS-Box gene family on the whole-genome level of A. trifoliata. There were 47 MADS-box genes (13 type I and 34 type II genes) in the A. trifoliata genome; type I genes had a greater gene length and coefficient of variation and a smaller exon number than type II genes. A total of 27 (57.4%) experienced whole or segmental genome duplication and purifying selection. A transcriptome analysis suggested that three and eight genes were involved in whole fruit and seed development, respectively. The diversification and phylogenetic analysis of 1479 type II MADS-box genes of 22 angiosperm species provided some clues indicating that a γ whole genome triplication event of eudicots possibility experienced a two-step process. These results are valuable for improving A. trifoliata fruit traits and theoretically elucidating evolutionary processes of angiosperms, especially eudicots.
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Affiliation(s)
- Shengfu Zhong
- Key Laboratory of Plant Genetics and Breeding at Sichuan Agricutural University of Sichuan Province, College of Agronomy, Sichuan Agricultural University, Chengdu 611130, China
| | - Huai Yang
- Key Laboratory of Plant Genetics and Breeding at Sichuan Agricutural University of Sichuan Province, College of Agronomy, Sichuan Agricultural University, Chengdu 611130, China
| | - Ju Guan
- Key Laboratory of Plant Genetics and Breeding at Sichuan Agricutural University of Sichuan Province, College of Agronomy, Sichuan Agricultural University, Chengdu 611130, China
| | - Jinliang Shen
- College of Forestry, Sichuan Agricultural University, Chengdu 611130, China
| | - Tianheng Ren
- Key Laboratory of Plant Genetics and Breeding at Sichuan Agricutural University of Sichuan Province, College of Agronomy, Sichuan Agricultural University, Chengdu 611130, China
| | - Zhi Li
- Key Laboratory of Plant Genetics and Breeding at Sichuan Agricutural University of Sichuan Province, College of Agronomy, Sichuan Agricultural University, Chengdu 611130, China
| | - Feiquan Tan
- Key Laboratory of Plant Genetics and Breeding at Sichuan Agricutural University of Sichuan Province, College of Agronomy, Sichuan Agricultural University, Chengdu 611130, China
| | - Qing Li
- Department of Biology and Chemistry, Chongqing Industry and Trade Polytechnic, Chongqing 408000, China
| | - Peigao Luo
- Key Laboratory of Plant Genetics and Breeding at Sichuan Agricutural University of Sichuan Province, College of Agronomy, Sichuan Agricultural University, Chengdu 611130, China
- Correspondence:
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Abstract
The origin of the flower was a key innovation in the history of complex organisms, dramatically altering Earth's biota. Advances in phylogenetics, developmental genetics, and genomics during the past 25 years have substantially advanced our understanding of the evolution of flowers, yet crucial aspects of floral evolution remain, such as the series of genetic and morphological changes that gave rise to the first flowers; the factors enabling the origin of the pentamerous eudicot flower, which characterizes ∼70% of all extant angiosperm species; and the role of gene and genome duplications in facilitating floral innovations. A key early concept was the ABC model of floral organ specification, developed by Elliott Meyerowitz and Enrico Coen and based on two model systems,Arabidopsis thalianaandAntirrhinum majus Yet it is now clear that these model systems are highly derived species, whose molecular genetic-developmental organization must be very different from that of ancestral, as well as early, angiosperms. In this article, we will discuss how new research approaches are illuminating the early events in floral evolution and the prospects for further progress. In particular, advancing the next generation of research in floral evolution will require the development of one or more functional model systems from among the basal angiosperms and basal eudicots. More broadly, we urge the development of "model clades" for genomic and evolutionary-developmental analyses, instead of the primary use of single "model organisms." We predict that new evolutionary models will soon emerge as genetic/genomic models, providing unprecedented new insights into floral evolution.
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Wu F, Shi X, Lin X, Liu Y, Chong K, Theißen G, Meng Z. The ABCs of flower development: mutational analysis of AP1/FUL-like genes in rice provides evidence for a homeotic (A)-function in grasses. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 89:310-324. [PMID: 27689766 DOI: 10.1111/tpj.13386] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 09/15/2016] [Accepted: 09/21/2016] [Indexed: 05/26/2023]
Abstract
The well-known ABC model describes the combinatorial interaction of homeotic genes in specifying floral organ identities. While the B- and C-functions are highly conserved throughout flowering plants and even in gymnosperms, the A-function, which specifies the identity of perianth organs (sepals and petals in eudicots), remains controversial. One reason for this is that in most plants that have been investigated thus far, with Arabidopsis being a remarkable exception, one does not find recessive mutants in which the identity of both types of perianth organs is affected. Here we report a comprehensive mutational analysis of all four members of the AP1/FUL-like subfamily of MADS-box genes in rice (Oryza sativa). We demonstrate that OsMADS14 and OsMADS15, in addition to their function of specifying meristem identity, are also required to specify palea and lodicule identities. Because these two grass-specific organs are very likely homologous to sepals and petals of eudicots, respectively, we conclude that there is a floral homeotic (A)-function in rice as defined previously. Together with other recent findings, our data suggest that AP1/FUL-like genes were independently recruited to fulfil the (A)-function in grasses and some eudicots, even though other scenarios cannot be excluded and are discussed.
