scholarly journals A Very Oil Yellow1 modifier of the Oil Yellow1-N1989 allele uncovers a cryptic phenotypic impact of cis-regulatory variation in maize

2017 ◽  
Author(s):  
Rajdeep S. Khangura ◽  
Sandeep Marla ◽  
Bala P. Venkata ◽  
Nicholas J. Heller ◽  
Gurmukh S. Johal ◽  
...  
Keyword(s):  
Natural Variation ◽  
Chlorophyll Biosynthesis ◽  
Transcript Abundance ◽  
Forward Genetics ◽  
Expression Level ◽  
Dna Polymorphisms ◽  
Regulatory Sequence ◽  
Chlorophyll Metabolism ◽  
Magnesium Chelatase ◽  
Regulatory Variation

AbstractForward genetics determines the function of genes underlying trait variation by identifying the change in DNA responsible for changes in phenotype. Detecting phenotypically-relevant variation outside protein coding sequences and distinguishing this from neutral variants is not trivial; partly because the mechanisms by which DNA polymorphisms in the intergenic regions affect gene regulation are poorly understood. Here we utilized a dominant genetic marker with a convenient phenotype to investigate the effect of cis and trans-acting regulatory variation. We performed a forward genetic screen for natural variation that suppress or enhance the semi-dominant mutant allele Oy1-N1989, encoding the magnesium chelatase subunit I of maize. This mutant permits rapid phenotyping of leaf color as a reporter for chlorophyll accumulation, and mapping of natural variation in maize affecting chlorophyll metabolism. We identified a single modifier locus segregating between B73 and Mo17 that was linked to the reporter gene itself, which we call very oil yellow1. Based on the variation in OY1 transcript abundance and genome-wide association data, vey1 is predicted to consist of multiple cis-acting regulatory sequence polymorphisms encoded at the wild-type oy1 alleles. The vey1 allele appears to be a common polymorphism in the maize germplasm that alters the expression level of a key gene in chlorophyll biosynthesis. These vey1 alleles have no discernable impact on leaf chlorophyll in the absence of the Oy1-N1989 reporter. Thus, use of a mutant as a simple and efficient reporter for magnesium chelatase activity resulted in the detection of expression-level polymorphisms not readily visible in the laboratory.

scholarly journals Effect of chlorophyll biosynthesis-related genes on the leaf color in Hosta (Hosta plantaginea Aschers) and tobacco (Nicotiana tabacum L.)

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Jingying Zhang ◽  
Changhai Sui ◽  
Huimin Liu ◽  
Jinjiao Chen ◽  
Zhilin Han ◽  
...  
Keyword(s):  
Light Intensity ◽  
Antioxidant Capacity ◽  
Aminolevulinic Acid ◽  
Chlorophyll Biosynthesis ◽  
Expression Level ◽  
Virus Induced Gene Silencing ◽  
Leaf Color ◽  
Color Changes ◽  
Light Intensities ◽  
Structure Changes

Abstract Background ‘Regal Splendour’ (Hosta variety) is famous for its multi-color leaves, which are useful resources for exploring chloroplast development and color changes. The expressions of chlorophyll biosynthesis-related genes (HrHEMA, HrPOR and HrCAO) in Hosta have been demonstrated to be associated with leaf color. Herein, we isolated, sequenced, and analyzed HrHEMA, HrPOR and HrCAO genes. Subcellular localization was also performed to determine the location of the corresponding enzymes. After plasmid construction, virus-induced gene silencing (VIGS) was carried out to reduce the expressions of those genes. In addition, HrHEMA-, HrPOR- and HrCAO-overexpressing tobacco plants were made to verify the genes function. Changes of transgenic tobacco were recorded under 2000 lx, 6000 lx and 10,000 lx light intensity. Additionally, the contents of enzyme 5-aminolevulinic acid (5-ALA), porphobilinogen (PBG), chlorophyll a and b (Chla and Chlb), carotenoid (Cxc), superoxide dismutase (SOD), peroxidase (POD), malondialdehyde (MDA), proline (Pro) and catalase (CAT) under different light intensities were evaluated. Results The silencing of HrHEMA, HrPOR and HrCAO genes can induce leaf yellowing and chloroplast structure changes in Hosta. Specifically, leaves of Hosta with HrCAO silencing were the most affected, while those with HrPOR silencing were the least affected. Moreover, all three genes in tobacco were highly expressed, whereas no expression was detected in wild-type (WT). However, the sensitivities of the three genes to different light intensities were different. The highest expression level of HrHEMA and HrPOR was detected under 10,000 lx of illumination, while HrCAO showed the highest expression level under 6000 lx. Lastly, the 5-ALA, Chla, Cxc, SOD, POD, MDA, Pro and CAT contents in different transgenic tobaccos changed significantly under different light intensities. Conclusion The overexpression of these three genes in tobacco enhanced photosynthesis by accumulating chlorophyll content, but the influential level varied under different light intensities. Furthermore, HrHEMA-, HrPOR- and HrCAO- overexpressing in tobacco can enhance the antioxidant capacity of plants to cope with stress under higher light intensity. However, under lower light intensity, the antioxidant capacity was declined in HrHEMA-, HrPOR- and HrCAO- overexpressing tobaccos.

