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Jiang M, Jian J, Zhou C, Li L, Wang Y, Zhang W, Song Z, Yang J. Does integument arise de novo or from pre-existing structures? ── Insights from the key regulatory genes controlling integument development. FRONTIERS IN PLANT SCIENCE 2023; 13:1078248. [PMID: 36714739 PMCID: PMC9880897 DOI: 10.3389/fpls.2022.1078248] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 12/29/2022] [Indexed: 06/18/2023]
Abstract
The origin of seeds is one of the key innovations in land plant evolution. Ovules are the developmental precursors of seeds. The integument is the envelope structure surrounding the nucellus within the ovule and developing into the seed coat when ovules mature upon fertilization. The question of whether the integument arise de novo or evolve from elaboration of pre-existing structures has caused much debate. By exploring the origin and evolution of the key regulatory genes controlling integument development and their functions during both individual and historical developmental processes, we showed the widespread presence of the homologs of ANT, CUC, BEL1, SPL, C3HDZ, INO, ATS, and ETT in seedless plant genomes. All of these genes have undergone duplication-divergence events in their evolutionary history, with most of the descendant paralogous suffering motif gain and/or loss in the coding regions. Expression and functional characterization have shown that these genes are key components of the genetic program that patterns leaf-like lateral organs. Serial homology can thus be postulated between integuments and other lateral organs in terms of the shared master regulatory genes. Given that the genetic program patterning leaf-like lateral organs formed in seedless plants, and was reused during seed origin, the integument is unlikely to arise de novo but evolved from the stem segment-specific modification of pre-existing serially homologous structures. The master 'switches' trigging the modification to specify the integument identity remain unclear. We propose a successive transformation model of integument origin.
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Affiliation(s)
- Min Jiang
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Center for Evolutionary Biology, Fudan University, Shanghai, China
- Shanghai Key Laboratory of Plant Functional Genomics and Resources, Shanghai Chenshan Botanical Garden, Shanghai, China
| | - Jinjing Jian
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Center for Evolutionary Biology, Fudan University, Shanghai, China
| | - Chengchuan Zhou
- Institute of Tree Genetics Breeding and Cultivation, Jiangxi Academy of Forestry, Nanchang, China
| | - Linfeng Li
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Center for Evolutionary Biology, Fudan University, Shanghai, China
| | - Yuguo Wang
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Center for Evolutionary Biology, Fudan University, Shanghai, China
| | - Wenju Zhang
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Center for Evolutionary Biology, Fudan University, Shanghai, China
| | - Zhiping Song
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Center for Evolutionary Biology, Fudan University, Shanghai, China
| | - Ji Yang
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Center for Evolutionary Biology, Fudan University, Shanghai, China
- Shanghai Key Laboratory of Plant Functional Genomics and Resources, Shanghai Chenshan Botanical Garden, Shanghai, China
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Klimpert NJ, Mayer JLS, Sarzi DS, Prosdocimi F, Pinheiro F, Graham SW. Phylogenomics and plastome evolution of a Brazilian mycoheterotrophic orchid, Pogoniopsis schenckii. AMERICAN JOURNAL OF BOTANY 2022; 109:2030-2050. [PMID: 36254561 DOI: 10.1002/ajb2.16084] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 09/23/2022] [Accepted: 09/27/2022] [Indexed: 06/16/2023]
Abstract
PREMISE Pogoniopsis likely represents an independent photosynthesis loss in orchids. We use phylogenomic data to better identify the phylogenetic placement of this fully mycoheterotrophic taxon, and investigate its molecular evolution. METHODS We performed likelihood analysis of plastid and mitochondrial phylogenomic data to localize the position of Pogoniopsis schenckii in orchid phylogeny, and investigated the evolution of its plastid genome. RESULTS All analyses place Pogoniopsis in subfamily Epidendroideae, with strongest support from mitochondrial data, which also place it near tribe Sobralieae with moderately strong support. Extreme rate elevation in Pogoniopsis plastid genes broadly depresses branch support; in contrast, mitochondrial genes are only mildly rate elevated and display very modest and localized reductions in bootstrap support. Despite considerable genome reduction, including loss of photosynthesis genes and multiple translation apparatus genes, gene order in Pogoniopsis plastomes is identical to related autotrophs, apart from moderately shifted inverted repeat (IR) boundaries. All cis-spliced introns have been lost in retained genes. Two plastid genes (accD, rpl2) show significant strengthening of purifying selection. A retained plastid tRNA gene (trnE-UUC) of Pogoniopsis lacks an anticodon; we predict that it no longer functions in translation but retains a secondary role in heme biosynthesis. CONCLUSIONS Slowly evolving mitochondrial genes clarify the placement of Pogoniopsis in orchid phylogeny, a strong contrast with analysis of rate-elevated plastome data. We documented the effects of the novel loss of photosynthesis: for example, despite massive gene loss, its plastome is fully colinear with other orchids, and it displays only moderate shifts in selective pressure in retained genes.
