Selection and evaluation of reference genes for qRT-PCR analysis in Euscaphis konishii Hayata based on transcriptome data

Selection and Validation of qRT-PCR Internal Reference Genes to Study Flower Color Formation in Camellia impressinervis

Real-time quantitative PCR (qRT-PCR) is a pivotal technique for gene expression analysis. To ensure reliable and accurate results, the internal reference genes must exhibit stable expression across varied experimental conditions. Currently, no internal reference genes for Camellia impressinervis have been established. This study aimed to identify stable internal reference genes from eight candidates derived from different developmental stages of C. impressinervis flowers. We employed geNorm, NormFinder, and BestKeeper to evaluate the expression stability of these candidates, which was followed by a comprehensive stability analysis. The results indicated that CiTUB, a tubulin gene, exhibited the most stable expression among the eight reference gene candidates in the petals. Subsequently, CiTUB was utilized as an internal reference for the qRT-PCR analysis of six genes implicated in the petal pigment synthesis pathway of C. impressinervis. The qRT-PCR results were corroborated by transcriptome sequencing data, affirming the stability and suitability of CiTUB as a reference gene. This study marks the first identification of stable internal reference genes within the entire genome of C. impressinervis, establishing a foundation for future gene expression and functional studies. Identifying such stable reference genes is crucial for advancing molecular research on C. impressinervis.

Screening and validation of optimal miRNA reference genes in different developing stages and tissues of Lilium henryi Baker

Dynamic miRNA detection using the qRT-PCR technique requires appropriate reference genes to ensure data reliability. Previous studies have screened internal reference genes in plants during embryonic development and various stress treatment, involving relatively few tissues and organs. There is no relevant miRNA study in Lilium henryi Baker and limited research on the optimal miRNA reference genes in lilies, such as 5S, 18S, U6 and Actin. Twelve genes were selected as candidate reference genes whose expression stability was analyzed in petals at different developmental stages and other tissues using various algorithms, such as geNorm, NormFinder, BestKeeper, and Delta CT. The results revealed that the optimal combination of reference genes for Lilium henryi Baker petals at different developmental stages was osa-miR166m and osa-miR166a-3p, while that for different tissues of Lilium henryi Baker was osa-miR166g-3p and osa-miR166a-3p.Four important genes related to growth and development regulation, namely, osa-miR156a, osa-miR395b, osa-miR396a-3p, and osa-miR396a-5p, were selected for validation. The findings of the present study could contribute to future investigations onmiRNA expression and the related functions in Lilium henryi Baker while providing important references for the normalization of the miRNA expression in other varieties of lily.

Selection and Verification of Standardized Reference Genes of Angelica dahurica under Various Abiotic Stresses by Real-Time Quantitative PCR

In traditional Chinese medicine, Angelica dahurica is a valuable herb with numerous therapeutic applications for a range of ailments. There have not yet been any articles on the methodical assessment and choice of the best reference genes for A. dahurica gene expression studies. Real-time quantitative PCR (RT-qPCR) is widely employed as the predominant method for investigating gene expression. In order to ensure the precise determination of target gene expression outcomes in RT-qPCR analysis, it is imperative to employ stable reference genes. In this study, a total of 11 candidate reference genes including SAND family protein (SAND), polypyrimidine tract-binding protein (PTBP), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), actin (ACT), TIP41-like protein (TIP41), cyclophilin 2 (CYP2), elongation factor 1 α (EF1α), ubiquitin-protein ligase 9 (UBC9), tubulin β-6 (TUB6), thioredoxin-like protein YLS8 (YLS8), and tubulin-α (TUBA) were selected from the transcriptome of A. dahurica. Subsequently, three statistical algorithms (geNorm, NormFinder, and BestKeeper) were employed to assess the stability of their expression patterns across seven distinct stimulus treatments. The outcomes obtained from these analyses were subsequently amalgamated into a comprehensive ranking using RefFinder. Additionally, one target gene, phenylalanine ammonia-lyase (PAL), was used to confirm the effectiveness of the selected reference genes. According to the findings of this study, the two most stable reference genes for normalizing the expression of genes in A. dahurica are TIP41 and UBC9. Overall, our research has determined the appropriate reference genes for RT-qPCR in A. dahurica and provides a crucial foundation for gene screening and identifying genes associated with the biosynthesis of active ingredients in A. dahurica.

