1
|
Jacob D, Brian J. The short and intricate life of the suspensor. PHYSIOLOGIA PLANTARUM 2020; 169:110-121. [PMID: 31808953 DOI: 10.1111/ppl.13057] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 11/04/2019] [Accepted: 12/04/2019] [Indexed: 06/10/2023]
Abstract
The suspensor is a short-lived tissue critical for proper embryonic development in many higher plants. While the tissue was initially thought to simply suspend the embryo in the endosperm, it has been found through decades of research that it serves multiple important purposes. The suspensor has been found to be vital for proper embryo patterning and numerous studies have been undertaken into the complex transcriptional cross-talk between the suspensor and the embryo proper. Indeed, many suspensor mutants also display abnormalities in the embryo. The suspensor's role as a nutrient conduit has been shown using ultrastructural and histochemical techniques. Biochemical approaches have found that the suspensor is a centre of early embryonic hormone production in several species. The suspensor has also been frequently used as a model for programmed cell death as it shows signs of termination almost immediately upon developing. This review covers the essential functions of the suspensor throughout its short existence from multiple disciplines including structural, genetic and biochemical perspectives.
Collapse
Affiliation(s)
- Downs Jacob
- Faculty of Science, University of Sydney, Sydney, NSW, 2006, Australia
| | - Jones Brian
- Faculty of Science, University of Sydney, Sydney, NSW, 2006, Australia
| |
Collapse
|
2
|
Igielski R, Kępczyńska E. Gene expression and metabolite profiling of gibberellin biosynthesis during induction of somatic embryogenesis in Medicago truncatula Gaertn. PLoS One 2017; 12:e0182055. [PMID: 28750086 PMCID: PMC5531487 DOI: 10.1371/journal.pone.0182055] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 07/11/2017] [Indexed: 01/02/2023] Open
Abstract
Gibberellins (GAs) are involved in the regulation of numerous developmental processes in plants including zygotic embryogenesis, but their biosynthesis and role during somatic embryogenesis (SE) is mostly unknown. In this study we show that during three week- long induction phase, when cells of leaf explants from non-embryogenic genotype (M9) and embryogenic variant (M9-10a) were forming the callus, all the bioactive gibberellins from non-13-hydroxylation (GA4, GA7) and 13-hydroxylation (GA1, GA5, GA3, GA6) pathways were present, but the contents of only a few of them differed between the tested lines. The GA53 and GA19 substrates synthesized by the 13-hydroxylation pathway accumulated specifically in the M9-10a line after the first week of induction; subsequently, among the bioactive gibberellins detected, only the content of GA3 increased and appeared to be connected with acquisition of embryogenic competence. We fully annotated 20 Medicago truncatula orthologous genes coding the enzymes which catalyze all the known reactions of gibberellin biosynthesis. Our results indicate that, within all the genes tested, expression of only three: MtCPS, MtGA3ox1 and MtGA3ox2, was specific to embryogenic explants and reflected the changes observed in GA53, GA19 and GA3 contents. Moreover, by analyzing expression of MtBBM, SE marker gene, we confirmed the inhibitory effect of manipulation in GAs metabolism, applying exogenous GA3, which not only impaired the production of somatic embryos, but also significantly decreased expression of this gene.
Collapse
Affiliation(s)
- Rafał Igielski
- Department of Plant Biotechnology, University of Szczecin, Szczecin, Poland
| | - Ewa Kępczyńska
- Department of Plant Biotechnology, University of Szczecin, Szczecin, Poland
| |
Collapse
|
3
|
Igielski R, Kępczyńska E. Gene expression and metabolite profiling of gibberellin biosynthesis during induction of somatic embryogenesis in Medicago truncatula Gaertn. PLoS One 2017; 12:e0182055. [PMID: 28750086 DOI: 10.1371/journal.pone.018205] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 07/11/2017] [Indexed: 05/18/2023] Open
Abstract
Gibberellins (GAs) are involved in the regulation of numerous developmental processes in plants including zygotic embryogenesis, but their biosynthesis and role during somatic embryogenesis (SE) is mostly unknown. In this study we show that during three week- long induction phase, when cells of leaf explants from non-embryogenic genotype (M9) and embryogenic variant (M9-10a) were forming the callus, all the bioactive gibberellins from non-13-hydroxylation (GA4, GA7) and 13-hydroxylation (GA1, GA5, GA3, GA6) pathways were present, but the contents of only a few of them differed between the tested lines. The GA53 and GA19 substrates synthesized by the 13-hydroxylation pathway accumulated specifically in the M9-10a line after the first week of induction; subsequently, among the bioactive gibberellins detected, only the content of GA3 increased and appeared to be connected with acquisition of embryogenic competence. We fully annotated 20 Medicago truncatula orthologous genes coding the enzymes which catalyze all the known reactions of gibberellin biosynthesis. Our results indicate that, within all the genes tested, expression of only three: MtCPS, MtGA3ox1 and MtGA3ox2, was specific to embryogenic explants and reflected the changes observed in GA53, GA19 and GA3 contents. Moreover, by analyzing expression of MtBBM, SE marker gene, we confirmed the inhibitory effect of manipulation in GAs metabolism, applying exogenous GA3, which not only impaired the production of somatic embryos, but also significantly decreased expression of this gene.
