Validation of reference genes for quantitative RT-PCR normalization inSuaeda aralocaspica, an annual halophyte with heteromorphism and C4 pathway without Kranz anatomy

Reverse transcription quantitative real-time polymerase chain reaction (qRT-PCR) is a powerful analytical technique for the measurement of gene expression, which depends on the stability of the reference gene used for data normalization.Suaeda aralocaspica, an annual halophyte with heteromorphic seeds and possessing C4 photosynthesis pathway without Kranz anatomy, is an ideal plant species to identify stress tolerance-related genes and compare relative expression at transcriptional level. So far, no molecular information is available for this species. In the present study, six traditionally used reference genes were selected and their expression stability in two types of seeds ofS. aralocaspicaunder different experimental conditions was evaluated. Three analytical programs, geNorm, NormFinder and BestKeeper, were used to assess and rank the stability of reference gene expression. Results revealed that although some reference genes may display different transcriptional profiles between the two types of seeds,β-TUB andGAPDHappeared to be the most suitable references under different developmental stages and tissues.GAPDHwas the appropriate reference gene under different germination time points and salt stress conditions, andACTINwas suitable for various abiotic stress treatments for the two types of seeds. For all the sample pools,β-TUB served as the most stable reference gene, whereas18S rRNAand28S rRNAperformed poorly and presented as the least stable genes in our study.UBQseemed to be unsuitable as internal control under different salt treatments. In addition, the expression of a photosynthesis-related gene (PPDK) of C4 pathway and a salt tolerance-related gene (SAT) ofS. aralocaspicawere used to validate the best performance reference genes. This is the first systematic comparison of reference gene selection for qRT-PCR work inS. aralocaspicaand these data will facilitate further studies on gene expression in this species and other euhalophytes.

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Optimizations for identifying reference genes in bone and cartilage bioengineering

BMC Biotechnology ◽

10.1186/s12896-021-00685-8 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Fei Xiong ◽

Xiangyun Cheng ◽

Chao Zhang ◽

Roland Manfred Klar ◽

Tao He

Keyword(s):

Gene Expression ◽

Skeletal Muscle ◽

Adipose Tissue ◽

Real Time ◽

Reference Gene ◽

Muscle Tissue ◽

Reference Genes ◽

Target Genes ◽

The Stability ◽

And Cartilage

Abstract Background Reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) remains one of the best-established techniques to assess gene expression patterns. However, appropriate reference gene(s) selection remains a critical and challenging subject in which inappropriate reference gene selction can distort results leading to false interpretations. To date, mixed opinions still exist in how to choose the most optimal reference gene sets in accodrance to the Minimum Information for Publication of Quantitative Real-Time PCR Experiments (MIQE) guideline. Therefore, the purpose of this study was to investigate which schemes were the most feasible for the identification of reference genes in a bone and cartilage bioengineering experimental setting. In this study, rat bone mesenchymal stem cells (rBMSCs), skeletal muscle tissue and adipose tissue were utilized, undergoing either chondrogenic or osteogenic induction, to investigate the optimal reference gene set identification scheme that would subsequently ensure stable and accurate interpretation of gene expression in bone and cartilage bioengineering. Results The stability and pairwise variance of eight candidate reference genes were analyzed using geNorm. The V0.15- vs. Vmin-based normalization scheme in rBMSCs had no significant effect on the eventual normalization of target genes. In terms of the muscle tissue, the results of the correlation of NF values between the V0.15 and Vmin schemes and the variance of target genes expression levels generated by these two schemes showed that different schemes do indeed have a significant effect on the eventual normalization of target genes. Three selection schemes were adopted in terms of the adipose tissue, including the three optimal reference genes (Opt3), V0.20 and Vmin schemes, and the analysis of NF values with eventual normalization of target genes showed that the different selection schemes also have a significant effect on the eventual normalization of target genes. Conclusions Based on these results, the proposed cut-off value of Vn/n + 1 under 0.15, according to the geNorm algorithm, should be considered with caution. For cell only experiments, at least rBMSCs, a Vn/n + 1 under 0.15 is sufficient in RT-qPCR studies. However, when using certain tissue types such as skeletal muscle and adipose tissue the minimum Vn/n + 1 should be used instead as this provides a far superior mode of generating accurate gene expression results. We thus recommended that when the stability and variation of a candidate reference genes in a specific study is unclear the minimum Vn/n + 1 should always be used as this ensures the best and most accurate gene expression value is achieved during RT-qPCR assays.

