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Sorojsrisom ES, Haller BC, Ambrose BA, Eaton DAR. Selection on the gametophyte: Modeling alternation of generations in plants. APPLICATIONS IN PLANT SCIENCES 2022; 10:e11472. [PMID: 35495198 PMCID: PMC9039789 DOI: 10.1002/aps3.11472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 03/14/2022] [Indexed: 05/12/2023]
Abstract
PREMISE The degree of gametophyte dependence on the sporophyte life stage is a major feature that differentiates the life cycles of land plants, yet the evolutionary consequences of this difference remain poorly understood. Most evolutionary models assume organisms are either haploid or diploid for their entire lifespan, which is not appropriate for simulating plant life cycles. Here, we introduce shadie (Simulating Haploid-Diploid Evolution), a new, simple Python program for implementing simulations with biphasic life cycles and analyzing their results, using SLiM 3 as a simulation back end. METHODS We implemented evolutionary simulations under three realistic plant life cycle models supported in shadie, using either standardized or biologically realistic parameter settings to test how variation in plant life cycles and sexual systems affects patterns of genome diversity. RESULTS The dynamics of single beneficial mutation fixation did not vary dramatically between different models, but the patterns of spatial variation did differ, demonstrating that different life histories and model parameters affect both genetic diversity and linkage disequilibrium. The rate of linkage disequilibrium decay away from selected sites varied depending on model parameters such as cloning and selfing rates, through their impact on effective population sizes. DISCUSSION Evolutionary simulations are an exciting, underutilized approach in evolutionary research and education. shadie can aid plant researchers in developing null hypotheses, examining theory, and designing empirical studies, in order to investigate the role of the gametophyte life stage, and the effects of variation in plant life cycles, on plant genome evolution.
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Affiliation(s)
- Elissa S. Sorojsrisom
- Department of Ecology, Evolution, and Environmental BiologyColumbia University1200 Amsterdam Ave., Schermerhorn Ext.New York10027USA
- New York Botanical Garden2900 Southern Blvd.BronxNew York10458USA
| | - Benjamin C. Haller
- Department of Computational BiologyCornell University, IthacaNew York14853USA
| | | | - Deren A. R. Eaton
- Department of Ecology, Evolution, and Environmental BiologyColumbia University1200 Amsterdam Ave., Schermerhorn Ext.New York10027USA
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Gotelli MM, Lattar EC, Zini LM, Galati BG. Style morphology and pollen tube pathway. PLANT REPRODUCTION 2017; 30:155-170. [PMID: 29116403 DOI: 10.1007/s00497-017-0312-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 10/31/2017] [Indexed: 06/07/2023]
Abstract
The style morphology and anatomy vary among different species. Three basic types are: open, closed, and semi-closed. Cells involved in the pollen tube pathway in the different types of styles present abundant endoplasmic reticulum, dictyosomes, mitochondria, and ribosomes. These secretory characteristics are related to the secretion where pollen tube grows. This secretion can be represented by the substances either in the canal or in the intercellular matrix or in the cell wall. Most studies suggest that pollen tubes only grow through the secretion of the canal in open styles. However, some species present pollen tubes that penetrate the epithelial cells of the canal, or grow through the middle lamella between these cells and subepithelial cells. In species with a closed style, a pathway is provided by the presence of an extracellular matrix, or by the thickened cell walls of the stylar transmitting tissue. There are reports in some species where pollen tubes can also penetrate the transmitting tissue cells and continue their growth through the cell lumen. In this review, we define subtypes of styles according to the path of the pollen tube. Style types were mapped on an angiosperm phylogenetic tree following the maximum parsimony principle. In line with this, it could be hypothesized that: the open style appeared in the early divergent angiosperms; the closed type of style originated in Asparagales, Poales, and Eudicots; and the semi-closed style appeared in Rosids, Ericales, and Gentianales. The open style seems to have been lost in core Eudicots, with reversions in some Rosids and Asterids.