scholarly journals Interaction Between Induced and Natural Variation at oil yellow1 Delays Reproductive Maturity in Maize

2019 ◽  
Vol 10 (2) ◽  
pp. 797-810
Author(s):  
Rajdeep S. Khangura ◽  
Bala P. Venkata ◽  
Sandeep R. Marla ◽  
Michael V. Mickelbart ◽  
Singha Dhungana ◽  
...  
Keyword(s):  
Flowering Time ◽  
Chlorophyll Content ◽  
Chlorophyll Biosynthesis ◽  
Wild Type ◽  
Reproductive Maturity ◽  
Magnesium Chelatase ◽  
Chlorophyll Contents ◽  
Delayed Flowering ◽  
Mapping Populations ◽  
Expression Polymorphism

We previously demonstrated that maize (Zea mays) locus very oil yellow1 (vey1) encodes a putative cis-regulatory expression polymorphism at the magnesium chelatase subunit I gene (aka oil yellow1) that strongly modifies the chlorophyll content of the semi-dominant Oy1-N1989 mutants. The vey1 allele of Mo17 inbred line reduces chlorophyll content in the mutants leading to reduced photosynthetic output. Oy1-N1989 mutants in B73 reached reproductive maturity four days later than wild-type siblings. Enhancement of Oy1-N1989 by the Mo17 allele at the vey1 QTL delayed maturity further, resulting in detection of a flowering time QTL in two bi-parental mapping populations crossed to Oy1-N1989. The near isogenic lines of B73 harboring the vey1 allele from Mo17 delayed flowering of Oy1-N1989 mutants by twelve days. Just as previously observed for chlorophyll content, vey1 had no effect on reproductive maturity in the absence of the Oy1-N1989 allele. Loss of chlorophyll biosynthesis in Oy1-N1989 mutants and enhancement by vey1 reduced CO2 assimilation. We attempted to separate the effects of photosynthesis on the induction of flowering from a possible impact of chlorophyll metabolites and retrograde signaling by manually reducing leaf area. Removal of leaves, independent of the Oy1-N1989 mutant, delayed flowering but surprisingly reduced chlorophyll contents of emerging leaves. Thus, defoliation did not completely separate the identity of the signal(s) that regulates flowering time from changes in chlorophyll content in the foliage. These findings illustrate the necessity to explore the linkage between metabolism and the mechanisms that connect it to flowering time regulation.

scholarly journals Dark/Light Treatments Followed by γ-Irradiation Increase the Frequency of Leaf-Color Mutants in Cymbidium

Plants ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 532 ◽  
Author(s):  
Sang Hoon Kim ◽  
Se Won Kim ◽  
Jaihyunk Ryu ◽  
Si-Yong Kang ◽  
Byoung-Cheorl Kang ◽  
...  
Keyword(s):  
Chlorophyll Biosynthesis ◽  
Flower Color ◽  
Light Treatment ◽  
Leaf Color ◽  
Γ Irradiation ◽  
Dark Light ◽  
Chlorophyll Metabolism ◽  
Anthocyanin Pathway ◽  
Pathway Gene ◽  
Radiation Treatments