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Current Practices for Reference Gene Selection in RT-qPCR of Aspergillus: Outlook and Recommendations for the Future

Genes ◽

10.3390/genes12070960 ◽

2021 ◽

Vol 12 (7) ◽

pp. 960

Author(s):

Meagan Archer ◽

Jianping Xu

Keyword(s):

Gene Expression ◽

Reference Gene ◽

Reference Genes ◽

Gene Selection ◽

Quantitative Polymerase Chain Reaction ◽

Specific Method ◽

Experimental Conditions ◽

Reference Gene Selection ◽

Physiological Processes ◽

The Stability

Aspergillus is a genus of filamentous fungi with vast geographic and ecological distributions. Species within this genus are clinically, agriculturally and biotechnologically relevant, leading to increasing interest in elucidating gene expression dynamics of key metabolic and physiological processes. Reverse-transcription quantitative Polymerase Chain Reaction (RT-qPCR) is a sensitive and specific method of quantifying gene expression. A crucial step for comparing RT-qPCR results between strains and experimental conditions is normalisation to experimentally validated reference gene(s). In this review, we provide a critical analysis of current reference gene selection and validation practices for RT-qPCR gene expression analyses of Aspergillus. Of 90 primary research articles obtained through our PubMed query, 17 experimentally validated the reference gene(s) used. Twenty reference genes were used across the 90 studies, with beta-tubulin being the most used reference gene, followed by actin, 18S rRNA and glyceraldehyde 3-phosphate dehydrogenase. Sixteen of the 90 studies used multiple reference genes for normalisation. Failing to experimentally validate the stability of reference genes can lead to conflicting results, as was the case for four studies. Overall, our review highlights the need to experimentally validate reference genes in RT-qPCR studies of Aspergillus.

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Identification and validation of miRNA reference genes in poplar under pathogen stress

10.21203/rs.3.rs-225734/v1 ◽

2021 ◽

Author(s):

Lichun Zhang ◽

Xiaoqian Yang ◽

Yiyi Yin ◽

Jinxing Wang ◽

Yanwei Wang

Keyword(s):

Gene Expression ◽

Reference Gene ◽

Small Rna ◽

Reference Genes ◽

Expression Profiles ◽

Small Rna Sequencing ◽

Rna Seq ◽

Internal Standards ◽

Qrt Pcr ◽

Canker Pathogen

Abstract Quantitative real time polymerase chain reaction (qRT-PCR) is a common method to analyze gene expression. Due to differences in RNA quantity, quality, and reverse transcription efficiency between qRT-PCR samples, reference genes are used as internal standards to normalize gene expression. However, few universal genes especially miRNAs have been identified as reference so far. Therefore, it is essential to identify reference genes that can be used across various experimental conditions, stress treatments, or tissues. In this study, 14 microRNAs (miRNAs) and 5.8S rRNA were assessed for expression stability in poplar trees infected with canker pathogen. Using three reference gene analysis programs, we found that miR156g and miR156a exhibited stable expression throughout the infection process. miR156g and miR156a were then tested as internal standards to measure the expression of miR1447 and miR171c, and the results were compared to small RNA sequencing (RNA-seq) data. We found that when miR156a was used as the reference gene, the expression of miR1447 and miR171c were consistent with the small RNA-seq expression profiles. Therefore, miR156a was the most stable miRNAs examined in this study, and could be used as a reference gene in poplar under canker pathogen stress, which should enable comprehensive comparisons of miRNAs expression and avoid the bias caused by different lenth between detected miRNAs and traditional referece genes. The present study has expanded the miRNA reference genes available for gene expression studies in trees under biotic stress.

