Efficient sweet pepper transformation mediated by the BABY BOOM transcription factor.
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ABSTRACT:
SUBMITTER: Heidmann I
PROVIDER: S-EPMC3092944 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BABY BOOM (BBM) is a member of the APETALA2/ETHYLENE RESPONSE FACTOR (AP2/ERF) family and its expression has been shown to improve herbaceous plant transformation and regeneration. However, this improvement has not been shown clearly for tree species. This study demonstrated that the efficiency of transgenic apple (Malus domestica Borkh.) plant production was dramatically increased by ectopic expression of the MdBBM1 gene. "Royal Gala" apple plants were first transformed with a CaMV35S-MdBBM1 construct (MBM) under kanamycin selection. These MBM transgenic plants exhibited enhanced shoot regeneration from leaf explants on tissue culture media, with most plants displaying a close-to-normal phenotype compared with CaMV35S-GUS transgenic plants when grown under greenhouse conditions, the exception being that some plants had slightly curly leaves. Thin leaf sections revealed the MBM plants produced more cells than the GUS plants, indicating that ectopic-expression of MdBBM1 enhanced cell division. Transcriptome analysis showed that mRNA levels for cell division activators and repressors linked to hormone (auxin, cytokinin and brassinosteroid) signalling pathways were enhanced and reduced, respectively, in the MBM plants compared with the GUS plants. Plants of eight independent MBM lines were compared with the GUS plants by re-transforming them with an herbicide-resistant gene construct. The number of transgenic plants produced per 100 leaf explants was 0-3% for the GUS plants, 3-8% for five MBM lines, and 20-30% for three MBM lines. Our results provided a solution for overcoming the barriers to transgenic plant production in apple, and possibly in other trees.
| S-EPMC8795818 | biostudies-literature
Project description:BackgroundTheobroma cacao, the chocolate tree, is an important economic crop in East Africa, South East Asia, and South and Central America. Propagation of elite varieties has been achieved through somatic embryogenesis (SE) but low efficiencies and genotype dependence still presents a significant limitation for its propagation at commercial scales. Manipulation of transcription factors has been used to enhance the formation of SEs in several other plant species. This work describes the use of the transcription factor Baby Boom (BBM) to promote the transition of somatic cacao cells from the vegetative to embryonic state.ResultsAn ortholog of the Arabidopsis thaliana BBM gene (AtBBM) was characterized in T. cacao (TcBBM). TcBBM expression was observed throughout embryo development and was expressed at higher levels during SE as compared to zygotic embryogenesis (ZE). TcBBM overexpression in A. thaliana and T. cacao led to phenotypes associated with SE that did not require exogenous hormones. While transient ectopic expression of TcBBM provided only moderate enhancements in embryogenic potential, constitutive overexpression dramatically increased SE proliferation but also appeared to inhibit subsequent development.ConclusionOur work provides validation that TcBBM is an ortholog to AtBBM and has a specific role in both somatic and zygotic embryogenesis. Furthermore, our studies revealed that TcBBM transcript levels could serve as a biomarker for embryogenesis in cacao tissue. Results from transient expression of TcBBM provide confirmation that transcription factors can be used to enhance SE without compromising plant development and avoiding GMO plant production. This strategy could compliment a hormone-based method of reprogramming somatic cells and lead to more precise manipulation of SE at the regulatory level of transcription factors. The technology would benefit the propagation of elite varieties with low regeneration potential as well as the production of transgenic plants, which similarly requires somatic cell reprogramming.
