Table of Contents

The RXLR effectors of plant pathogenic oomycetes are shown to be under adaptive selection. Positive selection has acted for the most part on the C-terminal region consistent with the view that RXLR effectors are modular proteins, with the C-terminal domain dedicated to modulating host defenses inside plant cells.

Ovule development requires a correct balance of factors determining ovule and carpel identity. It is shown that this balance is obtained by complex formation between BELL1 and AGAMOUS. Furthermore, ovule differentiation requires the regulation of the stem cell maintenance gene WUSCHEL, the repression of which is predominantly maintained by BELL1 during ovule development.

Ovule development requires a correct balance of factors determining ovule and carpel identity. It is shown that this balance is obtained by complex formation between BELL1 and AGAMOUS. Furthermore, ovule differentiation requires the regulation of the stem cell maintenance gene WUSCHEL, the repression of which is predominantly maintained by BELL1 during ovule development.

The transition from growth to dormancy is part of the seasonal growth cycle in perennial plants. In a systems biology approach involving transcriptome, metabolome, and electron microscopy analyses, autumnal bud development is dissected into its molecular programs. A comparative approach identified common genes for growth-to-dormancy transitions across different plant organs.

The transition from growth to dormancy is part of the seasonal growth cycle in perennial plants. In a systems biology approach involving transcriptome, metabolome, and electron microscopy analyses, autumnal bud development is dissected into its molecular programs. A comparative approach identified common genes for growth-to-dormancy transitions across different plant organs.

The RXLR effectors of plant pathogenic oomycetes are shown to be under adaptive selection. Positive selection has acted for the most part on the C-terminal region consistent with the view that RXLR effectors are modular proteins, with the C-terminal domain dedicated to modulating host defenses inside plant cells.

The RXLR effectors of plant pathogenic oomycetes are shown to be under adaptive selection. Positive selection has acted for the most part on the C-terminal region consistent with the view that RXLR effectors are modular proteins, with the C-terminal domain dedicated to modulating host defenses inside plant cells.

N-acylethanolamines (NAEs) are important lipid mediators in the endocannabinoid signaling pathway, which influences a variety of physiological processes in vertebrates. This work indicates that NAEs, which are also endogenous metabolites in plants, act in concert with abscisic acid in the negative regulation of seed germination and early seedling establishment.

Genetic analysis of various combinations of yuc mutants and polar auxin transport mutants pin1 and aux1 establish that auxin synthesized by the YUC flavin monooxygenases is essential for the establishment of the basal body region during embryogenesis and the formation of embryonic and postembryonic organs.

Protein degradation regulates the Arabidopsis circadian clock. It is shown that the F-box protein ZEITLUPE mediates degradation of PRR5, a putative component of the central oscillator.

Ovule development requires a correct balance of factors determining ovule and carpel identity. It is shown that this balance is obtained by complex formation between BELL1 and AGAMOUS. Furthermore, ovule differentiation requires the regulation of the stem cell maintenance gene WUSCHEL, the repression of which is predominantly maintained by BELL1 during ovule development.

Arabidopsis HIGH SUGAR RESPONSE8 (HSR8) is found to be allelic to the MUR4 gene involved in arabinose synthesis. Genetic analyses show that nuclear-localized Pleiotropic Regulatory Locus1 (PRL1) is required for enhanced sugar responses in hsr8 mutant plants and reveal a pathway through PRL1 that signals changes in the cell wall to alter gene expression and sugar-responsive metabolic and developmental changes.

This work reports the cloning of maize Floury1 (Fl1), which encodes a novel zein protein body membrane protein with three predicted transmembrane domains and a C-terminal plant-specific domain of unknown function. It is shown that FL1 likely participates in protein body formation by facilitating the localization of 22-kD α-zein and that this is essential for the formation of vitreous endosperm.

In this study, the WD40-containing cyclophilin CYP71 is identified as an essential factor for normal development in Arabidopsis. CYP71 physically interacts with histone H3 and regulates the level of histone methylation of target loci, thus affecting gene expression. CYP71 is conserved among eukaryotes and may serve as a ubiquitous chromatin remodeling factor involved in epigenetic silencing.

