Table of Contents

This work identifies the Arabidopsis basic leucine zipper protein bZIP53 as a regulator of seed maturation genes. The mechanism of transcriptional control is defined by heterodimerization with bZIP10 or bZIP25 and ternary complex formation with ABI3.

Analysis of apm1 loss-of-function mutants and inducible expression/silencing transformants indicate that this M1 metallopeptidase is required for root meristem initiation during embryogenesis and meristem maintenance during seedling establishment. Meristem identity and maintenance also require auxin, and APM1 is a low-affinity target of the auxin transport inhibitor NPA.

A mutation in the lycopene β-cyclase gene of Arabidopsis increases the accumulation of lutein, which can partially substitute for the role of zeaxanthin in regulation of photosynthetic light harvesting via thermal dissipation of excess absorbed light energy.

Analysis of apm1 loss-of-function mutants and inducible expression/silencing transformants indicate that this M1 metallopeptidase is required for root meristem initiation during embryogenesis and meristem maintenance during seedling establishment. Meristem identity and maintenance also require auxin, and APM1 is a low-affinity target of the auxin transport inhibitor NPA.

In a comprehensive metabolomics and precursor feeding approach, a network of indole-3-acetonitrile (IAN)–derived metabolites was identified in mutants of camalexin biosynthesis. A Cys conjugate of IAN was shown to be turned over directly to camalexin and cyanide by PHYTOALEXIN DEFICIENT3, a multifunctional cytochrome P450 enzyme.

The structural study of a rice cell wall–degrading esterase LipA from Xanthomonas oryzae pv oryzae, the causal agent of bacterial leaf blight disease, reveals a unique domain that is essential for LipA function in planta and is conserved across the phytopathogenic genus Xanthomonas.

This work provides biochemical evidence of the association of miRNAs with translating polysomes in Arabidopsis. These data support the idea that RNA silencing mechanisms in animal and plant kingdoms are more similar than previously thought.

This work identifies the Arabidopsis basic leucine zipper protein bZIP53 as a regulator of seed maturation genes. The mechanism of transcriptional control is defined by heterodimerization with bZIP10 or bZIP25 and ternary complex formation with ABI3.

Resistance to bacterial speck disease in tomato is activated upon interaction of the host Pto kinase with either of two pathogen proteins. This work provides structural insight into how a single host resistance protein can recognize two divergent bacterial effector proteins and supports a proposed mechanism in which each of these effector proteins relieves negative regulation by Pto.

This work provides biochemical evidence of the association of miRNAs with translating polysomes in Arabidopsis. These data support the idea that RNA silencing mechanisms in animal and plant kingdoms are more similar than previously thought.

This work demonstrates that the chloroplastidic BAT5 transporter is required for side chain elongation of Met-derived glucosinolates in Arabidopsis. Comparative feeding experiments of bat5 and wild-type plants using 2-keto acids and amino acids of different chain length suggested that BAT5 functions as a plastidic transporter for 2-keto acids.

This study describes a novel method for cell-specific analysis of the important plant hormone auxin. Cell sorting on cell type–specific tagged lines followed by precise mass spectrometry measurements were used to produce a high-resolution auxin distribution map of the Arabidopsis root, demonstrating the existence of an auxin gradient and maximum and sites of high auxin biosynthesis rates.

After-ripening is a little-known process occurring in dry seeds that results in loss of dormancy upon imbibition. This work shows that after-ripening affects the expression of genes comprising the circadian oscillator and that well-known circadian clock genes have roles in the control of Arabidopsis seed germination.

This work describes the identification of a 1-MD translocation complex as a novel intermediate during general protein translocation across the inner membrane of chloroplasts. Tic20 and Tic21 are involved in the 1-MD complex, whereas Tic110, the most characterized component of the protein translocon at the inner membrane, exists as a distinct entity from the 1-MD complex.

Analysis of apm1 loss-of-function mutants and inducible expression/silencing transformants indicate that this M1 metallopeptidase is required for root meristem initiation during embryogenesis and meristem maintenance during seedling establishment. Meristem identity and maintenance also require auxin, and APM1 is a low-affinity target of the auxin transport inhibitor NPA.

A mutation in the lycopene β-cyclase gene of Arabidopsis increases the accumulation of lutein, which can partially substitute for the role of zeaxanthin in regulation of photosynthetic light harvesting via thermal dissipation of excess absorbed light energy.

Mutant, microscopy, and large-scale comparative proteome analyses of Arabidopsis demonstrate a central role of the Clp protease complex in chloroplast biogenesis and protein homeostasis, with different contributions of the ClpP and ClpR subunits. Lack of transcriptional and translational regulation suggests that regulation of Clp activity occurs through Clp complex assembly and substrate delivery.