Grapevine scion gene expression is driven by rootstock and environment interaction

BACKGROUND

Grafting is a horticultural practice used widely across woody perennial crop species to fuse together the root and shoot system of two distinct genotypes, the rootstock and the scion, combining beneficial traits from both. In grapevine, grafting is used in nearly 80% of all commercial vines to optimize fruit quality, regulate vine vigor, and enhance biotic and abiotic stress-tolerance. Rootstocks have been shown to modulate elemental composition, metabolomic profiles, and the shape of leaves in the scion, among other traits. However, it is currently unclear how rootstock genotypes influence shoot system gene expression as previous work has reported complex and often contradictory findings.

RESULTS

In the present study, we examine the influence of grafting on scion gene expression in leaves and reproductive tissues of grapevines growing under field conditions for three years. We show that the influence from the rootstock genotype is highly tissue and time dependent, manifesting only in leaves, primarily during a single year of our three-year study. Further, the degree of rootstock influence on scion gene expression is driven by interactions with the local environment.

CONCLUSIONS

Our results demonstrate that the role of rootstock genotype in modulating scion gene expression is not a consistent, unchanging effect, but rather an effect that varies over time in relation to local environmental conditions.

Flavonoid and chromone-rich extract from Euscaphis Konishii Hayata leaf attenuated alcoholic liver injury in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Euscaphis konishii Hayata is a traditional medicinal plant in China, and its leaves are usually used to make dishes for hepatic or gastrointestinal issues by Chinese She nationality. Pharmacological analysis showed that E. konishii leaves contain high levels of flavonoids and chromones with favorable anti-hepatoma effect.

AIM OF THE STUDY

The extract from E. konishii leaves was detected to evaluate its chemical composition, and the alcoholic liver injury mice model was adopted to elucidate its hepatoprotective effects.

MATERIALS AND METHODS

The total leaf extract from E. konishii was separated by polyamide column to get the flavonoid and chromone-rich extract (FCE). Single compounds from FCE was purified by gel and Sephadex LH-20 chromatography and analyzed by nuclear magnetic resonance (NMR). The chemical component of FCE was confirmed and quantified by HPLC-MS. The OH·, O₂^-, DPPH and ABTS ⁺ free radical assays were adopted to estimate the antioxidant activity of FCE in vitro. The alcohol-fed model mice were established to assess the hepatoprotective capacity of FCE in vivo, through biochemical determination, histopathological analysis, mitochondrial function measurement, quantitative Real-Time Polymerase Chain Reaction (qRT-PCR) detection and Western blot determination.

RESULTS

8 flavonoids and 2 chromones were recognized in the FCEextract by both NMR and HPLC-MS. FCE represented strong free radicals scavenging activity in vitro. With oral administration, FCE (50, 100 and 200 mg/kg) dose-dependently decreased the serum levels of alanine aminotransferase (ALT), alkaline phosphatase (ALP) and aspartate aminotransferase (AST) in alcohol-fed mice. FCE gradually reduced the malondialdehyde (MDA) content, increased the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in the alcohol-treated liver tissues. FCE also alleviated the hepatic inflammation, inhibited the hepatocyte apoptosis and lessened the alcohol-induced histological alteration and lipid accumulation in the liver tissues. FCE administration inhibited the overexpression of endoplasmic reticulum (ER) chaperones signaling and unfolded protein response (UPR) pathways to defense the ER-induced apoptosis. Pretreatment with FCE also restored the mitochondrial membrane potentials andadenosine triphosphate (ATP) levels, which in turn suppressed the Cytochrome C release and mitochondria-induced apoptosis.

CONCLUSIONS

FCE conferred great protection against alcoholic liver injury, which might be associated with its viability through suppressing reactive oxygen species (ROS) stress and hepatocyte apoptosis.

