Project description:In-vitro induced establishment and activity of the interfascicular cambium in Arabidopsis thaliana stems under auxin treatments. We used microarrays to detail the global programme of gene expression underlying the establishment and activity of the interfascicular cambium and identified tissue-speciffic up-regulated genes during this process.
Project description:In-vivo induced establishment and activity of the interfascicular cambium in Arabidopsis thaliana stems under NPA treatments. We used microarrays to detail the global programme of gene expression underlying the establishment and activity of the interfascicular cambium.
Project description:The douple mutant Arabidopsis thaliana soc1 ful, in contrast with WT, produces an interfascicular cambium and a large wood cylinder is the flowering stem. We present the RNAseq data for polyA mRNA of different developmental stages of cambium and wood formation in Arabidopsis thaliana. We sequenced 7 stages; 4 in the woody mutant soc1-6 ful-7 (herbaceous, cambium initiation, wood initiation and leaf) and 3 stages in the WT Col-0 (herbaceous, cambium and leaf). The corresponding stem anatomy is also presented in the manuscript indicating the stage of cambium development and the production of secondary xylem.
Project description:In-vitro induced establishment and activity of the interfascicular cambium in Arabidopsis thaliana stems under auxin treatments. We used microarrays to detail the global programme of gene expression underlying the establishment and activity of the interfascicular cambium and identified tissue-speciffic up-regulated genes during this process. Different tissue types from in-vitro auxin treated stems were selected at successive stages of cambium establishment using laser capture microdissection for RNA extraction and hybridization on Affymetrix microarrays. We aimed to obtain genes exclussively upregulated in the interfascicular region responsible for cambium establishment and activity.
Project description:In-vivo induced establishment and activity of the interfascicular cambium in Arabidopsis thaliana stems under NPA treatments. We used microarrays to detail the global programme of gene expression underlying the establishment and activity of the interfascicular cambium. 3 mm stem pieces were collected after being in treated with NPA for a week in order to stop the polar auxin transport and induce secondary growth. Collected samples were used for RNA extraction and hybridization on Affymetrix microarrays. We aimed to obtain genes responsible for auxin-induced cambium establishment and activity.
Project description:Vascular cambium is a secondary meristem which produces xylem (wood) inwards and phloem (bark) outwards. The activity of cambium leads to expansion in the diameters in plants, that is, secondary growth, and thus contributes to biomass increase. The regulation of cambium development is at multilevel including phytohormones and peptide-receptor kinase (CLE41/44-PXY) signalling pathways. However, only limited progress has been made on the transcriptional regulation level. To construct the transcriptional network that regulates cambium development, we performed a genome wide transcript profiling in sorted procambial and cambial cells in Arabidopsis roots. More than 500 genes were identified as cambium abundant genes via comparison against transcriptomes of other Arabidopsis root cell types. We then investigated the roles of almost all the cambial transcription factors (TFs) and some of their homologous genes during secondary growth. Many of the candidate TFs were highly expressed in cambium based on the promoter GUS fusion and in situ hybridization. An unbiased transcriptional regulatory network was constructed using transcript profiling data collected from inducible overexpression lines for selected candidate TFs and a few major nodes were identified in the network including WOX4 and KNAT1. Moreover, the severity of mutant phenotypes was predicted based on the network. Next, we used the predication as a guide and generated over 70 double mutants within the same or among different TF families to explore the genetic interactions of candidate genes. Phenotype characterization on the secondary growth of the mutants and the overexpression lines identified promoters and inhibitors of cambium activity. The phenotypic data also suggested the redundancy within and among TF families because the phenotypes could be enhanced when additional TFs were mutated. We also found that combinations of certain overexpression lines and mutants led to pronounced increase of cell proliferation or xylem differentiation and in the extreme case the formation of ectopic cambium. We herein propose that cambium development is orchestrated by a wide network at the transcriptional level, where each TF has a different contribution to cell proliferation and differentiation.
Project description:Vascular formation in the leaves of higher plants begins with the selection of cells poised to become preprocambial cells, some of which eventually develop into procambial cells. The initiation of this process is accompanied by auxin-responsive and MONOPTEROS (MP) transcription factor-mediated modulations in gene expression. Here, we show that MP directly activates the expression of Dof5.8, which encodes a transcriptional repressor. Consistently, mutations within Dof5.8 enhanced the phenotype of a weak allele of mp, resulting in abnormal root and cotyledon development. However, although mp mutants showed reduced vascular patterns in cotyledons, the mp dof5.8 double mutants displayed both reduced and more complex vascular patterns in individual cotyledons. Thus, Dof5.8 appears to be associated with both positive and negative regulatory mechanisms for vascular network formation in leaves. Furthermore, both over-expression of Dof5.8 and expression of a Dof5.8 construct engineered to possess enhanced repressor activity in preprocambial cells prevented the formation of procambium for secondary and higher order veins, suggesting a predominantly negative regulatory role for Dof5.8. These results imply that proper vascular patterns in leaves are formed through the modulation of both positive and negative regulation by Dof5.8. MP may direct this fine-tuning mechanism by mediating the expression of Dof5.8.
Project description:Macrophomina phaseolina (Mp) is a soil-borne pathogenic fungus known to infect more than 500 plants species including important crops. Here we report the use of a novel agar plate-based pathosystem using the model plant Arabidopsis thaliana (Arabidopsis) to study plant defense reponses to Mp, specifically a comparison between wild type Col-0 and double mutant ein2/jar1 roots with and without Mp infection, at two time points, by RNA-seq.