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Affiliation(s)
- Feng Wu
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Xiaowei Shi
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100039, China
| | - Xuelei Lin
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Yuan Liu
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Kang Chong
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Günter Theißen
- Department of Genetics, Friedrich Schiller University Jena, D-07743, Jena, Germany
| | - Zheng Meng
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
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Su K, Li Z, Chen Z. CsPI from the perianthless early-diverging Chloranthus spicatus show function on petal development in Arabidopsis thaliana. BOTANICAL STUDIES 2014; 55:21. [PMID: 28510925 PMCID: PMC5430364 DOI: 10.1186/1999-3110-55-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/07/2013] [Accepted: 12/23/2013] [Indexed: 06/07/2023]
Abstract
BACKGROUND In the floral ABC model, B-class genes comprised of DEFICIENS (DEF)/APETALA3 (AP3) and GLOBOSA (GLO)/PISTILLATA (PI) had been proposed to involve in second and third whorl floral organ development. However, less is known about the function of B-class genes from early-diverging angiosperms. Chloranthaceae is one of the early-diverging angiosperm families. In this study, we characterized the role of the PI-like gene CsPI cloned from Chloranthus spicatus which have the simplest perianthless bisexual flowers. RESULTS The expression profile analysis reveals high levels of CsPI mRNA in stamens in Chloranthus spicatus, with weak distribution in leaves and other floral organs. Nevertheless, CsPI rescued both stamen and petal development in Arabidopsis thaliana pi-1 mutants and caused partially conversion of sepals into petaloid organs in wild-type Arabidopsis thaliana plants. Yeast two-hybrid analysis showed that CsPI can form not only homodimers but also heterodimers with proteins encoded by Arabidopsis thaliana and Chloranthus spicatus AP3-like genes. CONCLUSIONS These results suggested that CsPI has an ancestral function on stamen development and that CsPI has capability to specify petal development in Arabidopsis thaliana. The finding indicates that the activity of the encoded PI-like proteins is highly conserved between the early-diverging Chloranthus and Arabidopsis. Moreover, our results appear to suggest that B-function genes may not play a role in perianth development in Chloranthus spicatus.
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Affiliation(s)
- Kunmei Su
- School of Environment and Chemistry Engineering, Tianjin Polytechnic University, Tianjin, 300387 China
| | - Zhenhuan Li
- School of Environment and Chemistry Engineering, Tianjin Polytechnic University, Tianjin, 300387 China
| | - Zhiduan Chen
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Xiangshan, China
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Lin X, Wu F, Du X, Shi X, Liu Y, Liu S, Hu Y, Theißen G, Meng Z. The pleiotropic SEPALLATA-like gene OsMADS34 reveals that the 'empty glumes' of rice (Oryza sativa) spikelets are in fact rudimentary lemmas. THE NEW PHYTOLOGIST 2014; 202:689-702. [PMID: 24372518 DOI: 10.1111/nph.12657] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Accepted: 11/22/2013] [Indexed: 05/07/2023]
Abstract
The single floret of the rice (Oryza sativa) spikelet is subtended by a pair of enigmatic organs usually termed 'empty glumes' or 'sterile lemmas'. As the identity of these organs remains essentially unknown, we refer to them as 'organs of unknown identity' (OUIs). Here we present a novel mutant of the rice SEPALLATA-like gene OsMADS34 which develops, in addition to disorganized branches and sterile seeds, elongated OUIs. The function and evolution of OsMADS34 were studied. Morphological and molecular markers indicate that the elongated OUIs have adopted lemma identity. Evolutionary analyses show that the ancestral genes of the OsM34 subclade evolved under positive selection, and that three specific motifs occur in the C-terminal region of proteins in the OsM34 subclade. Yeast two-hybrid assays revealed that the C-terminal region of OsMADS34 plays a crucial role in mediating protein interactions. Sequence analyses for the wild rice Oryza grandiglumis which has elongated OUIs revealed the association of OsMADS34 functionality with OUI identity. Our findings support the hypothesis that OUIs originated from the lemmas of degenerate florets under the negative control of OsMADS34. As OUIs neither are homologues to glumes nor have the identity of lemmas any more, but originated from these organs, we suggest calling them 'rudimentary lemmas'.
