Project description:Over time, plants have evolved flexible self-organizing patterning mechanisms to adapt tissue functionality to continuous organ growth. A clear example of this process is the multicellular organization of vascular cells into narrow and elongated conductive channels in foliar organs of Arabidopsis thaliana such as cotyledons. The establishment of a closed vascular network is achieved through the coordinated specification of newly recruited procambial cells by means of their proliferation and elongation. An important and yet poorly understood component of this process is secondary vein branching; a mechanism employed to extend vascular tissues throughout cotyledon surface. Here we revise the directionality of the formation of vascular tissues in the embryonic cotyledon of Arabidopsis and show that distal veins arise from the bifurcation of cell files contained in the midvein. Instead, proximal veins emerge from the division of provascular cells, a process partially constrained by RECEPTOR LIKE PROTEIN KINASE 2 (RPK2). Utilizing genetic, transcriptomic and live-cell imaging analyses, we show that RPK2 function is antagonized by COTYLEDON VASCULAR PATTERN 2 and its homologous CVP2 LIKE 1. Whilst RPK2 expression at the cotyledon margin prevents the branching of secondary proximal veins, the divergence of the midvein into distal veins appears to be auxin-dependent and follows a distinct regulatory mechanism. Our work supports a model in which RPK2 modulates vascular complexity independently of cell-to-cell auxin-propagation to adapt the spatial configuration of vascular tissues to organ growth.
Project description:In an effort to identify genetic regulators for the cell ontogeny around the veins in Arabidopsis thaliana leaves, an activation-tagged mutant line with altered leaf morphology and altered bundle sheath anatomy was characterized. This mutant had a bundle sheath-specific promoter from the gene GLYCINE DECARBOXYLASE SUBUNIT-T from the C4 species Flaveria trinervia (GLDTFt promoter) inserted in the coding region of the transcriptional repressor NAC052. Reconstruction of the mutation event of our activation-tagged line by creating a line expressing an amino-terminally truncated sequence of NAC052 under control of the GLDTFt promoter as well as creating a line expressing the full sequence of NAC052 under control of the GLDTFT promoter, as well as creating a CRISPR/Cas mutant line of NAC052, confirmed the involvement of NAC052 in leaf development.
Project description:The aim of this project is to deeply map the proteome of mitochondria from the model plant Arabidopsis thaliana. For this purpose, mitochondria were isolated from Arabidopsis cell cultures, their proteins extracted and processed using SP3 digestion. To achieve high sequence coverage, the proteins were digested with a total of six different proteases and measured using sensitive timsTOF Pro hardware and TIMS fractionation.