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Affiliation(s)
- M M Gotelli
- Cátedra de Botánica General, Depto. de Recursos Naturales y Ambiente, Facultad de Agronomía, Universidad de Buenos Aires, Buenos Aires, Argentina.
- CONICET, Buenos Aires, Argentina.
| | - E C Lattar
- IBONE-UNNE-CONICET, Corrientes, Argentina
- Cátedra de Morfología de Plantas Vasculares, Facultad de Ciencias Agrarias, Universidad Nacional del Nordeste (FCA-UNNE), Corrientes, Argentina
| | - L M Zini
- IBONE-UNNE-CONICET, Corrientes, Argentina
| | - B G Galati
- Cátedra de Botánica General, Depto. de Recursos Naturales y Ambiente, Facultad de Agronomía, Universidad de Buenos Aires, Buenos Aires, Argentina
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Lora J, Hormaza JI, Herrero M. The Diversity of the Pollen Tube Pathway in Plants: Toward an Increasing Control by the Sporophyte. FRONTIERS IN PLANT SCIENCE 2016; 7:107. [PMID: 26904071 PMCID: PMC4746263 DOI: 10.3389/fpls.2016.00107] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 01/20/2016] [Indexed: 05/06/2023]
Abstract
Plants, unlike animals, alternate multicellular diploid, and haploid generations in their life cycle. While this is widespread all along the plant kingdom, the size and autonomy of the diploid sporophyte and the haploid gametophyte generations vary along evolution. Vascular plants show an evolutionary trend toward a reduction of the gametophyte, reflected both in size and lifespan, together with an increasing dependence from the sporophyte. This has resulted in an overlooking of the importance of the gametophytic phase in the evolution of higher plants. This reliance on the sporophyte is most notorious along the pollen tube journey, where the male gametophytes have to travel a long way inside the sporophyte to reach the female gametophyte. Along evolution, there is a change in the scenery of the pollen tube pathway that favors pollen competition and selection. This trend, toward apparently making complicated what could be simple, appears to be related to an increasing control of the sporophyte over the gametophyte with implications for understanding plant evolution.
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Affiliation(s)
- Jorge Lora
- Department of Subtropical Fruit Crops, Instituto de Hortofruticultura Subtropical y Mediterránea La Mayora – University of Málaga – Consejo Superior de Investigaciones CientíficasMálaga, Spain
| | - José I. Hormaza
- Department of Subtropical Fruit Crops, Instituto de Hortofruticultura Subtropical y Mediterránea La Mayora – University of Málaga – Consejo Superior de Investigaciones CientíficasMálaga, Spain
| | - María Herrero
- Department of Pomology, Estación Experimental Aula Dei, Consejo Superior de Investigaciones CientíficasZaragoza, Spain
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Mangla Y, Tandon R, Goel S, Raina SN. Structural organization of the gynoecium and pollen tube path in
Himalayan sea buckthorn, Hippophae rhamnoides
(Elaeagnaceae). AOB PLANTS 2013; 5:plt015. [PMCID: PMC4130438 DOI: 10.1093/aobpla/plt015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2012] [Accepted: 02/18/2013] [Indexed: 06/04/2023]
Abstract
Gynoecium of Hippophae rhamnoides (Elaeagnaceae) is comprised of a
single carpel and develops by enfolding of the carpel margins. The enfolding results
in a vertical slit over the ventral surface of ovary. The pollen tube path is
initially sub-stigmatic and is subsequently along the epidermal surface of slit. The
tube accesses the solitary ovule through a pore positioned in the slit. These
findings would be useful in understanding the evolution of transmitting tract in
general and knowledge of pollen-pistil interaction of the species in particular. Closure of carpels or angiospermy, a key developmental innovation, has been
accomplished through different ontogenic routes among the flowering plants. The
mechanism of angiospermy produces structural novelties in the gynoecium, which in
turn affects the progamic phase. In this paper, we present the structural details of
the gynoecium and functional attributes of the progamic phase of Hippophae
rhamnoides, a dioecious species of Elaeagnaceae. The gynoecium is
unicarpellate, and the carpel is dorsiventrally symmetric and conduplicate. The
pollen tube path comprises a prominent, ventrally localized dry and non-papillate
stigma, a pseudostyle and a dorsally protruded superior ovary. The pollen tube path
in the stigmatic region is subdermal, and from the pseudostyle onwards, it resides
over the epidermis of conduplicated margins. The epidermal cells along this region
are secretory but produce sparse extracellular matrix. The tube approaches the
solitary ovule through a tiny conduit in the carpel, the ventral pore. The duration
of the entire progamic phase is ∼72 h. The observed mean pollen tube length
from stigma to ovule was 908.13 ± 180 µm and the mean tube growth rate
was 18.75 µm h−1. The study demonstrates that sea buckthorn,
a core eudicot, has a simple gynoecium with a pollen tube pathway that incorporates
elements of both completely externalized and internalized compitum.