Identification and Validation of Reference Genes for Expression Analysis Using qRT-PCR in Cimex hemipterus (Hemiptera: Cimicidae)

The tropical bed bug, Cimex hemipterus (F.) (Hemiptera: Cimicidae) is an important public-health pest that feeds on the blood of humans and some other animals. To explore the function of the target genes of C. hemipterus, it is essential to select suitable reference genes for the accurate quantification of gene expression. Here, we selected 10 frequently used reference genes in insects and evaluated their stability in C. hemipterus under various biotic (developmental stage, sex, and tissue) and abiotic (gas stimulation and temperature) conditions through RefFinder (which integrates four computational programs: geNorm, NormFinder, BestKeeper, and ∆Ct). Results indicate that the optimal combination of reference genes for each experimental condition was as follows: RPL8 and EF1α for the developmental stage (eggs, early instar nymphs, late instar nymphs, and adults), RPL8 and RPS16 for adult sex, RPL8 and RPL11 for adult tissue (head, thorax, abdomen, and legs), RPL8 and β-tubulin for gas stimulation (air and carbon dioxide), and RPL8 and NADH for temperature (0, 5, 17, 30, and 37 °C). Finally, the expression pattern of the HSP70 and GR21 genes were analyzed, and the results highlight the importance of appropriate reference-gene selection. Our results provide a comprehensive list of optimal reference genes from C. hemipterus for the first time, which will contribute to accurately analyzing the expression of target genes.

Selection of Suitable Reference Genes for Gene Expression Normalization Studies in Dendrobium huoshanense

Dendrobium huoshanense is a kind of precious herb with important medicinal and edible value in China, which is widely used in traditional Chinese medicine for various diseases. Recent studies have paid close attention to the genetic expression of the biosynthetic pathway of the main active components (polysaccharides, alkaloids, and flavonoids), and real-time polymerase chain reaction (qPCR) is one of the most widely used methods for doing so. However, so far, no reference gene selections have been reported in D. huoshanense. In this study, 15 reference gene candidates (GAPDH, eIF, EF-1α, PP2A, UBCE, RPL5, TBP, APT1, MDH, PTBP3, PEPC, CYP71, NCBP2, TIP41, and F-box) were selected and evaluated for their expression stability in D. huoshanense under various experimental conditions, including in different tissues (root, stem, and leaf), abiotic stresses (oxidative, drought, cold, and UV), and hormone treatment (methyl jasmonate) using three statistical programs (geNorm, NormFinder, and BestKeeper). Then, the RefFinder program was employed to comprehensively validate the stability of the selected reference genes. Finally, the expression profiles of the CESA and GMPP genes were further analyzed, and these results indicated that TBP, NCBP2, and CYP71 were the top three most stable reference genes after comprehensive comparison, which could be used as stable reference genes for normalizing the genes expression in D. huoshanense. This study described here provides the first data regarding on reference gene selection in D. huoshanense, which will be extremely beneficial for future research on the gene expression normalization in D. huoshanense.

Genome-Wide Identification and Co-Expression Analysis of ARF and IAA Family Genes in Euscaphis konishii: Potential Regulators of Triterpenoids and Anthocyanin Biosynthesis

Euscaphis konishii is an evergreen plant that is widely planted as an industrial crop in Southern China. It produces red fruits with abundant secondary metabolites, giving E. konishii high medicinal and ornamental value. Auxin signaling mediated by members of the AUXIN RESPONSE FACTOR (ARF) and auxin/indole-3-acetic acid (Aux/IAA) protein families plays important roles during plant growth and development. Aux/IAA and ARF genes have been described in many plants but have not yet been described in E. konishii. In this study, we identified 34 EkIAA and 29 EkARF proteins encoded by the E. konishii genome through database searching using HMMER. We also performed a bioinformatic characterization of EkIAA and EkARF genes, including their phylogenetic relationships, gene structures, chromosomal distribution, and cis-element analysis, as well as conserved motifs in the proteins. Our results suggest that EkIAA and EkARF genes have been relatively conserved over evolutionary history. Furthermore, we conducted expression and co-expression analyses of EkIAA and EkARF genes in leaves, branches, and fruits, which identified a subset of seven EkARF genes as potential regulators of triterpenoids and anthocyanin biosynthesis. RT-qPCR, yeast one-hybrid, and transient expression analyses showed that EkARF5.1 can directly interact with auxin response elements and regulate downstream gene expression. Our results may pave the way to elucidating the function of EkIAA and EkARF gene families in E. konishii, laying a foundation for further research on high-yielding industrial products and E. konishii breeding.

