In mammals, cadmium is widely considered as a non-genotoxic carcinogen acting through a methylation-dependent epigenetic mechanism. Here, the effects of Cd treatment on the DNA methylation patten are examined together with its effect on chromatin reconfiguration in Posidonia oceanica. DNA methylation level and pattern were analysed in actively growing organs, under short- (6 h) and long- (2 d or 4 d) term and low (10 mM) and high (50 mM) doses of Cd, through a Methylation-Sensitive Amplification Polymorphism technique and an immunocytological approach, respectively. The expression of one member of the CHROMOMETHYLASE (CMT) family, a DNA methyltransferase, was also assessed by qRT-PCR. Nuclear chromatin ultrastructure was investigated by transmission electron microscopy. Cd treatment induced a DNA hypermethylation, as well as an up-regulation of CMT, indicating that de novo methylation did indeed occur. Moreover, a high dose of Cd led to a progressive heterochromatinization of interphase nuclei and apoptotic figures were also observed after long-term treatment. The data demonstrate that Cd perturbs the DNA methylation status through the involvement of a specific methyltransferase. Such changes are linked to nuclear chromatin reconfiguration likely to establish a new balance of expressed/repressed chromatin. Overall, the data show an epigenetic basis to the mechanism underlying Cd toxicity in plants.

/pdf/in-posidonia-oceanica-cadmium-induces-changes-in-dna-3cu7uj83mr.pdf

In Posidonia oceanica cadmium induces changes in DNA methylation and chromatin patterning

Real-time reverse transcription PCR (RT-qPCR) has emerged as an accurate and widely used technique for expression profiling of selected genes. However, obtaining reliable measurements depends on the selection of appropriate reference genes for gene expression normalization. The aim of this work was to assess the expression stability of 15 candidate genes to determine which set of reference genes is best suited for transcript normalization in citrus in different tissues and organs and leaves challenged with five pathogens (Alternaria alternata, Phytophthora parasitica, Xylella fastidiosa and Candidatus Liberibacter asiaticus). We tested traditional genes used for transcript normalization in citrus and orthologs of Arabidopsis thaliana genes described as superior reference genes based on transcriptome data. geNorm and NormFinder algorithms were used to find the best reference genes to normalize all samples and conditions tested. Additionally, each biotic stress was individually analyzed by geNorm. In general, FBOX (encoding a member of the F-box family) and GAPC2 (GAPDH) was the most stable candidate gene set assessed under the different conditions and subsets tested, while CYP (cyclophilin), TUB (tubulin) and CtP (cathepsin) were the least stably expressed genes found. Validation of the best suitable reference genes for normalizing the expression level of the WRKY70 transcription factor in leaves infected with Candidatus Liberibacter asiaticus showed that arbitrary use of reference genes without previous testing could lead to misinterpretation of data. Our results revealed FBOX, SAND (a SAND family protein), GAPC2 and UPL7 (ubiquitin protein ligase 7) to be superior reference genes, and we recommend their use in studies of gene expression in citrus species and relatives. This work constitutes the first systematic analysis for the selection of superior reference genes for transcript normalization in different citrus organs and under biotic stress.

/pdf/reference-genes-for-accurate-transcript-normalization-in-h8hthsldpv.pdf

Reference Genes for Accurate Transcript Normalization in Citrus Genotypes under Different Experimental Conditions

Plant responses to abiotic stresses are coordinated by arrays of growth and developmental processes. Indole-3-acetic acid (IAA) and abscisic acid (ABA) play critical roles in developmental programmes and environmental responses, respectively, through complex signalling and metabolism networks. However, crosstalk between the two phytohormones in the stress responses remains largely unknown. Here, it is reported that a GH3 family gene, OsGH3-2, encoding an enzyme catalysing IAA conjugation to amino acids, is involved in the modulation of ABA level and stress tolerance. Expression of OsGH3-2 was induced by drought but was suppressed by cold. Overexpression of OsGH3-2 in rice caused significant morphological aberrations related to IAA deficiency, such as dwarfism, smaller leaves, and fewer crown roots and root hairs. The overexpressing line showed significantly reduced carotene, ABA, and free IAA levels, greater stomata aperture, and faster water loss, and was hypersensitive to drought stress. However, the overexpressing line showed increased cold tolerance, which was due to the combined effects of reduced free IAA content, alleviated oxidative damage, and decreased membrane penetrability. Furthermore, expression levels of some ABA synthesis- and stress-related genes were significantly changed in the overexpression line. It was conclude that OsGH3-2 modulates both endogenous free IAA and ABA homeostasis and differentially affects drought and cold tolerance in rice.

