title: From Arabidopsis to cereal crops: Conservation of chloroplast protein degradation by autophagy indicates its fundamental role in plant productivity.
abstract: Autophagy is an evolutionarily conserved process leading to the degradation of intracellular components in eukaryotes, which is important for nutrient recycling especially in response to starvation conditions. Nutrient recycling is an essential process that underpins productivity in crop plants, such that remobilized nitrogen derived from older organs supports the formation of new organs or grain-filling within a plant. We extended our understanding of autophagy in a model plant, Arabidopsis thaliana, to an important cereal, rice (Oryza sativa). Through analysis of transgenic rice plants stably expressing fluorescent marker proteins for autophagy or chloroplast stroma, we revealed that chloroplast proteins are partially degraded in the vacuole via Rubisco-containing bodies (RCBs), a type of autophagosomes containing stroma. We further reported evidence that the RCB pathway functions during natural leaf senescence to facilitate subsequent nitrogen remobilization into newly expanding leaves. Thus, our recent studies establish the importance of autophagy in biomass production of cereals.
authors.affiliation: a Frontier Research Institute for Interdisciplinary Sciences; Tohoku University ; Sendai , Japan.|b Department of Environmental Life Sciences ; Graduate School of Life Sciences; Tohoku University ; Sendai , Japan.
authors.forename: Masanori
authors.initials: M
authors.lastname: Izumi
authors.affiliation: b Department of Environmental Life Sciences ; Graduate School of Life Sciences; Tohoku University ; Sendai , Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Hidema
authors.affiliation: c Department of Applied Plant Science ; Graduate School of Agricultural Sciences; Tohoku University ; Sendai , Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Ishida
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D001343:Autophagy; D060365:Chloroplast Proteins / Q000378:metabolism*; D018556:Crops, Agricultural; D017343:Genes, Plant; D059748:Proteolysis
chemical_list: D060365:Chloroplast Proteins
keywords: autophagy; chloroplasts; crop plants; nitrogen remobilization; protein degradation; rice