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Affiliation(s)
- Xuelei Lin
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100039, China
| | - Feng Wu
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Xiaoqiu Du
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Xiaowei Shi
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Yuan Liu
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Shujun Liu
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Yuxin Hu
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Günter Theißen
- Department of Genetics, Friedrich Schiller University Jena, D-07743, Jena, Germany
| | - Zheng Meng
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
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Liu S, Sun Y, Du X, Xu Q, Wu F, Meng Z. Analysis of the APETALA3- and PISTILLATA-like genes in Hedyosmum orientale (Chloranthaceae) provides insight into the evolution of the floral homeotic B-function in angiosperms. ANNALS OF BOTANY 2013; 112:1239-51. [PMID: 23956161 PMCID: PMC3806522 DOI: 10.1093/aob/mct182] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Accepted: 06/28/2013] [Indexed: 05/21/2023]
Abstract
BACKGROUND AND AIMS According to the floral ABC model, B-function genes appear to play a key role in the origin and diversification of the perianth during the evolution of angiosperms. The basal angiosperm Hedyosmum orientale (Chloranthaceae) has unisexual inflorescences associated with a seemingly primitive reproductive morphology and a reduced perianth structure in female flowers. The aim of this study was to investigate the nature of the perianth and the evolutionary state of the B-function programme in this species. METHODS A series of experiments were conducted to characterize B-gene homologues isolated from H. orientale, including scanning electron microscopy to observe the development of floral organs, phylogenetic analysis to reconstruct gene evolutionary history, reverse transcription-PCR, quantitative real-time PCR and in situ hybridization to identify gene expression patterns, the yeast two-hybrid assay to explore protein dimerization affinities, and transgenic analyses in Arabidopsis thaliana to determine activities of the encoded proteins. KEY RESULTS The expression of HoAP3 genes was restricted to stamens, whereas HoPI genes were broadly expressed in all floral organs. HoAP3 was able to partially restore the stamen but not petal identity in Arabidopsis ap3-3 mutants. In contrast, HoPI could rescue aspects of both stamen and petal development in Arabidopsis pi-1 mutants. When the complete C-terminal sequence of HoPI was deleted, however, no or weak transgenic phenotypes were observed and homodimerization capability was completely abolished. CONCLUSIONS The results suggest that Hedyosmum AP3-like genes have an ancestral function in specifying male reproductive organs, and that the activity of the encoded PI-like proteins is highly conserved between Hedyosmum and Arabidopsis. Moreover, there is evidence that the C-terminal region is important for the function of HoPI. Our findings indicate that the development of the proposed perianth in Hedyosmum does not rely on the B homeotic function.
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Affiliation(s)
- Shujun Liu
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yonghua Sun
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaoqiu Du
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Qijiang Xu
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- Department of Botany, Northeast Forestry University, Haerbin 150040, China
| | - Feng Wu
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Zheng Meng
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- For correspondence. E-mail
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Yockteng R, Almeida AMR, Morioka K, Alvarez-Buylla ER, Specht CD. Molecular evolution and patterns of duplication in the SEP/AGL6-like lineage of the Zingiberales: a proposed mechanism for floral diversification. Mol Biol Evol 2013; 30:2401-22. [PMID: 23938867 DOI: 10.1093/molbev/mst137] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The diversity of floral forms in the plant order Zingiberales has evolved through alterations in floral organ morphology. One striking alteration is the shift from fertile, filamentous stamens to sterile, laminar (petaloid) organs in the stamen whorls, attributed to specific pollination syndromes. Here, we examine the role of the SEPALLATA (SEP) genes, known to be important in regulatory networks underlying floral development and organ identity, in the evolution of development of the diverse floral organs phenotypes in the Zingiberales. Phylogenetic analyses show that the SEP-like genes have undergone several duplication events giving rise to multiple copies. Selection tests on the SEP-like genes indicate that the two copies of SEP3 have mostly evolved under balancing selection, probably due to strong functional restrictions as a result of their critical role in floral organ specification. In contrast, the two LOFSEP copies have undergone differential positive selection, indicating neofunctionalization. Reverse transcriptase-polymerase chain reaction, gene expression from RNA-seq data, and in situ hybridization analyses show that the recovered genes have differential expression patterns across the various whorls and organ types found in the Zingiberales. Our data also suggest that AGL6, sister to the SEP-like genes, may play an important role in stamen morphology in the Zingiberales. Thus, the SEP-like genes are likely to be involved in some of the unique morphogenetic patterns of floral organ development found among this diverse order of tropical monocots. This work contributes to a growing body of knowledge focused on understanding the role of gene duplications and the evolution of entire gene networks in the evolution of flower development.