A GH3 family member, OsGH3-2, modulates auxin and abscisic acid levels and differentially affects drought and cold tolerance in rice

Post-genomics era has witnessed the development of cutting-edge technologies that have offered cost-efficient and high-throughput ways for molecular characterization of the function of a cell or organism. Large-scale metabolite profiling assays have allowed researchers to access the global data sets of metabolites and the corresponding metabolic pathways in an unprecedented way. Recent efforts in metabolomics have been directed to improve the quality along with a major focus on yield. Importantly, an integration of metabolomics with other approaches such as quantitative genetics, transcriptomics and genetic modification has established its immense relevance to plant improvement. An effective combination of these modern approaches guide researchers to pinpoint the functional gene(s) and the characterization of massive metabolites, in order to prioritize the candidate genes for downstream analyses and ultimately, offering trait specific markers to improve commercially important traits. This in turn will improve the ability of a plant breeders by allowing them to make more informed decisions. Given this, the present review captures the significant leads gained in the past decade in the field of plant metabolomics accompanied by a brief discussion on the current contribution and the future scope of metabolomics to accelerate plant improvement.

/pdf/metabolomics-for-plant-improvement-status-and-prospects-4kd8ttusnt.pdf

Metabolomics for Plant Improvement: Status and Prospects.

Although remarkable progress has been made toward understanding carotenoid biosynthesis, the mechanisms that regulate the transcription of carotenogenic genes remain poorly understood. Lycopene β-cyclases (LCYb) are critical enzymes located at the branch point of the carotenoid biosynthetic pathway. Here, we used the promoter sequence of LCYb1 as bait in a yeast one-hybrid screen for promoter-binding proteins from sweet orange (Citrus sinensis). This screen identified a MADS transcription factor, CsMADS6, that was coordinately expressed with fruit development and coloration. Acting as a nucleus-localized transcriptional activator, CsMADS6 directly bound the promoter of LCYb1 and activated its expression. Overexpression of CsMADS6 in citrus calli increased carotenoid contents and induced the expression of LCYb1 and other carotenogenic genes, including phytoene synthase (PSY), phytoene desaturase (PDS), and carotenoid cleavage dioxygenase1 (CCD1). CsMADS6 up-regulated the expression of PSY, PDS, and CCD1 by directly binding to their promoters, which suggested the multitargeted regulation of carotenoid metabolism by CsMADS6. In addition, the ectopic expression of CsMADS6 in tomato (Solanum lycopersicum) affected carotenoid contents and the expression of carotenogenic genes. The sepals of CsMADS6-overexpressing tomato lines exhibited dramatic changes in carotenoid profiles, accompanied by changes in plastid ultrastructure. Global transcriptome analysis of transgenic sepals revealed that CsMADS6 regulates a series of pathways that promote increases in flux through the carotenoid pathway. Overall, these findings establish that CsMADS6 directly regulates LCYb1 and other carotenogenic genes to coordinately and positively modulate carotenoid metabolism in plants, which may provide strategies to improve the nutritional quality of crops.

The Citrus Transcription Factor CsMADS6 Modulates Carotenoid Metabolism by Directly Regulating Carotenogenic Genes

Citrus is an important fruit crop as regards accumulation of carotenoids. In plant carotenoid biosynthesis, phytoene synthase gene (Psy) plays a key role in catalyzing the head-to-head condensation of geranylgeranyl diphosphate molecules to produce colorless phytoene. In the present paper, we reported the phytoene contents determination and characterization of Psy during fruit ripening of "Washington" navel orange and its red-fleshed mutant "Cara Cara". Results showed that phytoene was exclusively accumulated in peel and pulp of "Cara Cara". Although phytoene was observed accumulating with fruit ripening of "Cara Cara", the contents in pulp were 10 times higher than those in peel. The isolated two Psy cDNAs were both 1520 bp in full length, containing 436 deduced amino acid residues, with a different amino acid at 412th. Genomic hybridization results showed that one or two copies might be present in "Cara Cara" and "Washington" genomes. During "Cara Cara" and "Washington" fruit coloration, expression of Psy was observed to be up-regulated, as revealed by tissue specific profiles in the flavedo, albedo, segment membrane and juice sacs. However, Psy expression in albedo of "Cara Cara" was higher than that in "Washington", as evidenced by phytoene accumulation in the peel.

Expression of phytoene synthase gene (Psy) is enhanced during fruit ripening of Cara Cara navel orange (Citrus sinensis Osbeck)

Zaohong' navel orange (Citrus sinensis (L.) Osbeck + C. unshiu Marc.), a new strain of citrus from a graft chimera, was discovered in China. It was diploid and arose at the junction where a 'Robertson' navel orange scion was top-worked onto a Satsuma mandarin (C. unshiu). Some characteristics determined by the L1 cell layer, such as juice sacs of fruit and stoma length, were similar to those of Satsuma mandarin, while others, including leaf index, fruit shape, navel, and color and aroma of the rind, were determined by the L2 cell layer, were similar to 'Robertson' navel orange. High-performance liquid chromatography analysis of the carotenoid extracts of the flesh of 'Zaohong' navel orange indicated that it had the carotenoids profile of Satsuma mandarin with b-cryptoxanthin as the predominant component in the juice sacs in mature fruit. Simple sequence repeats (SSR) and chloroplast simple sequence repeats (cpSSR) analysis showed that both nuclear and chloroplast genomes of 'Zaohong' navel orange were composed of both donor plants. On the basis of these facts, 'Zaohong' navel orange was found to be a periclinal chimera consisting of L1 derived from Satsuma mandarin and L2/L3 from 'Robertson' navel orange. It combined the valuable traits of both donor plants, matured '1 month earlier than the present navel orange cultivars, and therefore had good potential in citrus fresh market.

/pdf/characterization-of-a-new-natural-periclinal-navel-satsuma-30yjr3ntsz.pdf

Characterization of a New Natural Periclinal Navel-Satsuma Chimera of Citrus: 'Zaohong' Navel Orange

A novel, pleiotropic sweet orange (Citrus sinensis L. Osbeck) mutant, ‘Hong Anliu’, is described. This mutation causes carotenoid accumulation, high sugar, and low acid in the fruits. Gas chromatographic analysis revealed that high sugar and low acid in the fruit were caused by the accumulation of sucrose and the deficiency of citric acid. The dominant carotenoid accumulated in albedo, segment membranes, and juice sacs is lycopene, which can reach levels that are a 1000-fold higher than those in comparable wild-type fruits. This mutation does not affect the carotenoid composition of leaves. Carotenoid concentration and biosynthetic gene expression of albedo, segment membranes, and juice sacs were dramatically altered by the mutation. Lycopene accumulation in the juice sacs was regulated by co-ordinate expression of carotenoid biosynthetic genes. However, in albedo and segment membranes, the expression of downstream carotenogenic genes seems to be feedback induced by lycopene accumulation. This implies that there must be at least two modes regulating lycopene accumulation in ‘Hong Anliu’ fruit. Taken together, these results suggest that massive amounts of lycopene might be synthesized in the juice sacs and then transported to the segment membrane and the albedo, which leads to lycopene accumulation there.

A novel bud mutation that confers abnormal patterns of lycopene accumulation in sweet orange fruit (Citrus sinensis L. Osbeck).

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Linlin Guo

Author Tools

Chat about Author

Papers

Expression of phytoene synthase gene (Psy) is enhanced during fruit ripening of Cara Cara navel orange (Citrus sinensis Osbeck)

Characterization of a New Natural Periclinal Navel-Satsuma Chimera of Citrus: 'Zaohong' Navel Orange

A novel bud mutation that confers abnormal patterns of lycopene accumulation in sweet orange fruit (Citrus sinensis L. Osbeck).