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Affiliation(s)
- Nathaniel J Klimpert
- Department of Botany, University of British Columbia, 6270 University Boulevard, Vancouver, British Columbia, V6T 1Z4, Canada
| | - Juliana Lischka Sampaio Mayer
- Departamento de Biologia Vegetal, Universidade Estadual de Campinas, 255 Rua Monteiro Lobato, Campinas, São Paulo, 13.083-862, Brazil
| | - Deise Schroder Sarzi
- Laboratório de Genômica e Biodiversidade, Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal Do Rio de Janeiro, UFRJ/CCS/Bloco B33, Rio de Janeiro, RJ, 21.941-902, Brazil
| | - Francisco Prosdocimi
- Laboratório de Genômica e Biodiversidade, Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal Do Rio de Janeiro, UFRJ/CCS/Bloco B33, Rio de Janeiro, RJ, 21.941-902, Brazil
| | - Fábio Pinheiro
- Departamento de Biologia Vegetal, Universidade Estadual de Campinas, 255 Rua Monteiro Lobato, Campinas, São Paulo, 13.083-862, Brazil
| | - Sean W Graham
- Department of Botany, University of British Columbia, 6270 University Boulevard, Vancouver, British Columbia, V6T 1Z4, Canada
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Ibarra-Laclette E, Venancio-Rodríguez CA, Vásquez-Aguilar AA, Alonso-Sánchez AG, Pérez-Torres CA, Villafán E, Ramírez-Barahona S, Galicia S, Sosa V, Rebollar EA, Lara C, González-Rodríguez A, Díaz-Fleisher F, Ornelas JF. Transcriptional Basis for Haustorium Formation and Host Establishment in Hemiparasitic Psittacanthus schiedeanus Mistletoes. Front Genet 2022; 13:929490. [PMID: 35769994 PMCID: PMC9235361 DOI: 10.3389/fgene.2022.929490] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 05/20/2022] [Indexed: 11/13/2022] Open
Abstract
The mistletoe Psittacanthus schiedeanus, a keystone species in interaction networks between plants, pollinators, and seed dispersers, infects a wide range of native and non-native tree species of commercial interest. Here, using RNA-seq methodology we assembled the whole circularized quadripartite structure of P. schiedeanus chloroplast genome and described changes in the gene expression of the nuclear genomes across time of experimentally inoculated seeds. Of the 140,467 assembled and annotated uniGenes, 2,000 were identified as differentially expressed (DEGs) and were classified in six distinct clusters according to their expression profiles. DEGs were also classified in enriched functional categories related to synthesis, signaling, homoeostasis, and response to auxin and jasmonic acid. Since many orthologs are involved in lateral or adventitious root formation in other plant species, we propose that in P. schiedeanus (and perhaps in other rootless mistletoe species), these genes participate in haustorium formation by complex regulatory networks here described. Lastly, and according to the structural similarities of P. schiedeanus enzymes with those that are involved in host cell wall degradation in fungi, we suggest that a similar enzymatic arsenal is secreted extracellularly and used by mistletoes species to easily parasitize and break through tissues of the host.
