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Withers KA, Kvamme A, Youngstrom CE, Yarvis RM, Orpano R, Simons GP, Irish EE, Cheng CL. Auxin Involvement in Ceratopteris Gametophyte Meristem Regeneration. Int J Mol Sci 2023; 24:15832. [PMID: 37958815 PMCID: PMC10647518 DOI: 10.3390/ijms242115832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 10/27/2023] [Accepted: 10/29/2023] [Indexed: 11/15/2023] Open
Abstract
Growth and development of the Ceratopteris hermaphroditic gametophytes are dependent on cell proliferation in the marginal meristem, which when destroyed will regenerate at a new location on the body margin. We established a laser ablation method to destroy a single initial cell in the meristem. Ablation caused the cessation of cell proliferation accompanied by the disappearance of the expression of an auxin synthesis gene (CrTAA2) and a cell proliferation marker gene (CrWOXB). New meristem regeneration occurred within a predictable distance from the original two days post-ablation, signified by cell proliferation and the expression of CrTAA2. Treatment with the naturally occurring auxin indole-3-acetic acid (IAA), synthetic auxin 2,4-dichlorophenoxyacetic acid (2,4-D), or the transport inhibitor naphthylphthalamic acid (NPA) altered positioning of the original marginal meristem toward the apex of the gametophyte. IAA altered positioning of the regenerated meristem after damaging the original meristem. A model of auxin involvement in the positioning of the marginal meristem in Ceratopteris is presented to encompass these results.
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Affiliation(s)
| | | | | | | | | | | | | | - Chi-Lien Cheng
- Department of Biology, University of Iowa, Iowa City, IA 52242, USA; (K.A.W.); (A.K.); (C.E.Y.); (R.M.Y.); (R.O.); (G.P.S.); (E.E.I.)
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Wu X, Liu X, Zhang S, Zhou Y. Cell Division and Meristem Dynamics in Fern Gametophytes. PLANTS (BASEL, SWITZERLAND) 2023; 12:209. [PMID: 36616337 PMCID: PMC9823664 DOI: 10.3390/plants12010209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 12/31/2022] [Accepted: 12/31/2022] [Indexed: 06/17/2023]
Abstract
One of the most important questions in all multicellular organisms is how to define and maintain different cell fates during continuous cell division and proliferation. Plant meristems provide a unique research system to address this fundamental question because meristems dynamically maintain themselves and sustain organogenesis through balancing cell division and cell differentiation. Different from the gametophytes of seed plants that depend on their sporophytes and lack meristems, the gametophytes of seed-free ferns develop different types of meristems (including apical cell-based meristems and multicellular apical and marginal meristems) to promote independent growth and proliferation during the sexual gametophyte phase. Recent studies combining confocal time-lapse imaging and computational image analysis reveal the cellular basis of the initiation and proliferation of different types of meristems in fern gametophytes, providing new insights into the evolution of meristems in land plants. In this review, we summarize the recent progress in understanding the cell growth dynamics in fern gametophytes and discuss both conserved and diversified mechanisms underlying meristem cell proliferation in seed-free vascular plants.
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Affiliation(s)
- Xiao Wu
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907, USA
- Purdue Center for Plant Biology, Purdue University, West Lafayette, IN 47907, USA
- Center of Pear Engineering Technology Research, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China
| | - Xing Liu
- Purdue Center for Plant Biology, Purdue University, West Lafayette, IN 47907, USA
- Department of Biochemistry, Purdue University, West Lafayette, IN 47907, USA
| | - Shaoling Zhang
- Center of Pear Engineering Technology Research, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China
| | - Yun Zhou
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907, USA
- Purdue Center for Plant Biology, Purdue University, West Lafayette, IN 47907, USA
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Geng Y, Yan A, Zhou Y. Positional cues and cell division dynamics drive meristem development and archegonium formation in Ceratopteris gametophytes. Commun Biol 2022; 5:650. [PMID: 35778477 PMCID: PMC9249879 DOI: 10.1038/s42003-022-03627-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 06/22/2022] [Indexed: 11/17/2022] Open
Abstract
Fern gametophytes are autotrophic and independent of sporophytes, and they develop pluripotent meristems that drive prothallus development and sexual reproduction. To reveal cellular dynamics during meristem development in fern gametophytes, we performed long-term time-lapse imaging and determined the real-time lineage, identity and division activity of each single cell from meristem initiation to establishment in gametophytes of the fern Ceratopteris richardii. Our results demonstrate that in Ceratopteris gametophytes, only a few cell lineages originated from the marginal layer contribute to meristem initiation and proliferation, and the meristem lacks a distinguishable central zone or apical cell with low division activity. Within the meristem, cell division is independent of cell lineages and cells at the marginal layer are more actively dividing than inner cells. Furthermore, the meristem triggers differentiation of adjacent cells into egg-producing archegonia in a position-dependent manner. These findings advance the understanding of diversified meristem and gametophyte development in land plants. Time-lapse imaging of the fern Ceratopteris richardii during meristem initiation and proliferation provides insights into the lineage, identity and division activity of each cell throughout the growth of gametophytes.