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Affiliation(s)
- Roxana Yockteng
- Department of Plant and Microbial Biology, Department of Integrative Biology and the University and Jepson Herbaria, University of California, Berkeley
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Zhao YH, Larson-Rabin Z, Li DZ, Wang GY, Peng S, Li CY. The expression and phylogenetic analysis of four AP3-like paralogs in the stamens, carpels, and single-whorl perianth of the paleoherb Asarum caudigerum. Mol Biol Rep 2013; 40:4691-9. [PMID: 23657595 DOI: 10.1007/s11033-013-2564-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2012] [Accepted: 04/29/2013] [Indexed: 10/26/2022]
Abstract
The paleoherb species Asarum caudigerum (Aristolochiaceae) is important for research into the origin and evolution of angiosperm flowers due to its basal position in the angiosperm phylogeny. In this study, four MADS-box-containing transcripts were isolated from A. caudigerum by rapid amplification of cDNA ends (RACE). Sequence comparisons and phylogenetic analyses indicated that they possess high homology to AP3 subfamily genes, which have been shown previously to be involved in petal and stamen development in eudicots. Reverse-transcription quantitative PCR (RT-qPCR) and in situ hybridization analyses showed AcAP3-A expression mainly in the second whorl (stamens) and AcAP3-B expression in whorls 1 and 3 (perianth and carpels). Compared with eudicot AP3 homologs, premature translation termination codons were caused by an insertion in the K1 domain of AcAP3-C, and by a deletion in the 7th exon of AcAP3-D. Sequence analyses suggested that the A. caudigerum AP3 lineage had undergone gene duplication and subfunctionalization, diverging in expression patterns during perianth, stamen, and carpel development. Based on comparative genomic and phylogenetic analyses, we concluded that subfunctionalization has likely contributed to the persistence of two functional AP3 paralogs, that two other copies may have become pseudogenes, and that these AP3 duplication and subfunctionalization events may have contributed to the evolution of the unusual floral morphology of A. caudigerum.
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Affiliation(s)
- Yin-He Zhao
- Faculty of Agronomy and Biotechnology and Key Laboratory of Agro-biodiversity and Pest Management of Education Ministry of China, Yunnan Agricultural University, Kunming, 650201, China
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Su HJ, Hu JM. Rate heterogeneity in six protein-coding genes from the holoparasite Balanophora (Balanophoraceae) and other taxa of Santalales. ANNALS OF BOTANY 2012; 110:1137-1147. [PMID: 23041381 PMCID: PMC3478055 DOI: 10.1093/aob/mcs197] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Accepted: 07/23/2012] [Indexed: 06/01/2023]
Abstract
BACKGROUND AND AIMS The holoparasitic flowering plant Balanophora displays extreme floral reduction and was previously found to have enormous rate acceleration in the nuclear 18S rDNA region. So far, it remains unclear whether non-ribosomal, protein-coding genes of Balanophora also evolve in an accelerated fashion and whether the genes with high substitution rates retain their functionality. To tackle these issues, six different genes were sequenced from two Balanophora species and their rate variation and expression patterns were examined. METHODS Sequences including nuclear PI, euAP3, TM6, LFY and RPB2 and mitochondrial matR were determined from two Balanophora spp. and compared with selected hemiparasitic species of Santalales and autotrophic core eudicots. Gene expression was detected for the six protein-coding genes and the expression patterns of the three B-class genes (PI, AP3 and TM6) were further examined across different organs of B. laxiflora using RT-PCR. KEY RESULTS Balanophora mitochondrial matR is highly accelerated in both nonsynonymous (d(N)) and synonymous (d(S)) substitution rates, whereas the rate variation of nuclear genes LFY, PI, euAP3, TM6 and RPB2 are less dramatic. Significant d(S) increases were detected in Balanophora PI, TM6, RPB2 and d(N) accelerations in euAP3. All of the protein-coding genes are expressed in inflorescences, indicative of their functionality. PI is restrictively expressed in tepals, synandria and floral bracts, whereas AP3 and TM6 are widely expressed in both male and female inflorescences. CONCLUSIONS Despite the observation that rates of sequence evolution are generally higher in Balanophora than in hemiparasitic species of Santalales and autotrophic core eudicots, the five nuclear protein-coding genes are functional and are evolving at a much slower rate than 18S rDNA. The mechanism or mechanisms responsible for rapid sequence evolution and concomitant rate acceleration for 18S rDNA and matR are currently not well understood and require further study in Balanophora and other holoparasites.
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MESH Headings
- Balanophoraceae/genetics
- Balanophoraceae/ultrastructure
- DNA, Mitochondrial/chemistry
- DNA, Mitochondrial/genetics
- DNA, Plant/chemistry
- DNA, Plant/genetics
- DNA, Ribosomal/chemistry
- DNA, Ribosomal/genetics
- Evolution, Molecular
- Flowers/genetics
- Flowers/ultrastructure
- Inflorescence/genetics
- Inflorescence/ultrastructure
- Microscopy, Electron, Scanning
- Mitochondria/genetics
- Nuclear Proteins/genetics
- Phylogeny
- Plant Epidermis/genetics
- Plant Epidermis/ultrastructure
- Plant Proteins/genetics
- RNA, Ribosomal, 18S/genetics
- Santalaceae/genetics
- Santalaceae/ultrastructure
- Sequence Analysis, DNA
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Hu J, Zhang J, Shan H, Chen Z. Expression of floral MADS-box genes in Sinofranchetia chinensis (Lardizabalaceae): implications for the nature of the nectar leaves. ANNALS OF BOTANY 2012; 110:57-69. [PMID: 22652421 PMCID: PMC3380600 DOI: 10.1093/aob/mcs104] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