| S-EPMC4449528 | biostudies-literature
Project description:A glucocorticoid-regulated BBM protein (35S:BBM-GR) was used in combination with microarray analysis to identify genes directly activated by BBM. We employed the system described by (Lloyd et al., 1994) in which dexamethasone (DEX) and cycloheximide (CHX) are applied together to respectively, induce nuclear localization of the BBM-GR protein and prevent translation of the primary targets mRNAs. In this way it is possible to identify direct targets of a transcriptional activator by comparing gene expression profiles between DEX+CHX-treated transgenic and wild-type tissues. The ability of the 35S:BBM GR construct to induce somatic embryogenesis in Arabidopsis seedlings was determined by phenotypic observation of 35S:BBM GR seeds germinated and grown in the presence of 10 µM dexamethasone (DEX). As in 35S:BBM seedlings, we observed somatic embryo formation on the cotyledons, first leaves and shoot meristem of DEX-treated 35S:BBM GR seedlings. We identified a set of 20 genes (including BBM itself) and our analysis indicates that BBM directly activates a signaling pathway comprising transcription factors and other signaling molecules, but which does not initially include genes known to induce somatic embryogenesis, such as LEC1, LEC2 or WUS. The functions of the BBM target genes are unknown, however a number of them have recently been identified in microarray screens for meristem-expressed genes. The identification of BBM-interacting partners and downstream targets provides new tools for unraveling pathways related to plant cell growth and organogenesis. Keywords: transcriptional activation
2008-09-22 | GSE3399 | GEO
Project description:A glucocorticoid-regulated BBM protein (35S:BBM-GR) was used in combination with microarray analysis to identify genes directly activated by BBM. We employed the system described by (Lloyd et al., 1994) in which dexamethasone (DEX) and cycloheximide (CHX) are applied together to respectively, induce nuclear localization of the BBM-GR protein and prevent translation of the primary targets mRNAs. In this way it is possible to identify direct targets of a transcriptional activator by comparing gene expression profiles between DEX+CHX-treated transgenic and wild-type tissues. The ability of the 35S:BBM GR construct to induce somatic embryogenesis in Arabidopsis seedlings was determined by phenotypic observation of 35S:BBM GR seeds germinated and grown in the presence of 10 µM dexamethasone (DEX). As in 35S:BBM seedlings, we observed somatic embryo formation on the cotyledons, first leaves and shoot meristem of DEX-treated 35S:BBM GR seedlings. We identified a set of 20 genes (including BBM itself) and our analysis indicates that BBM directly activates a signaling pathway comprising transcription factors and other signaling molecules, but which does not initially include genes known to induce somatic embryogenesis, such as LEC1, LEC2 or WUS. The functions of the BBM target genes are unknown, however a number of them have recently been identified in microarray screens for meristem-expressed genes. The identification of BBM-interacting partners and downstream targets provides new tools for unraveling pathways related to plant cell growth and organogenesis. Keywords: transcriptional activation To identify candidate BBM targets, we treated 4 day old 35S:BBM-GR seedlings for 8 hours with 10 µM DEX in the presence of 10 µM CHX and compared the mRNA population from these seedlings using Arabidopsis Operon microarrays (http://www.ag.arizona.edu/microarray/) to that of 4 day old wild-type seedlings treated in the same way. The seed batches used in this analysis showed 100% EFS when grown continuously on media with 10 µM DEX. Four day old seedlings were chosen as the experimental material because they are highly responsive to BBM GR activation and provide sufficient RNA for the microarray experiments. The biological reproducibility of the data was monitored using two independent single locus 35S:BBM GR lines. The technical reproducibility of the data was monitored using two independently DEX + CHX-treated samples from each transgenic line. Dye effects were monitored in a dye-swap experiment using one of the four RNA samples from the two biological replicates
2010-06-25 | E-GEOD-3399 | biostudies-arrayexpress
Project description:The BABY BOOM (BBM) AINTEGUMENTA-LIKE (AIL) AP2/ERF domain transcription factor is a major regulator of plant cell totipotency, as it induces asexual embryo formation when ectopically expressed. Surprisingly, only limited information is available on the role of BBM during zygotic embryogenesis. Here we reexamined BBM expression and function in the model plant Arabidopsis thaliana (Arabidopsis) using reporter analysis and newly developed CRISPR mutants. BBM was expressed in the embryo from the zygote stage and also in the maternal (nucellus) and filial (endosperm) seed tissues. Analysis of CRISPR mutant alleles for BBM (bbm-cr) and the redundantly acting AIL gene PLETHORA2 (PLT2) (plt2-cr) uncovered individual roles for these genes in the timing of embryo progression. We also identified redundant roles for BBM and PLT2 in endosperm proliferation and cellularization and the maintenance of zygotic embryo development. Finally, we show that ectopic BBM expression in the egg cell of Arabidopsis and the dicot crops Brassica napus and Solanum lycopersicon is sufficient to bypass the fertilization requirement for embryo development. Together these results highlight roles for BBM and PLT2 in seed development and demonstrate the utility of BBM genes for engineering asexual embryo development in dicot species.
