Development of Photochemical Activity in Chloroplast Membranes. II. Studies With a Mutant of Barley Grown Under Different Environments

1977 ◽  
Vol 4 (3) ◽  
pp. 439 ◽  
Author(s):  
RM Smillie ◽  
NC Nielsen ◽  
KW Henningsen ◽  
DV Wettstein
Keyword(s):  
Light Intensity ◽  
Developmental Stages ◽  
Chloroplast Development ◽  
Nuclear Gene ◽  
Photochemical Activity ◽  
Hordeum Vulgare L ◽  
Chloroplast Membranes ◽  
Photochemical Activities ◽  
Gene Mutant ◽  
Isolated Chloroplasts

Chloroplast development in the barley mutant xantha-b12, a nuclear gene mutant derived from Hordeum vulgare L. cv. Sval�fs Bonus, was profoundly influenced by the temperature and light intensity to which the plants were subjected during growth. Low temperatures and high light intensities retarded chloroplast development. By growing this mutant under different combinations of temperature and light intensity, seedlings were produced containing chloroplasts at different developmental stages. Measurements of photochemical activities of the isolated chloroplasts indicated a sequence for development of photochemical competence in chloroplast membranes very similar to that adduced from a study of several different barley mutants grown under a single environment. A photoreductive capacity is initially acquired but energy conservation sites only become fully functional at an advanced stage of membrane development.

Development of Photochemical Activity in Chloroplast Membranes. I. Studies With Mutants of Barley Grown Under a Single Environment

1977 ◽  
Vol 4 (3) ◽  
pp. 415 ◽  
Author(s):  
RM Smillie ◽  
NC Nielsen ◽  
KW Kenningsen ◽  
DV Wettstein
Keyword(s):  
Nuclear Gene ◽  
Protein Composition ◽  
Thylakoid Membranes ◽  
Photochemical Activity ◽  
Wild Type ◽  
Membrane Systems ◽  
Chloroplast Membranes ◽  
Pump Activity ◽  
Low Activity ◽  
Single Set

The development of photochemical competence in chloroplast thylakoid membranes was studied using a series of nuclear gene mutants of barley. The chloroplasts of each mutant reached a different developmental stage when grown under a single set of environmental conditions. Photochemical capacity as well as morphological and compositional features were compared for chloroplasts in the primary leaves of eight mutants and wild-type barley (Hordeum vulgare cv. Sval�fs Bonus) after growth of the plants for 7 days at 21°C and 1700 lux. The results obtained indicated a sequence for the progressive acquisition of photochemical capability by the chloroplast membranes. The least developed of the mutant chloroplasts photoreduced ferricyanide but not 2,6-dichloroindophenol (DCIP). Immature chloroplast membrane systems from other slightly more developed mutants showed a low activity for DCIP photoreduction which was stimulated by diphenylcarbazide. In these mutants, however, the rate of photoreduction of ferricyanide was not stimulated by the uncoupler methylamine, proton pump activity was not detected and photosystem I activity was low. In the more developed of the mutant thylakoid systems, photoreductive activity was stimulated by methylamine and a proton gradient was generated in the light. The more developed the system, the greater was the stimulation obtained with methylamine. Other changes which were correlated with lamellar membrane development included a decrease in the light intensity required to saturate ferricyanide and DCIP photoreductive activities and an increase in the degree of inhibition of the photoreduction of ferricyanide by the photosystem II inhibitor 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU). The activity changes were not correlated with either the amount of grana present or the ratio of chlorophyll a to b. Mutants showing low rates of DCMU-sensitive photoreduction of ferricyanide and DCIP were aberrant in protein composition of the chloroplast membranes.

scholarly journals Exogenous application of growth stimulators improves the condition of maize exposed to soil drought

2021 ◽  
Vol 43 (4) ◽  
Author(s):  
Agnieszka Ostrowska ◽  
Maciej T. Grzesiak ◽  
Tomasz Hura
Keyword(s):  
Plant Growth ◽  
Developmental Stages ◽  
Aminolevulinic Acid ◽  
Stem Elongation ◽  
Development Stage ◽  
Photochemical Activity ◽  
Soil Drought ◽  
Beneficial Effects ◽  
Induced Changes ◽  
The Impact