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Affiliation(s)
- Yuan Geng
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA.,Purdue Center for Plant Biology, Purdue University, West Lafayette, IN, 47907, USA
| | - An Yan
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125, USA.,Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Yun Zhou
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA. .,Purdue Center for Plant Biology, Purdue University, West Lafayette, IN, 47907, USA.
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Wu X, Yan A, Yang X, Banks JA, Zhang S, Zhou Y. Cell growth dynamics in two types of apical meristems in fern gametophytes. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 111:149-163. [PMID: 35451138 PMCID: PMC9541313 DOI: 10.1111/tpj.15784] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 04/11/2022] [Accepted: 04/19/2022] [Indexed: 05/02/2023]
Abstract
In contrast to seed plants, the gametophytes of seed-free plants develop pluripotent meristems, which promote and sustain their independent growth and development. To date, the cellular basis of meristem development in gametophytes of seed-free ferns remains largely unknown. In this study, we used Woodsia obtusa, the blunt-lobe cliff fern, to quantitatively determine cell growth dynamics in two different types of apical meristems - the apical initial centered meristem and the multicellular apical meristem in gametophytes. Through confocal time-lapse live imaging and computational image analysis and quantification, we determined unique patterns of cell division and growth that sustain or terminate apical initials, dictate the transition from apical initials to multicellular apical meristems, and drive proliferation of apical meristems in ferns. Quantitative results showed that small cells correlated to active cell division in fern gametophytes. The marginal cells of multicellular apical meristems in fern gametophytes undergo division in both anticlinal and periclinal orientations, not only increasing cell numbers but also playing a dominant role in increasing cell layers during gametophyte development. All these findings provide insights into the function and regulation of meristems in gametophytes of seed-free vascular plants, suggesting both conserved and diversified mechanisms underlying meristem cell proliferation across land plants.
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Affiliation(s)
- Xiao Wu
- Department of Botany and Plant PathologyPurdue UniversityWest LafayetteIndiana47907USA
- Purdue Center for Plant BiologyPurdue UniversityWest LafayetteIndiana47907USA
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Center of Pear Engineering Technology ResearchNanjing Agricultural UniversityNanjingJiangsu210095China
| | - An Yan
- Division of Biology and Biological EngineeringCalifornia Institute of TechnologyPasadenaCalifornia91125USA
- Howard Hughes Medical InstituteCalifornia Institute of TechnologyPasadenaCalifornia91125USA
| | - Xi Yang
- Department of Botany and Plant PathologyPurdue UniversityWest LafayetteIndiana47907USA
- Purdue Center for Plant BiologyPurdue UniversityWest LafayetteIndiana47907USA
| | - Jo Ann Banks
- Department of Botany and Plant PathologyPurdue UniversityWest LafayetteIndiana47907USA
- Purdue Center for Plant BiologyPurdue UniversityWest LafayetteIndiana47907USA
| | - Shaoling Zhang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Center of Pear Engineering Technology ResearchNanjing Agricultural UniversityNanjingJiangsu210095China
| | - Yun Zhou
- Department of Botany and Plant PathologyPurdue UniversityWest LafayetteIndiana47907USA
- Purdue Center for Plant BiologyPurdue UniversityWest LafayetteIndiana47907USA
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Wu X, Yan A, Liu X, Zhang S, Zhou Y. Quantitative live-imaging reveals the dynamics of apical cells during gametophyte development in ferns. QUANTITATIVE PLANT BIOLOGY 2022; 3:e25. [PMID: 37077984 PMCID: PMC10095955 DOI: 10.1017/qpb.2022.21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 09/19/2022] [Accepted: 10/08/2022] [Indexed: 05/02/2023]
Abstract
Meristems in land plants share conserved functions but develop highly variable structures. Meristems in seed-free plants, including ferns, usually contain one or a few pyramid-/wedge-shaped apical cells (ACs) as initials, which are lacking in seed plants. It remained unclear how ACs promote cell proliferation in fern gametophytes and whether any persistent AC exists to sustain fern gametophyte development continuously. Here, we uncovered previously undefined ACs maintained even at late developmental stages in fern gametophytes. Through quantitative live-imaging, we determined division patterns and growth dynamics that maintain the persistent AC in Sphenomeris chinensis, a representative fern. The AC and its immediate progenies form a conserved cell packet, driving cell proliferation and prothallus expansion. At the apical centre of gametophytes, the AC and its adjacent progenies display small dimensions resulting from active cell division instead of reduced cell expansion. These findings provide insight into diversified meristem development in land plants.
