Integration of the SMXL/D53 strigolactone signalling repressors in the model of shoot branching regulation in Pisum sativum.

DWARF53 (D53) in rice (Oryza sativa) and its homologs in Arabidopsis (Arabidopsis thaliana), SUPPRESSOR OF MAX2-LIKE 6 (SMXL6), SMXL7 and SMXL8, are well established negative regulators of strigolactone (SL) signalling in shoot branching regulation. Little is known of pea (Pisum sativum) homologs and whether D53 and related SMXLs are specific to SL signalling pathways. Here, we identify two allelic pea mutants, dormant3 (dor3), and demonstrate through gene mapping and sequencing that DOR3 corresponds to a homolog of D53 and SMXL6/SMXL7, designated PsSMXL7.

Correction to "Dynamic Contrast for Plant Phenotyping".

[This corrects the article DOI: 10.1021/acsomega.0c00957.

Dynamic Contrast for Plant Phenotyping.

Noninvasiveness, minimal handling, and immediate response are favorable features of fluorescence readout for high-throughput phenotyping of labeled plants.Yet, remote fluorescence imaging may suffer from an autofluorescent background and artificial or natural ambient light. In this work, the latter limitations are overcome by adopting reversibly photoswitchable fluorescent proteins (RSFPs) as labels and Speed OPIOM (out-of-phase imaging after optical modulation), a fluorescence imaging protocol exploiting dynamic contrast.

Selective gene dosage by CRISPR-Cas9 genome editing in hexaploid Camelina sativa.

In many plant species, gene dosage is an important cause of phenotype variation. Engineering gene dosage, particularly in polyploid genomes, would provide an efficient tool for plant breeding. The hexaploid oilseed crop Camelina sativa, which has three closely related expressed subgenomes, is an ideal species for investigation of the possibility of creating a large collection of combinatorial mutants.

Dual Fatty Acid Elongase Complex Interactions in Arabidopsis.

Very long chain fatty acids (VLCFAs) are involved in plant development and particularly in several cellular processes such as membrane trafficking, cell division and cell differentiation. However, the precise role of VLCFAs in these different cellular processes is still poorly understood in plants. In order to identify new factors associated with the biosynthesis or function of VLCFAs, a yeast multicopy suppressor screen was carried out in a yeast mutant strain defective for fatty acid elongation.

The Zinc-Finger Protein SOP1 Is Required for a Subset of the Nuclear Exosome Functions in Arabidopsis.

Correct gene expression requires tight RNA quality control both at transcriptional and post-transcriptional levels. Using a splicing-defective allele of PASTICCINO2 (PAS2), a gene essential for plant development, we isolated suppressor mutations modifying pas2-1 mRNA profiles and restoring wild-type growth. Three suppressor of pas2 (sop) mutations modified the degradation of mis-spliced pas2-1 mRNA species, allowing the synthesis of a functional protein.

Inhibition of very long acyl chain sphingolipid synthesis modifies membrane dynamics during plant cytokinesis.

Plant cytokinesis requires intense membrane trafficking and remodeling to form a specific membrane structure, the cell plate that will ultimately separate the daughter cells. The nature and the role of lipids involved in the formation of the cell plate remain unclear. Plant membranes are particularly rich in sphingolipids such as glucosyl-ceramides with long (16 carbons) or very long (24 carbons) acyl chains.

Evaluation of the potential for interspecific hybridization between Camelina sativa and related wild Brassicaceae in anticipation of field trials of GM camelina.

Camelina (Camelina sativa (L.) Crantz) is a re-emergent oilseed crop that is also becoming important as a model for applied projects based on studies in Arabidopsis thaliana, since the two species are closely related members of the tribe Camelineae of the Brassicaeae. Since camelina can be transformed genetically by floral dip, genetically modified (GM) camelina is being created in many laboratories, and small-scale field trials are already being conducted in the US and Canada.

Sphingolipids containing very-long-chain fatty acids define a secretory pathway for specific polar plasma membrane protein targeting in Arabidopsis.

Sphingolipids are a class of structural membrane lipids involved in membrane trafficking and cell polarity. Functional analysis of the ceramide synthase family in Arabidopsis thaliana demonstrates the existence of two activities selective for the length of the acyl chains. Very-long-acyl-chain (C > 18 carbons) but not long-chain sphingolipids are essential for plant development.

Sphingolipids involvement in plant endomembrane differentiation: the BY2 case.

Sphingolipids play an essential role in the functioning of the secretory pathway in eukaryotic organisms. Their importance in the functional organization of plant cells has not been studied in any detail before. The sphingolipid synthesis inhibitor fumonisin B1 (FB1), a mycotoxin acting as a specific inhibitor of ceramide synthase, was tested for its effects on cell growth, cell polarity, cell shape, cell cycle and on the ultrastructure of BY2 cells.

Links between lipid homeostasis, organelle morphodynamics and protein trafficking in eukaryotic and plant secretory pathways.