This study describes a novel method for cell-specific analysis of the important plant hormone auxin. Cell sorting on cell type–specific tagged lines followed by precise mass spectrometry measurements were used to produce a high-resolution auxin distribution map of the Arabidopsis root, demonstrating the existence of an auxin gradient and maximum and sites of high auxin biosynthesis rates.

This work describes the identification of a 1-MD translocation complex as a novel intermediate during general protein translocation across the inner membrane of chloroplasts. Tic20 and Tic21 are involved in the 1-MD complex, whereas Tic110, the most characterized component of the protein translocon at the inner membrane, exists as a distinct entity from the 1-MD complex.

A mutation in the lycopene β-cyclase gene of Arabidopsis increases the accumulation of lutein, which can partially substitute for the role of zeaxanthin in regulation of photosynthetic light harvesting via thermal dissipation of excess absorbed light energy.

This study describes a novel method for cell-specific analysis of the important plant hormone auxin. Cell sorting on cell type–specific tagged lines followed by precise mass spectrometry measurements were used to produce a high-resolution auxin distribution map of the Arabidopsis root, demonstrating the existence of an auxin gradient and maximum and sites of high auxin biosynthesis rates.

In contrast with most algae, in which chloroplast division keeps pace with cell division, land plant cells change the chloroplast division rate (i.e., size and number of chloroplasts) in accord with cell differentiation. This study suggests that acquisition of PLASTID DIVISION proteins by land plants enabled cells to change the chloroplast division rate based on cell differentiation.

In contrast with most algae, in which chloroplast division keeps pace with cell division, land plant cells change the chloroplast division rate (i.e., size and number of chloroplasts) in accord with cell differentiation. This study suggests that acquisition of PLASTID DIVISION proteins by land plants enabled cells to change the chloroplast division rate based on cell differentiation.

In contrast with most algae, in which chloroplast division keeps pace with cell division, land plant cells change the chloroplast division rate (i.e., size and number of chloroplasts) in accord with cell differentiation. This study suggests that acquisition of PLASTID DIVISION proteins by land plants enabled cells to change the chloroplast division rate based on cell differentiation.

In contrast with most algae, in which chloroplast division keeps pace with cell division, land plant cells change the chloroplast division rate (i.e., size and number of chloroplasts) in accord with cell differentiation. This study suggests that acquisition of PLASTID DIVISION proteins by land plants enabled cells to change the chloroplast division rate based on cell differentiation.

In contrast with most algae, in which chloroplast division keeps pace with cell division, land plant cells change the chloroplast division rate (i.e., size and number of chloroplasts) in accord with cell differentiation. This study suggests that acquisition of PLASTID DIVISION proteins by land plants enabled cells to change the chloroplast division rate based on cell differentiation.

This work identifies the Arabidopsis basic leucine zipper protein bZIP53 as a regulator of seed maturation genes. The mechanism of transcriptional control is defined by heterodimerization with bZIP10 or bZIP25 and ternary complex formation with ABI3.

After-ripening is a little-known process occurring in dry seeds that results in loss of dormancy upon imbibition. This work shows that after-ripening affects the expression of genes comprising the circadian oscillator and that well-known circadian clock genes have roles in the control of Arabidopsis seed germination.

This work provides biochemical evidence of the association of miRNAs with translating polysomes in Arabidopsis. These data support the idea that RNA silencing mechanisms in animal and plant kingdoms are more similar than previously thought.

The structural study of a rice cell wall–degrading esterase LipA from Xanthomonas oryzae pv oryzae, the causal agent of bacterial leaf blight disease, reveals a unique domain that is essential for LipA function in planta and is conserved across the phytopathogenic genus Xanthomonas.

In a comprehensive metabolomics and precursor feeding approach, a network of indole-3-acetonitrile (IAN)–derived metabolites was identified in mutants of camalexin biosynthesis. A Cys conjugate of IAN was shown to be turned over directly to camalexin and cyanide by PHYTOALEXIN DEFICIENT3, a multifunctional cytochrome P450 enzyme.

This work provides biochemical evidence of the association of miRNAs with translating polysomes in Arabidopsis. These data support the idea that RNA silencing mechanisms in animal and plant kingdoms are more similar than previously thought.

This work identifies the Arabidopsis basic leucine zipper protein bZIP53 as a regulator of seed maturation genes. The mechanism of transcriptional control is defined by heterodimerization with bZIP10 or bZIP25 and ternary complex formation with ABI3.

This work identifies the Arabidopsis basic leucine zipper protein bZIP53 as a regulator of seed maturation genes. The mechanism of transcriptional control is defined by heterodimerization with bZIP10 or bZIP25 and ternary complex formation with ABI3.