BACKGROUND AND AIMS The perianths of the Lardizabalaceae are diverse. The second-whorl floral organs of Sinofranchetia chinensis (Lardizabalaceae) are nectar leaves. The aim of this study was to explore the nature of this type of floral organ, and to determine its relationship to nectar leaves in other Ranunculales species, and to other floral organs in Sinofranchetia chinensis. METHODS Approaches of evolutionary developmental biology were used, including 3' RACE (rapid amplification of cDNA ends) for isolating floral MADS-box genes, phylogenetic analysis for reconstructing gene evolutionary history, in situ hybridization and tissue-specific RT-PCR for identifying gene expression patterns and SEM (scanning electron microscopy) for observing the epidermal cell morphology of floral organs. KEY RESULTS Fourteen new floral MADS-box genes were isolated from Sinofranchetia chinensis and from two other species of Lardizabalaceae, Holboellia grandiflora and Decaisnea insignis. The phylogenetic analysis of AP3-like genes in Ranunculales showed that three AP3 paralogues from Sinofranchetia chinensis belong to the AP3-I, -II and -III lineages. In situ hybridization results showed that SIchAP3-3 is significantly expressed only in nectar leaves at the late stages of floral development, and SIchAG, a C-class MADS-box gene, is expressed not only in stamens and carpels, but also in nectar leaves. SEM observation revealed that the adaxial surface of nectar leaves is covered with conical epidermal cells, a hallmark of petaloidy. CONCLUSIONS The gene expression data imply that the nectar leaves in S. chinensis might share a similar genetic regulatory code with other nectar leaves in Ranunculales species. Based on gene expression and morphological evidence, it is considered that the nectar leaves in S. chinensis could be referred to as petals. Furthermore, the study supports the hypothesis that the nectar leaves in some Ranunculales species might be derived from stamens.
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Affiliation(s)
- Jin Hu
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- Graduate University of Chinese Academy of Sciences, Beijing 100049, China
- South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Jian Zhang
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Hongyan Shan
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Zhiduan Chen
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- For correspondence. E-mail
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Hidalgo O, Bartholmes C, Gleissberg S. Virus-induced gene silencing (VIGS) in Cysticapnos vesicaria, a zygomorphic-flowered Papaveraceae (Ranunculales, basal eudicots). ANNALS OF BOTANY 2012; 109:911-20. [PMID: 22307568 PMCID: PMC3310490 DOI: 10.1093/aob/mcs008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
BACKGROUND AND AIMS Studies of evolutionary diversification in the basal eudicot family Papaveraceae, such as the transition from actinomorphy to zygomorphy, are hampered by the lack of comparative functional studies. So far, gene silencing methods are only available in the actinomorphic species Eschscholzia californica and Papaver somniferum. This study addresses the amenability of Cysticapnos vesicaria, a derived fumitory with zygomorphic flowers, to virus-induced gene silencing (VIGS), and describes vegetative and reproductive traits in this species. METHODS VIGS-mediated downregulation of the C. vesicaria PHYTOENE DESATURASE gene (CvPDS) and of the FLORICAULA gene CvFLO was carried out using Agrobacterium tumefaciens transfer of Tobacco rattle virus (TRV)-based vectors. Wild-type and vector-treated plants were characterized using reverse transcription-PCR (RT-PCR), in situ hybridization, and macroscopic and scanning electron microscopic imaging. KEY RESULTS Cysticapnos vesicaria germinates rapidly, can be grown at high density, has a short life cycle and is self-compatible. Inoculation of C. vesicaria with a CvPDS-VIGS vector resulted in strong photobleaching of green parts and reduction of endogenous CvPDS transcript levels. Gene silencing persisted during inflorescence development until fruit set. Inoculation of plants with CvFLO-VIGS affected floral phyllotaxis, symmetry and floral organ identities. CONCLUSIONS The high penetrance, severity and stability of pTRV-mediated silencing, including the induction of meristem-related phenotypes, make C. vesicaria a very promising new focus species for evolutionary-developmental (evo-devo) studies in the Papaveraceae. This now enables comparative studies of flower symmetry, inflorescence determinacy and other traits that diversified in the Papaveraceae.
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Zhang Q, Wang BG, Duan K, Wang LG, Wang M, Tang XM, Pan AH, Sui SZ, Wang GD. The paleoAP3-type gene CpAP3, an ancestral B-class gene from the basal angiosperm Chimonanthus praecox, can affect stamen and petal development in higher eudicots. Dev Genes Evol 2011; 221:83-93. [PMID: 21505842 DOI: 10.1007/s00427-011-0361-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Accepted: 03/30/2011] [Indexed: 11/25/2022]
Abstract
Wintersweet (Chimonanthus praecox), a basal angiosperm endemic to China, has high ornamental value for developing beautiful flowers with strong fragrance. The molecular mechanism regulating flower development in wintersweet remains largely elusive. In this project, we seek to determine the molecular features and expression patterns of the C. praecox paleoAP3-type gene CpAP3 and examine its potential role in regulating floral development via ectopic expression in Arabidopsis thaliana and Petunia hybrida. The expression of CpAP3 is tissue-specific, with the highest level in the tepals, moderate level in carpels, and weak levels in stamen and vegetative stem tissues. Its dynamic expression during flowering is associated with flower-bud formation. Ectopic expression of CpAP3 partially rescued stamen development in ap3 mutant Arabidopsis. Although no phenotypic effect has been observed in wild-type Arabidopsis, CpAP3 overexpression in petunia brought rich morphological changes and homeotic conversions to flowers, mainly involving disruption of petal and stamen development. Expressed in a broader range than those canonical B-function regulators, the ancestral B-class gene CpAP3 can affect petal and stamen development in higher eudicots. This gene also holds some bioengineering potential in creating novel floral germplasms.
