Proton exchange by the vacuolar nitrate transporter CLCa is required for plant growth and nitrogen use efficiency.

Nitrate is a major nutrient and osmoticum for plants. To deal with fluctuating nitrate availability in soils, plants store this nutrient in their vacuoles. Chloride channel a (CLCa), a 2NO3-/1H+ exchanger localized to the vacuole in Arabidopsis (Arabidopsis thaliana), ensures this storage process.

Root Hair Sizer: an algorithm for high throughput recovery of different root hair and root developmental parameters.

Background: The root is an important organ for water and nutrient uptake, and soil anchorage. It is equipped with root hairs (RHs) which are elongated structures increasing the exchange surface with the soil. RHs are also studied as a model for plant cellular development, as they represent a single cell with specific and highly regulated polarized elongation.

DNA Remodeling by Strict Partial Endoreplication in Orchids, an Original Process in the Plant Kingdom.

DNA remodeling during endoreplication appears to be a strong developmental characteristic in orchids. In this study, we analyzed DNA content and nuclei in 41 species of orchids to further map the genome evolution in this plant family. We demonstrate that the DNA remodeling observed in 36 out of 41 orchids studied corresponds to strict partial endoreplication.

Folding into an autophagosome: ATG5 sheds light on how plants do it.

Autophagosomes arise in yeast and animals from the sealing of a cup-shaped double-membrane precursor, the phagophore. The concerted action of about 30 evolutionarily conserved autophagy related (ATG) proteins lies at the core of this process. However, the mechanisms allowing phagophore generation and its differentiation into a sealed autophagosome are still not clear in detail, and very little is known in plants.

ATG5 defines a phagophore domain connected to the endoplasmic reticulum during autophagosome formation in plants.

Autophagosomes are the organelles responsible for macroautophagy and arise, in yeast and animals, from the sealing of a cup-shaped double-membrane precursor, the phagophore. How the phagophore is generated and grows into a sealed autophagosome is still not clear in detail, and unknown in plants. This is due, in part, to the scarcity of structurally informative, real-time imaging data of the required protein machinery at the phagophore formation site.

The RNA binding protein Tudor-SN is essential for stress tolerance and stabilizes levels of stress-responsive mRNAs encoding secreted proteins in Arabidopsis.

Tudor-SN (TSN) copurifies with the RNA-induced silencing complex in animal cells where, among other functions, it is thought to act on mRNA stability via the degradation of specific dsRNA templates. In plants, TSN has been identified biochemically as a cytoskeleton-associated RNA binding activity. In eukaryotes, it has recently been identified as a conserved primary target of programmed cell death-associated proteolysis.

Functional studies of shaggy/glycogen synthase kinase 3 phosphorylation sites in Drosophila melanogaster.

Early studies of glycogen synthase kinase 3 (GSK-3) in mammalian systems focused on its pivotal role in glycogen metabolism and insulin-mediated signaling. It is now recognized that GSK-3 is central to a number of diverse signaling systems. Here, we show that the major form of the kinase Shaggy (Sgg), the GSK-3 fly ortholog, is negatively regulated during insulin-like/phosphatidylinositol 3-kinase (PI3K) signaling in vivo.

Identification of proteins regulated by cross-talk between drought and hormone pathways in Arabidopsis wild-type and auxin-insensitive mutants, axr1 and axr2.

Ten proteins differentially regulated by progressive drought stress in Arabidopsis Columbia wild-type, axr1-3 and axr2-1auxin-insensitive mutants, were identified from internal amino acid microsequencing. These proteins fell into two categories: (i) stress-related proteins, known to be induced by rapid water stress via abscisic acid (ABA)-dependent or -independent pathways [late embryogenesis abundant (LEA)-like and heat shock cognate (HS) 70, respectively], or in response to pathogens or oxidative stress [β-1,3 glucanase (BG), annexin] and (ii) metabolic enzymes [glutamine synthetase (GS), fructokinase (Frk), caffeoyl-CoA-3-O-methyltransferase (CCoAOMT)]. The differential behaviour of these proteins highlighted a role for AXR2 and/or AXR1 in the regulation of their abundance during drought adaptation.