Table of Contents

Group II introns are protein-dependent ribozymes prevalent in plant organelles. It is shown that the CRM RNA binding domain protein CFM2 acts with other CRM proteins to promote splicing of plastid group II introns and also aids group I intron splicing. This work expands the repertoire of RNA ligands known for CRM proteins and suggests an unanticipated complexity of chloroplast splicing mechanisms.

This study shows that rice gibberellin (GA)–deficient mutations are transmitted in a non-Mendelian manner, whereas GA-insensitive mutations are transmitted normally. Analysis of pollen phenotypes and expression patterns of GA-related genes revealed that the transmission of GA-signaling genes occurs in a sporophytic manner and that of GA synthesis genes occurs in a gametophytic manner.

Whilst a great deal is known about how auxin promotes lateral root development, the mechanism of cytokinin repression is still unclear. This study shows that cytokinin inhibits lateral root initiation by downregulating the expression of auxin efflux carrier-encoding PIN genes in lateral root founder cells.

Whilst a great deal is known about how auxin promotes lateral root development, the mechanism of cytokinin repression is still unclear. This study shows that cytokinin inhibits lateral root initiation by downregulating the expression of auxin efflux carrier-encoding PIN genes in lateral root founder cells.

The authors show that association in vivo between the plant cochaperone SGT1 and cytosolic/nuclear HSC70 chaperones is necessary for several biotic and abiotic stress responses. The SGT1-HSC70 interaction is mediated by the evolutionarily conserved SGT1 C-terminal SGS domain.

Whilst a great deal is known about how auxin promotes lateral root development, the mechanism of cytokinin repression is still unclear. This study shows that cytokinin inhibits lateral root initiation by downregulating the expression of auxin efflux carrier-encoding PIN genes in lateral root founder cells.

Whilst a great deal is known about how auxin promotes lateral root development, the mechanism of cytokinin repression is still unclear. This study shows that cytokinin inhibits lateral root initiation by downregulating the expression of auxin efflux carrier-encoding PIN genes in lateral root founder cells.

Whilst a great deal is known about how auxin promotes lateral root development, the mechanism of cytokinin repression is still unclear. This study shows that cytokinin inhibits lateral root initiation by downregulating the expression of auxin efflux carrier-encoding PIN genes in lateral root founder cells.

Rac/Rop GTPase plays an important role in innate immune responses in rice, but its molecular mechanism is not well understood. This study shows that it can form a complex with RAR1 and HSP90, which are conserved components of innate immunity responses in plants.

The Arabidopsis ABC membrane transporter P-glycoprotein4 (PGP4) exhibits auxin influx transporter activity in vitro in yeast and animal cells. Taking advantage of the auxin-sensitive Arabidopsis root hair and tobacco cell suspension systems, this study indicates that PGP4 functions as an auxin efflux transporter in plant cells and that its membrane trafficking can be modulated by auxin.

This work demonstrates that the Arabidopsis seed coat can be used as a model system to identify enzymes that impact the properties of pectins in seed mucilage. The MUM2 gene encodes a β-galactosidase that is secreted to the apoplast and is required for the modification of pectin side chains, thus allowing mucilage expansion when mature seeds are hydrated.

This work shows that phosphorylation of the receiver domain is required for type-A ARR function, and negative regulation of cytokinin signaling by type-A ARRs most likely involves phosphorylation-dependent interactions. The results shed light on the mechanism by which type-A ARRs negatively regulate cytokinin signaling and reveal a novel mechanism by which cytokinin controls type-A ARR function.

The nodule-specific receptor-like kinase NORK is part of the Nod factor signaling pathway mediating root nodule development. This study shows that HMGR1, a key enzyme in the mevalonate biosynthetic pathway, interacts specifically with NORK and is crucial for nodulation. Recruitment of HMGR1 by NORK couples the isoprenoid pathway to symbiotic signaling and nodule development.