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Affiliation(s)
- Xiao Wu
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana47907, USA
- Purdue Centre for Plant Biology, Purdue University, West Lafayette, Indiana47907, USA
- Centre of Pear Engineering Technology Research, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, China
| | - An Yan
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California91125, USA
- Howard Hughes Medical Institute, California Institute of Technology, Pasadena, California91125, USA
| | - Xing Liu
- Purdue Centre for Plant Biology, Purdue University, West Lafayette, Indiana47907, USA
- Department of Biochemistry, Purdue University, West Lafayette, Indiana47907, USA
| | - Shaoling Zhang
- Centre of Pear Engineering Technology Research, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, China
- Authors for correspondence: S. Zhang, Y. Zhou, E-mail: ;
| | - Yun Zhou
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana47907, USA
- Purdue Centre for Plant Biology, Purdue University, West Lafayette, Indiana47907, USA
- Authors for correspondence: S. Zhang, Y. Zhou, E-mail: ;
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Wu X, Yan A, McAdam SAM, Banks JA, Zhang S, Zhou Y. Timing of meristem initiation and maintenance determines the morphology of fern gametophytes. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:6990-7001. [PMID: 34181730 DOI: 10.1093/jxb/erab307] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 06/25/2021] [Indexed: 06/13/2023]
Abstract
The alternation of generations in land plants occurs between the sporophyte phase and the gametophyte phase. The sporophytes of seed plants develop self-maintained, multicellular meristems, and these meristems determine plant architecture. The gametophytes of seed plants lack meristems and are heterotrophic. In contrast, the gametophytes of seed-free vascular plants, including ferns, are autotrophic and free-living, developing meristems to sustain their independent growth and proliferation. Compared with meristems in the sporophytes of seed plants, the cellular mechanisms underlying meristem development in fern gametophytes remain largely unknown. Here, using confocal time-lapse live imaging and computational segmentation and quantification, we determined different patterns of cell divisions associated with the initiation and proliferation of two distinct types of meristems in gametophytes of two closely related Pteridaceae ferns, Pteris vittata and Ceratopteris richardii. Our results reveal how the simple timing of a switch between two meristems has considerable consequences for the divergent gametophyte morphologies of the two ferns. They further provide evolutionary insight into the function and regulation of gametophyte meristems in seed-free vascular plants.
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Affiliation(s)
- Xiao Wu
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, USA
- Purdue Center for Plant Biology, Purdue University, West Lafayette, IN, USA
- Center of Pear Engineering Technology Research, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - An Yan
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
- Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA, USA
| | - Scott A M McAdam
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, USA
- Purdue Center for Plant Biology, Purdue University, West Lafayette, IN, USA
| | - Jo Ann Banks
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, USA
- Purdue Center for Plant Biology, Purdue University, West Lafayette, IN, USA
| | - Shaoling Zhang
- Center of Pear Engineering Technology Research, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Yun Zhou
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, USA
- Purdue Center for Plant Biology, Purdue University, West Lafayette, IN, USA
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Youngstrom CE, Geadelmann LF, Irish EE, Cheng CL. A fern WUSCHEL-RELATED HOMEOBOX gene functions in both gametophyte and sporophyte generations. BMC PLANT BIOLOGY 2019; 19:416. [PMID: 31601197 PMCID: PMC6788082 DOI: 10.1186/s12870-019-1991-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Accepted: 08/27/2019] [Indexed: 05/02/2023]
Abstract
BACKGROUND Post-embryonic growth of land plants originates from meristems. Genetic networks in meristems maintain the stem cells and direct acquisition of cell fates. WUSCHEL-RELATED HOMEOBOX (WOX) transcription factors involved in meristem networks have only been functionally characterized in two evolutionarily distant taxa, mosses and seed plants. This report characterizes a WOX gene in a fern, which is located phylogenetically between the two taxa. RESULTS CrWOXB transcripts were detected in proliferating tissues, including gametophyte and sporophyte meristems of Ceratopteris richardii. In addition, CrWOXB is expressed in archegonia but not the antheridia of gametophytes. Suppression of CrWOXB expression in wild-type RN3 plants by RNAi produced abnormal morphologies of gametophytes and sporophytes. The gametophytes of RNAi lines produced fewer cells, and fewer female gametes compared to wild-type. In the sporophyte generation, RNAi lines produced fewer leaves, pinnae, roots and lateral roots compared to wild-type sporophytes. CONCLUSIONS Our results suggest that CrWOXB functions to promote cell divisions and organ development in the gametophyte and sporophyte generations, respectively. CrWOXB is the first intermediate-clade WOX gene shown to function in both generations in land plants.
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Affiliation(s)
| | - Lander F. Geadelmann
- Department of Biology, University of Iowa, 129 E. Jefferson St., Iowa City, Iowa 52242 USA
| | - Erin E. Irish
- Department of Biology, University of Iowa, 129 E. Jefferson St., Iowa City, Iowa 52242 USA
| | - Chi-Lien Cheng
- Department of Biology, University of Iowa, 129 E. Jefferson St., Iowa City, Iowa 52242 USA
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