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Affiliation(s)
- Qiong Zhang
- Shanghai Key Laboratory of Agricultural Genetics and Breeding, Institute of Biotechnology, Shanghai Academy of Agricultural Sciences (SAAS), Minhang District, Shanghai, China
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Yoo MJ, Chanderbali AS, Altman NS, Soltis PS, Soltis DE. Evolutionary trends in the floral transcriptome: insights from one of the basalmost angiosperms, the water lily Nuphar advena (Nymphaeaceae). THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2010; 64:687-98. [PMID: 21070420 DOI: 10.1111/j.1365-313x.2010.04357.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Current understanding of floral developmental genetics comes primarily from the core eudicot model Arabidopsis thaliana. Here, we explore the floral transcriptome of the basal angiosperm, Nuphar advena (water lily), for insights into the ancestral developmental program of flowers. We identify several thousand Nuphar genes with significantly upregulated floral expression, including homologs of the well-known ABCE floral regulators, deployed in broadly overlapping transcriptional programs across floral organ categories. Strong similarities in the expression profiles of different organ categories in Nuphar flowers are shared with the magnoliid Persea americana (avocado), in contrast to the largely organ-specific transcriptional cascades evident in Arabidopsis, supporting the inference that this is the ancestral condition in angiosperms. In contrast to most eudicots, floral organs are weakly differentiated in Nuphar and Persea, with staminodial intermediates between stamens and perianth in Nuphar, and between stamens and carpels in Persea. Consequently, the predominantly organ-specific transcriptional programs that characterize Arabidopsis flowers (and perhaps other eudicots) are derived, and correlate with a shift towards morphologically distinct floral organs, including differentiated sepals and petals, and a perianth distinct from stamens and carpels. Our findings suggest that the genetic regulation of more spatially discrete transcriptional programs underlies the evolution of floral morphology.
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Affiliation(s)
- Mi-Jeong Yoo
- Department of Biology, University of Florida, Gainesville, FL 32611, USA.
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van Dijk ADJ, van Ham RCHJ. Conserved and variable correlated mutations in the plant MADS protein network. BMC Genomics 2010; 11:607. [PMID: 20979667 PMCID: PMC3017862 DOI: 10.1186/1471-2164-11-607] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2010] [Accepted: 10/28/2010] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Plant MADS domain proteins are involved in a variety of developmental processes for which their ability to form various interactions is a key requisite. However, not much is known about the structure of these proteins or their complexes, whereas such knowledge would be valuable for a better understanding of their function. Here, we analyze those proteins and the complexes they form using a correlated mutation approach in combination with available structural, bioinformatics and experimental data. RESULTS Correlated mutations are affected by several types of noise, which is difficult to disentangle from the real signal. In our analysis of the MADS domain proteins, we apply for the first time a correlated mutation analysis to a family of interacting proteins. This provides a unique way to investigate the amount of signal that is present in correlated mutations because it allows direct comparison of mutations in various family members and assessing their conservation. We show that correlated mutations in general are conserved within the various family members, and if not, the variability at the respective positions is less in the proteins in which the correlated mutation does not occur. Also, intermolecular correlated mutation signals for interacting pairs of proteins display clear overlap with other bioinformatics data, which is not the case for non-interacting protein pairs, an observation which validates the intermolecular correlated mutations. Having validated the correlated mutation results, we apply them to infer the structural organization of the MADS domain proteins. CONCLUSION Our analysis enables understanding of the structural organization of the MADS domain proteins, including support for predicted helices based on correlated mutation patterns, and evidence for a specific interaction site in those proteins.