S-nitrosylation is emerging as an important mechanism for the transduction of nitric oxide bioactivity. This study characterizes the molecular mechanism and functional significance for S-nitrosylation of peroxiredoxin II E, a protein that appears to play a crucial role in scavenging peroxynitrite, the product of the reaction of nitric oxide with superoxide, whose function in plants is still obscure

As the sun tracks daily through the sky from east to west, different parts of the canopy are exposed to excess light. This study demonstrates that a novel, systemic signal is rapidly transmitted within 15 min from exposed to shaded leaves, resulting in similar global transcriptional and acclimatory responses in exposed and shaded leaves of wild-type and stress signaling mutants of Arabidopsis.

Rac/Rop GTPase plays an important role in innate immune responses in rice, but its molecular mechanism is not well understood. This study shows that it can form a complex with RAR1 and HSP90, which are conserved components of innate immunity responses in plants.

This work demonstrates that the Arabidopsis seed coat can be used as a model system to identify enzymes that impact the properties of pectins in seed mucilage. The MUM2 gene encodes a β-galactosidase that is secreted to the apoplast and is required for the modification of pectin side chains, thus allowing mucilage expansion when mature seeds are hydrated.

Whilst a great deal is known about how auxin promotes lateral root development, the mechanism of cytokinin repression is still unclear. This study shows that cytokinin inhibits lateral root initiation by downregulating the expression of auxin efflux carrier-encoding PIN genes in lateral root founder cells.

As the sun tracks daily through the sky from east to west, different parts of the canopy are exposed to excess light. This study demonstrates that a novel, systemic signal is rapidly transmitted within 15 min from exposed to shaded leaves, resulting in similar global transcriptional and acclimatory responses in exposed and shaded leaves of wild-type and stress signaling mutants of Arabidopsis.

This work demonstrates that the Arabidopsis seed coat can be used as a model system to identify enzymes that impact the properties of pectins in seed mucilage. The MUM2 gene encodes a β-galactosidase that is secreted to the apoplast and is required for the modification of pectin side chains, thus allowing mucilage expansion when mature seeds are hydrated.

This work shows that phosphorylation of the receiver domain is required for type-A ARR function, and negative regulation of cytokinin signaling by type-A ARRs most likely involves phosphorylation-dependent interactions. The results shed light on the mechanism by which type-A ARRs negatively regulate cytokinin signaling and reveal a novel mechanism by which cytokinin controls type-A ARR function.

The M-locus protein kinase (MLPK) is a cytoplasmic protein kinase essential for self-incompatibility (SI) signaling in Brassica. This work shows that MLPK has two isoforms that localize to the plasma membrane by different molecular mechanisms. Further analyses suggest that these MLPK isoforms interact directly with the S-locus receptor kinase on the plasma membrane to transduce SI signaling.

S-nitrosylation is emerging as an important mechanism for the transduction of nitric oxide bioactivity. This study characterizes the molecular mechanism and functional significance for S-nitrosylation of peroxiredoxin II E, a protein that appears to play a crucial role in scavenging peroxynitrite, the product of the reaction of nitric oxide with superoxide, whose function in plants is still obscure

An analysis of Arabidopsis accessions differing in resistance to Pseudomonas syringae pv tomato containing the avrRpt2 effector gene shows that natural variation in induced gene expression profiles is correlated with natural variation in phenotypic responses, such as the hypersensitive response and resistance.

As the sun tracks daily through the sky from east to west, different parts of the canopy are exposed to excess light. This study demonstrates that a novel, systemic signal is rapidly transmitted within 15 min from exposed to shaded leaves, resulting in similar global transcriptional and acclimatory responses in exposed and shaded leaves of wild-type and stress signaling mutants of Arabidopsis.

The nodule-specific receptor-like kinase NORK is part of the Nod factor signaling pathway mediating root nodule development. This study shows that HMGR1, a key enzyme in the mevalonate biosynthetic pathway, interacts specifically with NORK and is crucial for nodulation. Recruitment of HMGR1 by NORK couples the isoprenoid pathway to symbiotic signaling and nodule development.