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Affiliation(s)
- Yash Mangla
- Department of Botany,
University of Delhi, Delhi 110
007, India
| | - Rajesh Tandon
- Department of Botany,
University of Delhi, Delhi 110
007, India
| | - Shailendra Goel
- Department of Botany,
University of Delhi, Delhi 110
007, India
| | - S. N. Raina
- Amity Institute of Biotechnology,
Amity University, Sector 125, Noida 210 303,
Uttar Pradesh, India
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Williams JH. Pollen Tube Growth Rates and the Diversification of Flowering Plant Reproductive Cycles. INTERNATIONAL JOURNAL OF PLANT SCIENCES 2012. [PMID: 0 DOI: 10.1086/665822] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
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Lora J, Herrero M, Hormaza JI. Stigmatic receptivity in a dichogamous early-divergent angiosperm species, Annona cherimola (Annonaceae): influence of temperature and humidity. AMERICAN JOURNAL OF BOTANY 2011; 98:265-74. [PMID: 21613115 DOI: 10.3732/ajb.1000185] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
PREMISE OF THE STUDY A variety of mechanisms to prevent inbreeding have arisen in different angiosperm taxa during plant evolution. In early-divergent angiosperms, a widespread system is dichogamy, in which female and male structures do not mature simultaneously, thus encouraging cross pollination. While this system is common in early-divergent angiosperms, it is less widespread in more recently evolved clades. An evaluation of the consequences of this system on outbreeding may provide clues on this change, but this subject has been little explored. METHODS In this work, we characterized the cycle and anatomy of the flower and studied the influence of temperature and humidity on stigmatic receptivity in Annona cherimola, a member of an early-divergent angiosperm clade with protogynous dichogamy. KEY RESULTS Paternity analysis reveals a high proportion of seeds resulting from self-fertilization, indicating that self-pollination can occur in spite of the dichogamous system. Stigmatic receptivity is environmentally modulated--shortened by high temperatures and prolonged by high humidity. CONCLUSIONS Although spatial and temporal sexual separation in this system seems to effectively decrease selfing, the system is modulated by environmental conditions and may allow high levels of selfing that can guarantee reproductive assurance.