Radiation randomly induces chromosomal mutations in plants. However, it was recently found that the frequency of flower-color mutants could be specifically increased by upregulating anthocyanin pathway gene expression before radiation treatments. The mechanisms of chlorophyll biosynthesis and degradation are active areas of plant study because chlorophyll metabolism is closely connected to photosynthesis. In this study, we determined the dark/light treatment conditions that resulted in upregulation of the expression levels of six chlorophyll pathway genes, uroporphyrinogen III synthase (HEMD), uroporphyrinogen III decarboxylase (HEME2), NADPH-protochlorophyllide oxidoreductase (POR) A (PORA), chlorophyll synthase (CHLG), chlorophyllase (CLH2), and red chlorophyll catabolite reductase (RCCR), and measured their effects on the γ-irradiation-induced frequencies of leaf-color mutants in two Cymbidium cultivars. To degrade chlorophyll in rhizomes, 60–75 days of dark treatment were required. To upregulate the expressions of chlorophyll pathway genes, 10 days of light treatment appeared to be optimal. Dark/light treatments followed by γ-irradiation increased chlorophyll-related leaf mutants by 1.4- to 2.0-fold compared with γ-ray treatment alone. Dark/light treatments combined with γ-irradiation increased the frequency of leaf-color mutants in Cymbidium, which supports the wider implementation of a plant breeding methodology that increases the mutation frequency of a target trait by controlling the expression of target trait-related genes.

Characterization of the magnesium chelatase from Thermosynechococcus elongatus

2013 ◽  
Vol 457 (1) ◽  
pp. 163-170 ◽  
Author(s):  
Nathan B. P. Adams ◽  
Christopher J. Marklew ◽  
Amanda A. Brindley ◽  
C. Neil Hunter ◽  
James D. Reid
Keyword(s):  
Chlorophyll Biosynthesis ◽  
Thermostable Enzyme ◽  
Enzyme Complex ◽  
Magnesium Chelatase

Magnesium chelatase is the ‘gatekeeper’ multi-subunit enzyme complex that initiates chlorophyll biosynthesis; we present the first characterization of an active thermostable enzyme complex and we use hybrid mesophilic/thermophilic chelatase complexes to reveal that Mg2+ co-operativity resides in the ChlD subunit.

scholarly journals iTRAQ-based comparative proteomic analysis of differences in the protein profiles of stems and leaves from two alfalfa genotypes

2020 ◽  
Author(s):  
Hao Sun ◽  
Jie Yu ◽  
Fan Zhang ◽  
Junmei Kang ◽  
Mingna Li ◽  
...  
Keyword(s):  
Leaf Development ◽  
Proteomic Analysis ◽  
Regulatory Networks ◽  
Carbon Fixation ◽  
Chlorophyll Biosynthesis ◽  
Chlorophyll Synthesis ◽  
Phenylpropanoid Pathway ◽  
Chlorophyll Metabolism ◽  
Phenylpropanoid Biosynthesis ◽  
Proteomic Study

Abstract Background: To explore the molecular regulatory mechanisms of early stem and leaf development, proteomic analysis was performed on leaves and stems of F genotype alfalfa, with thin stems and small leaves, and M genotype alfalfa, with thick stems and large leaves.Results: Based on fold-change thresholds of >1.20 or <0.83 (p<0.05), a large number of proteins were identified as being differentially enriched between the M and F genotypes: 249 downregulated and 139 upregulated in stems and 164 downregulated and 134 upregulated in leaves. The differentially enriched proteins in stems were mainly involved in amino acid biosynthesis, phenylpropanoid biosynthesis, carbon fixation, and phenylalanine metabolism. The differentially enriched proteins in leaves were mainly involved in porphyrin and chlorophyll metabolism, phenylpropanoid biosynthesis, starch and sucrose metabolism, and carbon fixation in photosynthetic organisms. Six differentially enriched proteins were mapped onto the porphyrin and chlorophyll metabolism pathway in leaves of the M genotype, including five upregulated proteins involved in chlorophyll biosynthesis and one downregulated protein involved in chlorophyll degradation. Eleven differentially enriched proteins were mapped onto the phenylpropanoid pathway in stems of the M genotype, including two upregulated proteins and nine downregulated proteins. Conclusion: Enhanced chlorophyll synthesis and decreased lignin synthesis provided a reasonable explanation for the larger leaves and lower levels of stem lignification in M genotype alfalfa. This proteomic study aimed to classify the functions of differentially enriched proteins and to provide information on the molecular regulatory networks involved in stem and leaf development.

scholarly journals Bilin-dependent regulation of chlorophyll biosynthesis by GUN4