Chloroplasts harbor numerous group II introns, ribozymes whose activity is facilitated by proteins in vivo. This study shows that RNC1, a protein with catalytically inactive RNAse III domains, promotes the splicing of many group II introns in chloroplasts and is bound to those introns in vivo. RNC1 functions both together with and independently of previously described chloroplast splicing factors.

N-acylethanolamines (NAEs) are important lipid mediators in the endocannabinoid signaling pathway, which influences a variety of physiological processes in vertebrates. This work indicates that NAEs, which are also endogenous metabolites in plants, act in concert with abscisic acid in the negative regulation of seed germination and early seedling establishment.

Os BOR1 is a plasma membrane–localized efflux boron transporter from rice that is essential for xyelm loading of boron. This study shows that the cell-type specificity of Os BOR1 expression depends on the boron status, providing an example of a mineral-nutrient transporter whose tissue-specific expression pattern changes depending on nutritional conditions.

This work demonstrates that the WRKY transcription factor TTG2 functions in a regulatory cascade in the formation of trichomes and root hair. Complexes containing R2R3 MYB and bHLH transcription factors regulate the expression of TTG2, and TTG2 acts redundantly with these complexes to regulate GL2, which encodes a homeodomain protein that promotes formation of trichomes and root hairless cells.

In this study, the WD40-containing cyclophilin CYP71 is identified as an essential factor for normal development in Arabidopsis. CYP71 physically interacts with histone H3 and regulates the level of histone methylation of target loci, thus affecting gene expression. CYP71 is conserved among eukaryotes and may serve as a ubiquitous chromatin remodeling factor involved in epigenetic silencing.

This work employs mass spectrometry and site-directed mutagenesis to examine the redox response of Arabidopsis glutamate-cysteine ligase (GCL), which catalyzes the first step in glutathione biosynthesis, and shows that thiol-based regulation of GCL provides a posttranslational mechanism for modulating enzyme activity in response to the in vivo redox environment.

This work demonstrates a functional link between the SnRK1A protein kinase and the MYBS1 transcription factor as essential components in the sugar signaling pathway regulating the α-amylase gene promoter. The results provide new insight into mechanisms of sugar regulation and the physiological relevance of SnRK1A in germination and seedling growth.

This work demonstrates a functional link between the SnRK1A protein kinase and the MYBS1 transcription factor as essential components in the sugar signaling pathway regulating the α-amylase gene promoter. The results provide new insight into mechanisms of sugar regulation and the physiological relevance of SnRK1A in germination and seedling growth.

This work demonstrates that the WRKY transcription factor TTG2 functions in a regulatory cascade in the formation of trichomes and root hair. Complexes containing R2R3 MYB and bHLH transcription factors regulate the expression of TTG2, and TTG2 acts redundantly with these complexes to regulate GL2, which encodes a homeodomain protein that promotes formation of trichomes and root hairless cells.

This work employs mass spectrometry and site-directed mutagenesis to examine the redox response of Arabidopsis glutamate-cysteine ligase (GCL), which catalyzes the first step in glutathione biosynthesis, and shows that thiol-based regulation of GCL provides a posttranslational mechanism for modulating enzyme activity in response to the in vivo redox environment.

The RXLR effectors of plant pathogenic oomycetes are shown to be under adaptive selection. Positive selection has acted for the most part on the C-terminal region consistent with the view that RXLR effectors are modular proteins, with the C-terminal domain dedicated to modulating host defenses inside plant cells.

This work demonstrates that the WRKY transcription factor TTG2 functions in a regulatory cascade in the formation of trichomes and root hair. Complexes containing R2R3 MYB and bHLH transcription factors regulate the expression of TTG2, and TTG2 acts redundantly with these complexes to regulate GL2, which encodes a homeodomain protein that promotes formation of trichomes and root hairless cells.

N-acylethanolamines (NAEs) are important lipid mediators in the endocannabinoid signaling pathway, which influences a variety of physiological processes in vertebrates. This work indicates that NAEs, which are also endogenous metabolites in plants, act in concert with abscisic acid in the negative regulation of seed germination and early seedling establishment.