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Affiliation(s)
- Jorge Lora
- Department of Subtropical Pomology, Instituto de Hortofruticultura Subtropical y Mediterránea la Mayora (IHSM la Mayora-CSIC), 29750 Algarrobo-Costa, Málaga, Spain
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Klein DE, Freitas L, Da Cunha M. Self-incompatibility in a distylous species of Rubiaceae: is there a single incompatibility response of the morphs? ACTA ACUST UNITED AC 2009; 22:121-31. [DOI: 10.1007/s00497-009-0097-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2008] [Accepted: 05/02/2009] [Indexed: 11/29/2022]
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Sage TL, Hristova-Sarkovski K, Koehl V, Lyew J, Pontieri V, Bernhardt P, Weston P, Bagha S, Chiu G. Transmitting tissue architecture in basal-relictual angiosperms: Implications for transmitting tissue origins. AMERICAN JOURNAL OF BOTANY 2009; 96:183-206. [PMID: 21628183 DOI: 10.3732/ajb.0800254] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Carpel transmitting tissue is a major floral innovation that is essential for angiosperm success. It facilitates the rapid adhesion, hydration, and growth of the male gametophyte to the female gametophyte. As well, it functions as a molecular screen to promote male gametophytic competition and species-specific recognition and compatibility. Here, we characterize the transmitting tissue extracellular matrix (ECM) and pollen tube growth in basal-relictual angiosperms and test the hypothesis that a freely flowing ECM (wet stigma) was ancestral to a cuticle-bound ECM (dry stigma). We demonstrate that the most recent common ancestor of extant angiosperms produced an ECM that was structurally and functionally equivalent to a dry stigma. Dry stigmas are composed of a cuticle and primary wall that contains compounds that facilitate the adhesion and growth of the male gametophyte. These compounds include methyl-esterified homogalacturonans, arabinogalactan-proteins, and lipids. We propose that transmitting tissue evolved in concert with an increase in cuticle permeability that resulted from modifications in the biosynthesis and secretion of fatty acids needed for cuticle construction. Increased cuticle permeability exposed the male gametophyte to pre-existing molecules that enabled rapid male gametophyte adhesion, hydration, and growth as well as species-specific recognition and compatibility.
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Affiliation(s)
- Tammy L Sage
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada M5S 3B2
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Lyew J, Li Z, Liang-Chen Y, Yi-Bo L, Sage TL. Pollen tube growth in association with a dry-type stigmatic transmitting tissue and extragynoecial compitum in the basal angiosperm Kadsura longipedunculata (Schisandraceae). AMERICAN JOURNAL OF BOTANY 2007; 94:1170-82. [PMID: 21636484 DOI: 10.3732/ajb.94.7.1170] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Spatial features of pollen tube growth and the composition of the extracellular matrix (ECM) of transmitting tissue in carpels of Kadsura longipedunculata, a member of the basal angiosperm taxon Schisandraceae, were characterized to identify features of transmitting tissue that might have been important for pollen-carpel interactions during the early history of angiosperms. In addition to growing extracellularly along epidermal cells that make up stigmatic crests of individual carpels, pollen tubes grow on abaxial carpel epidermal cells between unfused carpels along an extragynoecial compitum to subsequently enter an adjacent carpel, a feature important for enhancing seed set in apocarpous species. Histo- and immunochemical data indicated that transmitting tissue ECM is not freely flowing as previously hypothesized. Rather, the ECM is similar to that of a dry-type stigma whereby a cuticular boundary with associated esterase activity confines a matrix containing methyl-esterified homogalacturonans. The Schisandraceae joins an increasing number of basal angiosperm taxa that have a transmitting tissue ECM similar to a dry-type stigma, thereby challenging traditional views that the ancestral pollen tube pathway was similar to a wet-type stigma covered with a freely flowing exudate. Dry-type stigmas are posited to provide tighter control over pollen capture, retention, and germination than wet-type stigmas.
