Project description:Profiling the transcriptome of the early stage of Arabidopsis callus induction variable_1 = root explants variable_2 = aerial organ explants variable_3 = 0 h on callus inducing medium variable_4 = 12 h on callus inducing medium variable_5 = 24 h on callus inducing medium variable_6 = 48 h on callus inducing medium variable_7 = 96 h on callus inducing medium
Project description:The cost of Carica papaya production through seed-based propagation is increased by sex segregation, making in vitro techniques a more appealing option for clonal propagation. Inducing embryogenic callus with 2,4-dichlorophenoxyacetic acid (2,4-D) hold the potential to large-scale cloning, although the molecular mechanisms underlying this process are still not well understood. In this study, we performed a temporal analysis in the proteome of C. papaya callus to identify the key players involved in embryogenic differentiation. Mature zygotic embryos were used as explants and treated with 20 μM 2,4-D to induce embryogenic callus. Total proteins were extracted at 0, 7, 14, and 21 days (T0, T7, T14, and T21), and 1407 proteins were identified using bottom-up proteomic approach. Comparative proteomics revealed 957 differentially accumulated proteins (DAPs) (p<0.05 and log2FC >0.585 or <-0.585) in at least one comparison between the analyzed induction times points. The clustering analysis revealed four clusters with distinct patterns of protein accumulation throughout the embryogenic callus induction treatment. The cluster 1 contains 386 DAPs that accumulated at all analyzed times after treatment with 2,4-D. In contrast, cluster 2 contains 165 DAPs that decrease in abundance during the induction. The cluster 3 contains 251 proteins that are most abundant just after the start of incubation in 2,4-D (T7) and cluster 4 grouped 155 proteins that accumulate after callus formation. Functional analysis revealed that proteins involved with reserve storage and seed maturation were more abundant in the explant at T0 and decreased as callus formation progressed. Biological processes involving carbohydrate and amino acid metabolism, aerobic respiration, and protein catabolic processes were enriched after induction treatment. Regulatory proteins, including histone deacetylase (HDT3) and argonaute 1, were more abundant after the start of induction treatment with 2,4-D, suggesting their role in acquisition of embryogenic competence. Predicted protein-protein networks revealed the regulatory role of proteins 14.3.3 accumulated during callus induction and the association of proteins involved in oxidative phosphorylation, hormone response, and SAM metabolism. Our findings emphasize the modulation of the proteome at different stages during embryogenic callus initiation and identify regulatory proteins that might be involved with the activation of this process.
Project description:Arabidopsis thaliana plant expressing 35S:WIND1 shows callus-like morphology without hormone treatment. Transcriptomes of the callus-like cell expressing 35S:WIND1, callus of T87 cultured cell, 2,4-D-induced callus and control seedling plant were compared by Agilent microarray. Comparison of four kinds of Arabidopsis thaliana plants. Biological replicates: three for each.
Project description:Arabidopsis thaliana plant expressing 35S:WIND1 shows callus-like morphology without hormone treatment. Transcriptomes of the callus-like cell expressing 35S:WIND1, callus of T87 cultured cell, 2,4-D-induced callus and control seedling plant were compared by Agilent microarray.
Project description:Purpose: Maize somatic embryogenesis is usually required to achieve genetic transformation and represents an important alternative in plant development. Although many embryogenesis-related genes have been studied in this model, the molecular mechanisms underlying cell dedifferentiation and further plant regeneration are not completely understood. Methods: Immature embryos smRNA profiles of 15-day-after-pollination (IE) and Embryogenic Callus from one (C1), four (C4), and ten months (C10) were generated by deep sequencing, using Illumina GAIIx. The sequence reads that passed quality filters were analyzed with two methods: Bowtie 1.1.2 and ShortStack 3.4. qRT–PCR validation for selected miRNAs was performed using SYBR Green assays. Results: We used high throughput sequencing to explore the sRNA populations during maize embryogenic callus induction and established subcultures from the Mexican cultivar VS-535, Tuxpeño landrace. We detected readjustments in 24 nt and 21-22 nt sRNA populations during the embryogenic callus establishment and maintenance. miRNAs related to stress response substantially increased upon callus proliferation establishment, correlating with a reduction in some of their target levels. On the other hand, while 24 nt-long hc-siRNAs derived from transposable retroelements transiently decreased in abundance during the embryogenic callus establishment, a population of 22 nt- hc-siRNAs increased. This was accompanied by reduction in transposon expression in the established callus subcultures. Conclusions: Stress- and development-related miRNAs are highly expressed upon maize EC callus induction and during maintenance subcultures, while miRNAs involved in hormone response only transiently increase during induction. The establishment of proliferative maize embryogenic callus is accompanied by important readjustments in the length of hc-siRNAs mapping to LTR retrotransposons, and their expression regulation.