| S-EPMC9231476 | biostudies-literature
Project description:After fertilization, a plant's life relies on progression through embryogenesis and maintenance of the stem cell niches from which all post-embryonic organs arise. BABY BOOM (BBM) and other members of the AINTEGUMENTA-LIKE (AIL)/PLETHORA (PLT) clade of the AP2-type transcription factor family play important roles controlling these processes in Arabidopsis thaliana (Arabidopsis). Development of the plt2/bbm double mutant is blocked at during early embryogenesis (Galinha et al., 2007), and combinations of bbm with plt1 and plt3 lead to short roots as a result of meristem differentiation. In contrast, overexpression of BBM in Arabidopsis seedlings induces the formation of somatic embryos on cotyledons and leaves (Boutilier, 2002), showing that BBM is a key regulator of cell identity and proliferation. Although the functions of BBM and other AIL genes have been well described, the molecular mode of action of these transcription factors has not been well examined (reviewed in Horstman et al., 2013). Our previous study provided the first insight into BBM molecular function by identifying BBM targets through a microarray-based approach (Passarinho, 2008), but only a few BBM targets have been functionally characterized. To obtain a better understanding of BBM function, we identified direct BBM targets using a chromatin immunoprecipitation (ChIP) combined with massively-parallel DNA sequencing (ChIP-seq) approach.
2014-12-17 | GSE52400 | GEO
Project description:After fertilization, a plant's life relies on progression through embryogenesis and maintenance of the stem cell niches from which all post-embryonic organs arise. BABY BOOM (BBM) and other members of the AINTEGUMENTA-LIKE (AIL)/PLETHORA (PLT) clade of the AP2-type transcription factor family play important roles controlling these processes in Arabidopsis thaliana (Arabidopsis). Development of the plt2/bbm double mutant is blocked at during early embryogenesis (Galinha et al., 2007), and combinations of bbm with plt1 and plt3 lead to short roots as a result of meristem differentiation. In contrast, overexpression of BBM in Arabidopsis seedlings induces the formation of somatic embryos on cotyledons and leaves (Boutilier, 2002), showing that BBM is a key regulator of cell identity and proliferation. Although the functions of BBM and other AIL genes have been well described, the molecular mode of action of these transcription factors has not been well examined (reviewed in Horstman et al., 2013). Our previous study provided the first insight into BBM molecular function by identifying BBM targets through a microarray-based approach (Passarinho, 2008), but only a few BBM targets have been functionally characterized. To obtain a better understanding of BBM function, we identified direct BBM targets using a chromatin immunoprecipitation (ChIP) combined with massively-parallel DNA sequencing (ChIP-seq) approach. Somatic embryo tissue was used for the ChIP-seq experiments with the native BBM promoter (pBBM::BBM-YFP), with a line expressing nuclear-localized GFP from the same BBM promoter (pBBM::NLS-GFP) as a negative control. Whole, embryogenic seedlings of the 35S::BBM-GFP line were used for the 35S::BBM-GFP ChIP-seq experiments, with 35S::BBM embryogenic seedlings serving as a negative control. Both experiments were performed once, making a total of 4 samples.