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Affiliation(s)
- Joelle Lyew
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada M5S 3B2
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HRISTOVA KATERINA, LAM MATTHEW, FEILD TAYLOR, SAGE TAMMYL. Transmitting tissue ECM distribution and composition, and pollen germinability in Sarcandra glabra and Chloranthus japonicus (Chloranthaceae). ANNALS OF BOTANY 2005; 96:779-91. [PMID: 16046459 PMCID: PMC4247049 DOI: 10.1093/aob/mci235] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2005] [Revised: 03/23/2005] [Accepted: 06/14/2005] [Indexed: 05/03/2023]
Abstract
BACKGROUND and Aims Free-flowing surface exudates at the stigmatic (wet versus dry stigma) and adaxial epidermis at the site of angiospermy in carpels of Chloranthaceous species have been proposed to comprise a continuous extracellular matrix (ECM) operating in pollen tube transmission to the ovary. The aim of this research was to establish the spatial distribution and histo/immunochemical composition of the ECM involved in pollen tube growth in Sarcandra glabra and Chloranthus japonicus (Chloranthaceae). METHODS Following confirmation of the pollen tube pathway, the histo/immunochemical make-up of the ECM was determined with histochemistry on fresh tissue to detect cuticle, esterase, proteins, pectins, and lipids and immunolocalization at the level of the TEM on sections from cryofixed/freeze-substituted tissue to detect molecules recognized by antibodies to homogalacturonans (JIM7, 5), arabinogalactan-proteins (JIM13) and cysteine-rich adhesion (SCA). KEY RESULTS Pollen germinability is low in both species. When grains germinate, they do so on an ECM comprised of an esterase-positive cuticle proper (dry versus wet stigma). Pollen tubes do not track the surface ECM of stigma or adaxial epidermal cells at the site of angiospermy. Instead, tubes grow between stigmatic cells and subsequently along the inner tangential walls of the stigmatic and adaxial carpel cells at the site of angiospermy. Pollen tubes enter the ovary locule at the base of the funiculus. The stigmatic ECM is distinct by virtue of the presence of anti-JIM5 aggregates, lipids, and a protein recognized by anti-SCA. CONCLUSIONS The Chloranthaceae joins a growing number of basal angiosperm taxa whereby pollen tubes germinate on a dry versus wet stigma to subsequently grow intercellularly en route to the ovary thereby challenging traditional views that the archetype pollen tube pathway was composed of the surface of stigma and adaxial epidermal cells covered with a free-flowing exudate.
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Affiliation(s)
- KATERINA HRISTOVA
- Department of Botany, University of Toronto, 25 Willcocks Street, Toronto, Ontario, Canada M5S 3B2
| | - MATTHEW LAM
- Department of Botany, University of Toronto, 25 Willcocks Street, Toronto, Ontario, Canada M5S 3B2
| | - TAYLOR FEILD
- Department of Botany, University of Toronto, 25 Willcocks Street, Toronto, Ontario, Canada M5S 3B2
| | - TAMMY L. SAGE
- Department of Botany, University of Toronto, 25 Willcocks Street, Toronto, Ontario, Canada M5S 3B2
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Acosta-García G, Vielle-Calzada JP. A classical arabinogalactan protein is essential for the initiation of female gametogenesis in Arabidopsis. THE PLANT CELL 2004; 16:2614-28. [PMID: 15377758 PMCID: PMC520959 DOI: 10.1105/tpc.104.024588] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2004] [Accepted: 08/03/2004] [Indexed: 05/18/2023]
Abstract
Classical arabinogalactan proteins (AGPs) are an abundant class of cell surface proteoglycans widely distributed in flowering plants. We have used a combination of enhancer detection tagging and RNA interference (RNAi)-induced posttrancriptional silencing to demonstrate that AGP18, a gene encoding a classical arabinogalactan protein, is essential for female gametogenesis in Arabidopsis thaliana. AGP18 is expressed in cells that spatially and temporally define the sporophytic to gametophytic transition and during early stages of seed development. More than 75% of the T1 transformants resulted in T2 lines showing reduced seed set during at least three consecutive generations but no additional developmental defects. AGP18-silenced T2 lines showed reduced AGP18 transcript levels in female reproductive organs, the presence of 21-bp RNA fragments specific to the AGP18 gene, and the absence of in situ AGP18 mRNA localization in developing ovules. Reciprocal crosses to wild-type plants indicate that the defect is female specific. The genetic and molecular analysis of AGP18-silenced plants containing a single T-DNA RNAi insertion suggests that posttranscriptional silencing of AGP18 is acting both at the sporophytic and gametophytic levels. A cytological analysis of all defective AGP18-RNAi lines, combined with the analysis of molecular markers acting at key stages of female gametogenesis, showed that the functional megaspore fails to enlarge and mitotically divide, indicating that AGP18 is essential to initiate female gametogenesis in Arabidopsis. Our results assign a specific function in plant development to a gene encoding a classical AGP.