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Affiliation(s)
- Aalt DJ van Dijk
- Applied Bioinformatics, PRI, Wageningen UR, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Roeland CHJ van Ham
- Applied Bioinformatics, PRI, Wageningen UR, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
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Cui R, Han J, Zhao S, Su K, Wu F, Du X, Xu Q, Chong K, Theissen G, Meng Z. Functional conservation and diversification of class E floral homeotic genes in rice (Oryza sativa). THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2010; 61:767-81. [PMID: 20003164 DOI: 10.1111/j.1365-313x.2009.04101.x] [Citation(s) in RCA: 138] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Mutant analyses in different eudicotyledonous flowering plants demonstrated that SEPALLATA-like MADS-box genes are required for the specification of sepals, petals, stamens and carpels, and for floral determinacy, thus defining class E floral organ identity genes. SEP-like genes encode MADS-domain transcription factors and constitute an angiosperm-specific gene clade whose members show remarkably different degrees of redundancy and sub-functionalization within eudicots. To better understand the evolutionary dynamics of SEP-like genes throughout the angiosperms we have knocked down SEP-like genes of rice (Oryza sativa), a distant relative of eudicots within the flowering plants. Plants affected in both OsMADS7 and OsMADS8 show severe phenotypes including late flowering, homeotic changes of lodicules, stamens and carpels into palea/lemma-like organs, and a loss of floral determinacy. Simultaneous knockdown of the four rice SEP-like genes OsMADS1, OsMADS5, OsMADS7 and OsMADS8, leads to homeotic transformation of all floral organs except the lemma into leaf-like organs. This mimics the phenotype observed with the sep1 sep2 sep3 sep4 quadruple mutant of Arabidopsis. Detailed analyses of the spatial and temporal mRNA expression and protein interaction patterns corresponding to the different rice SEP-like genes show strong similarities, but also gene-specific differences. These findings reveal conservation of SEP-like genes in specifying floral determinacy and organ identities since the separation of eudicots and monocots about 150 million years ago. However, they indicate also monocot-specific neo- and sub-functionalization events and hence underscore the evolutionary dynamics of SEP-like genes. Moreover, our findings corroborate the view that the lodicules of grasses are homologous to eudicot petals.
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Affiliation(s)
- Rongfeng Cui
- Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
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Liu C, Zhang J, Zhang N, Shan H, Su K, Zhang J, Meng Z, Kong H, Chen Z. Interactions among Proteins of Floral MADS-Box Genes in Basal Eudicots: Implications for Evolution of the Regulatory Network for Flower Development. Mol Biol Evol 2010; 27:1598-611. [DOI: 10.1093/molbev/msq044] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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18
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Shan H, Zahn L, Guindon S, Wall PK, Kong H, Ma H, DePamphilis CW, Leebens-Mack J. Evolution of plant MADS box transcription factors: evidence for shifts in selection associated with early angiosperm diversification and concerted gene duplications. Mol Biol Evol 2009; 26:2229-44. [PMID: 19578156 DOI: 10.1093/molbev/msp129] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Phylogenomic analyses show that gene and genome duplication events have led to the diversification of transcription factor gene families throughout the evolutionary history of land plants and that gene duplications have played an important role in shaping regulatory networks influencing key phenotypic characters including floral development and flowering time. A molecular evolutionary investigation of the mode and tempo of selection acting on the angiosperm MADS box AP1/SQUA, AP3/PI, AG/AGL11, and SEP gene subfamilies revealed site-specific patterns of shifting evolutionary constraint throughout angiosperm history. Specific positions in the four canonical MADS box gene regions, especially K domains and C-terminal regions of all four of these MADS box gene subfamilies exhibited clade-specific shifts in selective constraint following concerted duplication events. Moreover, the frequency of site-specific shifts in constraint was correlated with gene duplications and early angiosperm diversification. We hypothesize that coevolution among interacting MADS box proteins may be responsible for simultaneous increases in the ratio of nonsynonymous to synonymous substitutions (d(N)/d(S) = omega) early in angiosperm history and following concerted duplication events.
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Affiliation(s)
- Hongyan Shan
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, the Chinese Academy of Sciences, Xiangshan, Beijing, People's Republic of China
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Rasmussen DA, Kramer EM, Zimmer EA. One size fits all? Molecular evidence for a commonly inherited petal identity program in Ranunculales. AMERICAN JOURNAL OF BOTANY 2009; 96:96-109. [PMID: 21628178 DOI: 10.3732/ajb.0800038] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Petaloid organs are a major component of the floral diversity observed across nearly all major clades of angiosperms. The variable morphology and development of these organs has led to the hypothesis that they are not homologous but, rather, have evolved multiple times. A particularly notable example of petal diversity, and potential homoplasy, is found within the order Ranunculales, exemplified by families such as Ranunculaceae, Berberidaceae, and Papaveraceae. To investigate the molecular basis of petal identity in Ranunculales, we used a combination of molecular phylogenetics and gene expression analysis to characterize APETALA3 (AP3) and PISTILLATA (PI) homologs from a total of 13 representative genera of the order. One of the most striking results of this study is that expression of orthologs of a single AP3 lineage is consistently petal-specific across both Ranunculaceae and Berberidaceae. We conclude from this finding that these supposedly homoplastic petals in fact share a developmental genetic program that appears to have been present in the common ancestor of the two families. We discuss the implications of this type of molecular data for long-held typological definitions of petals and, more broadly, the evolution of petaloid organs across the angiosperms.