Ammonium uptake across the plasma membrane of plant roots is mediated by AMT-type transporters. By generating triple and quadruple amt mutants in Arabidopsis, this study shows that four individual AMTs that differ in cell type–specific expression and substrate affinity contribute to high-affinity ammonium influx with different nitrogen-dependent transport capacities.

Chloroplasts harbor numerous group II introns, ribozymes whose activity is facilitated by proteins in vivo. This study shows that RNC1, a protein with catalytically inactive RNAse III domains, promotes the splicing of many group II introns in chloroplasts and is bound to those introns in vivo. RNC1 functions both together with and independently of previously described chloroplast splicing factors.

This work reports the cloning of maize Floury1 (Fl1), which encodes a novel zein protein body membrane protein with three predicted transmembrane domains and a C-terminal plant-specific domain of unknown function. It is shown that FL1 likely participates in protein body formation by facilitating the localization of 22-kD α-zein and that this is essential for the formation of vitreous endosperm.

In this study, the WD40-containing cyclophilin CYP71 is identified as an essential factor for normal development in Arabidopsis. CYP71 physically interacts with histone H3 and regulates the level of histone methylation of target loci, thus affecting gene expression. CYP71 is conserved among eukaryotes and may serve as a ubiquitous chromatin remodeling factor involved in epigenetic silencing.

This work reports the cloning of maize Floury1 (Fl1), which encodes a novel zein protein body membrane protein with three predicted transmembrane domains and a C-terminal plant-specific domain of unknown function. It is shown that FL1 likely participates in protein body formation by facilitating the localization of 22-kD α-zein and that this is essential for the formation of vitreous endosperm.

Two homologous microtubule motor kinesins in Arabidopsis, Kinesin-12A and Kinesin-12B, localize at juxtaposing plus ends of antiparallel microtubules in the middle of the phragmoplast. Postmeiotic development of the male gametophyte is severely inhibited in the absence of both kinesins, indicating that they jointly play a key role in the organization of phragmoplast microtubules during cytokinesis in the microspore.

This work demonstrates a functional link between the SnRK1A protein kinase and the MYBS1 transcription factor as essential components in the sugar signaling pathway regulating the α-amylase gene promoter. The results provide new insight into mechanisms of sugar regulation and the physiological relevance of SnRK1A in germination and seedling growth.

This work demonstrates a functional link between the SnRK1A protein kinase and the MYBS1 transcription factor as essential components in the sugar signaling pathway regulating the α-amylase gene promoter. The results provide new insight into mechanisms of sugar regulation and the physiological relevance of SnRK1A in germination and seedling growth.

This work demonstrates a functional link between the SnRK1A protein kinase and the MYBS1 transcription factor as essential components in the sugar signaling pathway regulating the α-amylase gene promoter. The results provide new insight into mechanisms of sugar regulation and the physiological relevance of SnRK1A in germination and seedling growth.

This work reports the cloning of maize Floury1 (Fl1), which encodes a novel zein protein body membrane protein with three predicted transmembrane domains and a C-terminal plant-specific domain of unknown function. It is shown that FL1 likely participates in protein body formation by facilitating the localization of 22-kD α-zein and that this is essential for the formation of vitreous endosperm.

Arabidopsis HIGH SUGAR RESPONSE8 (HSR8) is found to be allelic to the MUR4 gene involved in arabinose synthesis. Genetic analyses show that nuclear-localized Pleiotropic Regulatory Locus1 (PRL1) is required for enhanced sugar responses in hsr8 mutant plants and reveal a pathway through PRL1 that signals changes in the cell wall to alter gene expression and sugar-responsive metabolic and developmental changes.

Cytological analyses of retrotransposon-tagged lines show that the rice MEL1 gene of the ARGONAUTE family plays important roles in germ cell mitosis, faithful meiosis progression, and maintenance of copy number of rDNA repeats.