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Affiliation(s)
- Gerardo Acosta-García
- Laboratory of Reproductive Development and Apomixis, Department of Genetic Engineering, Centro de Investigación y Estudios Avanzados, Unidad Irapuato, Irapuato Guanajuato, Mexico
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KOEHL VERONICA, THIEN LEONARDB, HEIJ ELIZABETHG, SAGE TAMMYL. The Causes of self-sterility in natural populations of the relictual angiosperm, Illicium floridanum (Illiciaceae). ANNALS OF BOTANY 2004; 94:43-50. [PMID: 15155377 PMCID: PMC4242369 DOI: 10.1093/aob/mch113] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
BACKGROUND AND AIMS Illicium floridanum, a species belonging to the basal extant angiosperm taxon Illiciaceae, reportedly exhibits self-incompatibility (SI). To date, the site and timing of SI within the carpel of this species remains unidentified. Thus, the objective of this research was to determine the cellular and temporal aspects of SI in I. floridanum. METHODS Following controlled application of cross- and self-pollen in natural populations of I. floridanum, embryo sac development and temporal aspects of stigma receptivity, as well as pollen tube growth, fertilization, and embryo and endosperm development, were investigated with the aid of light and fluorescence microscopy. KEY RESULTS Flowers of I. floridanum exhibited complete dichogamy whereby stigmas only supported cross- and self-pollen tube growth prior to anther dehiscence. In contrast to earlier reports of SI in this species, a prezygotic SI resulting in rejection of self-pollen tube growth at the stigma was absent and there were no significant differences between cross- versus self-pollen germination and pollen tube growth within the style and ovary during the first 5 d after pollination. Structural development of the four-celled embryo sac was not differentially influenced by pollen type as noted to occur in other angiosperms with late-acting ovarian SI. The ovule micropyle and embryo sac were penetrated equally by cross- and self-pollen tubes. In addition, there were no statistically significant differences in cross- versus self-fertilization. A resting zygote and multicellular endosperm at a variety of developmental stages was present by 30 d after application of cross- or self-pollen. CONCLUSIONS In the clear absence of a prezygotic SI that was previously reported to result in differential self-pollen tube growth at the stigma, self- sterility in I. floridanum is likely due to early-acting inbreeding depression, although late-acting post-zygotic ovarian SI cannot be ruled out.
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Affiliation(s)
- VERONICA KOEHL
- Department of Botany, University of Toronto, 25 Willcocks Street, Toronto, Ontario, Canada M5S 3B2
| | - LEONARD B. THIEN
- Cell and Molecular Biology Department, Tulane University (Uptown), New Orleans, LA 70118, USA
| | | | - TAMMY L. SAGE
- Department of Botany, University of Toronto, 25 Willcocks Street, Toronto, Ontario, Canada M5S 3B2
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Bernhardt P, Sage T, Weston P, Azuma H, Lam M, Thien LB, Bruhl J. The pollination of Trimenia moorei (Trimeniaceae): floral volatiles, insect/wind pollen vectors and stigmatic self-incompatibility in a basal angiosperm. ANNALS OF BOTANY 2003; 92:445-58. [PMID: 12930730 PMCID: PMC4257518 DOI: 10.1093/aob/mcg157] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Trimenia moorei (Oliv.) Philipson is an andromonoecious liane with >0.40 of the total flower buds maturing as bisexual flowers. Male and bisexual flowers are strongly scented with pollen, anther sacs and receptacle scars testing positively for volatile emissions. Scent analyses detect over 20 components. The major fatty acid derivative is 8-heptadecene, and 2-phenylethanol dominates the benzenoids. While hover-flies in the genera Melangyna and Triglyphus contact the stigma with their probosces, the stigma secretes no free-flowing, edible fluids. Copious pollen is the only edible reward consumed by hover-flies (Syprhidae), sawflies (Pergidae) and bees in the families Apidae, Colletidae and Halictidae. All these insects carried pollen of T. moorei on their heads, legs and thoraces and female bees in the