AbstractSoil drought is a major problem in plant cultivation. This is particularly true for thermophilic plants, such as maize, which grow in areas often affected by precipitation shortage. The problem may be alleviated using plant growth and development stimulators. Therefore, the aim of the study was to analyze the effects of 5-aminolevulinic acid (5-ALA), zearalenone (ZEN), triacontanol (TRIA) and silicon (Si) on water management and photosynthetic activity of maize under soil drought. The experiments covered three developmental stages: three leaves, stem elongation and heading. The impact of these substances applied during drought stress depended on the plant development stage. 5-ALA affected chlorophyll levels, gas exchange and photochemical activity of PSII. Similar effects were observed for ZEN, which additionally induced stem elongation and limited dehydration. Beneficial effects of TRIA were visible at the stage of three leaves and involved leaf hydration and plant growth. A silicon preparation applied at the same developmental stage triggered similar effects and additionally induced changes in chlorophyll levels. All the stimulators significantly affected transpiration intensity at the heading stage.

scholarly journals A PPR Protein ACM1 Is Involved in Chloroplast Gene Expression and Early Plastid Development in Arabidopsis

2021 ◽  
Vol 22 (5) ◽  
pp. 2512
Author(s):  
Xinwei Wang ◽  
Yaqi An ◽  
Ye Li ◽  
Jianwei Xiao
Keyword(s):  
Fluorescent Protein ◽  
Chloroplast Development ◽  
Nuclear Gene ◽  
Pentatricopeptide Repeat ◽  
Plastid Development ◽  
Chloroplast Gene Expression ◽  
Knock Out ◽  
Rnai Line ◽  
Ppr Protein ◽  
P Type

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.

Yeast CBP1 mRNA 3' end formation is regulated during the induction of mitochondrial function

1991 ◽  
Vol 11 (2) ◽  
pp. 813-821
Author(s):  
S A Mayer ◽  
C L Dieckmann
Keyword(s):  
Mitochondrial Function ◽  
Developmental Stages ◽  
Single Gene ◽  
Mitochondrial Protein ◽  
Nuclear Gene ◽  
State Level ◽  
Yeast Cells ◽  
Cdna Clones ◽  
Coding Sequence ◽  
Polyadenylation Sites

Alternative mRNA processing is one mechanism for generating two or more polypeptides from a single gene. While many mammalian genes contain multiple mRNA 3' cleavage and polyadenylation signals that change the coding sequence of the mature mRNA when used at different developmental stages or in different tissues, only one yeast gene has been identified with this capacity. The Saccharomyces cerevisiae nuclear gene CPB1 encodes a mitochondrial protein that is required for cytochrome b mRNA stability. This 66-kDa protein is encoded by a 2.2-kb mRNA transcribed from CPB1. Previously we showed that a second 1.2-kb transcript is initiated at the CBP1 promoter but has a 3' end near the middle of the coding sequence. Furthermore, it was shown that the ratio of the steady-state level of 2.2-kb CBP1 message to 1.2-kb message decreases 10-fold during the induction of mitochondrial function, while the combined levels of both messages remain constant. Having proposed that regulation of 3' end formation dictates the amount of each CBP1 transcript, we now show that a 146-bp fragment from the middle of CBP1 is sufficient to direct carbon source-regulated production of two transcripts when inserted into the yeast URA3 gene. This fragment contains seven polyadenylation sites for the wild-type 1.2-kb mRNA, as mapped by sequence analysis of CBP1 cDNA clones. Deletion mutations upstream of the polyadenylation sites abolished formation of the 1.2-kb transcript, whereas deletion of three of the sites only led to a reduction in abundance of the 1.2-kb mRNA. Our results indicate that regulation of the abundance of both CBP1 transcripts is controlled by elements in a short segment of the gene that directs 3' end formation of the 1.2-kb transcript, a unique case in yeast cells.

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