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Affiliation(s)
- Enrique Ibarra-Laclette
- Instituto de Ecología A.C. (INECOL), Red de Estudios Moleculares Avanzados (REMAv), Xalapa, Mexico
- *Correspondence: Enrique Ibarra-Laclette, ; Juan Francisco Ornelas,
| | | | | | | | - Claudia-Anahí Pérez-Torres
- Instituto de Ecología A.C. (INECOL), Red de Estudios Moleculares Avanzados (REMAv), Xalapa, Mexico
- Investigador por Mexico-CONACyT en el Instituto de Ecología A.C. (INECOL), Xalapa, Mexico
| | - Emanuel Villafán
- Instituto de Ecología A.C. (INECOL), Red de Estudios Moleculares Avanzados (REMAv), Xalapa, Mexico
| | - Santiago Ramírez-Barahona
- Departamento de Botánica, Instituto de Biología, Universidad Nacional Autónoma de Mexico (UNAM), Ciudad de Mexico, Mexico
| | - Sonia Galicia
- Instituto de Ecología A.C. (INECOL), Red de Biología Evolutiva, Xalapa, Mexico
| | - Victoria Sosa
- Instituto de Ecología A.C. (INECOL), Red de Biología Evolutiva, Xalapa, Mexico
| | - Eria A. Rebollar
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de Mexico, Cuernavaca, Mexico
| | - Carlos Lara
- Centro de Investigación en Ciencias Biológicas, Universidad Autónoma de Tlaxcala, Tlaxcala, Mexico
| | - Antonio González-Rodríguez
- Laboratorio de Genética de la Conservación, Instituto de Investigaciones en Ecosistemas y Sustentabilidad (IIES), UNAM, Morelia, Mexico
| | | | - Juan Francisco Ornelas
- Instituto de Ecología A.C. (INECOL), Red de Biología Evolutiva, Xalapa, Mexico
- *Correspondence: Enrique Ibarra-Laclette, ; Juan Francisco Ornelas,
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Zumajo-Cardona C, Ambrose BA. Deciphering the evolution of the ovule genetic network through expression analyses in Gnetum gnemon. ANNALS OF BOTANY 2021; 128:217-230. [PMID: 33959756 PMCID: PMC8324035 DOI: 10.1093/aob/mcab059] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Accepted: 04/30/2021] [Indexed: 05/16/2023]
Abstract
BACKGROUND AND AIMS The ovule is a synapomorphy of all seed plants (gymnosperms and angiosperms); however, there are some striking differences in ovules among the major seed plant lineages, such as the number of integuments or the orientation of the ovule. The genetics involved in ovule development have been well studied in the model species Arabidopsis thaliana, which has two integuments and anatropous orientation. This study is approached from what is known in arabidopsis, focusing on the expression patterns of homologues of four genes known to be key for the proper development of the integuments in arabidopsis: AINTEGUMENTA (ANT), BELL1, (BEL1), KANADIs (KANs) and UNICORN (UCN). METHODS We used histology to describe the morphoanatomical development from ovules to seeds in Gnetum gnemon. We carried out spatiotemporal expression analyses in G. gnemon, a gymnosperm, which has a unique ovule morphology with an integument covering the nucellus, two additional envelopes where the outermost becomes fleshy as the seed matures, and an orthotropous orientation. KEY RESULTS Our anatomical and developmental descriptions provide a framework for expression analyses in the ovule of G. gnemon. Our expression results show that although ANT, KAN and UCN homologues are expressed in the inner integument, their spatiotemporal patterns differ from those found in angiosperms. Furthermore, all homologues studied here are expressed in the nucellus, revealing major differences in seed plants. Finally, no expression of the studied homologues was detected in the outer envelopes. CONCLUSIONS Altogether, these analyses provide significant comparative data that allows us to better understand the functional evolution of these gene lineages, providing a compelling framework for evolutionary and developmental studies of seeds. Our findings suggest that these genes were most likely recruited from the sporangium development network and became restricted to the integuments of angiosperm ovules.
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Affiliation(s)
- Cecilia Zumajo-Cardona
- New York Botanical Garden, Bronx, NY, USA
- The Graduate Center, City University of New York, New York, NY, USA
| | - Barbara A Ambrose
- The Graduate Center, City University of New York, New York, NY, USA
- For correspondence. E-mail
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Rudall PJ. Evolution and patterning of the ovule in seed plants. Biol Rev Camb Philos Soc 2021; 96:943-960. [PMID: 33432779 DOI: 10.1111/brv.12684] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 12/23/2020] [Accepted: 01/04/2021] [Indexed: 02/06/2023]
Abstract
The ovule and its developmental successor, the seed, together represent a highly characteristic feature of seed plants that has strongly enhanced the reproductive and dispersal potential of this diverse group of taxa. Ovules encompass multiple tissues that perform various roles within a highly constrained space, requiring a complex cascade of genes that generate localized cell proliferation and programmed cell death during different developmental stages. Many heritable morphological differences among lineages reflect relative displacement of these tissues, but others, such as the second (outer) integuments of angiosperms and Gnetales, represent novel and apparently profound and independent innovations. Recent studies, mostly on model taxa, have considerably enhanced our understanding of gene expression in the ovule. However, understanding its evolutionary history requires a comparative and phylogenetic approach that is problematic when comparing extant angiosperms not only with phylogenetically distant extant gymnosperms but also with taxa known only from fossils. This paper reviews ovule characters across a phylogenetically broad range of seed plants in a dynamic developmental context. It discusses both well-established and recent theories of ovule and seed evolution and highlights potential gaps in comparative data that will usefully enhance our understanding of evolutionary transitions and developmental mechanisms.
