Beck, C. F. Signaling pathways from the chloroplast to the nucleus. Planta 222, 743-756
ABSTRACT Genetic and physiological studies have to-date revealed evidence for five signaling pathways by which the chloroplast exerts retrograde control over nuclear genes. One of these pathways is dependent on product(s) of plastid protein synthesis, for another the signal is singlet oxygen, a third employs chloroplast-generated hydrogen peroxide, a fourth is controlled by the redox state of the photosynthetic electron transport chain, and a fifth involves intermediates and possibly proteins of tetrapyrrole biosynthesis. These five pathways may be part of a complex signaling network that links the functional and physiological state of the chloroplast to the nucleus. Mutants defective in various steps of photosynthesis reveal a surprising diversity in nuclear responses suggesting the existence of a complex signaling network.
- SourceAvailable from: Georges Ngando
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- "Genetic activity in the nucleus and the plastids is expected to simultaneously increase because many plastid-generated signals control the expression of nuclear genes responsible for encoding plastid chloroplast and mitochondrial genes (Emanuel et al. 2004; Yurina et al. 2006). There is evidence for chloroplast-tonuclear and mitochondria-to-nuclear retrograde regulation signalling pathways responding to abiotic stress (Beck 2005). "
ABSTRACT: Breeding and seed production activities in oil palm have been hampered because of the inability of the male parent Pisifera to produce male inflorescence as source of pollen under normal conditions. Researchers are using complete defoliation to induce male inflorescences, but the biological and molecular processes responsible for this morphological change are yet to be revealed. To understand the underlying network of genes that initiate and control this phenotypically documented activity, we initiated a study aimed at identifying differentially expressed genes (DEGs) in three stages of an oil palm inflorescence under complete defoliation stress using RNA-seq. Sequencing on an Illumina platform produced 82 631 476 reads consisting of 8 345 779 076 bases. A total of 60 700 genes were obtained after transcript filtering and normalisation and 54% of them were downregulated. Differences in gene expression levels were significant between tissues under stress. The farther the distance between tissues, the more DEGs recorded. Comparison between stage 2 and stage 1 induced 3893 DEGs whereas 10 136 DEGs were induced between stage 3 and stage 1. Stress response genes and flower development genes were among the highly expressed genes. This study suggests a link between complete defoliation and meristem differentiation from vegetative to reproductive phase in oil palm.Functional Plant Biology 01/2015; 42(6). DOI:10.1071/FP14343 · 3.15 Impact Factor
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- "Some protein complexes, such as Rubisco, are encoded in separate genomes, nucleus and plastid. The control of gene expression in the separate genomes needs to be coordinated for plant cells to function correctly (Beck 2005). Prior study has revealed that RBCL is a ''control by epistasy of synthesis'' (CES) protein in Chlamydomonas (Wollman et al. 1999). "
ABSTRACT: Key message: Cosuppression of an Arabidopsis Rubisco small subunit gene RBCS3B at Arabidopsis resulted in albino or pale green phenotypes which were caused by ROS accumulation As the most abundant protein on Earth, Rubisco has received much attention in the past decades. Even so, its function is still not understood thoroughly. In this paper, four Arabidopsis transgenic lines (RBCS3B-7, 18, 33, and 35) with albino or pale green phenotypes were obtained by transformation with a construct driving expression of sense RBCS3B, a Rubisco small subunit gene. The phenotypes produced in these transgenic lines were found to be caused by cosuppression. Among these lines, RBCS3B-7 displayed the most severe phenotypes including reduced height, developmental arrest and plant mortality before flowering when grown under normal light on soil. Chloroplast numbers in mesophyll cells were decreased compared to WT, and stacked thylakoids of chloroplasts were broken down gradually in RBCS3B-7 throughout development. In addition, the RBCS3B-7 line was light sensitive, and PSII activity measurement revealed that RBCS3B-7 suffered severe photoinhibition, even under normal light. We found that photoinhibition was due to accumulation of ROS, which accelerated photodamage of PSII and inhibited the repair of PSII in RBCS3B-7.Plant Cell Reports 03/2014; 33(7). DOI:10.1007/s00299-014-1597-4 · 3.07 Impact Factor
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- "Signaling pathways of these ROS seem to be distinctive, yet the cell is similarly damaged , . Porphyrin may also be viewed as an attractive candidate for chloroplast molecules in the organelle-to-nucleus signaling pathways . In a previous report, tetrapyrroles were found to be involved in the complex network controlling the stress-responsive genes and were greatly reduced in plants following drought treatment . "
ABSTRACT: The perturbation of the steady state of reactive oxygen species (ROS) due to biotic and abiotic stresses in a plant could lead to protein denaturation through the modification of amino acid residues, including the oxidation of methionine residues. Methionine sulfoxide reductases (MSRs) catalyze the reduction of methionine sulfoxide back to the methionine residue. To assess the role of this enzyme, we generated transgenic rice using a pepper CaMSRB2 gene under the control of the rice Rab21 (responsive to ABA protein 21) promoter with/without a selection marker, the bar gene. A drought resistance test on transgenic plants showed that CaMSRB2 confers drought tolerance to rice, as evidenced by less oxidative stress symptoms and a strengthened PSII quantum yield under stress conditions, and increased survival rate and chlorophyll index after the re-watering. The results from immunoblotting using a methionine sulfoxide antibody and nano-LC-MS/MS spectrometry suggest that porphobilinogen deaminase (PBGD), which is involved in chlorophyll synthesis, is a putative target of CaMSRB2. The oxidized methionine content of PBGD expressed in E. coli increased in the presence of H2O2, and the Met-95 and Met-227 residues of PBGD were reduced by CaMSRB2 in the presence of dithiothreitol (DTT). An expression profiling analysis of the overexpression lines also suggested that photosystems are less severely affected by drought stress. Our results indicate that CaMSRB2 might play an important functional role in chloroplasts for conferring drought stress tolerance in rice.PLoS ONE 03/2014; 9(3):e90588. DOI:10.1371/journal.pone.0090588 · 3.23 Impact Factor