This work shows that phosphorylation of the receiver domain is required for type-A ARR function, and negative regulation of cytokinin signaling by type-A ARRs most likely involves phosphorylation-dependent interactions. The results shed light on the mechanism by which type-A ARRs negatively regulate cytokinin signaling and reveal a novel mechanism by which cytokinin controls type-A ARR function.

This study shows that rice gibberellin (GA)–deficient mutations are transmitted in a non-Mendelian manner, whereas GA-insensitive mutations are transmitted normally. Analysis of pollen phenotypes and expression patterns of GA-related genes revealed that the transmission of GA-signaling genes occurs in a sporophytic manner and that of GA synthesis genes occurs in a gametophytic manner.

The nodule-specific receptor-like kinase NORK is part of the Nod factor signaling pathway mediating root nodule development. This study shows that HMGR1, a key enzyme in the mevalonate biosynthetic pathway, interacts specifically with NORK and is crucial for nodulation. Recruitment of HMGR1 by NORK couples the isoprenoid pathway to symbiotic signaling and nodule development.

This report provides evidence for a plastid signal that allows plants to integrate signals describing the functional and developmental state of plastids with signals describing particular light environments to regulate the expression of nuclear genes encoding proteins active in photosynthesis and chloroplast biogenesis.

The Arabidopsis ABC membrane transporter P-glycoprotein4 (PGP4) exhibits auxin influx transporter activity in vitro in yeast and animal cells. Taking advantage of the auxin-sensitive Arabidopsis root hair and tobacco cell suspension systems, this study indicates that PGP4 functions as an auxin efflux transporter in plant cells and that its membrane trafficking can be modulated by auxin.

An analysis of Arabidopsis accessions differing in resistance to Pseudomonas syringae pv tomato containing the avrRpt2 effector gene shows that natural variation in induced gene expression profiles is correlated with natural variation in phenotypic responses, such as the hypersensitive response and resistance.

This work demonstrates that the Shahdara accession is a naturally occurring mutant affected in the MUM2 gene. The β-d-galactosidase enzyme it encodes was shown to be required for the removal of galactose/galactan branches from the major polysaccharide constituting Arabidopsis mucilage, rhamnogalacturonan I, thus altering its physicochemical properties and increasing hydrated mucilage swelling.

Whilst a great deal is known about how auxin promotes lateral root development, the mechanism of cytokinin repression is still unclear. This study shows that cytokinin inhibits lateral root initiation by downregulating the expression of auxin efflux carrier-encoding PIN genes in lateral root founder cells.

The nodule-specific receptor-like kinase NORK is part of the Nod factor signaling pathway mediating root nodule development. This study shows that HMGR1, a key enzyme in the mevalonate biosynthetic pathway, interacts specifically with NORK and is crucial for nodulation. Recruitment of HMGR1 by NORK couples the isoprenoid pathway to symbiotic signaling and nodule development.

This work demonstrates that the Shahdara accession is a naturally occurring mutant affected in the MUM2 gene. The β-d-galactosidase enzyme it encodes was shown to be required for the removal of galactose/galactan branches from the major polysaccharide constituting Arabidopsis mucilage, rhamnogalacturonan I, thus altering its physicochemical properties and increasing hydrated mucilage swelling.

This study shows that rice gibberellin (GA)–deficient mutations are transmitted in a non-Mendelian manner, whereas GA-insensitive mutations are transmitted normally. Analysis of pollen phenotypes and expression patterns of GA-related genes revealed that the transmission of GA-signaling genes occurs in a sporophytic manner and that of GA synthesis genes occurs in a gametophytic manner.