genera Apis, Exoneura, Leioproctus and Lasioglossum stored pollen on their hind legs. Pollen traps also indicate that pollen is shed directly into the air, permitting wind pollination. When bisexual flower buds are bagged (isolated from insect foragers) on the liane then subjected to a series of hand-pollination experiments after perianth segments open, the structural analyses of pollen-carpel interactions indicate that T. moorei has a trichome-rich dry-type stigma with an early-acting self-incompatibility (SI) system. Bicellular pollen grains deposited on stigmas belonging to the same plant germinate but fail to penetrate intercellular spaces, while grains deposited following cross-pollination reach the ovule within 24 h. Fluorescence analyses of 76 carpels collected at random from unbagged (open-pollinated) flowers on five plants indicates that at least 64% of carpels are cross-pollinated in situ. Trimenia moorei is the first species within the ANITA group, and second within reilictual-basal angiosperm lineages, to exhibit stigmatic SI in combination with dry-type stigma and bicellular pollen, a condition once considered to be atypical for angiosperms as a whole but now known to be present in numerous taxa.
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Affiliation(s)
- Peter Bernhardt
- Department of Biology, St Louis University, St Louis, MO 63103, USA.
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Sage TL, Sampson FB. Evidence for ovarian self-incompatibility as a cause of self-sterility in the relictual woody angiosperm, Pseudowintera axillaris (Winteraceae). ANNALS OF BOTANY 2003; 91:807-16. [PMID: 12730068 PMCID: PMC4242389 DOI: 10.1093/aob/mcg085] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Species within the genus Pseudowintera exhibit high rates of self-sterility. Self-sterility in the genus has been previously posited-but not confirmed-to be the result of late-acting ovarian self-incompatibility (OSI) functioning within nucellar tissue of the ovule to prevent self pollen tubes from entering the embryo sac. Structural and functional aspects of pollen-carpel interactions and early seed development following cross- and self-pollination were investigated in P. axillaris to determine the site, timing and possible mechanisms of self-sterility. No significant differences were observed between pollen tube growth, ovule penetration and double fertilization following cross- and self-pollination. Pollen tubes exhibited phasic growth in an extracellular matrix composed of proteins and carbohydrates, as well as arabinogalactans/arabinogalactan proteins. A uniform failure in embryo sac development prior to division of the zygote was apparent within 15 d following double fertilization by self gametes. Results indicate that SI mechanisms in P. axillaris do not prevent double fertilization from occurring. Instead, mechanisms of self-sterility affect post-zygotic development of the embryo sac. Although self-sterility may be attributed to inbreeding depression, given the post-zygotic nature of failure in embryo sac development, the possibility of late-acting OSI is discussed.
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Affiliation(s)
- Tammy L Sage
- Department of Botany, University of Toronto, 25 Willcocks Street, Toronto, Ontario, Canada M5S 3B2.
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Lolle SJ, Pruitt RE. Epidermal cell interactions: a case for local talk. TRENDS IN PLANT SCIENCE 1999; 4:14-20. [PMID: 10234265 DOI: 10.1016/s1360-1385(98)01353-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Epidermal cell interactions play an important role in reproduction, creating variation in floral structure and modulating gametophyte selection and growth during pollination. Recent progress in understanding the processes by which epidermal cells become responsive to contact, indicate that the developmental quiescence of the epidermis is regulated by a set of genes, some of which modulate the permeability properties of the cell wall and cuticle. Research on mutants of Arabidopsis has revealed a mechanistic uniformity between two processes involving epidermis-mediated interactions that had hitherto been considered to be biologically distinct: postgenital organ fusion and pollen hydration.
