The MON1-CCZ1 complex plays dual roles in autophagic degradation and vacuolar protein transport in rice.

Autophagy is a highly conserved cellular program in eukaryotic cells which mediates the degradation of cytoplasmic components through the lysosome, also named the vacuole in plants. However, the molecular mechanisms underlying the fusion of autophagosomes with the vacuole remain unclear. Here, we report the functional characterization of a rice (Oryza sativa) mutant with defects in storage protein transport in endosperm cells and accumulation of numerous autophagosomes in root cells.

Young Leaf White Stripe encodes a P-type PPR protein required for chloroplast development.

Pentatricopeptide repeat (PPR) proteins function in post-transcriptional regulation of organellar gene expression. Although several PPR proteins are known to function in chloroplast development in rice (Oryza sativa), the detailed molecular functions of many PPR proteins remain unclear. Here, we characterized a rice young leaf white stripe (ylws) mutant, which has defective chloroplast development during early seedling growth.

A deleterious Sar1c variant in rice inhibits export of seed storage proteins from the endoplasmic reticulum.

We identified a dosage-dependent dominant negative form of Sar1c, which confirms the essential role of COPII system in mediating ER export of storage proteins in rice endosperm. Higher plants accumlate large amounts of seed storage proteins (SSPs). However, mechanisms underlying SSP trafficking are largely unknown, especially the ER-Golgi anterograde process.

Post-Golgi trafficking of rice storage proteins requires the small GTPase Rab7 activation complex MON1-CCZ1.

Protein storage vacuoles (PSVs) are unique organelles that accumulate storage proteins in plant seeds. Although morphological evidence points to the existence of multiple PSV-trafficking pathways for storage protein targeting, the molecular mechanisms that regulate these processes remain mostly unknown. Here, we report the functional characterization of the rice (Oryza sativa) glutelin precursor accumulation7 (gpa7) mutant, which over-accumulates 57-kDa glutelin precursors in dry seeds.

Subunit E isoform 1 of vacuolar H+-ATPase OsVHA enables post-Golgi trafficking of rice seed storage proteins.

Dense vesicles (DVs) are Golgi-derived plant-specific carriers that mediate post-Golgi transport of seed storage proteins in angiosperms. How this process is regulated remains elusive. Here, we report a rice (Oryza sativa) mutant, named glutelin precursor accumulation8 (gpa8) that abnormally accumulates 57-kDa proglutelins in the mature endosperm.

Rice FLOURY ENDOSPERM 18 encodes a pentatricopeptide repeat protein required for 5' processing of mitochondrial nad5 messenger RNA and endosperm development.

Pentatricopeptide repeat (PPR) proteins, composing one of the largest protein families in plants, are involved in RNA binding and regulation of organelle RNA metabolism at the post-transcriptional level. Although several PPR proteins have been implicated in endosperm development in rice (Oryza sativa), the molecular functions of many PPRs remain obscure. Here, we identified a rice endosperm mutant named floury endosperm 18 (flo18) with pleiotropic defects in both reproductive and vegetative development.

Transcriptional activation and phosphorylation of OsCNGC9 confer enhanced chilling tolerance in rice.

Low temperature is a major environmental factor that limits plant growth and productivity. Although transient elevation of cytoplasmic calcium has long been recognized as a critical signal for plant cold tolerance, the calcium channels responsible for this process have remained largely elusive. Here we report that OsCNGC9, a cyclic nucleotide-gated channel, positively regulates chilling tolerance by mediating cytoplasmic calcium elevation in rice (Oryza sativa).

Small grain and semi-dwarf 3, a WRKY transcription factor, negatively regulates plant height and grain size by stabilizing SLR1 expression in rice.

OsWRKY36 represses plant height and grain size by inhibiting gibberellin signaling. Plant height and grain size are important agronomic traits affecting yield in cereals, including rice. Gibberellins (GAs) are plant hormones that promote plant growth and developmental processions such as stem elongation and grain size.

Encodes a Rab5a Effector Required for Post-Golgi Trafficking of Rice Storage Proteins.

Dense vesicles (DVs) are vesicular carriers, unique to plants, that mediate post-Golgi trafficking of storage proteins to protein storage vacuoles (PSVs) in seeds. However, the molecular mechanisms regulating the directional targeting of DVs to PSVs remain elusive. Here, we show that the rice () () mutant is defective in directional targeting of DVs to PSVs, resulting in discharge of its cargo proteins into the extracellular space.

OsPEX5 regulates rice spikelet development through modulating jasmonic acid biosynthesis.

Spikelet is the primary reproductive structure and a critical determinant of grain yield in rice. The molecular mechanisms regulating rice spikelet development still remain largely unclear. Here, we report that mutations in OsPEX5, which encodes a peroxisomal targeting sequence 1 (PTS1) receptor protein, cause abnormal spikelet morphology.