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Stability of Nuclear and Mitochondrial Reference Genes in Selected Tissues of the Ambrosia Beetle Xylosandrus germanus

Insects ◽

10.3390/insects12121125 ◽

2021 ◽

Vol 12 (12) ◽

pp. 1125

Author(s):

Nisha Patwa ◽

Christopher M. Ranger ◽

Maximilian Lehenberger ◽

Peter H. Biedermann ◽

Michael E. Reding

Keyword(s):

Gene Expression ◽

Reference Gene ◽

Reference Genes ◽

Target Genes ◽

Ambrosia Beetle ◽

Whole Body ◽

28S Rrna ◽

Carbamoyl Phosphate ◽

Aspartate Transcarbamylase ◽

Xylosandrus Germanus

The fungus-farming ambrosia beetle Xylosandrus germanus (Blandford) uses a pouch-like structure (i.e., mycangium) to transport spores of its nutritional fungal mutualist. Our current study sought to identify reference genes necessary for future transcriptome analyses aimed at characterizing gene expression within the mycangium. Complementary DNA was synthesized using selected tissue types from laboratory-reared and field-collected X. germanus consisting of the whole body, head + thorax, deflated or inflated mycangium + scutellum, inflated mycangium, and thorax + abdomen. Quantitative reverse-transcription PCR reactions were performed using primers for 28S ribosomal RNA (28S rRNA), arginine kinase (AK), carbamoyl-phosphate synthetase 2-aspartate transcarbamylase-dihydroorotase (CAD), mitochondrial cytochrome oxidase 1 (CO1), and elongation factor-1α (EF1α). Reference gene stability was analyzed using GeNorm, NormFinder, BestKeeper, ΔCt, and a comprehensive final ranking by RefFinder. The gene CO1 was identified as the primary reference gene since it was generally ranked in first or second position among the tissue types containing the mycangium. Reference gene AK was identified as a secondary reference gene. In contrast, EF1α was generally ranked in the last or penultimate place. Identification of two stable reference genes will aid in normalizing the expression of target genes for subsequent gene expression studies of X. germanus’ mycangium.

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Selection of suitable reference genes for qRT-PCR studies during SE initial dedifferentiation in cotton of different SE capability

10.7287/peerj.preprints.27138 ◽

2018 ◽

Author(s):

Cao Ai Ping ◽

Shao Dong Nan ◽

Cui Bai Ming ◽

Zheng Yin Ying ◽

Sun jie

Keyword(s):

Gene Expression ◽

Reference Genes ◽

Gene Expression Level ◽

Expression Level ◽

Rna Seq ◽

Qrt Pcr ◽

Cotton Species ◽

Wide Range ◽

The Stability ◽

Suitable Reference

Analysis of gene expression level by RNA sequencing (RNA-seq ) has a wide range of biological purposes in various species. Real-time fluorescent quantitative PCR (qRT-PCR) evaluated gene expression levels and validated transcriptomic, which will depend on the stably expressed reference genes for normalization of the gene expression level under specific situations. In this study, 15 candidate genes were selected from transcriptome datasets during somatic embryogenesis (SE) initial dedifferentiation in Gossypium hirsutum L. of different SE capability. To evaluate the stability of those genes, geNorm, NormFinder and BestKeeper were used. The results revealed that ENDO4 and 18srRNA could be as appropriate reference genes under all conditions. The stability and reliability of the reference genes were further tested through comparison of qRT-PCR results and RNA-seq data, as well as evaluation of the expression profiles of auxin-responsive protein (AUX22) and ethylene-responsive transcription factor (ERF17). In summary, the results of our study indicate the most suitable reference genes for qRT-PCR during three induction stages in four cotton species.

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Validation of Reference Genes for Quantitative Real-time PCR in Diaphanosoma Celebensis: For Chemical Exposure Conditions and Different Ages

10.21203/rs.3.rs-847536/v1 ◽

2021 ◽

Author(s):

Young-Mi Lee ◽

Soyeon In ◽

Se-Joo Kim ◽

Eun-Ji Won ◽

Hayoung Cho ◽

...

Keyword(s):

Gene Expression ◽

Real Time ◽

Reference Gene ◽

Reference Genes ◽

Expression Profiles ◽

Chemical Exposure ◽

Mrna Levels ◽

Qrt Pcr ◽

Different Ages ◽

Diaphanosoma Celebensis

Abstract Real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR), a primary approach for evaluating gene expression, requires an appropriate normalization strategy to rule out variations in gene expression among samples. The best option is to use a reference gene whose expression level is stable across various experimental conditions to compare the mRNA levels of a target gene. However, there is limited information on how the reference gene is differentially expressed at different ages (growth) in small invertebrates with notable changes such as molting. In this study, expression profiles of nine candidate reference genes from the brackish water flea, Diaphanosoma celebensis, were evaluated under diverse exposure to toxicants and according to growth. As a result, four different algorithms showed similar stabilities of genes for chemical exposures in the case of limited conditions using the same developmental stage (e.g., adult), while the results according to age showed a significantly different pattern in suite of candidate reference genes. This affected the results of genes EcRA and GST, which are involved in development and detoxification mechanisms, respectively. Our finding is the first step towards establishing a standardized real-time qRT-PCR analysis of this environmentally important invertebrate that has potential for aquatic ecotoxicology, particularly in estuarine environments.