The RXLR effectors of plant pathogenic oomycetes are shown to be under adaptive selection. Positive selection has acted for the most part on the C-terminal region consistent with the view that RXLR effectors are modular proteins, with the C-terminal domain dedicated to modulating host defenses inside plant cells.

The transition from growth to dormancy is part of the seasonal growth cycle in perennial plants. In a systems biology approach involving transcriptome, metabolome, and electron microscopy analyses, autumnal bud development is dissected into its molecular programs. A comparative approach identified common genes for growth-to-dormancy transitions across different plant organs.

Cytological analyses of retrotransposon-tagged lines show that the rice MEL1 gene of the ARGONAUTE family plays important roles in germ cell mitosis, faithful meiosis progression, and maintenance of copy number of rDNA repeats.

Ammonium uptake across the plasma membrane of plant roots is mediated by AMT-type transporters. By generating triple and quadruple amt mutants in Arabidopsis, this study shows that four individual AMTs that differ in cell type–specific expression and substrate affinity contribute to high-affinity ammonium influx with different nitrogen-dependent transport capacities.

This work employs mass spectrometry and site-directed mutagenesis to examine the redox response of Arabidopsis glutamate-cysteine ligase (GCL), which catalyzes the first step in glutathione biosynthesis, and shows that thiol-based regulation of GCL provides a posttranslational mechanism for modulating enzyme activity in response to the in vivo redox environment.

The transition from growth to dormancy is part of the seasonal growth cycle in perennial plants. In a systems biology approach involving transcriptome, metabolome, and electron microscopy analyses, autumnal bud development is dissected into its molecular programs. A comparative approach identified common genes for growth-to-dormancy transitions across different plant organs.

This work demonstrates that the WRKY transcription factor TTG2 functions in a regulatory cascade in the formation of trichomes and root hair. Complexes containing R2R3 MYB and bHLH transcription factors regulate the expression of TTG2, and TTG2 acts redundantly with these complexes to regulate GL2, which encodes a homeodomain protein that promotes formation of trichomes and root hairless cells.

This study provides new insight into the regulation of auxin-responsive gene expression in plant cells. Biochemical and genetic analyses show that MYB77 interacts with auxin response factors (ARFs) to modulate auxin-responsive gene expression affecting lateral root growth under low potassium conditions.

This work demonstrates that the WRKY transcription factor TTG2 functions in a regulatory cascade in the formation of trichomes and root hair. Complexes containing R2R3 MYB and bHLH transcription factors regulate the expression of TTG2, and TTG2 acts redundantly with these complexes to regulate GL2, which encodes a homeodomain protein that promotes formation of trichomes and root hairless cells.

This work demonstrates that the WRKY transcription factor TTG2 functions in a regulatory cascade in the formation of trichomes and root hair. Complexes containing R2R3 MYB and bHLH transcription factors regulate the expression of TTG2, and TTG2 acts redundantly with these complexes to regulate GL2, which encodes a homeodomain protein that promotes formation of trichomes and root hairless cells.

Stomatal development in Arabidopsis involves guard cell differentiation, amplification divisions of precursor cells, and placement of stomata. This work shows that formation of higher-order stomatal complexes depends on regulation of the MADS box protein AGL16 by miR824, a recently evolved microRNA conserved in the Brassicaceae. This interaction could account for some Brassica-specific features of stomatal organization.

Arabidopsis HIGH SUGAR RESPONSE8 (HSR8) is found to be allelic to the MUR4 gene involved in arabinose synthesis. Genetic analyses show that nuclear-localized Pleiotropic Regulatory Locus1 (PRL1) is required for enhanced sugar responses in hsr8 mutant plants and reveal a pathway through PRL1 that signals changes in the cell wall to alter gene expression and sugar-responsive metabolic and developmental changes.

Stomatal development in Arabidopsis involves guard cell differentiation, amplification divisions of precursor cells, and placement of stomata. This work shows that formation of higher-order stomatal complexes depends on regulation of the MADS box protein AGL16 by miR824, a recently evolved microRNA conserved in the Brassicaceae. This interaction could account for some Brassica-specific features of stomatal organization.