Project description:Transcriptional profiling of age-related change of callus formation capability in Arabidopsis hypocotyls Organogenesis in vitro consists of many aspects such as phytohormone perception, dedifferentiation of differentiated cell to acquire organogenic competence, and re-entry of quiescent cells into cell cycle. In this study, we established an in vitro experimental system to study the age-dependent callus formation capacity in Arabidopsis. Interestingly, mature (35- to 38-day-old) hypocotyl explants exhibited better callus-forming potential than that of juvenile (7- to 10-day-old), determined by callus growth rates. To explore genome-wide expression changes underlying the phenomenon of age-dependent callus formation, a transcriptome-based analysis was performed. Gene expression profiling indicated that age-dependent callus formation capacity was associated with changes in phytohormone (auxins, cytokinins, abscisic acid, brassinosteroids and gibberellins) homeostasis, epigenetic mechanism and the cell cycle regulation. Besides, we identified two groups of genes involved in age-dependent callus formation capacity: (1) positive regulatory and (2) negative regulatory categories, i.e. genes that were significantly up- or down-regulated during callus formation derived from mature explants, respectively. One gene encoding DNA-binding protein (VARIANT IN METHYLATION 1, VIM1) belonging to the positive regulatory category was selected for functional analysis and assessment of age-dependent callus formation capacity. Indeed, vim1 reduced the efficiency of callus formation in mature explants, but not in juvenile. The result suggests that VIM1 plays an important role in regulating age-dependent callus formation capacity. Taken together, the investigation will help to better understand the molecular regulatory mechanism of age-dependent callus formation. Comparison of young and mature Arabidopsis hypocotyls either with or without auxin treatment for 1 day
Project description:Transcriptional profiling of age-related change of callus formation capability in Arabidopsis hypocotyls Organogenesis in vitro consists of many aspects such as phytohormone perception, dedifferentiation of differentiated cell to acquire organogenic competence, and re-entry of quiescent cells into cell cycle. In this study, we established an in vitro experimental system to study the age-dependent callus formation capacity in Arabidopsis. Interestingly, mature (35- to 38-day-old) hypocotyl explants exhibited better callus-forming potential than that of juvenile (7- to 10-day-old), determined by callus growth rates. To explore genome-wide expression changes underlying the phenomenon of age-dependent callus formation, a transcriptome-based analysis was performed. Gene expression profiling indicated that age-dependent callus formation capacity was associated with changes in phytohormone (auxins, cytokinins, abscisic acid, brassinosteroids and gibberellins) homeostasis, epigenetic mechanism and the cell cycle regulation. Besides, we identified two groups of genes involved in age-dependent callus formation capacity: (1) positive regulatory and (2) negative regulatory categories, i.e. genes that were significantly up- or down-regulated during callus formation derived from mature explants, respectively. One gene encoding DNA-binding protein (VARIANT IN METHYLATION 1, VIM1) belonging to the positive regulatory category was selected for functional analysis and assessment of age-dependent callus formation capacity. Indeed, vim1 reduced the efficiency of callus formation in mature explants, but not in juvenile. The result suggests that VIM1 plays an important role in regulating age-dependent callus formation capacity. Taken together, the investigation will help to better understand the molecular regulatory mechanism of age-dependent callus formation.
Project description:In plant tissue culture, callus forms from detached explants in response to a high-auxin-to-low-cytokinin ratio on callus-inducing medium. Callus is a group of pluripotent cells because it can regenerate either roots or shoots in response to a low level of auxin on root-inducing medium or a high-cytokinin-to-low-auxin ratio on shoot-inducing medium, respectively1. However, our knowledge of the mechanism of pluripotency acquisition during callus formation is limited. On the basis of analyses at the single-cell level, we show that the tissue structure of Arabidopsis thaliana callus on callus-inducing medium is similar to that of the root primordium or root apical meristem, and the middle cell layer with quiescent centre-like transcriptional identity exhibits the ability to regenerate organs. In the middle cell layer, WUSCHEL-RELATED HOMEOBOX5 (WOX5) directly interacts with PLETHORA1 and 2 to promote TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS1 expression for endogenous auxin production. WOX5 also interacts with the B-type ARABIDOPSIS RESPONSE REGULATOR12 (ARR12) and represses A-type ARRs to break the negative feedback loop in cytokinin signalling. Overall, the promotion of auxin production and the enhancement of cytokinin sensitivity are both required for pluripotency acquisition in the middle cell layer of callus for organ regeneration.