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Affiliation(s)
- SJ Lolle
- Dept of Molecular and Cellular Biology, Harvard University, 16 Divinity Avenue, Cambridge, MA 02138, USA
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16
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McCubbin AG, Chung YY, Kao T. A Mutant S3 RNase of Petunia inflata Lacking RNase Activity Has an Allele-Specific Dominant Negative Effect on Self-Incompatibility Interactions. THE PLANT CELL 1997; 9:85-95. [PMID: 12237345 PMCID: PMC156903 DOI: 10.1105/tpc.9.1.85] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Gametophytic self-incompatibility in the Solanaceae is controlled by a multiallelic locus called the S locus. Growth of pollen tubes in the pistil is inhibited when the pollen has one of the two S alleles carried by the pistil. The products of a number of pistil S alleles[mdash]S proteins or S RNases[mdash]have been identified, and their role in controlling the pistil's ability to reject self-pollen has been positively established. In contrast, the existence of pollen S allele products has so far been inferred entirely from genetic evidence. Here, we introduced a modified S3 gene of Petunia inflata encoding an S3 RNase lacking RNase activity into P. inflata plants of the S2S3 genotype to determine whether the production of the mutant protein, designated S3(H93R), would have any effect on the ability of the transgenic plants to reject S2 and S3 pollen. Analysis of the self-incompatibility behavior of 49 primary transgenic plants and the progeny of three plants (H30, H37, and H40) that produced S3(H93R) in addition to producing wild-type levels of endogenous S2 and S3 RNases revealed that S3(H93R) had a dominant negative effect on the function of the S3 RNase in rejecting self-pollen; however, it had no effect on the function of the S2 RNase. One likely explanation of the results is that S3(H93R) competes with the S3 RNase for binding to a common molecule, which is presumably the product of the pollen S3 allele.
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Affiliation(s)
- A. G. McCubbin
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania 16802-4500
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Hampson CR, Coleman GD, Azarenko AN. Does the genome of Corylus avellana L. contain sequences homologous to the self-incompatibility gene of Brassica? TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 1996; 93:759-764. [PMID: 24162405 DOI: 10.1007/bf00224073] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/1995] [Accepted: 12/22/1995] [Indexed: 06/02/2023]
Abstract
Self-incompatibility is a genetic mechanism enforcing cross-pollination in plants. Hazelnut (Corylus avellana L.) expresses the sporophytic type of self-incompatibility, for which the molecular genetic basis is characterized only in Brassica. The hypothesis that the hazelnut genome contains homologs of Brassica self-incompatibility genes was tested. The S-locus glycoprotein gene (SLG) and the kinase-encoding domain of the S-receptor kinase (SRK) gene of B. oleracea L. were used to probe blots of genomic DNA from six genotypes of hazelnut. Weak hybridization with the SLG probe was detected for all hazelnut genotypes tested; however, no hybridization was detected with PCR-generated probes corresponding to two conserved regions of the SLG gene. One of these PCR probes included the region of SLG encoding the 11 invariant cysteine residues that are an important structural feature of all S-family genes. The present evidence suggests that hazelnut DNA hybridizing to SLG differs significantly from the Brassica gene, and that the S-genes cloned from Brassica will not be useful for exploring self-incompatibility in hazelnut.
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Affiliation(s)
- C R Hampson
- Department of Horticulture, Oregon State University, 4017 Agriculture and Life Sciences Building, 97331, Corvallis, OR, USA
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Read SM, Newbigin E, Clarke AE, McClure BA, Kao T. Disputed Ancestry: Comments on a Model for the Origin of Incompatibility in Flowering Plants. THE PLANT CELL 1995; 7:661-664. [PMID: 12242380 PMCID: PMC160812 DOI: 10.1105/tpc.7.6.661] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Bell PR. Reply. THE PLANT CELL 1995; 7:664-665. [PMID: 12242381 PMCID: PMC160813 DOI: 10.1105/tpc.7.6.664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Affiliation(s)
- P. R. Bell
- Department of Botany and Microbiology, University College, London WC1E 6BT, United Kingdom
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