Dataset Information

Gene expression analysis in microdissected shoot meristems of Brassica napus microspore-derived embryos with altered levels of SHOOTMERISTEMLESS

ABSTRACT: SHOOTMERISTEMLESS (STM) is a well characterized key regulator of the shoot apical meristem (SAM) activity in diverse plant species. We used a transgenic approach to investigate how the altered expression of Brassica napus (Bn) STM affects the morphology and behavior of microspore-derived embryos (MDEs). Down-regulation of BnSTM repressed the formation of the SAM and reduced the number of MDEs able to regenerate viable plants at germination. This was in contrast to embryos over-expressing BnSTM which displayed enlarged SAMs with an improved regeneration frequency. To further investigate the regulatory mechanisms underpinning these different responses, global changes in transcript levels were analysed in laser micro dissected SAMs of the transformed MDEs. The induction of BnSTM up-regulated the expression of many transcription factors (TFs) some of which directly involved in the formation of the SAM, i.e. CUPSHAPED COTYLEDON1 and WUSCHEL, and regulatory components ofthe antioxidant response, hormone signalling, and cell wall synthesis and modification. Opposite expression patterns for some of these genes were observed in the SAMs of MDEs down-regulating BnSTM. These data were interpreted in relation to the ability of BnSTM to modulate the size and functionality of the SAM. Structural and expression studies were further conducted to confirm the role of BnSTM in mediating the regulatory network of cell wall and lignin synthesis. Besides lowering the transcript levels of early components of cell wall and lignin biosynthetic pathways in the SAM, BnSTM had a remarkable repressing effect on the expression of PHENYLALANINE AMMONIA LYASE2, CINNAMATE 4-4HYDROXYLASE, andCINNAMYL ALCOHOL DEHYDROGENASE. Since lignin formation is a feature of irreversible cell differentiation, these results suggest that one way in which BnSTM promotes indeterminate cell fate may be by preventing the expression of components of biochemical pathways involved in the accumulation of lignin in the meristematic cells. Overall these studies provide evidence for a novel function of BnSTM in enhancing the quality of in vitro produced meristems, and propose that this gene can be used as a potential target to improve regeneration of cultured embryos.

ORGANISM(S): Brassica napus

PROVIDER: GSE35992 | GEO | 2012/02/23

SECONDARY ACCESSION(S): PRJNA151681

REPOSITORIES: GEO

ACCESS DATA

Dataset's files

Source:

			Action	DRS
		Other

Items per page:

1 - 1 of 1

Similar Datasets

Project description:SHOOTMERISTEMLESS (STM) is a well characterized key regulator of the shoot apical meristem (SAM) activity in diverse plant species. We used a transgenic approach to investigate how the altered expression of Brassica napus (Bn) STM affects the morphology and behavior of microspore-derived embryos (MDEs). Down-regulation of BnSTM repressed the formation of the SAM and reduced the number of MDEs able to regenerate viable plants at germination. This was in contrast to embryos over-expressing BnSTM which displayed enlarged SAMs with an improved regeneration frequency. To further investigate the regulatory mechanisms underpinning these different responses, global changes in transcript levels were analysed in laser micro dissected SAMs of the transformed MDEs. The induction of BnSTM up-regulated the expression of many transcription factors (TFs) some of which directly involved in the formation of the SAM, i.e. CUPSHAPED COTYLEDON1 and WUSCHEL, and regulatory components ofthe antioxidant response, hormone signalling, and cell wall synthesis and modification. Opposite expression patterns for some of these genes were observed in the SAMs of MDEs down-regulating BnSTM. These data were interpreted in relation to the ability of BnSTM to modulate the size and functionality of the SAM. Structural and expression studies were further conducted to confirm the role of BnSTM in mediating the regulatory network of cell wall and lignin synthesis. Besides lowering the transcript levels of early components of cell wall and lignin biosynthetic pathways in the SAM, BnSTM had a remarkable repressing effect on the expression of PHENYLALANINE AMMONIA LYASE2, CINNAMATE 4-4HYDROXYLASE, andCINNAMYL ALCOHOL DEHYDROGENASE. Since lignin formation is a feature of irreversible cell differentiation, these results suggest that one way in which BnSTM promotes indeterminate cell fate may be by preventing the expression of components of biochemical pathways involved in the accumulation of lignin in the meristematic cells. Overall these studies provide evidence for a novel function of BnSTM in enhancing the quality of in vitro produced meristems, and propose that this gene can be used as a potential target to improve regeneration of cultured embryos. 2 mutants and 1 wild type

Project description:All above ground organs of higher plants are ultimately derived from specialized organogenic structures termed shoot apical meristems (SAMs). The SAM exhibits distinctive structural organization, marked by cell layering. Maize SAMs are comprised of two cell layers, L1 (single cell layered tunica) and L2 (corpus). To identify genes required for layer-specific functions intact maize SAMs were fixed, embedded in paraffin and sectioned. L1 and L2 cells were isolated from these sections via laser capture microdissection (LCM). RNA was isolated from six biological replications of L1 and L2, amplified and hybridized to microarrays spotted with ~37,000 maize cDNA clones. This experiment identified ~700 ESTs that are preferentially expressed in the L1 or the L2 (P <0.001). The L1-up-regulated ESTs included ZmOCL1 and ZmOCL4, which are known to exhibit L1-specific expression in the maize SAM. The L2-up-regulated ESTs included KNOTTED1, whose transcripts are known to accumulate in the L2 but not in the L1 of the maize SAM. Differentially expressed ESTs included genes involved in transcription, signal transduction, transport and metabolism, many of which are novel candidates that are required for layer-specific functions in the maize SAM. Several L1-up-regulated ESTs were annotated as yabby family genes or basic helix-loop-helix transcription factor-like genes, which have not previously been reported as having layer-specific expression in the SAM. Novel WW domain-containing genes (WW genes) were identified in this study. The WW domain mediates protein-protein interactions, often with signal transduction components. These WW genes were substantially up-regulated in the L1 relative to the L2. Keywords: Cell Type Comparison An experimental aim is to identify genes that are differentially expressed in distinct histological cell layers of maize SAM by comparing the transcript accumulation between L1 (single cell layered tunica) and L2 (corpus) using cDNA microarrays that have over 37,000 informative spots from maize.

Dataset Information

Gene expression analysis in microdissected shoot meristems of Brassica napus microspore-derived embryos with altered levels of SHOOTMERISTEMLESS

Dataset's files

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets