scholarly journals Identification of Small RNAs During High Light Acclimation in Arabidopsis thaliana

2021 ◽  
Vol 12 ◽  
Author(s):  
Bhavika Tiwari ◽  
Kristin Habermann ◽  
M. Asif Arif ◽  
Oguz Top ◽  
Wolfgang Frank
Keyword(s):  
Small Rnas ◽  
Regulation Of Gene Expression ◽  
Biological Significance ◽  
Light Treatment ◽  
High Light ◽  
Light Acclimation ◽  
Light Conditions ◽  
Gene Pairs ◽  
High Light Treatment ◽  
Non Coding Rnas

The biological significance of non-coding RNAs (ncRNAs) has been firmly established to be important for the regulation of genes involved in stress acclimation. Light plays an important role for the growth of plants providing the energy for photosynthesis; however, excessive light conditions can also cause substantial defects. Small RNAs (sRNAs) are a class of non-coding RNAs that regulate transcript levels of protein-coding genes and mediate epigenetic silencing. Next generation sequencing facilitates the identification of small non-coding RNA classes such as miRNAs (microRNAs) and small-interfering RNAs (siRNAs), and long non-coding RNAs (lncRNAs), but changes in the ncRNA transcriptome in response to high light are poorly understood. We subjected Arabidopsis plants to high light conditions and performed a temporal in-depth study of the transcriptome data after 3 h, 6 h, and 2 days of high light treatment. We identified a large number of high light responsive miRNAs and sRNAs derived from NAT gene pairs, lncRNAs and TAS transcripts. We performed target predictions for differentially expressed miRNAs and correlated their expression levels through mRNA sequencing data. GO analysis of the targets revealed an overrepresentation of genes involved in transcriptional regulation. In A. thaliana, sRNA-mediated regulation of gene expression in response to high light treatment is mainly carried out by miRNAs and sRNAs derived from NAT gene pairs, and from lncRNAs. This study provides a deeper understanding of sRNA-dependent regulatory networks in high light acclimation.

Wood Density and Above-Ground Growth in High and Low Wood Density Clones of Pinus radiata D. Don

1990 ◽  
Vol 17 (6) ◽  
pp. 615 ◽  
Author(s):  
DW Sheriff ◽  
DA Rook
Keyword(s):  
Wood Density ◽  
Pinus Radiata ◽  
Light Treatment ◽  
High Light ◽  
The Other ◽  
Stem Volume ◽  
Carbon Gain ◽  
Simple Relationship ◽  
Ground Biomass ◽  
High Light Treatment

In Pinus radiata a negative relationship has usually been found between stem volume and wood density. Clones previously found to produce wood of high or low density were used to investigate interrelationships between above-ground partitioning coefficients, carbon gain, and wood density. Cuttings had been propagated c. 5 years earlier, and were 5 m high when the experiment started. Potential carbon gain of the tree was manipulated by using two light environments; one with a light level c. 1.5 times the other. Measurements were of changes in stem, branch, and needle biomass during the 305-day experiment, of rates of photosynthesis, and of wood density by β-ray densitometry and microscopy; densities determined by the two techniques were the same. For all but two trees, wood densities of a stem and its branches were the same; for the other two, stem density was 13% less than that of their branches. Trees in the high light treatment accumulated more above-ground biomass, but there was no simple relationship between wood density and either above-ground growth or photosynthesis. With one exception, partitioning of photosynthate to stem was constant. In most cases, proportionately less photosynthate (30-80%) was allocated to below-ground biomass in the low light treatment than in the high light treatment (60-80%).

scholarly journals miR-155 Inhibits Expression of the MEF2A Protein to Repress Skeletal Muscle Differentiation

2011 ◽  
Vol 286 (41) ◽  
pp. 35339-35346 ◽  
Author(s):  
Hee Young Seok ◽  
Mariko Tatsuguchi ◽  
Thomas E. Callis ◽  
Aibin He ◽  
William T. Pu ◽  
...  
Keyword(s):  
Gene Expression ◽  
Small Rnas ◽  
Myogenic Differentiation ◽  
Regulation Of Gene Expression ◽  
Myoblast Differentiation ◽  
Transcriptional Level ◽  
Muscle Gene Expression ◽  
Important Regulator ◽  
Non Coding Rnas ◽  
Muscle Gene