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Affiliation(s)
- Paula J Rudall
- Royal Botanic Gardens, Kew, Richmond, Surrey, TW9 3AB, U.K
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Huang S, Liu W, Xu J, Liu Z, Li C, Feng H. The SAP function in pistil development was proved by two allelic mutations in Chinese cabbage (Brassica rapa L. ssp. pekinensis). BMC PLANT BIOLOGY 2020; 20:538. [PMID: 33256588 PMCID: PMC7708145 DOI: 10.1186/s12870-020-02741-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 11/16/2020] [Indexed: 06/12/2023]
Abstract
BACKGROUND Pistil development is a complicated process in plants, and female sterile mutants are ideal material for screening and cloning pistil development-related genes. Using the female sterile mutant (fsm1), BraA04g009730.3C was previously predicted as a candidate mutant gene encoding the STERILE APETALA (SAP) transcriptional regulator. In the current study, a parallel female sterile mutant (fsm2) was derived from EMS mutagenesis of a Chinese cabbage DH line 'FT' seeds. RESULTS Both fsm2 and fsm1 mutant phenotypes exhibited pistil abortion and smaller floral organs. Genetic analysis indicated that the phenotype of mutant fsm2 was also controlled by a single recessive nuclear gene. Allelism testing showed that the mutated fsm1 and fsm2 genes were allelic. A single-nucleotide mutation (G-to-A) in the first exon of BraA04g009730.3C caused a missense mutation from GAA (glutamic acid) to GGA (glycine) in mutant fsm2 plants. Both allelic mutations of BraA04g009730.3C in fsm1 and fsm2 conferred the similar pistil abortion phenotype, which verified the SAP function in pistil development. To probe the mechanism of SAP-induced pistil abortion, we compared the mutant fsm1 and wild-type 'FT' pistil transcriptomes. Among the 3855 differentially expressed genes obtained, 29 were related to ovule development and 16 were related to organ size. CONCLUSION Our study clarified the function of BraA04g009730.3C and revealed that it was responsible for ovule development and organ size. These results lay a foundation to elucidate the molecular mechanism of pistil development in Chinese cabbage.
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Affiliation(s)
- Shengnan Huang
- Department of Horticulture, Shenyang Agricultural University, 120 Dongling Road, Shenhe District, Shenyang, 110866, China
| | - Wenjie Liu
- Department of Horticulture, Shenyang Agricultural University, 120 Dongling Road, Shenhe District, Shenyang, 110866, China
| | - Junjie Xu
- Department of Horticulture, Shenyang Agricultural University, 120 Dongling Road, Shenhe District, Shenyang, 110866, China
| | - Zhiyong Liu
- Department of Horticulture, Shenyang Agricultural University, 120 Dongling Road, Shenhe District, Shenyang, 110866, China
| | - Chengyu Li
- Department of Horticulture, Shenyang Agricultural University, 120 Dongling Road, Shenhe District, Shenyang, 110866, China
| | - Hui Feng
- Department of Horticulture, Shenyang Agricultural University, 120 Dongling Road, Shenhe District, Shenyang, 110866, China.