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Identification of suitable reference genes of Scylla paramamosain for gene expression profiling in various tissues and under vibrio challenge

Crustaceana ◽

10.1163/15685403-00003823 ◽

2018 ◽

Vol 91 (10) ◽

pp. 1195-1210 ◽

Cited By ~ 2

Author(s):

Yabo Fang ◽

Le Diao ◽

Fengying Zhang ◽

Lingbo Ma ◽

Mengdi Zhao ◽

...

Keyword(s):

Gene Expression ◽

Reference Gene ◽

Reference Genes ◽

18S Rrna ◽

Elongation Factor ◽

Scylla Paramamosain ◽

Mud Crab ◽

Expression Levels ◽

Qrt Pcr ◽

Elongation Factor 1

Abstract The quantitative real-time transcription-polymerase chain reaction (qRT-PCR) is now used widely in studies about mRNA expression levels. The selection of one or more stable reference gene(s) used for data normalization is substantial. In this study, expression levels of eleven candidate reference genes (β-actin, 16S rRNA, 18S rRNA, 28S rRNA, α-I tubulin, GAPDH, ribosomal protein L13, elongation factor 1 α, elongation factor 2, arginine kinase and ubiquitin) were examined using the GenomeLab GeXP analysis system (Beckman Coulter). Gene expression data were analysed using two different statistical models: geNorm and NormFinder. (1) In six different tissues (hepatopancreas, haemocytes, heart, gill, muscle, and testis) from the mud crab, Scylla paramamosain, 18S rRNA and elongation factor 1 α were identified as the two best reference genes. (2) In the haemocytes after being challenged by Vibro parahaemolyticus, the result suggested that ubiquitin was the most stable gene after the treatment. 18S rRNA, elongation factor 1 α and ubiquitin are herein recommended as the best combination. These results provide useful options for reference gene selection under different experimental conditions in qRT-PCR studies in the mud crab.

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Identification and Evaluation of Reference Genes for Normalization of Gene Expression in Developmental Stages, Sexes, and Tissues of Diaphania caesalis (Lepidoptera, Pyralidae)

Journal of Insect Science ◽

10.1093/jisesa/iez130 ◽

2020 ◽

Vol 20 (1) ◽

Cited By ~ 2

Author(s):

Zheng Wang ◽

Qianqian Meng ◽

Xi Zhu ◽

Shiwei Sun ◽

Aiqin Liu ◽

...

Keyword(s):

Gene Expression ◽

Reference Genes ◽

Target Gene ◽

Target Genes ◽

Developmental Stages ◽

Expression Profiles ◽

Transcriptional Level ◽

Internal Reference ◽

Target Gene Expression ◽

Qrt Pcr

Abstract Diaphania caesalis (Walker) is an important boring insect mainly distributed in subtropical and tropical areas and attacked tropical woody grain crops, such as starchy plants of Artocarpus. Quantitative real-time polymerase chain reaction (qRT-PCR) is a powerful approach for investigating target genes expression profiles at the transcriptional level. However, the identification and selection of internal reference genes, which is often overlooked, is the most vital step before the analysis of target gene expression by qRT-PCR. So far, the reliable internal reference genes under a certain condition of D. caesalis have not been investigated. Therefore, this study evaluated the expression stability of eight candidate reference genes including ACT, β-TUB, GAPDH, G6PDH, RPS3a, RPL13a, EF1α, and EIF4A in different developmental stages, tissues and sexes using geNorm, NormFinder and BestKeeper algorithms. To verify the stability of the recommended internal reference genes, the expression levels of DcaeOBP5 were analyzed under different treatment conditions. The results indicated that ACT, RPL13a, β-TUB, RPS3a, and EF1α were identified as the most stable reference genes for further studies on target gene expression involving different developmental stages of D. caesalis. And ACT and EIF4A were recommended as stable reference genes for different tissues. Furthermore, ACT, EF1α, and RPS3a were ranked as the best reference genes in different sexes based on three algorithms. Our research represents the critical first step to normalize qRT-PCR data and ensure the accuracy of expression of target genes involved in phylogenetic and physiological mechanism at the transcriptional level in D. caesalia.

