Table of Contents

DNA damage signaling of chromosomal DNA breaks is of primary importance for initiation of repair and, thus, for global genomic stability. This work confirms that the signaling of double-strand damage is conserved in plants and provides evidence for key roles of the MRN complex and ATR in assuring proper DNA replication in the absence of exogenously induced DNA damage.

The structure of maize VP14, a key oxidative enzyme in abscisic acid biosynthesis, provides a framework for understanding the mechanism of this important enzyme. Furthermore, the structure provides a template for the regio- and stereospecificity of VP14 as well as of other plant carotenoid cleavage dioxygenases.

Structural sterols are required for membrane integrity, cell growth, and plant development. This work shows that structural sterols are one of the early polarity markers during root hair formation and development in Arabidopsis. Local accumulation of structural sterols may regulate plasma membrane properties at the tip, vesicular trafficking, and progression of polarized tip growth of root hairs.

This report describes the genome sequence of Chlorella variabilis NC64A. Surprisingly, given that NC64A has been thought to be asexual and nonmotile, this work identifies homologs of genes involved in meiosis, gamete fusion, and flagella.

DNA damage signaling of chromosomal DNA breaks is of primary importance for initiation of repair and, thus, for global genomic stability. This work confirms that the signaling of double-strand damage is conserved in plants and provides evidence for key roles of the MRN complex and ATR in assuring proper DNA replication in the absence of exogenously induced DNA damage.

Replication of positive-strand RNA viruses, the largest group of plant viruses, is initiated by viral RNA-dependent RNA polymerase (RdRp). This work shows that Turnip yellow mosaic virus RdRp is a target of the ubiquitin-proteasome system in plant cells during viral infection and supports the idea that proteasomal degradation may constitute another level of regulation of viral replication.

This report describes the genome sequence of Chlorella variabilis NC64A. Surprisingly, given that NC64A has been thought to be asexual and nonmotile, this work identifies homologs of genes involved in meiosis, gamete fusion, and flagella.

Structural sterols are required for membrane integrity, cell growth, and plant development. This work shows that structural sterols are one of the early polarity markers during root hair formation and development in Arabidopsis. Local accumulation of structural sterols may regulate plasma membrane properties at the tip, vesicular trafficking, and progression of polarized tip growth of root hairs.

This work identifies a semidominant allele of an Arabidopsis conserved receptor-like protein that activates plant immunity and whose signal is transduced through the transcription factor WRKY70.

This study demonstrates that auxin and cytokinin regulate each other's biosynthesis, providing an intrinsic mechanism for optimizing the relative intracellular concentrations of both hormones.

This work examines the effects of RNA interference constructs expressed in host cells on target RNAs in Blumeria graminis, an obligate biotrophic fungal pathogen of barley, and finds that RNAs in the host can affect pathogen transcript levels and pathogen development, thereby providing both a useful research tool and a potentially important means for engineering plant disease resistance.

Replication of positive-strand RNA viruses, the largest group of plant viruses, is initiated by viral RNA-dependent RNA polymerase (RdRp). This work shows that Turnip yellow mosaic virus RdRp is a target of the ubiquitin-proteasome system in plant cells during viral infection and supports the idea that proteasomal degradation may constitute another level of regulation of viral replication.

This report describes the genome sequence of Chlorella variabilis NC64A. Surprisingly, given that NC64A has been thought to be asexual and nonmotile, this work identifies homologs of genes involved in meiosis, gamete fusion, and flagella.

The plant cell cytokinesis is driven from the onset by highly organized vesicle fusion resulting in cell plate and new cell wall formation separating daughter cells. The evolutionarily conserved exocyst complex regulating exocytic vesicle binding to the plasma membrane is involved in both the final separation of cells as in animals and also in the initiation of cell plate in plant cells.

The crystal structure of Chinese white poplar 4-coumaric acid:coenzyme A ligase, the enzyme that catalyzes the synthesis of an important precursor of lignin, was determined in the apo, adenosine monophosphate-, and adenosine 5′-(3-(4-hydroxyphenyl)propyl)phosphate-complexed forms. Enzymatic mechanisms were proposed for the protein. Residues responsible for substrate specificity were identified.