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Zumajo-Cardona C, Ambrose BA. Phylogenetic analyses of key developmental genes provide insight into the complex evolution of seeds. Mol Phylogenet Evol 2020; 147:106778. [PMID: 32165160 DOI: 10.1016/j.ympev.2020.106778] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 02/06/2020] [Accepted: 02/26/2020] [Indexed: 11/30/2022]
Abstract
Gene duplication plays a decisive role in organismal diversification and in the appearance of novel structures. In plants the megagametophyte covered by the integuments, which after fertilization becomes the seed constitutes a novel structure: the ovule. In Arabidopsis thaliana, genetic mechanisms regulating ovule development, including the genetics underlying ovule initiation, ovule patterning and integument development, have been identified. Among seed plants, integuments are not only a novelty in evolution, but integuments also present an enormous morphological variation. This study is focused on the evolution of gene families that play a role in the proper morphological development of the integuments, BELL1 (BEL1), KANADIs (KAN1, KAN2, and KAN4/ATS), UNICORN (UCN) and SHORT INTEGUMENTS1 (SIN1). In Arabidopsis, BEL1 establishes the initiation of integument development. KAN1 and 2 act in the proper development of the outer integument. While ABERRANT TESTA SHAPE (ATS), is involved in the correct separation of both integuments. UCN acts in planar growth of the outer integument repressing ATS. SIN1 is involved in cell elongation in the integuments. The results of our analyses show that each of these genes has a different evolutionary history and that while gymnosperms appear to have a simpler ovule morphology, they have more homologues of these candidate genes than angiosperms. In addition, we present the conserved and novel motifs for each of these genes among seed plants and their selection constraints, which may be related to functional changes and to the diversity of ovule morphologies.
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Affiliation(s)
- Cecilia Zumajo-Cardona
- New York Botanical Garden, Bronx, NY 10458, USA; The Graduate Center, City University of New York, New York, NY 10016, USA
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Xin GL, Liu JQ, Liu J, Ren XL, Du XM, Liu WZ. Anatomy and RNA-Seq reveal important gene pathways regulating sex differentiation in a functionally Androdioecious tree, Tapiscia sinensis. BMC PLANT BIOLOGY 2019; 19:554. [PMID: 31842763 PMCID: PMC6915933 DOI: 10.1186/s12870-019-2081-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 10/16/2019] [Indexed: 05/07/2023]
Abstract
BACKGROUND Gametogenesis is a key step in the production of ovules or pollen in higher plants. The sex-determination aspects of gametogenesis have been well characterized in the model plant Arabidopsis. However, little is known about this process in androdioecious plants. Tapiscia sinensis Oliv. is a functionally androdioecious tree, with both male and hermaphroditic individuals. Hermaphroditic flowers (HFs) are female-fertile flowers that can produce functional pollen and set fruits. However, compared with male flowers (MFs), the pollen viability and number of pollen grains per flower are markedly reduced in HFs. MFs are female-sterile flowers that fail to set fruit and that eventually drop. RESULTS Compared with HF, a notable cause of MF female sterility in T. sinensis is when the early gynoecium meristem is disrupted. During the early stage of HF development (stage 6), the ring meristem begins to form as a ridge around the center of the flower. At this stage, the internal fourth-whorl organ is stem-like rather than carpelloid in MF. A total of 52,945 unigenes were identified as transcribed in MF and HF. A number of differentially expressed genes (DEGs) and metabolic pathways were detected as involved in the development of the gynoecium, especially the ovule, carpel and style. At the early gynoecium development stage, DEGs were shown to function in the metabolic pathways regulating ethylene biosynthesis and signal transduction (upstream regulator), auxin, cytokinin transport and signalling, and sex determination (or flower meristem identity). CONCLUSIONS Pathways for the female sterility model were initially proposed to shed light on the molecular mechanisms of gynoecium development at early stages in T. sinensis.