The role of lipids as molecular actors of protein transport and organelle morphology in plant cells has progressed over the last years through pharmacological and genetic investigations. The manuscript is reviewing the roles of various lipid families in membrane dynamics and trafficking in eukaryotic cells, and summarizes some of the related physicochemical properties of the lipids involved. The article also focuses on the specific requirements of the sphingolipid glucosylceramide (GlcCer) in Golgi morphology and protein transport through the plant secretory pathway.

Very-long-chain fatty acids are involved in polar auxin transport and developmental patterning in Arabidopsis.

Very-long-chain fatty acids (VLCFAs) are essential for many aspects of plant development and necessary for the synthesis of seed storage triacylglycerols, epicuticular waxes, and sphingolipids. Identification of the acetyl-CoA carboxylase PASTICCINO3 and the 3-hydroxy acyl-CoA dehydratase PASTICCINO2 revealed that VLCFAs are important for cell proliferation and tissue patterning. Here, we show that the immunophilin PASTICCINO1 (PAS1) is also required for VLCFA synthesis.

Glucosylceramide biosynthesis is involved in Golgi morphology and protein secretion in plant cells.

Lipids have an established role as structural components of membranes or as signalling molecules, but their role as molecular actors in protein secretion is less clear. The complex sphingolipid glucosylceramide (GlcCer) is enriched in the plasma membrane and lipid microdomains of plant cells, but compared to animal and yeast cells, little is known about the role of GlcCer in plant physiology. We have investigated the influence of GlcCer biosynthesis by glucosylceramide synthase (GCS) on the efficiency of protein transport through the plant secretory pathway and on the maintenance of normal Golgi structure.

The very-long-chain hydroxy fatty acyl-CoA dehydratase PASTICCINO2 is essential and limiting for plant development.

Very-long-chain fatty acids (VLCFAs) are synthesized as acyl-CoAs by the endoplasmic reticulum-localized elongase multiprotein complex. Two Arabidopsis genes are putative homologues of the recently identified yeast 3-hydroxy-acyl-CoA dehydratase (PHS1), the third enzyme of the elongase complex. We showed that Arabidopsis PASTICCINO2 (PAS2) was able to restore phs1 cytokinesis defects and sphingolipid long chain base overaccumulation.

Systematic analysis of protein subcellular localization and interaction using high-throughput transient transformation of Arabidopsis seedlings.

The functional genomics approach requires systematic analysis of protein subcellular distribution and interaction networks, preferably by optimizing experimental simplicity and physiological significance. Here, we present an efficient in planta transient transformation system that allows single or multiple expression of constructs containing various fluorescent protein tags in Arabidopsis cotyledons. The optimized protocol is based on vacuum infiltration of agrobacteria directly into young Arabidopsis seedlings.

The C terminus of the immunophilin PASTICCINO1 is required for plant development and for interaction with a NAC-like transcription factor.

PASTICCINO1 (PAS1) is a high molecular weight FK506-binding protein (FKBP) involved in the control of cell proliferation and differentiation during plant development. Mutations in the C-terminal region of PAS1 result in severe developmental defects. We show here that the C-terminal domain of PAS1 controls the subcellular distribution of this protein.

Arabidopsis PASTICCINO2 is an antiphosphatase involved in regulation of cyclin-dependent kinase A.

PASTICCINO2 (PAS2), a member of the protein Tyr phosphatase-like family, is conserved among all eukaryotes and is characterized by a mutated catalytic site. The cellular functions of the Tyr phosphatase-like proteins are still unknown, even if they are essential in yeast and mammals. Here, we demonstrate that PAS2 interacts with a cyclin-dependent kinase (CDK) that is phosphorylated on Tyr and not with its unphosphorylated isoform.

gurke and pasticcino3 mutants affected in embryo development are impaired in acetyl-CoA carboxylase.

Normal embryo development is required for correct seedling formation. The Arabidopsis gurke and pasticcino3 mutants were isolated from different developmental screens and the corresponding embryos exhibit severe defects in their apical region, affecting bilateral symmetry. We have recently identified lethal acc1 mutants affected in acetyl-CoA carboxylase 1 (ACCase 1) that display a similar embryo phenotype.

Hormonal control of cell proliferation requires PASTICCINO genes.

PASTICCINO (PAS) genes are required for coordinated cell division and differentiation during plant development. In loss-of-function pas mutants, plant aerial tissues showed ectopic cell division that was specifically enhanced by cytokinins, leading to disorganized tumor-like tissue. To determine the role of the PAS genes in controlling cell proliferation, we first analyzed the expression profiles of several genes involved in cell division and meristem function.

Pasticcino2 is a protein tyrosine phosphatase-like involved in cell proliferation and differentiation in Arabidopsis.

The pasticcino2 (pas2) mutant shows impaired embryo and seedling development associated with cell de-differentiation and proliferation. This process is specifically enhanced in presence of cytokinins leading to callus-like structure of the apical part of the seedling. Cell proliferation concerns localized and stochastic nodules of dividing cells.