The crystal structure of Chinese white poplar 4-coumaric acid:coenzyme A ligase, the enzyme that catalyzes the synthesis of an important precursor of lignin, was determined in the apo, adenosine monophosphate-, and adenosine 5′-(3-(4-hydroxyphenyl)propyl)phosphate-complexed forms. Enzymatic mechanisms were proposed for the protein. Residues responsible for substrate specificity were identified.

This work identifies a semidominant allele of an Arabidopsis conserved receptor-like protein that activates plant immunity and whose signal is transduced through the transcription factor WRKY70.

This study demonstrates that auxin and cytokinin regulate each other's biosynthesis, providing an intrinsic mechanism for optimizing the relative intracellular concentrations of both hormones.

This report describes the genome sequence of Chlorella variabilis NC64A. Surprisingly, given that NC64A has been thought to be asexual and nonmotile, this work identifies homologs of genes involved in meiosis, gamete fusion, and flagella.

This study demonstrates that auxin and cytokinin regulate each other's biosynthesis, providing an intrinsic mechanism for optimizing the relative intracellular concentrations of both hormones.

This work examines the effects of RNA interference constructs expressed in host cells on target RNAs in Blumeria graminis, an obligate biotrophic fungal pathogen of barley, and finds that RNAs in the host can affect pathogen transcript levels and pathogen development, thereby providing both a useful research tool and a potentially important means for engineering plant disease resistance.

This work systematically examines the expression as well as the actin binding and actin regulatory activities of the Arabidopsis LIM proteins, finding differences in expression and changes in activity, which, for a subset of the LIM proteins, depends on pH and calcium.

The crystal structure of Chinese white poplar 4-coumaric acid:coenzyme A ligase, the enzyme that catalyzes the synthesis of an important precursor of lignin, was determined in the apo, adenosine monophosphate-, and adenosine 5′-(3-(4-hydroxyphenyl)propyl)phosphate-complexed forms. Enzymatic mechanisms were proposed for the protein. Residues responsible for substrate specificity were identified.

The structure of maize VP14, a key oxidative enzyme in abscisic acid biosynthesis, provides a framework for understanding the mechanism of this important enzyme. Furthermore, the structure provides a template for the regio- and stereospecificity of VP14 as well as of other plant carotenoid cleavage dioxygenases.

This work examines the effects of RNA interference constructs expressed in host cells on target RNAs in Blumeria graminis, an obligate biotrophic fungal pathogen of barley, and finds that RNAs in the host can affect pathogen transcript levels and pathogen development, thereby providing both a useful research tool and a potentially important means for engineering plant disease resistance.

The crystal structure of Chinese white poplar 4-coumaric acid:coenzyme A ligase, the enzyme that catalyzes the synthesis of an important precursor of lignin, was determined in the apo, adenosine monophosphate-, and adenosine 5′-(3-(4-hydroxyphenyl)propyl)phosphate-complexed forms. Enzymatic mechanisms were proposed for the protein. Residues responsible for substrate specificity were identified.

This work identifies a semidominant allele of an Arabidopsis conserved receptor-like protein that activates plant immunity and whose signal is transduced through the transcription factor WRKY70.

Structural sterols are required for membrane integrity, cell growth, and plant development. This work shows that structural sterols are one of the early polarity markers during root hair formation and development in Arabidopsis. Local accumulation of structural sterols may regulate plasma membrane properties at the tip, vesicular trafficking, and progression of polarized tip growth of root hairs.

This work characterizes infection of rice roots by Magnaporthe oryzae, a fungus that adopts a hemibiotrophic lifestyle during rice shoot infection. Unexpectedly, the cytological and molecular results reveal a largely biotrophic fungal lifestyle in roots, thus indicating that M. oryzae adopts tissue-specific invasion strategies that are accompanied by discrete host responses.

The structure of maize VP14, a key oxidative enzyme in abscisic acid biosynthesis, provides a framework for understanding the mechanism of this important enzyme. Furthermore, the structure provides a template for the regio- and stereospecificity of VP14 as well as of other plant carotenoid cleavage dioxygenases.

The structure of maize VP14, a key oxidative enzyme in abscisic acid biosynthesis, provides a framework for understanding the mechanism of this important enzyme. Furthermore, the structure provides a template for the regio- and stereospecificity of VP14 as well as of other plant carotenoid cleavage dioxygenases.

This work systematically examines the expression as well as the actin binding and actin regulatory activities of the Arabidopsis LIM proteins, finding differences in expression and changes in activity, which, for a subset of the LIM proteins, depends on pH and calcium.