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Affiliation(s)
- David A Rasmussen
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138 USA
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Su K, Zhao S, Shan H, Kong H, Lu W, Theissen G, Chen Z, Meng Z. The MIK region rather than the C-terminal domain of AP3-like class B floral homeotic proteins determines functional specificity in the development and evolution of petals. THE NEW PHYTOLOGIST 2008; 178:544-558. [PMID: 18298432 DOI: 10.1111/j.1469-8137.2008.02382.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
In core eudicots, euAP3-type MADS-box genes encode a PISTILLATA (PI)-derived motif, as well as a C-terminal euAP3 motif that originated from a paleoAP3 motif of an ancestral APETALA3 (AP3)-like protein through a translational frameshift mutation. To determine the functional and evolutionary relevance of these motifs, a series of point mutation and domain-swap constructs were generated, involving CsAP3, a paleoAP3-type gene from the basal angiosperm Chloranthus spicatus encoding a truncated paleoAP3 motif, and AtAP3, a euAP3-type gene from the core eudicot Arabidopsis thaliana. The chimeric constructs were expressed in A. thaliana under the control of the AP3 promoter or the CaMV 35S promoter in an ap3 mutant or wild-type background, respectively. Significant recovery of AP3 function was obtained in both complementation and ectopic expression experiments whenever the region upstream of the C-terminal motifs (MIK region) from A. thaliana was taken, even when the PI-derived motif and the truncated paleoAP3 motif of CsAP3 substituted for the corresponding sequences from AtAP3. However, no or very weak complementation or gain-of-function was seen when the MIK region was from CsAP3. Our data suggest that changes in the MIK region rather than mutations in the C-terminal domain were of crucial importance for the evolution of the functional specificity of euAP3-type proteins in stamen and petal development.
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Affiliation(s)
- Kunmei Su
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Xiangshan, Beijing, 100093, China
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Drea S, Hileman LC, de Martino G, Irish VF. Functional analyses of genetic pathways controlling petal specification in poppy. Development 2007; 134:4157-66. [PMID: 17959716 DOI: 10.1242/dev.013136] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
MADS-box genes are crucial regulators of floral development, yet how their functions have evolved to control different aspects of floral patterning is unclear. To understand the extent to which MADS-box gene functions are conserved or have diversified in different angiosperm lineages, we have exploited the capability for functional analyses in a new model system, Papaver somniferum (opium poppy). P. somniferum is a member of the order Ranunculales, and so represents a clade that is evolutionarily distant from those containing traditional model systems such as Arabidopsis, Petunia, maize or rice. We have identified and characterized the roles of several candidate MADS-box genes in petal specification in poppy. In Arabidopsis, the APETALA3 (AP3) MADS-box gene is required for both petal and stamen identity specification. By contrast, we show that the AP3 lineage has undergone gene duplication and subfunctionalization in poppy, with one gene copy required for petal development and the other responsible for stamen development. These differences in gene function are due to differences both in expression patterns and co-factor interactions. Furthermore, the genetic hierarchy controlling petal development in poppy has diverged as compared with that of Arabidopsis. As these are the first functional analyses of AP3 genes in this evolutionarily divergent clade, our results provide new information on the similarities and differences in petal developmental programs across angiosperms. Based on these observations, we discuss a model for how the petal developmental program has evolved.
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Affiliation(s)
- Sinéad Drea
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520, USA
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Ren Y, Li HF, Zhao L, Endress PK. Floral morphogenesis in Euptelea (Eupteleaceae, Ranunculales). ANNALS OF BOTANY 2007; 100:185-93. [PMID: 17550909 PMCID: PMC2735319 DOI: 10.1093/aob/mcm106] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2007] [Revised: 03/16/2007] [Accepted: 04/02/2007] [Indexed: 05/07/2023]
Abstract
BACKGROUND AND AIMS Based on molecular phylogenetic studies, the unigeneric family Eupteleaceae has a prominent phylogenetic position at or near the base of Ranunculales, which, in turn, appear at the base of eudicots. The aim of the present paper is to reveal developmental features of the flowers and to put the genus in a morphological context with other basal eudicots. METHODS Flowers in all developmental stages of Euptelea pleiosperma were collected in the wild at intervals of 7-10 d in the critical stages and studied with a scanning electron microscope. KEY RESULTS Remnants of a perianth are lacking throughout flower development. Floral symmetry changes from monosymmetric to asymmetric to disymmetric during development. Asymmetry is expressed in that the sequence of stamen initiation is from the centre to both lateral sides on the adaxial side of the flower but starting from one lateral side and proceeding to the other on the abaxial side. Despite the pronounced floral disymmetry, a dimerous pattern of floral organs was not found. The carpel primordia arise between the already large stamens and alternate with them. Stamens and carpels each form a somewhat irregular whorl. The carpels are ascidiate from the beginning. The stigma differentiates as two crests along the ventral slit of the ovary. The few lateral ovules alternate with each other. CONCLUSIONS Although the flowers have some unusual autapomorphies (wind pollination, lack of a perianth, pronounced disymmetry of the floral base, long connective protrusion, long temporal gap between androecium and gynoecium initiation, small space for carpel initiation), they show some plesiomorphies at the level of basal eudicots (free carpels, basifixed anthers, whorled phyllotaxis), and thus fit well in Ranunculales.
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Affiliation(s)
- Yi Ren
- College of Life Sciences, Key Laboratory of Medicinal Plant Resource and Natural Pharmaceutical Chemistry of Ministry of Education, Shaanxi Normal University, Xi'an, 710062 China.
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