Collapse
Affiliation(s)
- Rafał Igielski
- Department of Plant Biotechnology, University of Szczecin, Szczecin, Poland
| | - Ewa Kępczyńska
- Department of Plant Biotechnology, University of Szczecin, Szczecin, Poland
| |
Collapse
|
4
|
Liu Y, Li X, Zhao J, Tang X, Tian S, Chen J, Shi C, Wang W, Zhang L, Feng X, Sun MX. Direct evidence that suspensor cells have embryogenic potential that is suppressed by the embryo proper during normal embryogenesis. Proc Natl Acad Sci U S A 2015; 112:12432-7. [PMID: 26396256 PMCID: PMC4603499 DOI: 10.1073/pnas.1508651112] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The suspensor is a temporary supporting structure of proembryos. It has been proposed that suspensor cells also possess embryogenic potential, which is suppressed by the embryo as an effect of the embryo-suspensor interaction. However, data to support this hypothesis are not yet available. In this report, using an in vivo living cell laser ablation technique, we show that Arabidopsis suspensor cells can develop into embryos after removing the embryo proper. The embryo proper plays a critical role in maintaining suspensor cell identity. However, this depends on the developmental stage; after the globular embryo stage, the suspensors no longer possess the potential to develop into embryos. We also reveal that hypophysis formation may be essential for embryo differentiation. Furthermore, we show that, after removing the embryo, auxin gradually accumulates in the top suspensor cell where cell division occurs to produce an embryo. Auxin redistribution likely reprograms the fate of the suspensor cell and triggers embryogenesis in suspensor cells. Thus, we provide direct evidence that the embryo suppresses the embryogenic potential of suspensor cells.
Collapse
Affiliation(s)
- Yuan Liu
- Department of Cell and Developmental Biology, College of Life Science, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan 430072, China; College of Life Sciences, Hubei University, Wuhan, 430062, China
| | - Xinbo Li
- Department of Cell and Developmental Biology, College of Life Science, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan 430072, China
| | - Jing Zhao
- Department of Cell and Developmental Biology, College of Life Science, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan 430072, China
| | - Xingchun Tang
- Department of Cell and Developmental Biology, College of Life Science, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan 430072, China; College of Life Sciences, Hubei University, Wuhan, 430062, China
| | - Shujuan Tian
- Department of Cell and Developmental Biology, College of Life Science, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan 430072, China
| | - Junyi Chen
- Department of Cell and Developmental Biology, College of Life Science, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan 430072, China
| | - Ce Shi
- Department of Cell and Developmental Biology, College of Life Science, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan 430072, China
| | - Wei Wang
- Department of Cell and Developmental Biology, College of Life Science, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan 430072, China
| | - Liyao Zhang
- Department of Cell and Developmental Biology, College of Life Science, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan 430072, China
| | - Xianzhong Feng
- Northeast Institute of Geography and Agroecology, Key Laboratory of Soybean Molecular Design Breeding, Changchun, 130102, China
| | - Meng-Xiang Sun
- Department of Cell and Developmental Biology, College of Life Science, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan 430072, China;
| |
Collapse
|
5
|
Solfanelli C, Ceron F, Paolicchi F, Giorgetti L, Geri C, Ceccarelli N, Kamiya Y, Picciarelli P. Expression of two genes encoding gibberellin 2- and 3-oxidases in developing seeds of Phaseolus coccineus. PLANT & CELL PHYSIOLOGY 2005; 46:1116-24. [PMID: 15894806 DOI: 10.1093/pcp/pci124] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
We have isolated PcGA3ox1, a cDNA clone from developing runner bean (Phaseolus coccineus) seeds that shows significant amino acid homology with the gibberellin (GA) 3-oxidases. A recombinant fusion protein of PcGA3ox1 converted GA20 and GA9 to GA1 and GA4, respectively. In situ hybridization results showed that transcripts of this gene accumulate specifically within the suspensor of globular-stage embryos. PcGA3ox1 mRNA begins to accumulate in the epidermal cells of the embryo proper and is also detectable in the endosperm during the transition from globular- to heart-stage embryos. PcGA3ox1 transcripts were localized exclusively in the cotyledons from the early cotyledonary stage up to the cotyledonary stage. Transcripts of the previously cloned GA 2-oxidase (PcGA2ox1) from developing seeds of runner bean were found primarily within the suspensor neck region from the late globular stage up to the heart stage. PcGA2ox1 mRNA was detectable in the whole suspensor from the early cotyledonary stage, and was found in the inner layer of integuments at the cotyledonary stage. Soluble enzyme preparations made from suspensors and embryos at two stages of embryogenesis (the heart and cotyledonary stages) were incubated with [14C]GA20 and [14C]GA1. Only young suspensor preparations converted GA20 to GA1 and GA5. Both suspensor preparations converted GA1 to GA8. Both embryo preparations converted GA20 to GA1, but were unable to convert GA1 to GA8.