The plant cell cytokinesis is driven from the onset by highly organized vesicle fusion resulting in cell plate and new cell wall formation separating daughter cells. The evolutionarily conserved exocyst complex regulating exocytic vesicle binding to the plasma membrane is involved in both the final separation of cells as in animals and also in the initiation of cell plate in plant cells.

Microalgae induce a carbon-concentrating mechanism to acclimate to CO₂-limiting stress. This work provides evidence that a low CO₂–inducible plasma membrane protein, LCI1, contributes to the carbon-concentrating mechanism as a component of the inorganic carbon transport machinery.

This work systematically examines the expression as well as the actin binding and actin regulatory activities of the Arabidopsis LIM proteins, finding differences in expression and changes in activity, which, for a subset of the LIM proteins, depends on pH and calcium.

The plant cell cytokinesis is driven from the onset by highly organized vesicle fusion resulting in cell plate and new cell wall formation separating daughter cells. The evolutionarily conserved exocyst complex regulating exocytic vesicle binding to the plasma membrane is involved in both the final separation of cells as in animals and also in the initiation of cell plate in plant cells.

This study demonstrates that auxin and cytokinin regulate each other's biosynthesis, providing an intrinsic mechanism for optimizing the relative intracellular concentrations of both hormones.

Replication of positive-strand RNA viruses, the largest group of plant viruses, is initiated by viral RNA-dependent RNA polymerase (RdRp). This work shows that Turnip yellow mosaic virus RdRp is a target of the ubiquitin-proteasome system in plant cells during viral infection and supports the idea that proteasomal degradation may constitute another level of regulation of viral replication.

Nitric oxide has been proposed to act as a signal for numerous physiological and developmental processes in plants. This work describes the involvement of the mitogen-activated protein kinase (MPK) cascade in nitric oxide synthesis via nitrate reductase. It demonstrates H₂O₂-mediated MPK6 activation of nitric oxide production and signal transduction during root development in Arabidopsis.

Structural sterols are required for membrane integrity, cell growth, and plant development. This work shows that structural sterols are one of the early polarity markers during root hair formation and development in Arabidopsis. Local accumulation of structural sterols may regulate plasma membrane properties at the tip, vesicular trafficking, and progression of polarized tip growth of root hairs.

This study demonstrates that auxin and cytokinin regulate each other's biosynthesis, providing an intrinsic mechanism for optimizing the relative intracellular concentrations of both hormones.

This work shows that prolonged heat stress leads to activation of specific endogenous repeats. Unexpectedly, this heat-induced transcriptional activation does not require DNA demethylation or change of histone modification, but rather involves a dramatic reduction of nucleosome association with the DNA.

The plant cell cytokinesis is driven from the onset by highly organized vesicle fusion resulting in cell plate and new cell wall formation separating daughter cells. The evolutionarily conserved exocyst complex regulating exocytic vesicle binding to the plasma membrane is involved in both the final separation of cells as in animals and also in the initiation of cell plate in plant cells.

Arabidopsis ATP binding cassette (ABC) transporters, ABCG11 and ACBG12, are required for export of different lipids from the epidermis to the cuticle. This study shows that ABCG11 and ABCG12 can form an obligate heterodimer and that ABCG11 can homodimerize. Live-cell imaging in epidermal cells demonstrates that localization of these ABCGs to the plasma membrane is dependent upon dimerization.

This work systematically examines the expression as well as the actin binding and actin regulatory activities of the Arabidopsis LIM proteins, finding differences in expression and changes in activity, which, for a subset of the LIM proteins, depends on pH and calcium.

This study demonstrates that auxin and cytokinin regulate each other's biosynthesis, providing an intrinsic mechanism for optimizing the relative intracellular concentrations of both hormones.

This work systematically examines the expression as well as the actin binding and actin regulatory activities of the Arabidopsis LIM proteins, finding differences in expression and changes in activity, which, for a subset of the LIM proteins, depends on pH and calcium.

The plant cell cytokinesis is driven from the onset by highly organized vesicle fusion resulting in cell plate and new cell wall formation separating daughter cells. The evolutionarily conserved exocyst complex regulating exocytic vesicle binding to the plasma membrane is involved in both the final separation of cells as in animals and also in the initiation of cell plate in plant cells.