High nitrogen insensitive 9 (HNI9)-mediated systemic repression of root NO3- uptake is associated with changes in histone methylation.

In plants, root nitrate uptake systems are under systemic feedback repression by the N satiety of the whole organism, thus adjusting the N acquisition capacity to the N demand for growth; however, the underlying molecular mechanisms are largely unknown. We previously isolated the Arabidopsis high nitrogen-insensitive 9-1 (hni9-1) mutant, impaired in the systemic feedback repression of the root nitrate transporter NRT2.1 by high N supply.

Multiple FtsZ2 isoforms involved in chloroplast division and biogenesis are developmentally associated with thylakoid membranes in Arabidopsis.

Seed plants and algae have two distinct FtsZ protein families, FtsZ1 and FtsZ2, involved in plastid division. Distinctively, seed plants and mosses contain two FtsZ2 family members (FtsZ2-1 and FtsZ2-2) thus raising the question of the role of these FtsZ2 paralogs in plants. We show that both FtsZ2 paralogs, in addition to being present in the stroma, are associated with the thylakoid membranes and that association is developmentally regulated.

Identification of Arabidopsis mutants impaired in the systemic regulation of root nitrate uptake by the nitrogen status of the plant.

Nitrate uptake by the roots is under systemic feedback repression by high nitrogen (N) status of the whole plant. The NRT2.1 gene, which encodes a NO(3)(-) transporter involved in high-affinity root uptake, is a major target of this N signaling mechanism.

Developmentally regulated association of plastid division protein FtsZ1 with thylakoid membranes in Arabidopsis thaliana.

FtsZ is a key protein involved in bacterial and organellar division. Bacteria have only one ftsZ gene, while chlorophytes (higher plants and green alga) have two distinct FtsZ gene families, named FtsZ1 and FtsZ2. This raises the question of why chloroplasts in these organisms need distinct FtsZ proteins to divide.

The plastid division proteins, FtsZ1 and FtsZ2, differ in their biochemical properties and sub-plastidial localization.

Plastid division in higher plants is morphologically similar to bacterial cell division, with a process termed binary fission involving constriction of the envelope membranes. FtsZ proteins involved in bacterial division are also present in higher plants, in which the ftsZ genes belong to two distinct families: ftsZ1 and ftsZ2. However, the roles of the corresponding proteins FtsZ1 and FtsZ2 in plastid division have not been determined.