2021 ◽  
Vol 118 (20) ◽  
pp. e2104443118
Author(s):  
Weiqing Zhang ◽  
Robert D. Willows ◽  
Rui Deng ◽  
Zheng Li ◽  
Mengqi Li ◽  
...  
Keyword(s):  
Enzymatic Activity ◽  
Heme Oxygenase ◽  
Chlorophyll Biosynthesis ◽  
Protoporphyrin Ix ◽  
Common Trunk ◽  
Magnesium Chelatase ◽  
Photosynthetic Eukaryotes ◽  
Linear Tetrapyrroles ◽  
Oxygenic Phototrophs ◽  
Binding Component

Biosyntheses of chlorophyll and heme in oxygenic phototrophs share a common trunk pathway that diverges with insertion of magnesium or iron into the last common intermediate, protoporphyrin IX. Since both tetrapyrroles are pro-oxidants, it is essential that their metabolism is tightly regulated. Here, we establish that heme-derived linear tetrapyrroles (bilins) function to stimulate the enzymatic activity of magnesium chelatase (MgCh) via their interaction with GENOMES UNCOUPLED 4 (GUN4) in the model green alga Chlamydomonas reinhardtii. A key tetrapyrrole-binding component of MgCh found in all oxygenic photosynthetic species, CrGUN4, also stabilizes the bilin-dependent accumulation of protoporphyrin IX-binding CrCHLH1 subunit of MgCh in light-grown C. reinhardtii cells by preventing its photooxidative inactivation. Exogenous application of biliverdin IXα reverses the loss of CrCHLH1 in the bilin-deficient heme oxygenase (hmox1) mutant, but not in the gun4 mutant. We propose that these dual regulatory roles of GUN4:bilin complexes are responsible for the retention of bilin biosynthesis in all photosynthetic eukaryotes, which sustains chlorophyll biosynthesis in an illuminated oxic environment.

scholarly journals iTRAQ-based comparative proteomic analysis of differences in the protein profiles of stems and leaves from two alfalfa genotypes

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Hao Sun ◽  
Jie Yu ◽  
Fan Zhang ◽  
Junmei Kang ◽  
Mingna Li ◽  
...  
Keyword(s):  
Leaf Development ◽  
Proteomic Analysis ◽  
Regulatory Networks ◽  
Carbon Fixation ◽  
Chlorophyll Biosynthesis ◽  
Chlorophyll Synthesis ◽  
Phenylpropanoid Pathway ◽  
Chlorophyll Metabolism ◽  
Phenylpropanoid Biosynthesis ◽  
Proteomic Study

Abstract Background To explore the molecular regulatory mechanisms of early stem and leaf development, proteomic analysis was performed on leaves and stems of F genotype alfalfa, with thin stems and small leaves, and M genotype alfalfa, with thick stems and large leaves. Results Based on fold-change thresholds of > 1.20 or < 0.83 (p < 0.05), a large number of proteins were identified as being differentially enriched between the M and F genotypes: 249 downregulated and 139 upregulated in stems and 164 downregulated and 134 upregulated in leaves. The differentially enriched proteins in stems were mainly involved in amino acid biosynthesis, phenylpropanoid biosynthesis, carbon fixation, and phenylalanine metabolism. The differentially enriched proteins in leaves were mainly involved in porphyrin and chlorophyll metabolism, phenylpropanoid biosynthesis, starch and sucrose metabolism, and carbon fixation in photosynthetic organisms. Six differentially enriched proteins were mapped onto the porphyrin and chlorophyll metabolism pathway in leaves of the M genotype, including five upregulated proteins involved in chlorophyll biosynthesis and one downregulated protein involved in chlorophyll degradation. Eleven differentially enriched proteins were mapped onto the phenylpropanoid pathway in stems of the M genotype, including two upregulated proteins and nine downregulated proteins. Conclusion Enhanced chlorophyll synthesis and decreased lignin synthesis provided a reasonable explanation for the larger leaves and lower levels of stem lignification in M genotype alfalfa. This proteomic study aimed to classify the functions of differentially enriched proteins and to provide information on the molecular regulatory networks involved in stem and leaf development.