The nuclear-localized PPR protein OsNPPR1 is important for mitochondrial function and endosperm development in rice.

Pentatricopeptide repeat (PPR) proteins constitute one of the largest protein families in land plants. Recent studies revealed the functions of PPR proteins in organellar RNA metabolism and plant development, but the functions of most PPR proteins, especially PPRs localized in the nucleus, remain largely unknown. Here, we report the isolation and characterization of a rice mutant named floury and growth retardation1 (fgr1).

Rice FLOURY ENDOSPERM10 encodes a pentatricopeptide repeat protein that is essential for the trans-splicing of mitochondrial nad1 intron 1 and endosperm development.

Endosperm, the major storage organ in cereal grains, determines grain yield and quality. Despite the fact that a role for P-type pentatricopeptide repeat (PPR) proteins in the regulation of endosperm development has emerged, molecular functions of many P-type PPR proteins remain obscure. Here, we report a rice endosperm defective mutant, floury endosperm10 (flo10), which developed smaller starch grains in starchy endosperm and abnormal cells in the aleurone layer.

Ubiquitin Specific Protease 15 Has an Important Role in Regulating Grain Width and Size in Rice.

Ubiquitination and deubiquitination are reversible processes that play crucial roles in regulating organ size in plants. However, information linking deubiquitination and seed size in rice () is limited. Here, we characterized a dominant large-grain mutant, (), with a 30.

Disruption of gene SPL35, encoding a novel CUE domain-containing protein, leads to cell death and enhanced disease response in rice.

Lesion mimic mutants that exhibit spontaneous hypersensitive response (HR)-like necrotic lesions are ideal experimental systems for elucidating molecular mechanisms involved in plant cell death and defence responses. Here we report identification of a rice lesion mimic mutant, spotted leaf 35 (spl35), and cloning of the causal gene by TAIL-PCR strategy. spl35 exhibited decreased chlorophyll content, higher accumulation of H O , up-regulated expression of defence-related marker genes, and enhanced resistance to both fungal and bacterial pathogens of rice.

FLOURY ENDOSPERM15 encodes a glyoxalase I involved in compound granule formation and starch synthesis in rice endosperm.

FLO15encodes a plastidic glyoxalase I protein, OsGLYI7, which affects compound starch granule formation and starch synthesis in rice endosperm. Starch synthesis in rice (Oryza sativa) endosperm is a sophisticated process, and its underlying molecular machinery still remains to be elucidated. Here, we identified and characterized two allelic rice floury endosperm 15 (flo15) mutants, both with a white-core endosperm.

FLOURY ENDOSPERM11 encoding a plastid heat shock protein 70 is essential for amyloplast development in rice.

Mutations of stromal Hsp70 cause chloroplast developmental abnormalities and knockout mutants of stromal Hsp70 usually exhibit protein import deficiencies. However, their effects have not been studied in amyloplast development. Here, we identified an amyloplast abnormal development mutant, floury endosperm11 (flo11) that exhibited an opaque phenotype in the inner core and the periphery of grains.

OsNDUFA9 encoding a mitochondrial complex I subunit is essential for embryo development and starch synthesis in rice.

Loss of function of a mitochondrial complex I subunit (OsNDUFA9) causes abnormal embryo development and affects starch synthesis by altering the expression of starch synthesis-related genes and proteins. Proton-pumping NADH: ubiquinone oxidoreductase (also called complex I) is thought to be the largest and most complicated enzyme of the mitochondrial respiratory chain. Mutations of complex I subunits have been revealed to link with a number of growth inhibitions in plants.

Overexpression of OsbHLH107, a member of the basic helix-loop-helix transcription factor family, enhances grain size in rice (Oryza sativa L.).

Background: Grain size, which is determined by grain length, grain width, and grain thickness, is an important determinant for grain yield in rice. Identification and characterization of new genes that are associated with grain size will be helpful for the improvement of grain yield in rice.

Results: We characterized the grain size mutant, larger grain size 1 (lgs1), derived from rice activation-tagged T-DNA insertion lines.

GOLGI TRANSPORT 1B Regulates Protein Export from the Endoplasmic Reticulum in Rice Endosperm Cells.

Coat protein complex II (COPII) mediates the first step of anterograde transport of newly synthesized proteins from the endoplasmic reticulum (ER) to other endomembrane compartments in eukaryotes. A group of evolutionarily conserved proteins (Sar1, Sec23, Sec24, Sec13, and Sec31) constitutes the basic COPII coat machinery; however, the details of how the COPII coat assembly is regulated remain unclear. Here, we report a protein transport mutant of rice (Oryza sativa), named glutelin precursor accumulation4 (gpa4), which accumulates 57-kD glutelin precursors and forms two types of ER-derived abnormal structures.