NADPH oxidase-dependent reactive oxygen species formation required for root hair growth depends on ROP GTPase.

Reactive oxygen species (ROS) production by an NADPH oxidase (NOX) encoded by AtrbohC/RHD2 is required for root hair growth in Arabidopsis thaliana. ROP (RHO of plants) GTPases are also required for normal root hair growth and have been proposed to regulate ROS production in plants. Therefore, the role of ROP GTPase in NOX-dependent ROS formation by root hairs was investigated.

Arabidopsis thaliana VTC4 encodes L-galactose-1-P phosphatase, a plant ascorbic acid biosynthetic enzyme.

In plants, a proposed ascorbate (vitamin C) biosynthesis pathway occurs via GDP-D-mannose (GDP-D-Man), GDP-L-galactose (GDP-L-Gal), and L-galactose. However, the steps involved in the synthesis of L-Gal from GDP-L-Gal in planta are not fully characterized. Here we present evidence for an in vivo role for L-Gal-1-P phosphatase in plant ascorbate biosynthesis.

Analysis of the root-hair morphogenesis transcriptome reveals the molecular identity of six genes with roles in root-hair development in Arabidopsis.

Root-hair morphogenesis is a model for studying the genetic regulation of plant cell development, and double-mutant analyses have revealed a complex genetic network underlying the development of this type of cell. Therefore, to increase knowledge of gene expression in root hairs and to identify new genes involved in root-hair morphogenesis, the transcriptomes of the root-hair differentiation zone of wild-type (WT) plants and a tip-growth defective root-hair mutant, rhd2-1, were compared using Affymetrix ATH1 GeneChips. A set of 606 genes with significantly greater expression in WT plants defines the 'root-hair morphogenesis transcriptome'.

Proline metabolism and transport in maize seedlings at low water potential.

The growing zone of maize seedling primary roots accumulates proline at low water potential. Endosperm removal and excision of root tips rapidly decreased the proline pool and greatly reduced proline accumulation in root tips at low water potential. Proline accumulation was not restored by exogenous amino acids.