This work shows that phosphorylation of the receiver domain is required for type-A ARR function, and negative regulation of cytokinin signaling by type-A ARRs most likely involves phosphorylation-dependent interactions. The results shed light on the mechanism by which type-A ARRs negatively regulate cytokinin signaling and reveal a novel mechanism by which cytokinin controls type-A ARR function.

The nodule-specific receptor-like kinase NORK is part of the Nod factor signaling pathway mediating root nodule development. This study shows that HMGR1, a key enzyme in the mevalonate biosynthetic pathway, interacts specifically with NORK and is crucial for nodulation. Recruitment of HMGR1 by NORK couples the isoprenoid pathway to symbiotic signaling and nodule development.

This study shows that rice gibberellin (GA)–deficient mutations are transmitted in a non-Mendelian manner, whereas GA-insensitive mutations are transmitted normally. Analysis of pollen phenotypes and expression patterns of GA-related genes revealed that the transmission of GA-signaling genes occurs in a sporophytic manner and that of GA synthesis genes occurs in a gametophytic manner.

This work demonstrates that the Shahdara accession is a naturally occurring mutant affected in the MUM2 gene. The β-d-galactosidase enzyme it encodes was shown to be required for the removal of galactose/galactan branches from the major polysaccharide constituting Arabidopsis mucilage, rhamnogalacturonan I, thus altering its physicochemical properties and increasing hydrated mucilage swelling.

Plant pathogens secrete into host cell effector proteins that suppress plant immunity. This work reports the development of a system to engineer and deliver Hyaloperonospora parasitica effectors to plant cells via a bacterial secretion system. Using this system, multiple alleles of two H. parasitica effectors are found to confer resistance or enhance susceptibility of Arabidopsis accessions to this pathogen.

The authors show that association in vivo between the plant cochaperone SGT1 and cytosolic/nuclear HSC70 chaperones is necessary for several biotic and abiotic stress responses. The SGT1-HSC70 interaction is mediated by the evolutionarily conserved SGT1 C-terminal SGS domain.

S-nitrosylation is emerging as an important mechanism for the transduction of nitric oxide bioactivity. This study characterizes the molecular mechanism and functional significance for S-nitrosylation of peroxiredoxin II E, a protein that appears to play a crucial role in scavenging peroxynitrite, the product of the reaction of nitric oxide with superoxide, whose function in plants is still obscure

The authors show that association in vivo between the plant cochaperone SGT1 and cytosolic/nuclear HSC70 chaperones is necessary for several biotic and abiotic stress responses. The SGT1-HSC70 interaction is mediated by the evolutionarily conserved SGT1 C-terminal SGS domain.

The nodule-specific receptor-like kinase NORK is part of the Nod factor signaling pathway mediating root nodule development. This study shows that HMGR1, a key enzyme in the mevalonate biosynthetic pathway, interacts specifically with NORK and is crucial for nodulation. Recruitment of HMGR1 by NORK couples the isoprenoid pathway to symbiotic signaling and nodule development.

An analysis of Arabidopsis accessions differing in resistance to Pseudomonas syringae pv tomato containing the avrRpt2 effector gene shows that natural variation in induced gene expression profiles is correlated with natural variation in phenotypic responses, such as the hypersensitive response and resistance.

PIF5 is a phyB-interacting factor that inhibits growth in the dark, when expressed at abnormally high levels, by increasing ethylene production, and regulates growth in the light by modulating phyB levels via a negative feedback loop that induces phyB degradation.

The M-locus protein kinase (MLPK) is a cytoplasmic protein kinase essential for self-incompatibility (SI) signaling in Brassica. This work shows that MLPK has two isoforms that localize to the plasma membrane by different molecular mechanisms. Further analyses suggest that these MLPK isoforms interact directly with the S-locus receptor kinase on the plasma membrane to transduce SI signaling.

Rac/Rop GTPase plays an important role in innate immune responses in rice, but its molecular mechanism is not well understood. This study shows that it can form a complex with RAR1 and HSP90, which are conserved components of innate immunity responses in plants.