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Affiliation(s)
- Gui-Liang Xin
- Key Laboratory of Resource Biology and Biotechnology in Western China (Northwest University), Ministry of Education, School of Life Science, Northwest University, Xi’an, 710069 Shaanxi China
| | - Jia-Qian Liu
- Key Laboratory of Resource Biology and Biotechnology in Western China (Northwest University), Ministry of Education, School of Life Science, Northwest University, Xi’an, 710069 Shaanxi China
| | - Jia Liu
- Key Laboratory of Resource Biology and Biotechnology in Western China (Northwest University), Ministry of Education, School of Life Science, Northwest University, Xi’an, 710069 Shaanxi China
| | - Xiao-Long Ren
- Key Laboratory of Resource Biology and Biotechnology in Western China (Northwest University), Ministry of Education, School of Life Science, Northwest University, Xi’an, 710069 Shaanxi China
| | - Xiao-Min Du
- Key Laboratory of Resource Biology and Biotechnology in Western China (Northwest University), Ministry of Education, School of Life Science, Northwest University, Xi’an, 710069 Shaanxi China
| | - Wen-Zhe Liu
- Key Laboratory of Resource Biology and Biotechnology in Western China (Northwest University), Ministry of Education, School of Life Science, Northwest University, Xi’an, 710069 Shaanxi China
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Alves MF, Pinheiro F, Niedzwiedzki MP, Mayer JLS. First Record of Ategmic Ovules in Orchidaceae Offers New Insights Into Mycoheterotrophic Plants. FRONTIERS IN PLANT SCIENCE 2019; 10:1447. [PMID: 31850003 PMCID: PMC6895064 DOI: 10.3389/fpls.2019.01447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 10/17/2019] [Indexed: 06/10/2023]
Abstract
The number of integuments found in angiosperm ovules is variable. In orchids, most species show bitegmic ovules, except for some mycoheterotrophic species that show ovules with only one integument. Analysis of ovules and the development of the seed coat provide important information regarding functional aspects such as dispersal and seed germination. This study aimed to analyze the origin and development of the seed coat of the mycoheterotrophic orchid Pogoniopsis schenckii and to compare this development with that of other photosynthetic species of the family. Flowers and fruits at different stages of development were collected, and the usual methodology for performing anatomical studies, scanning microscopy, and transmission microscopy following established protocols. P. schenckii have ategmic ovules, while the other species are bitegmic. No evidence of integument formation at any stage of development was found through anatomical studies. The reduction of integuments found in the ovules could facilitate fertilization in this species. The seeds of P. schenckii, Vanilla planifolia, and V. palmarum have hard seed coats, while the other species have seed coats formed by the testa alone, making them thin and transparent. P. schenckii, in contrast to the other species analyzed, has a seed coat that originates from the nucellar epidermis, while in other species, the seed coat originates from the outer integument.
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Affiliation(s)
- Mariana Ferreira Alves
- Departamento de Biologia Vegetal, Instituto de Biologia, Universidade Estadual de Campinas, São Paulo, Brazil
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Nickrent DL, Anderson F, Kuijt J. Inflorescence evolution in Santalales: integrating morphological characters and molecular phylogenetics. AMERICAN JOURNAL OF BOTANY 2019; 106:402-414. [PMID: 30856677 DOI: 10.1002/ajb2.1250] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 12/17/2018] [Indexed: 06/09/2023]
Abstract
PREMISE OF THE STUDY The sandalwood order (Santalales) includes members that present a diverse array of inflorescence types, some of which are unique among angiosperms. This diversity presents not only interpretational challenges but also opportunities to test fundamental concepts in plant morphology. Here we used modern phylogenetic approaches to address the evolution of inflorescences in the sandalwood order. METHODS Phylogenetic analyses of two nuclear and three chloroplast genes were conducted on representatives of 146 of the 163 genera in the order. A matrix was constructed that scored nine characters dealing with inflorescences. One character, "trios", that encompasses any grouping of three flowers (i.e., both dichasia and triads) was optimized on samples of the posterior distribution of trees from the Bayesian analysis using BayesTraits. Three nodes were examined: the most recent common ancestors of (A) all ingroup members, (B) Loranthaceae, and (C) Opiliaceae, Santalaceae s.l., and Viscaceae. KEY RESULTS The phylogenetic analysis resulted in many fully resolved nodes across Santalales with strong support for 18 clades previously named as families. The trios character was not supported for nodes A and C, whereas it was supported for node B where this partial inflorescence type is best described as a triad. CONCLUSIONS Essentially every major inflorescence type can be found in Santalales; however, the dichasium, a type of partial inflorescence, is rarely seen and is not plesiomorphic for the order. In the family Erythropalaceae, inflorescences are mostly in small, axillary fascicles or cymes. Successive families show both cymose and racemose types and compound systems (e.g., thyrses). Inflorescences in Amphorogynaceae and Viscaceae are not dichasial and in general are difficult to compare to "standard" inflorescences.
