Chlorophyll Biosynthesis in Higher Plants

Tripathy, Baishnab C.; Pattanayak, Gopal K.

doi:10.1007/978-94-007-1579-0_3

Cited by 41 publications

(34 citation statements)

References 284 publications

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“…It is essential for light harvesting and energy transduction in photosynthesis. The chlorophyll biosynthesis pathway is complex and mediated by more than 17 enzymes in higher plants (Tripathy and Pattanayak 2012). An ATP-dependent insertion of Mg 2+ into protoporphyrin IX (Proto) is the first step of the chlorophyll synthesis.…”

Section: Introductionmentioning

confidence: 99%

A Point Mutation of Magnesium Chelatase OsCHLI Gene Dampens the Interaction Between CHLI and CHLD Subunits in Rice

et al. 2015

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Proper chloroplast development and chlorophyll biosynthesis are essential for the photoautotrophic plants. The insertion of magnesium (Mg 2+ ) into protoporphyrin IX (Proto), catalyzed by magnesium chelatase (Mgchelatase), is the first committed step of chlorophyll biosynthesis. In dicot plants, a proposed model revealed that Mg-chelatase I subunit (CHLI) and Mg-chelatase D subunit (CHLD) can interact directly; however, their relation remains elusive in rice, a monocot model plant. In this study, we characterized a chlorophyll-deficiency mutant, etiolated leaf and lethal (ell), which displayed a yellow leaf in young seedlings and became lethal after three-leaf stage. Chlorophyll content in homozygous ell mutant was approximately 1 % of that in the wild type. Besides, chloroplast development in the mutant was entirely arrested and no thylakoid structure was observed. By map-based cloning, the ell locus was delimited to a 3.9-Mb interval in chromosome 3. A single-base mutation (G529C) inOsCHLI was identified, leading to an amino acid substitution (G177R) in a highly conserved region. Compared with the wild type, more Proto but less magnesium protoporphyrin IX (Mg-Proto) was measured in the ell mutant. Using protoplast transfection and callus transformation, we found that exogenous OsCHLI could consistently recover the lesion of chloroplast in the ell mutant. By subcellar localization analysis, OsCHLI was detected in the chloroplast. Despite the secondary structure of OsCHLI that was predicted to be altered in the mutant, the point mutation did not affect subcellular localization. Real-time PCR demonstrated that the ell mutation induced significantly transcriptional downregulation of the photosynthesis-associated nuclear and plastid genes. Additionally, yeast-two-hybrid experiments indicated that the single amino acid substitution blocked the intrinsic interaction between OsCHLI and OsCHLD. Moreover, OsCHLI showed physical interactions with some thioredoxins (TRXs), suggesting a similar regulatory mechanism of Mg-chelatase activity in both monocot and dicot plants. Keywords Rice . Map-based cloning . Mg-chelatase . OsCHLI subunit . OsCHLD subunit . Thioredoxin Abbreviations Proto Protoporphyrin IX Mg-chelatase Magnesium chelatase ell Etiolated leaf and lethal Mg-Proto Magnesium protoporphyrin IX TRX Thioredoxin EMS Ethyl methyl sulfonate CHLH Mg-chelatase H subunit Electronic supplementary material The online version of this article (

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Section: Introductionmentioning

confidence: 99%

A Point Mutation of Magnesium Chelatase OsCHLI Gene Dampens the Interaction Between CHLI and CHLD Subunits in Rice

et al. 2015

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“…Chlorophylls are essential molecules for photosynthesis in plants (Tanaka and Tanaka, ). The biosynthesis of chlorophyll is embedded into a pathway network (Figure ; Beale, ), and all the enzymes in the pathway are nuclear‐encoded and have been well reviewed (Tripathy and Pattanayak, ). Some of the synthetic sites are often targets of endogenous and exogenous factors (Eckhardt et al ., ).…”

Section: Introductionmentioning

confidence: 99%

“…Unlike many other species, only a single POR gene has been identified in cucumber (Fusada et al ., ). For a description of the other steps in the chlorophyll biosynthesis pathway, please refer to Beale () and Tripathy and Pattanayak ().…”

Section: Introductionmentioning

confidence: 99%

Allopolyploidization in Cucumis contributes to delayed leaf maturation with repression of redundant homoeologous genes