microRNAs (miRNAs) are 21–23-nucleotide non-coding RNAs. It has become more and more evident that this class of small RNAs plays critical roles in the regulation of gene expression at the post-transcriptional level. MEF2A is a member of the MEF2 (myogenic enhancer factor 2) family of transcription factors. Prior report showed that the 3′-untranslated region (3′-UTR) of the Mef2A gene mediated its repression; however, the molecular mechanism underlying this intriguing observation was unknown. Here, we report that MEF2A is repressed by miRNAs. We identify miR-155 as one of the primary miRNAs that significantly represses the expression of MEF2A. We show that knockdown of the Mef2A gene by siRNA impairs myoblast differentiation. Similarly, overexpression of miR-155 leads to the repression of endogenous MEF2A expression and the inhibition of myoblast differentiation. Most importantly, reintroduction of MEF2A in miR-155 overexpressed myoblasts was able to partially rescue the miR-155-induced myoblast differentiation defect. Our data therefore establish miR-155 as an important regulator of MEF2A expression and uncover its function in muscle gene expression and myogenic differentiation.

scholarly journals Defoliation Significantly Suppressed Plant Growth Under Low Light Conditions in Two Leguminosae Species

2022 ◽  
Vol 12 ◽  
Author(s):  
Ning Wang ◽  
Tianyu Ji ◽  
Xiao Liu ◽  
Qiang Li ◽  
Kulihong Sairebieli ◽  
...  
Keyword(s):  
Plant Growth ◽  
Combined Treatment ◽  
Chlorophyll Concentration ◽  
Light Stress ◽  
Early Period ◽  
Light Treatment ◽  
High Light ◽  
Herbivorous Insects ◽  
Light Conditions ◽  
Low Light

Seedlings in regenerating layer are frequently attacked by herbivorous insects, while the combined effects of defoliation and shading are not fully understood. In the present study, two Leguminosae species (Robinia pseudoacacia and Amorpha fruticosa) were selected to study their responses to combined light and defoliation treatments. In a greenhouse experiment, light treatments (L+, 88% vs L−, 8% full sunlight) and defoliation treatments (CK, without defoliation vs DE, defoliation 50% of the upper crown) were applied at the same time. The seedlings’ physiological and growth traits were determined at 1, 10, 30, and 70 days after the combined treatment. Our results showed that the effects of defoliation on growth and carbon allocation under high light treatments in both species were mainly concentrated in the early stage (days 1–10). R. pseudoacacia can achieve growth recovery within 10 days after defoliation, while A. fruticosa needs 30 days. Seedlings increased SLA and total chlorophyll concentration to improve light capture efficiency under low light treatments in both species, at the expense of reduced leaf thickness and leaf lignin concentration. The negative effects of defoliation treatment on plant growth and non-structural carbohydrates (NSCs) concentration in low light treatment were significantly higher than that in high light treatment after recovery for 70 days in R. pseudoacacia, suggesting sufficient production of carbohydrate would be crucial for seedling growth after defoliation. Plant growth was more sensitive to defoliation and low light stress than photosynthesis, resulting in NSCs accumulating during the early period of treatment. These results illustrated that although seedlings could adjust their resource allocation strategy and carbon dynamics in response to combined defoliation and light treatments, individuals grown in low light conditions will be more suppressed by defoliation. Our results indicate that we should pay more attention to understory seedlings’ regeneration under the pressure of herbivorous insects.

LHCII organization and thylakoid lipids affect the sensitivity of the photosynthetic apparatus to high-light treatment

2011 ◽  
Vol 49 (6) ◽  
pp. 629-635 ◽  
Author(s):  
Kolyo G. Dankov ◽  
Anelia G. Dobrikova ◽  
Bettina Ughy ◽  
Balázs Bogos ◽  
Zoltan Gombos ◽  
...  
Keyword(s):  
Photosynthetic Apparatus ◽  
Light Treatment ◽  
High Light ◽  
High Light Treatment ◽  
Thylakoid Lipids

scholarly journals Selective Photobleaching of Chlorophylls and Carotenoids in Photosystem I Particles under High-Light Treatment

2007 ◽  
Vol 83 (6) ◽  
pp. 1301-1307 ◽  
Author(s):  
Atanaska Andreeva ◽  
Silvia Abarova ◽  
Katerina Stoitchkova ◽  
Rafael Picorel ◽  
Maya Velitchkova
Keyword(s):  
Photosystem I ◽  
Light Treatment ◽  
High Light ◽  
High Light Treatment
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