Selection and Validation of Reference Genes for Quantitative Real-Time PCR Analysis of Development and Tissue-Dependent Flower Color Formation in Cymbidium lowianum

The development and tissue-dependent color formation of the horticultural plant results in various color pattern flowers. Anthocyanins and carotenoids contribute to the red and yellow colors, respectively. In this study, quantitative real-time polymerase chain reaction (qRT-PCR) is used to analyze the expression profiles of anthocyanin and carotenoids biosynthesis genes in Cymbidium lowianum (Rchb.f.) Rchb.f. Appropriate reference gene selection and validation are required before normalization of gene expression in qRT-PCR analysis. Thus, we firstly selected 12 candidate reference genes from transcriptome data, and used geNorm and Normfinder to evaluate their expression stability in lip (divided into abaxial and adaxial), petal, and sepal of the bud and flower of C. lowianum. Our results show that the two most stable reference genes in different tissues of C. lowianum bud and flower are EF1δ and 60S, the most unstable reference gene is 26S. The expression profiles of the CHS and BCH genes were similar to FPKM value profiles after normalization to the two most stable reference genes, EF1δ and 60S, with the upregulated CHS and BCH expression in flower stage, indicating that the ABP and CBP were activated across the stages of flower development. However, when the most unstable reference gene, 26S, was used to normalize the qRT-PCR data, the expression profiles of CHS and BCH differed from FPKM value profiles, indicating the necessity of selecting stable reference genes. Moreover, CHS and BCH expression was highest in the abaxial lip and adaxial lip, respectively, indicating that the ABP and CBP were activated in abaxial and adaxial lip, respectively, resulting in a presence of red or yellow segments in abaxial and adaxial lip. This study is the first to provide reference genes in C. lowianum, and also provide useful information for studies that aim to understand the molecular mechanisms of flower color formation in C. lowianum.

Multi-dimensional leaf phenotypes reflect root system genotype in grafted grapevine over the growing season

BACKGROUND

Modern biological approaches generate volumes of multi-dimensional data, offering unprecedented opportunities to address biological questions previously beyond reach owing to small or subtle effects. A fundamental question in plant biology is the extent to which below-ground activity in the root system influences above-ground phenotypes expressed in the shoot system. Grafting, an ancient horticultural practice that fuses the root system of one individual (the rootstock) with the shoot system of a second, genetically distinct individual (the scion), is a powerful experimental system to understand below-ground effects on above-ground phenotypes. Previous studies on grafted grapevines have detected rootstock influence on scion phenotypes including physiology and berry chemistry. However, the extent of the rootstock's influence on leaves, the photosynthetic engines of the vine, and how those effects change over the course of a growing season, are still largely unknown.

RESULTS

Here, we investigate associations between rootstock genotype and shoot system phenotypes using 5 multi-dimensional leaf phenotyping modalities measured in a common grafted scion: ionomics, metabolomics, transcriptomics, morphometrics, and physiology. Rootstock influence is ubiquitous but subtle across modalities, with the strongest signature of rootstock observed in the leaf ionome. Moreover, we find that the extent of rootstock influence on scion phenotypes and patterns of phenomic covariation are highly dynamic across the season.

CONCLUSIONS

These findings substantially expand previously identified patterns to demonstrate that rootstock influence on scion phenotypes is complex and dynamic and underscore that broad understanding necessitates volumes of multi-dimensional data previously unmet.

Public transcriptome database-based selection and validation of reliable reference genes for breast cancer research

Background

Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) is the most sensitive technique for evaluating gene expression levels. Choosing appropriate reference genes (RGs) is critical for normalizing and evaluating changes in the expression of target genes. However, uniform and reliable RGs for breast cancer research have not been identified, limiting the value of target gene expression studies. Here, we aimed to identify reliable and accurate RGs for breast cancer tissues and cell lines using the RNA-seq dataset.

Methods

First, we compiled the transcriptome profiling data from the TCGA database involving 1217 samples to identify novel RGs. Next, ten genes with relatively stable expression levels were chosen as novel candidate RGs, together with six conventional RGs. To determine and validate the optimal RGs we performed qRT-PCR experiments on 87 samples from 11 types of surgically excised breast tumor specimens (n = 66) and seven breast cancer cell lines (n = 21). Five publicly available algorithms (geNorm, NormFinder, ΔCt method, BestKeeper, and ComprFinder) were used to assess the expression stability of each RG across all breast cancer tissues and cell lines.

Results

Our results show that RG combinations SF1 + TRA2B + THRAP3 and THRAP3 + RHOA + QRICH1 showed stable expression in breast cancer tissues and cell lines, respectively, and that they displayed good interchangeability. We propose that these combinations are optimal triplet RGs for breast cancer research.

