scholarly journals LTS3 gene controls light-independent chlorophyll biosynthesis in green algae Chlamydomonas reinhardtii

2010 ◽  
Vol 8 (2) ◽  
pp. 35-44
Author(s):  
Elena M Chekunova ◽  
Natalya V Savelieva
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Positional Cloning ◽  
Chlorophyll Biosynthesis ◽  
Plant Cells ◽  
Expression Of Genes ◽  
Gata Transcription Factor ◽  
Pigment Contents ◽  
Genes Encoding ◽  
Activity Of Enzymes ◽  
Mg Chelatase

The genetic control of light-independent chlorophyll biosynthesis in plant cells has been investigated using Chlamydomonas reinhardtii Lts3-mutants defective in dark chlorophyll biosynthesis on the stage before protochlorophyllide to chlorophyllide conversion. In heterotrophic conditions the mutants are unable to synthesize chlorophyll and accumulate protoporphyrins, after illumination they are greening. The mutants were tested for pigment contents, activity of enzymes and expression of the genes, encoding these enzymes. The LTS3 gene has been identified by positional cloning, and the predicted LTS3 protein appeared to be a GATA transcription factor, which activate the expression of genes encoded chlorophyll biosynthesis enzymes: Mg-chelatase and glutamate 1-semialdehyde aminotransferase in the dark, and possibly, important for adaptation of plant cells for autotrophic conditions. 

scholarly journals Structure of GUN4 fromChlamydomonas reinhardtii

2015 ◽  
Vol 71 (8) ◽  
pp. 1094-1099 ◽  
Author(s):  
Shabnam Tarahi Tabrizi ◽  
David B. Langley ◽  
Stephen J. Harrop ◽  
Anthony P. Duff ◽  
Robert D. Willows
Keyword(s):  
Crystal Structure ◽  
Chlamydomonas Reinhardtii ◽  
Chlorophyll Biosynthesis ◽  
Conformational Dynamics ◽  
Protoporphyrin Ix ◽  
Biosynthesis Pathway ◽  
Broad Agreement ◽  
Binding Cleft ◽  
Mg Chelatase

The genomes uncoupled 4 (GUN4) protein stimulates chlorophyll biosynthesis by increasing the activity of Mg-chelatase, the enzyme that inserts magnesium into protoporphyrin IX (PPIX) in the chlorophyll biosynthesis pathway. One of the roles of GUN4 is in binding PPIX and Mg-PPIX. In eukaryotes, GUN4 also participates in plastid-to-nucleus signalling, although the mechanism for this is unclear. Here, the first crystal structure of a eukaryotic GUN4, fromChlamydomonas reinhardtii, is presented. The structure is in broad agreement with those of previously solved cyanobacterial structures. Most interestingly, conformational divergence is restricted to several loops which cover the porphyrin-binding cleft. The conformational dynamics suggested by this ensemble of structures lend support to the understanding of how GUN4 binds PPIX or Mg-PPIX.

scholarly journals Molecular genetic mechanisms of sugar transport in plants in the absence and during arbuscular mycoryza development

2019 ◽  
Vol 17 (1) ◽  
pp. 81-99 ◽  
Author(s):  
Andrey P. Yurkov ◽  
Alexey A. Kryukov ◽  
Anastasia O. Gorbunova ◽  
Alexei M. Afonin ◽  
Anastasija A. Kirpichnikova ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Molecular Genetic ◽  
Sugar Transport ◽  
Carbon Assimilation ◽  
Plant Cells ◽  
Am Fungi ◽  
Root Cells ◽  
Expression Of Genes ◽  
Carbohydrate Transport ◽  
Genes Encoding

The review is aimed to analyze molecular mechanisms of carbohydrate transport during the formation of arbuscular mycorrhiza (AM), a widespread symbiosis of plants with Glomeromycotina subdivision fungi. Due to AM-symbiosis, plants receive microelements, mainly phosphorus, and fungi are supplied by products of carbon assimilation. The study of sugar transport mechanisms in plants as well as between plants and symbiont is methodologically difficult because of the obligatory status of AM fungi. The mechanisms of carbohydrate transport in leaf and root cells are concerned, particular interest is paid to transporters, specific to AM structures. Several resumptive schemes are designed. SWEET family of transporters (Sugars Will Eventually be Exported Transporters), including AM-specific uniporters are reviewed. We summarize results on expression of genes encoding transporter in cells of plants without AM, in AM-plant cells with arbuscules and AM-plant cells without arbuscules. The data on genes of MST proteins family (Monosaccharide Transporters) participating in direct transport of sugars from the soil to the foliar mycelium of AM fungi are considered.

scholarly journals NtbHLH1, a JAF13-like bHLH, interacts with NtMYB6 to enhance proanthocyanidin accumulation in Chinese Narcissus

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Yuxin Fan ◽  
Jiayu Peng ◽  
Jiacheng Wu ◽  
Ping Zhou ◽  
Ruijie He ◽  
...  
Keyword(s):  
Flavonoid Biosynthesis ◽  
Transcriptional Level ◽  
Flavonoid Pathway ◽  
Regulation Of Expression ◽  
Over Expression ◽  
Expression Of Genes ◽  
Genes Encoding ◽  
Regulatory Complex ◽  
Positive Regulators ◽  
R2r3 Myb

Abstract Background Flavonoid biosynthesis in plants is primarily regulated at the transcriptional level by transcription factors modulating the expression of genes encoding enzymes in the flavonoid pathway. One of the most studied transcription factor complexes involved in this regulation consists of a MYB, bHLH and WD40. However, in Chinese Narcissus (Narcissus tazetta L. var. chinensis), a popular monocot bulb flower, the regulatory mechanism of flavonoid biosynthesis remains unclear. Results In this work, genes related to the regulatory complex, NtbHLH1 and a R2R3-MYB NtMYB6, were cloned from Chinese Narcissus. Phylogenetic analysis indicated that NtbHLH1 belongs to the JAF13 clade of bHLH IIIf subgroup, while NtMYB6 was highly homologous to positive regulators of proanthocyanidin biosynthesis. Both NtbHLH1 and NtMYB6 have highest expression levels in basal plates of Narcissus, where there is an accumulation of proanthocyanidin. Ectopic over expression of NtbHLH1 in tobacco resulted in an increase in anthocyanin accumulation in flowers, and an up-regulation of expression of the endogenous tobacco bHLH AN1 and flavonoid biosynthesis genes. In contrast, the expression level of LAR gene was significantly increased in NtMYB6-transgenic tobacco. Dual luciferase assays showed that co-infiltration of NtbHLH1 and NtMYB6 significantly activated the promoter of Chinese Narcissus DFR gene. Furthermore, a yeast two-hybrid assay confirmed that NtbHLH1 interacts with NtMYB6. Conclusions Our results suggest that NtbHLH1 may function as a regulatory partner by interacting directly with NtMYB6 to enhance proanthocyanidin accumulation in Chinese Narcissus.

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