Wang

Hyldgaard

et al. 2018

The Plant Journal

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The important role of polyploidy in plant evolution is widely recognized. However, many questions remain to be explored to address how polyploidy affects the phenotype of the plant. To shed light on the phenotypic and molecular impacts of allopolyploidy, we investigated the leaf development of a synthesized allotetraploid (Cucumis × hytivus), with an emphasis on chlorophyll development. Delayed leaf maturation was identified in C. × hytivus, based on delayed leaf expansion, initial chlorophyll deficiency in the leaves and disordered sink-source transition. Anatomical observations also revealed disturbed chloroplast development in C. ×hytivus. The determination of chlorophyll biosynthesis intermediates suggested that the chlorophyll biosynthesis pathway of C. × hytivus is blocked at the site at which uroporphyrinogen III is catalysed to coproporphyrinogen III. Three chlorophyll biosynthesis-related genes, HEMA1, HEME2 and POR, were significantly repressed in C. × hytivus. Sequence alignment showed both synonymous and non-synonymous substitutions in the HEMA1, HEME2 and POR genes of the parents. Cloning of the chlorophyll biosynthetic genes suggested the retention of homoeologs. In addition, a chimeric clone of the HEMA1 gene that consisted of homologous genes from the parents was identified in C. × hytivus. Overall, our results showed that allopolyploidization in Cucumis has resulted in disturbed chloroplast development and reduced chlorophyll biosynthesis caused by the repressed expression of duplicated homologous genes, which further led to delayed leaf maturation in the allotetraploid, C. × hytivus. The preferential retention/loss of certain types of genes and non-reciprocal homoeologous recombination were also supported in the present study, which provides new insights into the impact of allopolyploidy.

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“…First, this metal could compete with iron to be taken up in the roots via low-affinity transporters, such as IRT1 (Sinclair and Krämer, 2012). Consequently, Zninduced iron starvation might repress chlorophyll biosynthesis, since heme synthesis requires iron and Zn is likely to replace Mg 2+ in the porphyrin ring (Tripathy and Pattanayak, 2012). Alternatively, stabilized ERF-VII proteins, induced by either Zn excess or waterlogging, could be involved in active repression of chlorophyll biosynthetic genes, as reported by Abbas et al (2015).…”

Section: Discussionmentioning

confidence: 93%

Zinc Excess Induces a Hypoxia-Like Response by Inhibiting Cysteine Oxidases in Poplar Roots

et al. 2019

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Poplar (Populus spp.) is a tree species considered for the remediation of soil contaminated by metals, including zinc (Zn). To improve poplar's capacity for Zn assimilation and compartmentalization, it is necessary to understand the physiological and biochemical mechanisms that enable these features as well as their regulation at the molecular level. We observed that the molecular response of poplar roots to Zn excess overlapped with that activated by hypoxia. Therefore, we tested the effect of Zn excess on hypoxia-sensing components and investigated the consequence of root hypoxia on poplar fitness and Zn accumulation capacity. Our results suggest that high intracellular Zn concentrations mimic iron deficiency and inhibit the activity of the oxygen sensors Plant Cysteine Oxidases, leading to the stabilization and activation of ERF-VII transcription factors, which are key regulators of the molecular response to hypoxia. Remarkably, excess Zn and waterlogging similarly decreased poplar growth and development. Simultaneous excess Zn and waterlogging did not exacerbate these parameters, although Zn uptake was limited. This study unveils the contribution of the oxygen-sensing machinery to the Zn excess response in poplar, which may be exploited to improve Zn tolerance and increase Zn accumulation capacity in plants.

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Chlorophyll Biosynthesis in Higher Plants

Cited by 41 publications

References 284 publications

A Point Mutation of Magnesium Chelatase OsCHLI Gene Dampens the Interaction Between CHLI and CHLD Subunits in Rice

A Point Mutation of Magnesium Chelatase OsCHLI Gene Dampens the Interaction Between CHLI and CHLD Subunits in Rice

Allopolyploidization in Cucumis contributes to delayed leaf maturation with repression of redundant homoeologous genes

Zinc Excess Induces a Hypoxia-Like Response by Inhibiting Cysteine Oxidases in Poplar Roots

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