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Reference gene selection for qRT-PCR analyses of luffa (Luffa cylindrica) plants under abiotic stress conditions

Scientific Reports ◽

10.1038/s41598-021-81524-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Min-dong Chen ◽

Bin Wang ◽

Yong-ping Li ◽

Mei-juan Zeng ◽

Jian-ting Liu ◽

...

Keyword(s):

Gene Expression ◽

Reference Gene ◽

Reference Genes ◽

Gene Selection ◽

Expression Patterns ◽

Suitable Reference Gene ◽

Expression Levels ◽

Qrt Pcr ◽

Suitable Reference ◽

Gene Expression Levels

AbstractSelecting suitable internal reference genes is an important prerequisite for the application of quantitative real-time PCR (qRT-PCR). However, no systematic studies have been conducted on reference genes in luffa. In this study, seven reference genes were selected, and their expression levels in luffa plants exposed to various simulated abiotic stresses [i.e., cold, drought, heat, salt, H2O2, and abscisic acid (ABA) treatments] were analyzed by qRT-PCR. The stability of the reference gene expression levels was validated using the geNorm, NormFinder, BestKeeper, and RefFinder algorithms. The results indicated that EF-1α was the most stably expressed and suitable reference gene overall and for the heat, cold, and ABA treatments. Additionally, UBQ expression was stable following the salt treatment, whereas TUB was identified as a suitable reference gene for H2O2 and drought treatments. The reliability of the selected reference genes was verified by analyzing the expression of copper/zinc superoxide dismutase (Cu/Zn-SOD) gene in luffa. When the most unstable reference genes were used for data normalizations, the resulting expression patterns had obvious biases when compared with the expression patterns for the most ideal reference genes used alone or combined. These results will be conducive to more accurate quantification of gene expression levels in luffa.

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Reference Gene Selection for Gene Expression Analyses in Mouse Models of Acute Lung Injury

International Journal of Molecular Sciences ◽

10.3390/ijms22157853 ◽

2021 ◽

Vol 22 (15) ◽

pp. 7853

Author(s):

Athanassios Fragoulis ◽

Kristina Biller ◽

Stephanie Fragoulis ◽

Dennis Lex ◽

Stefan Uhlig ◽

...

Keyword(s):

Gene Expression ◽

Acute Lung Injury ◽

Lung Injury ◽

Reference Gene ◽

Reference Genes ◽

Gene Selection ◽

Ex Vivo ◽

Qrt Pcr ◽

The Impact

qRT-PCR still remains the most widely used method for quantifying gene expression levels, although newer technologies such as next generation sequencing are becoming increasingly popular. A critical, yet often underappreciated, problem when analysing qRT-PCR data is the selection of suitable reference genes. This problem is compounded in situations where up to 25% of all genes may change (e.g., due to leukocyte invasion), as is typically the case in ARDS. Here, we examined 11 widely used reference genes for their suitability in commonly used models of acute lung injury (ALI): ventilator-induced lung injury (VILI), in vivo and ex vivo, lipopolysaccharide plus mechanical ventilation (MV), and hydrochloric acid plus MV. The stability of reference gene expression was determined using the NormFinder, BestKeeper, and geNorm algorithms. We then proceeded with the geNorm results because this is the only algorithm that provides the number of reference genes required to achieve normalisation. We chose interleukin-6 (Il‑6) and C-X-C motif ligand 1 (Cxcl-1) as the genes of interest to analyse and demonstrate the impact of inappropriate normalisation. Reference gene stability differed between the ALI models and even within the subgroup of VILI models, no common reference gene index (RGI) could be determined. NormFinder, BestKeeper, and geNorm produced slightly different, but comparable results. Inappropriate normalisation of Il-6 and Cxcl1 gene expression resulted in significant misinterpretation in all four ALI settings. In conclusion, choosing an inappropriate normalisation strategy can introduce different kinds of bias such as gain or loss as well as under- or overestimation of effects, affecting the interpretation of gene expression data.

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