Expression of a rice glutaredoxin in aleurone layers of developing and mature seeds: subcellular localization and possible functions in antioxidant defense.

A rice glutaredoxin isoform (OsGrxC2;2) with antioxidant capacity is expressed abundantly in seed tissues and is localized to storage vacuoles in aleurone layers in developing and mature seeds. Seed tissues undergo drastic water loss at the late stage of seed development, and thus need to tolerate oxidative injuries associated with desiccation. We previously found a rice glutaredoxin isoform, OsGrxC2;2, as a gene expressed abundantly in developing seeds.

Evidence for lateral gene transfer (LGT) in the evolution of eubacteria-derived small GTPases in plant organelles.

The genomes of free-living bacteria frequently exchange genes via lateral gene transfer (LGT), which has played a major role in bacterial evolution. LGT also played a significant role in the acquisition of genes from non-cyanobacterial bacteria to the lineage of "primary" algae and land plants. Small GTPases are widely distributed among prokaryotes and eukaryotes.

Light-dependent expression of flg22-induced defense genes in Arabidopsis.

Chloroplasts have been reported to generate retrograde immune signals that activate defense gene expression in the nucleus. However, the roles of light and photosynthesis in plant immunity remain largely elusive. In this study, we evaluated the effects of light on the expression of defense genes induced by flg22, a peptide derived from bacterial flagellins which acts as a potent elicitor in plants.

Chloroplast-mediated activation of plant immune signalling in Arabidopsis.

Chloroplasts have a critical role in plant immunity as a site for the production for salicylic acid and jasmonic acid, important mediators of plant immunity. However, the molecular link between chloroplasts and the cytoplasmic-nuclear immune system remains largely unknown. Here we show that pathogen-associated molecular pattern (PAMP) signals are quickly relayed to chloroplasts and evoke specific Ca(2+) signatures in the stroma.

Nuclear/nucleolar GTPase 2 proteins as a subfamily of YlqF/YawG GTPases function in pre-60S ribosomal subunit maturation of mono- and dicotyledonous plants.

The YlqF/YawG families are important GTPases involved in ribosome biogenesis, cell proliferation, or cell growth, however, no plant homologs have yet to be characterized. Here we isolated rice (Oryza sativa) and Arabidopsis nuclear/nucleolar GTPase 2 (OsNug2 and AtNug2, respectively) that belong to the YawG subfamily and characterized them for pre-60S ribosomal subunit maturation. They showed typical intrinsic YlqF/YawG family GTPase activities in bacteria and yeasts with k(cat) values 0.

AtObgC, a plant ortholog of bacterial Obg, is a chloroplast-targeting GTPase essential for early embryogenesis.

Obg is a ribosome-associated GTPase essential for bacterial viability and is conserved in most organisms, from bacteria to eukaryotes. Obg is also expressed in plants, which predicts an important role for this molecule in plant viability; however, the functions of the plant Obg homologs have not been reported. Here, we first identified Arabidopsis AtObgC as a plant chloroplast-targeting Obg and elucidated its molecular biological and physiological properties.

SYP71, a plant-specific Qc-SNARE protein, reveals dual localization to the plasma membrane and the endoplasmic reticulum in Arabidopsis.

SNAREs ('Soluble N-ethyl-maleimide sensitive factor attachment protein receptors') play a critical role in the membrane fusion step of the vesicular transport system in eukaryotes. The number of the genes encoding SNARE proteins is estimated to be 64 in Arabidopsis thaliana. This number is much larger than those in other eukaryotes, suggesting a complex membrane trafficking in plants.