PPR protein Early Chloroplast Development 2 is essential for chloroplast development at the early stage of Arabidopsis development

Chloroplasts cannot develop normally without the coordinated action of various proteins and signaling connections between the nucleus and the chloroplast genome. Many questions regarding these processes remain unanswered. Here, we report a novel P-type pentatricopeptide repeat (PPR) factor, named Albino Cotyledon Mutant1 (ACM1), which is encoded by a nuclear gene and involved in chloroplast development. Knock-down of ACM1 transgenic plants displayed albino cotyledons but normal true leaves, while knock-out of the ACM1 gene in seedlings was lethal. Fluorescent protein analysis showed that ACM1 was specifically localized within chloroplasts. PEP-dependent plastid transcript levels and splicing efficiency of several group II introns were seriously affected in cotyledons in the RNAi line. Furthermore, denaturing gel electrophoresis and Western blot experiments showed that the accumulation of chloroplast ribosomes was probably damaged. Collectively, our results indicate ACM1 is indispensable in early chloroplast development in Arabidopsis cotyledons.

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Changes of the Polypeptide Composition in Thylakoid Membranes during Differentiation

Zeitschrift für Naturforschung C ◽

10.1515/znc-1990-3-419 ◽

1990 ◽

Vol 45 (3-4) ◽

pp. 253-257 ◽

Cited By ~ 6

Author(s):

Magdolna Droppa ◽

Jiri Masojidek ◽

Gábor Horváth

Keyword(s):

Molecular Weight ◽

Chloroplast Development ◽

Early Stage ◽

Relative Concentration ◽

Thylakoid Membranes ◽

Low Molecular Weight ◽

Polypeptide Composition ◽

Lhc Ii

Changes in membrane polypeptide composition during greening of etiolated maize were investigated to confirm the existence of the developmental polypeptides of 12 - 15 kDa described recently in virescent soybean mutant [M. Droppa, M. L. Ghirardi, G. Horváth, and A. Melis, Biochim. Biophys. Acta 932, 138 - 145 (1988)]. These low molecular weight polypeptides were the most abundant proteins at the early stage of greening, but were largely absent from fully developed thylakoids. During greening the relative concentration of the 12-15 kDa polypeptides were inversely proportional to that of LHC II, suggesting a role of these polypeptides in the assembly of the LHC II and/or chloroplast development.

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Characterization and Fine Mapping of a Yellow-Virescent Gene Regulating Chlorophyll Biosynthesis and Early Stage Chloroplast Development in Brassica napus

G3 Genes|Genome|Genetics ◽

10.1534/g3.120.401460 ◽

2020 ◽

Vol 10 (9) ◽

pp. 3201-3211 ◽

Cited By ~ 2

Author(s):

Chuanji Zhao ◽

Lijiang Liu ◽

Luqman Bin Safdar ◽

Meili Xie ◽

Xiaohui Cheng ◽

...

Keyword(s):

Brassica Napus ◽

Chloroplast Development ◽

Early Stage ◽

Bulked Segregant Analysis ◽

Chlorophyll Biosynthesis ◽

Protoporphyrin Ix ◽

Chloroplast Ultrastructure ◽

Crop Species ◽

Chlorophyll Accumulation ◽

Nucleotide Mutation

Abstract Chlorophyll biosynthesis and chloroplast development are crucial to photosynthesis and plant growth, but their regulatory mechanism remains elusive in many crop species. We isolated a Brassica napus yellow-virescent leaf (yvl) mutant, which exhibited yellow-younger-leaf and virescent-older-leaf with decreased chlorophyll accumulation and delayed chloroplast development. We mapped yvl locus to a 70-kb interval between molecular markers yvl-O10 and InDel-O6 on chromosome A03 in BC2F2 population using whole genome re-sequencing and bulked segregant analysis. The mutant had a ‘C’ to ‘T’ substitution in the coding sequence of BnaA03.CHLH, which encodes putative H subunit of Mg-protoporphyrin IX chelatase (CHLH). The mutation resulted in an imperfect protein structure and reduced activity of CHLH. It also hampered the plastid encoded RNA polymerase which transcribes regulatory genes of photosystem II and I. Consequently, the chlorophyll a/b and carotenoid contents were reduced and the chloroplast ultrastructure was degraded in yvl mutant. These results explain that a single nucleotide mutation in BnaA03.CHLH impairs PEP activity to disrupt chloroplast development and chlorophyll biosynthesis in B. napus.

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Expression of the rpoB Gene at an Early Stage of Leaf Development is Essential for Chloroplast Development in Rice

Photosynthesis: from Light to Biosphere ◽

10.1007/978-94-009-0173-5_598 ◽

1995 ◽

pp. 2543-2546

Author(s):

Kensuke Kusumi ◽

Akiko Mizutani ◽

Mitsuo Nishimura ◽

Koh Iba

Keyword(s):

Leaf Development ◽

Chloroplast Development ◽

Early Stage ◽

Rpob Gene

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Alterations in the number of motoneurons containing immunoreactive calcitonin gene-related peptide(CGRP)& choline acetyltransferase(ChAT) in the cervical spinal cord of the wobbler mouse during the development of the motoneuron disease

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100141226 ◽

1995 ◽

Vol 53 ◽

pp. 970-971

Author(s):

