Transient plant transformation mediated by Agrobacterium tumefaciens: Principles, methods and applications.

Agrobacterium tumefaciens is widely used as a versatile tool for development of stably transformed model plants and crops. However, the development of Agrobacterium based transient plant transformation methods attracted substantial attention in recent years. Transient transformation methods offer several applications advancing stable transformations such as rapid and scalable recombinant protein production and in planta functional genomics studies.

Biotechnological aspects of cytoskeletal regulation in plants.

The cytoskeleton is a protein-based intracellular superstructure that evolved early after the appearance of bacterial prokaryotes. Eventually cytoskeletal proteins and their macromolecular assemblies were established in eukaryotes and assumed critical roles in cell movements, intracellular organization, cell division and cell differentiation. In biomedicine the small-molecules targeting cytoskeletal elements are in the frontline of anticancer research with plant-derived cytoskeletal drugs such as Vinca alkaloids and toxoids, being routinely used in the clinical practice.

Involvement of YODA and mitogen activated protein kinase 6 in Arabidopsis post-embryogenic root development through auxin up-regulation and cell division plane orientation.

The role of YODA MITOGEN ACTIVATED PROTEIN KINASE KINASE KINASE 4 (MAPKKK4) upstream of MITOGEN ACTIVATED PROTEIN KINASE 6 (MPK6) was studied during post-embryonic root development of Arabidopsis thaliana. Loss- and gain-of-function mutants of YODA (yda1 and ΔNyda1) were characterized in terms of root patterning, endogenous auxin content and global proteomes. We surveyed morphological and cellular phenotypes of yda1 and ΔNyda1 mutants suggesting possible involvement of auxin.

Fluorescent protein tagging of Arabidopsis MAPKs for in vivo localization studies.

Mitogen-activated protein kinases (MAPK) are key regulatory elements in many processes. They are highly conserved throughout eukaryotes. In plants, MAPKs are involved in biotic and abiotic stress responses; they regulate cell division, cell growth, and also programmed cell death.

Dynamics and organization of cortical microtubules as revealed by superresolution structured illumination microscopy.

Plants employ acentrosomal mechanisms to organize cortical microtubule arrays essential for cell growth and differentiation. Using structured illumination microscopy (SIM) adopted for the optimal documentation of Arabidopsis (Arabidopsis thaliana) hypocotyl epidermal cells, dynamic cortical microtubules labeled with green fluorescent protein fused to the microtubule-binding domain of the mammalian microtubule-associated protein MAP4 and with green fluorescent protein-fused to the alpha tubulin6 were comparatively recorded in wild-type Arabidopsis plants and in the mitogen-activated protein kinase mutant mpk4 possessing the former microtubule marker. The mpk4 mutant exhibits extensive microtubule bundling, due to increased abundance and reduced phosphorylation of the microtubule-associated protein MAP65-1, thus providing a very useful genetic tool to record intrabundle microtubule dynamics at the subdiffraction level.

Salt-induced subcellular kinase relocation and seedling susceptibility caused by overexpression of Medicago SIMKK in Arabidopsis.

Dual-specificity mitogen-activated protein kinases kinases (MAPKKs) are the immediate upstream activators of MAPKs. They simultaneously phosphorylate the TXY motif within the activation loop of MAPKs, allowing them to interact with and regulate multiple substrates. Often, the activation of MAPKs triggers their nuclear translocation.

Crosstalk between secondary messengers, hormones and MAPK modules during abiotic stress signalling in plants.

The crosstalk between second messengers, hormones and mitogen-activated protein kinases (MAPKs) in plant signalling systems facilitates adaptation and survival in the face of diverse environmental stresses. This review focuses on the transduction of second messenger and hormone signals by MAPK modules in plant abiotic stress responses. We discuss how this crosstalk regulates gene expression (e.

NITRILASE1 regulates the exit from proliferation, genome stability and plant development.

Nitrilases are highly conserved proteins with catabolic activity but much less understood functions in cell division and apoptosis. To elucidate the biological functions of Arabidopsis NITRILASE1, we characterized its molecular forms, cellular localization and involvement in cell proliferation and plant development. We performed biochemical and mass spectrometry analyses of NITRILASE1 complexes, electron microscopy of nitrilase polymers, imaging of developmental and cellular distribution, silencing and overexpression of nitrilases to study their functions.

Plant Aurora kinases play a role in maintenance of primary meristems and control of endoreduplication.

• The conserved family of Aurora kinases has multiple functions during mitosis. The roles of plant Aurora kinases have been characterized using inhibitor treatments. • We down-regulated Aurora kinases in Arabidopsis thaliana using RNA interference (RNAi).

A nodulin/glutamine synthetase-like fusion protein is implicated in the regulation of root morphogenesis and in signalling triggered by flagellin.

The nodulin/glutamine synthetase-like protein (NodGS) that we identified proteomically in Arabidopsis thaliana is a fusion protein composed of an N-terminal amidohydrolase domain that shares homology with nodulins and a C-terminal domain of prokaryotic glutamine synthetase type I. The protein is homologous to the FluG protein, a morphogenetic factor in fungi. Although genes encoding NodGS homologues are present in many plant genomes, their products have not yet been characterized.

Gamma-tubulin is essential for acentrosomal microtubule nucleation and coordination of late mitotic events in Arabidopsis.

Gamma-tubulin is required for microtubule (MT) nucleation at MT organizing centers such as centrosomes or spindle pole bodies, but little is known about its noncentrosomal functions. We conditionally downregulated gamma-tubulin by inducible expression of RNA interference (RNAi) constructs in Arabidopsis thaliana. Almost complete RNAi depletion of gamma-tubulin led to the absence of MTs and was lethal at the cotyledon stage.