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Affiliation(s)
- Daniel L Nickrent
- Department of Plant Biology, Southern Illinois University, Carbondale, IL, 62901-6509, USA
| | - Frank Anderson
- Department of Zoology, Southern Illinois University, Carbondale, IL, 62901-6509, USA
| | - Job Kuijt
- 649 Lost Lake Road, Victoria, BC, V9B 6E3, Canada
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Gasser CS, Skinner DJ. Development and evolution of the unique ovules of flowering plants. Curr Top Dev Biol 2018; 131:373-399. [PMID: 30612624 DOI: 10.1016/bs.ctdb.2018.10.007] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Ovules are the precursors to seeds and as such are critical to plant propagation and food production. Mutant studies have led to the identification of numerous genes regulating ovule development. Genes encoding transcription factors have been shown to direct ovule spacing, ovule identity and integument formation. Particular co-regulators have now been associated with activities of some of these transcription factors, and other protein families including cell surface receptors have been shown to regulate ovule development. Hormone levels and transport, especially of auxin, have also been shown to play critical roles in ovule emergence and morphogenesis and to interact with the transcriptional regulators. Ovule diversification has been studied using orthologs of regulatory genes in divergent angiosperm groups. Combining modern genetic evidence with expanding knowledge of the fossil record illuminates the possible origin of the unique bitegmic ovules of angiosperms.
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Affiliation(s)
- Charles S Gasser
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA, United States.
| | - Debra J Skinner
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA, United States
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Coen O, Magnani E. Seed coat thickness in the evolution of angiosperms. Cell Mol Life Sci 2018; 75:2509-2518. [PMID: 29730767 PMCID: PMC6003975 DOI: 10.1007/s00018-018-2816-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 04/10/2018] [Accepted: 04/13/2018] [Indexed: 10/26/2022]
Abstract
The seed habit represents a remarkable evolutionary advance in plant sexual reproduction. Since the Paleozoic, seeds carry a seed coat that protects, nourishes and facilitates the dispersal of the fertilization product(s). The seed coat architecture evolved to adapt to different environments and reproductive strategies in part by modifying its thickness. Here, we review the great natural diversity observed in seed coat thickness among angiosperms and its molecular regulation in Arabidopsis.
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Affiliation(s)
- Olivier Coen
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, University of Paris-Saclay, Route de St-Cyr (RD10), 78026, Versailles Cedex, France
- Ecole Doctorale 567 Sciences du Végétal, University Paris-Sud, University of Paris-Saclay, bat 360, 91405, Orsay Cedex, France
| | - Enrico Magnani
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, University of Paris-Saclay, Route de St-Cyr (RD10), 78026, Versailles Cedex, France.
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Chen L, Zhang J, Li H, Niu J, Xue H, Liu B, Wang Q, Luo X, Zhang F, Zhao D, Cao S. Transcriptomic Analysis Reveals Candidate Genes for Female Sterility in Pomegranate Flowers. FRONTIERS IN PLANT SCIENCE 2017; 8:1430. [PMID: 28878788 PMCID: PMC5572335 DOI: 10.3389/fpls.2017.01430] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Accepted: 08/03/2017] [Indexed: 05/19/2023]
Abstract
Pomegranate has two types of flowers on the same plant: functional male flowers (FMF) and bisexual flowers (BF). BF are female-fertile flowers that can set fruits. FMF are female-sterile flowers that fail to set fruit and that eventually drop. The putative cause of pomegranate FMF female sterility is abnormal ovule development. However, the key stage at which the FMF pomegranate ovules become abnormal and the mechanism of regulation of pomegranate female sterility remain unknown. Here, we studied ovule development in FMF and BF, using scanning electron microscopy to explore the key stage at which ovule development was terminated and then analyzed genes differentially expressed (differentially expressed genes - DEGs) between FMF and BF to investigate the mechanism responsible for pomegranate female sterility. Ovule development in FMF ceased following the formation of the inner integument primordium. The key stage for the termination of FMF ovule development was when the bud vertical diameter was 5.0-13.0 mm. Candidate genes influencing ovule development may be crucial factors in pomegranate female sterility. INNER OUTER (INO/YABBY4) (Gglean016270) and AINTEGUMENTA (ANT) homolog genes (Gglean003340 and Gglean011480), which regulate the development of the integument, showed down-regulation in FMF at the key stage of ovule development cessation (ATNSII). Their upstream regulator genes, such as AGAMOUS-like (AG-like) (Gglean028014, Gglean026618, and Gglean028632) and SPOROCYTELESS (SPL) homolog genes (Gglean005812), also showed differential expression pattern between BF and FMF at this key stage. The differential expression of the ethylene response signal genes, ETR (ethylene-resistant) (Gglean022853) and ERF1/2 (ethylene-responsive factor) (Gglean022880), between FMF and BF indicated that ethylene signaling may also be an important factor in the development of pomegranate female sterility. The increase in BF observed after spraying with ethephon supported this interpretation. Results from qRT-PCR confirmed the findings of the transcriptomic analysis.