Collapse
MESH Headings
- Cell-Free System
- Chromatography, High Pressure Liquid
- Cloning, Molecular
- Escherichia coli/genetics
- Gene Expression Regulation, Developmental
- Gene Expression Regulation, Enzymologic
- Gene Expression Regulation, Plant
- Genes, Plant/genetics
- Genome, Plant
- In Situ Hybridization
- Mixed Function Oxygenases/genetics
- Mixed Function Oxygenases/metabolism
- Molecular Sequence Data
- Phaseolus/embryology
- Phaseolus/genetics
- Phylogeny
- RNA Transport
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA, Plant/genetics
- RNA, Plant/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Seeds/embryology
- Seeds/genetics
- Transcription, Genetic
Collapse
Affiliation(s)
- Cinzia Solfanelli
- Dipartimento di Biologia delle Piante Agrarie, Università di Pisa, Via Mariscoglio, 34, 56124 Pisa, Italy
| | | | | | | | | | | | | | | |
Collapse
|
6
|
Lang JD, Ray S, Ray A. sin 1, a mutation affecting female fertility in Arabidopsis, interacts with mod 1, its recessive modifier. Genetics 1994; 137:1101-10. [PMID: 7982564 PMCID: PMC1206057 DOI: 10.1093/genetics/137.4.1101] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
In Arabidopsis thaliana, a mutation in the SIN 1 gene causes aberrant ovule development and female-specific sterility. The effect of the sin 1 mutation is polymorphic and pleiotropic in different genetic backgrounds. The polymorphism concerns morphology of the mutant ovules. The pleiotropism involves internodal distance and inflorescence initiation time. The particular ovule phenotype and the length of internodes are dependent on an interaction of sin 1 with a second recessive gene, which we term mod 1. The recessive mod 1 allele in a homozygous sin 1 mutant plant reduces internode length and ovule integument size. The mutation sin 1, but not mod 1, has a demonstrable effect on ovule morphology when acting independently. In our crosses mod 1 was inseparably linked to the well known mutation erecta that is known to cause a reduction in internode and pedicle lengths.
Collapse
Affiliation(s)
- J D Lang
- Department of Biology, University of Rochester, New York 14627
| | | | | |
Collapse
|
7
|
Yeung EC, Meinke DW. Embryogenesis in Angiosperms: Development of the Suspensor. THE PLANT CELL 1993; 5:1371-1381. [PMID: 12271036 PMCID: PMC160369 DOI: 10.1105/tpc.5.10.1371] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Affiliation(s)
- E. C. Yeung
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada T2N 1N4
| | | |
Collapse
|
8
|
Perata P, Picciarelli P, Alpi A. Pattern of Variations in Abscisic Acid Content in Suspensors, Embryos, and Integuments of Developing Phaseolus coccineus Seeds. PLANT PHYSIOLOGY 1990; 94:1776-80. [PMID: 16667915 PMCID: PMC1077452 DOI: 10.1104/pp.94.4.1776] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Free abscisic acid (ABA) content in suspensors, embryos, and integuments was determined during seed development of Phaseolus coccineus. A highly specific and sensitive solid-phase radioimmunoassay based on a monocional antibody raised against free (S)-ABA was used for ABA quantification. Very small amounts of ABA were detected in the suspensor during initial stages of development; later two peaks of ABA occurred. Levels of ABA in the embryo and integument show a coincident triphasic distribution: two maxima in ABA content occurred when the embryo was 11 to 12 and 15 to 16 millimeters in length; later, when the embryo was 19 to 20 millimeters long, a further increase was observed. The role of ABA in runner bean seeds is discussed in relation to the development of the different seed tissues.
Collapse
Affiliation(s)
- P Perata
- Dipartimento di Biologia delle Piante Agrarie, Università degli Studi di Pisa, Viale delle Piagge 23, 56124 Pisa, Italy
| | | | | |
Collapse
|