L. Vacca-Galloway ◽

Y.Q. Zhang ◽

P. Bose ◽

S.H. Zhang

Keyword(s):

Spinal Cord ◽

Early Stage ◽

Cervical Spinal Cord ◽

Wild Type Mouse ◽

Reflex Response ◽

Mouse Strains ◽

Behavioral Tests ◽

Wobbler Mouse ◽

Stage 4 ◽

Stage 1

The Wobbler mouse (wr) has been studied as a model for inherited human motoneuron diseases (MNDs). Using behavioral tests for forelimb power, walking, climbing, and the “clasp-like reflex” response, the progress of the MND can be categorized into early (Stage 1, age 21 days) and late (Stage 4, age 3 months) stages. Age-and sex-matched normal phenotype littermates (NFR/wr) were used as controls (Stage 0), as well as mice from two related wild-type mouse strains: NFR/N and a C57BI/6N. Using behavioral tests, we also detected pre-symptomatic Wobblers at postnatal ages 7 and 14 days. The mice were anesthetized and perfusion-fixed for immunocytochemical (ICC) of CGRP and ChAT in the spinal cord (C3 to C5).Using computerized morphomety (Vidas, Zeiss), the numbers of IR-CGRP labelled motoneurons were significantly lower in 14 day old Wobbler specimens compared with the controls (Fig. 1). The same trend was observed at 21 days (Stage 1) and 3 months (Stage 4). The IR-CGRP-containing motoneurons in the Wobbler specimens declined progressively with age.

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Automated high-resolution microscopy: the approaches so far

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100125312 ◽

1987 ◽

Vol 45 ◽

pp. 58-61

Author(s):

W. O. Saxton

Keyword(s):

High Resolution ◽

Early Stage ◽

Automatic Recording ◽

Microprocessor Control ◽

Alternative Systems ◽

Electron Image ◽

Complete Automation ◽

Analysis System ◽

High Resolution Microscopy

Recent commercial microscopes with internal microprocessor control of all major functions have already demonstrated some of the benefits anticipated from such systems, such as continuous magnification, rotation-free diffraction and magnification, automatic recording of mutually registered focal series, and fewer control knobs. Complete automation of the focusing, stigmating and alignment of a high resolution microscope, allowing focal series to be recorded at preselected focus values as well, is still imminent rather than accomplished, however; some kind of image pick-up and analysis system, fed with the electron image via a TV camera, is clearly essential for this, but several alternative systems and algorithms are still being explored. This paper reviews the options critically in turn, and stresses the need to consider alignment and focusing at an early stage, and not merely as an optional extension to a basic proposal.

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Direct observation of Fe-Al-Zn ternary intermetallic compound and its transformation during the early stage of hot-dip galvanizing

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100151416 ◽

1993 ◽

Vol 51 ◽

pp. 1116-1117

Author(s):

C. S. Lin ◽

W. A. Chiou ◽

M. Meshii

Keyword(s):

Intermetallic Compound ◽

Reaction Rate ◽

Diffusion Rate ◽

Early Stage ◽

Zinc Bath ◽

Steel Sheets ◽

Direct Observations ◽

Solid Iron ◽

Iron And Zinc ◽

Ternary Intermetallic Compound

The galvannealed steel sheets have received ever increased attention because of their excellent post-painting corrosion resistance and good weldability. However, its powdering and flaking tendency during press forming processes strongly impairs its performance. In order to optimize the properties of galvanneal coatings, it is critical to control the reaction rate between solid iron and molten zinc.In commercial galvannealing line, aluminum is added to zinc bath to retard the diffusion rate between iron and zinc by the formation of a thin layer of Al intermetallic compound on the surface of steel at initial hot-dip galvanizing. However, the form of this compound and its transformation are still speculated. In this paper, we report the direct observations of this compound and its transformation.The specimens were prepared in a hot-dip simulator in which the steel was galvanized in the zinc bath containing 0.14 wt% of Al at a temperature of 480 °C for 5 seconds and was quenched by liquid nitrogen.

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Anisotropy of interfacial defects in the initial stage of MOVPE GaAs growth On Si

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100176095 ◽

1990 ◽

Vol 48 (4) ◽

pp. 592-593

Author(s):

C. Vannuffel ◽

C. Schiller ◽

J. P. Chevalier

Keyword(s):

Early Stage ◽

Threading Dislocations ◽

Mbe Growth ◽

Detailed Mechanism ◽

Si Substrates ◽

Initial Stage ◽

Interfacial Defects ◽

Interfacial Dislocations ◽

Step Growth ◽

Essential Problem

Recently, interest has focused on the epitaxy of GaAs on Si as a promising material for electronic applications, potentially for integration of optoelectronic devices on silicon wafers. The essential problem concerns the 4% misfit between the two materials, and this must be accommodated by a network of interfacial dislocations with the lowest number of threading dislocations. It is thus important to understand the detailed mechanism of the formation of this network, in order to eventually reduce the dislocation density at the top of the layers.MOVPE growth is carried out on slightly misoriented, (3.5°) from (001) towards , Si substrates. Here we report on the effect of this misorientation on the interfacial defects, at a very early stage of growth. Only the first stage, of the well-known two step growth process, is thus considered. Previously, we showed that full substrate coverage occured for GaAs thicknesses of 5 nm in contrast to MBE growth, where substantially greater thicknesses are required.

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