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Endress PK. Angiosperm ovules: diversity, development, evolution. ANNALS OF BOTANY 2011; 107:1465-89. [PMID: 21606056 PMCID: PMC3108811 DOI: 10.1093/aob/mcr120] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Revised: 03/29/2011] [Accepted: 04/11/2011] [Indexed: 05/18/2023]
Abstract
BACKGROUND Ovules as developmental precursors of seeds are organs of central importance in angiosperm flowers and can be traced back in evolution to the earliest seed plants. Angiosperm ovules are diverse in their position in the ovary, nucellus thickness, number and thickness of integuments, degree and direction of curvature, and histological differentiations. There is a large body of literature on this diversity, and various views on its evolution have been proposed over the course of time. Most recently evo-devo studies have been concentrated on molecular developmental genetics in ovules of model plants. SCOPE The present review provides a synthetic treatment of several aspects of the sporophytic part of ovule diversity, development and evolution, based on extensive research on the vast original literature and on experience from my own comparative studies in a broad range of angiosperm clades. CONCLUSIONS In angiosperms the presence of an outer integument appears to be instrumental for ovule curvature, as indicated from studies on ovule diversity through the major clades of angiosperms, molecular developmental genetics in model species, abnormal ovules in a broad range of angiosperms, and comparison with gymnosperms with curved ovules. Lobation of integuments is not an atavism indicating evolution from telomes, but simply a morphogenetic constraint from the necessity of closure of the micropyle. Ovule shape is partly dependent on locule architecture, which is especially indicated by the occurrence of orthotropous ovules. Some ovule features are even more conservative than earlier assumed and thus of special interest in angiosperm macrosystematics.
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Affiliation(s)
- Peter K Endress
- Institute of Systematic Botany, University of Zurich, Zollikerstrasse 107, 8008 Zurich, Switzerland.
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Cross talk between the sporophyte and the megagametophyte during ovule development. ACTA ACUST UNITED AC 2011; 24:113-21. [PMID: 21298290 DOI: 10.1007/s00497-011-0162-3] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2010] [Accepted: 01/19/2011] [Indexed: 10/18/2022]
Abstract
In seed plant ovules, the diploid maternal sporophytic generation embeds and sustains the haploid generation (the female gametophyte); thus, two independent generations coexist in a single organ. Many independent studies on Arabidopsis ovule mutants suggest that embryo sac development requires highly synchronized morphogenesis of the maternal sporophyte surrounding the gametophyte, since megagametogenesis is severely perturbed in most of the known sporophytic ovule development mutants. Which are the messenger molecules involved in the haploid-diploid dialogue? And furthermore, is this one way communication or is a feedback cross talk? In this review, we discuss genetic and molecular evidences supporting the presence of a cross talk between the two generations, starting from the first studies regarding ovule development and ending to the recently sporophytic identified genes whose expression is strictly controlled by the haploid gametophytic generation. We will mainly focus on Arabidopsis studies since it is the species more widely studied for this aspect. Furthermore, possible candidate molecules involved in the diploid-haploid generations dialogue will be presented and discussed.
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Shi DQ, Yang WC. Ovule development in Arabidopsis: progress and challenge. CURRENT OPINION IN PLANT BIOLOGY 2011; 14:74-80. [PMID: 20884278 DOI: 10.1016/j.pbi.2010.09.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2010] [Revised: 08/31/2010] [Accepted: 09/01/2010] [Indexed: 05/18/2023]
Abstract
Female gametophyte, the central core of the ovule, is a simple seven-celled reproductive structure. Its stereotyped ontogeny provides a traceable model system to study mechanisms controlling cell growth, cell division, cell fate, pattern formation, and perhaps the function of essential genes in plants. An auxin concentration gradient was demonstrated for the first time in the embryo sac to control gametic cell fate. Mutant analysis also indicates a role of RNA processing in the mitotic progression of the gametophytic generation and cell fate determination in the embryo sac. Combined studies of genetics and transcriptome analysis revealed recently that epigenetic pathways play a critical role in female gametophyte development. In addition, the discovery that a large number of small secreted cysteine-rich proteins are enriched in embryo sac is of special interest. Except these insights and progresses, challenge ahead is to reveal the signaling pathways and their interactions that lead to the patterning of the female gametophyte.
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Affiliation(s)
- Dong-Qiao Shi
- Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, 1 West Beichen Road, Chaoyang District, Beijing 100101, China.
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