2014-12-17 | E-GEOD-52400 | biostudies-arrayexpress
Project description:Somatic embryogenesis is a type of plant cell totipotency where embryos develop from nonreproductive (vegetative) cells without fertilization. Somatic embryogenesis can be induced in vitro by auxins, and by ectopic expression of embryo-expressed transcription factors like the BABY BOOM (BBM) AINTEGUMENTA-LIKE APETALA2/ETHYLENE RESPONSE FACTOR domain protein. These different pathways are thought to converge to promote auxin response and biosynthesis, but the specific roles of the endogenous auxin pathway in somatic embryogenesis induction have not been well-characterized. Here we show that BBM transcriptionally regulates the YUCCA3 (YUC3) and YUC8 auxin biosynthesis genes during BBM-mediated somatic embryogenesis in Arabidopsis (Arabidopsis thaliana) seedlings. BBM induced local and ectopic YUC3 and YUC8 expression in seedlings, which coincided with increased DR5 auxin response and indole-3-acetic acid (IAA) biosynthesis and with ectopic expression of the WOX2 embryo reporter. YUC-driven auxin biosynthesis was required for BBM-mediated somatic embryogenesis, as the number of embryogenic explants was reduced by ca. 50% in yuc3 yuc8 mutants and abolished after chemical inhibition of YUC enzyme activity. However, a detailed YUC inhibitor time-course study revealed that YUC-dependent IAA biosynthesis is not required for the re-initiation of totipotent cell identity in seedlings. Rather, YUC enzymes are required later in somatic embryo development for the maintenance of embryo identity and growth. This study resolves a long-standing question about the role of endogenous auxin biosynthesis in transcription factor-mediated somatic embryogenesis and also provides an experimental framework for understanding the role of endogenous auxin biosynthesis in other in planta and in vitro embryogenesis systems.
| S-EPMC8825264 | biostudies-literature
Project description:Cyclin-dependent kinase (cdk)-3, a member of the cdk family of kinases, plays a critical role in cell cycle regulation and is involved in G(0)-G(1) and G(1)-S cell cycle transitions. However, the role of cdk3 in cell proliferation, as well as cell transformation, is not yet clearly understood. Here, we report that the protein expression level of cdk3 is higher in human cancer cell lines and human glioblastoma tissue compared with normal brain tissue. Furthermore, we found that cdk3 phosphorylates activating transcription factor 1 (ATF1) at serine 63 and enhances the transactivation and transcriptional activities of ATF1. Results also indicated that siRNA directed against cdk3 (si-cdk3) suppresses ATF1 activity, resulting in inhibition of proliferation and growth of human glioblastoma T98G cells in soft agar. Importantly, we showed that cdk3 enhances epidermal growth factor-induced transformation of JB6 Cl41 cells and si-cdk3 suppresses Ras(G12V)/cdk3/ATF1-induced foci formation in NIH3T3 cells. These results clearly showed that the cdk3-ATF1 signaling axis is critical for cell proliferation and transformation.
| S-EPMC2768358 | biostudies-literature
Project description:Poplar is a model system for the regeneration and genetic transformation of woody plants. To shorten the time required for studies of transgenic poplar, efforts have been made to optimize transformation methods that use Agrobacterium tumefaciens. In this study, an Agrobacterium infective suspension was treated at 4 °C for at least 10 h before infecting explants. By transforming the Populus hybrid clone "Nanlin895" (Populus deltoides×P. euramericana) with Agrobacterium harboring the PBI121:CarNAC6 binary vector, we showed that the transformation efficiency was improved significantly by multiple independent factors, including an Agrobacterium infective suspension with an OD600 of 0.7, an Agrobacterium infection for 120 min, an Agrobacterium infective suspension at a pH of 5.0, an acetosyringone concentration of 200 µM, a cocultivation at 28 °C, a cocultivation for 72 h and a sucrose concentration of 30 g/L in the cocultivation medium. We also showed that preculture of wounded leaf explants for two days increased the regeneration rate. The integration of the desired gene into transgenic poplars was detected using selective medium containing kanamycin, followed by southern blot analysis. The expression of the transgene in the transgenic lines was confirmed by northern blot analysis.
| S-EPMC4100180 | biostudies-literature