DNA polymorphisms and transcript abundance ofPRKAG2and phosphorylated AMP-activated protein kinase in the rumen are associated with gain and feed intake in beef steers

2014 ◽  
Vol 45 (4) ◽  
pp. 461-472 ◽  
Author(s):  
A. K. Lindholm-Perry ◽  
L. A. Kuehn ◽  
W. T. Oliver ◽  
R. J. Kern ◽  
R. A. Cushman ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Feed Intake ◽  
Transcript Abundance ◽  
Dna Polymorphisms ◽  
Beef Steers ◽  
Amp Activated Protein Kinase

scholarly journals Magnesium chelatase from Rhodobacter sphaeroides: initial characterization of the enzyme using purified subunits and evidence for a BchI–BchD complex

1999 ◽  
Vol 337 (2) ◽  
pp. 243-251 ◽  
Author(s):  
Lucien C. D. GIBSON ◽  
Poul Erik JENSEN ◽  
C. Neil HUNTER
Keyword(s):  
Rhodobacter Sphaeroides ◽  
Chlorophyll Biosynthesis ◽  
Gel Filtration ◽  
Protoporphyrin Ix ◽  
Photosynthetic Bacterium ◽  
Affinity Tags ◽  
Magnesium Chelatase ◽  
Highly Active ◽  
Mg Chelatase

The enzyme magnesium-protoporphyrin IX chelatase (Mg chelatase) catalyses the insertion of Mg into protoporphyrin IX, the first committed step in (bacterio)chlorophyll biosynthesis. In the photosynthetic bacterium Rhodobacter sphaeroides, this reaction is catalysed by the products of the bchI, bchDand bchH genes. These genes have been expressed in Escherichia coli so that the BchI, BchD and BchH proteins are produced with N-terminal His6 affinity tags, which has led to the production of large amounts of highly purified, highly active Mg chelatase subunits from a single chromatography step. Furthermore, BchD has been purifed free of contamination with the chaperone GroEL, which had proven to be a problem in the past. BchD, present largely as an insoluble protein in E. coli, was purified in 6 M urea and refolded by addition of BchI, MgCl2 and ATP, yielding highly active protein. BchI/BchD mixtures prepared in this way were used in conjunction with BchH to determine the kinetic parameters of R. sphaeroides Mg chelatase for its natural substrates. We have been able to demonstrate for the first time that BchI and BchD form a complex, and that Mg2+ and ATP are required to establish and maintain this complex. Gel filtration data suggest that BchI and BchD form a complex of molecular mass 200 kDa in the presence of Mg2+ and ATP. Our data suggest that, in vivo, BchD is only folded correctly and maintained in its correct conformation in the presence of BchI, Mg2+ and ATP.

scholarly journals Variation in maize chlorophyll biosynthesis alters plant architecture

2020 ◽  
Author(s):  
Rajdeep S. Khangura ◽  
Gurmukh S. Johal ◽  
Brian P. Dilkes
Keyword(s):  
Plant Height ◽  
Sweet Corn ◽  
Chlorophyll Biosynthesis ◽  
Growth Control ◽  
Magnesium Chelatase ◽  
Chlorophyll Contents ◽  
Dominant Mutant ◽  
Chlorophyll Level ◽  
Lateral Branches ◽  
Mapping Populations

AbstractChlorophyll is a tetrapyrrole metabolite essential for photosynthesis in plants. The oil yellow1 (oy1) gene of maize encodes subunit I of Magnesium chelatase, the enzyme catalyzing the first committed step of chlorophyll biosynthesis. A range of chlorophyll contents and net CO2 assimilation rates can be achieved in maize by combining a semi-dominant mutant allele, Oy1-N1989, and cis-regulatory alleles encoded by the Mo17 inbred called very oil yellow1 (vey1). We previously demonstrated that these allelic interactions can delay reproductive maturity. In this study, we demonstrate that multiple gross morphological traits respond to a reduction in chlorophyll. We found that stalk width, number of lateral branches (tillers), and branching of the inflorescence decline with a decrease in chlorophyll level. Chlorophyll variation suppressed tillering in multiple maize mutants including teosinte branched1, grassy tiller1, and Tillering1 as well as the tiller number1 QTL responsible for tillering in many sweet corn varieties. In contrast to these traits, plant height showed a non-linear response to chlorophyll levels. Weak suppression of Oy1-N1989 by vey1B73 resulted in a significant increase in mutant plant height. This was true in multiple mapping populations, isogenic inbreds, and hybrid backgrounds. Enhancement of the Oy1-N1989 mutants by the vey1Mo17 allele reduced chlorophyll contents and plant height in mapping populations and isogenic inbred background. We demonstrate that the effects of reduced chlorophyll content on plant growth and development are complex and that the genetic relationship depends on the trait. We propose that growth control for branching and architecture are downstream of energy balance sensing.

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