Conclusions

In summary, we identified novel and reliable RG combinations for breast cancer research based on a public RNA-seq dataset. Our results lay a solid foundation for the accurate normalization of qRT-PCR results across different breast cancer tissues and cells.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12938-021-00963-8.

Identification and validation of reference genes for qRT-PCR based studies in horse gram (Macrotyloma uniflorum)

The quantitative real-time polymerase chain reaction (qRT-PCR) is the most sensitive and commonly used technique for gene expression studies in biological systems. However, the reliability of qRT-PCR results depends on the selection of reference gene(s) for data normalization. Horse gram (Macrotyloma uniflorum) is an important legume crop on which several molecular studies have been reported. However, the stability of reference genes has not been evaluated. In the present study, nine candidate reference genes were identified from horse gram RNA-seq data and evaluated in two horse gram genotypes, HPK4 and HPKM317 under six abiotic stresses viz. cold, drought, salinity, heat, abscisic acid and methyl viologen-induced oxidative stress. The results were evaluated using geNorm, Bestkeeper, Normfinder and delta-delta Ct methods and comprehensive ranking was assigned using RefFinder and RankAggreg software. The overall result showed that TCTP was one of the most stable genes in all samples and in genotype HPK4, while in HPKM317 profilin was most stably expressed. However, PSMA5 was identified as least stable in all the experimental conditions. Expression of target genes dehydrin and early response to dehydration 6 under drought stress was also validated using TCTP and profilin for data normalization, either alone or in combination, which confirmed their suitability for qRT-PCR data normalization. Thus, TCTP and profilin genes may be used for qRT-PCR data normalization for molecular and genomic studies in horse gram.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s12298-021-01104-0.

The Euscaphis japonica genome and the evolution of malvids

Malvids is one of the largest clades of rosids, includes 58 families and exhibits remarkable morphological and ecological diversity. Here, we report a high-quality chromosome-level genome assembly for Euscaphis japonica, an early-diverging species within malvids. Genome-based phylogenetic analysis suggests that the unstable phylogenetic position of E. japonica may result from incomplete lineage sorting and hybridization event during the diversification of the ancestral population of malvids. Euscaphis japonica experienced two polyploidization events: the ancient whole genome triplication event shared with most eudicots (commonly known as the γ event) and a more recent whole genome duplication event, unique to E. japonica. By resequencing 101 samples from 11 populations, we speculate that the temperature has led to the differentiation of the evergreen and deciduous of E. japonica and the completely different population histories of these two groups. In total, 1012 candidate positively selected genes in the evergreen were detected, some of which are involved in flower and fruit development. We found that reddening and dehiscence of the E. japonica pericarp and long fruit-hanging time promoted the reproduction of E. japonica populations, and revealed the expression patterns of genes related to fruit reddening, dehiscence and abscission. The key genes involved in pentacyclic triterpene synthesis in E. japonica were identified, and different expression patterns of these genes may contribute to pentacyclic triterpene diversification. Our work sheds light on the evolution of E. japonica and malvids, particularly on the diversification of E. japonica and the genetic basis for their fruit dehiscence and abscission.

Validation of Reference Genes for Quantitative Real-Time PCR Normalization in Ananas comosus var. bracteatus During Chimeric Leaf Development and Response to Hormone Stimuli

Reverse transcription quantitative real-time PCR (RT-qPCR) is a common way to study gene regulation at the transcriptional level due to its sensibility and specificity, but it needs appropriate reference genes to normalize data. Ananas comosus var. bracteatus, with white-green chimeric leaves, is an important pantropical ornamental plant. Up to date, no reference genes have been evaluated in Ananas comosus var. bracteatus. In this work, we used five common statistics tools (geNorm, NormFinder, BestKeeper, ΔCt method, RefFinder) to evaluate 10 candidate reference genes. The results showed that Unigene.16454 and Unigene.16459 were the optimal reference genes for different tissues, Unigene.16454 and zinc finger ran-binding domain-containing protein 2 (ZRANB2) for chimeric leaf at different developmental stages, isocitrate dehydrogenase [NADP] (IDH) and triacylglycerol lipase SDP1-like (SDP) for seedlings under different hormone treatments. The comprehensive results showed IDH, pentatricopeptide repeat-containing protein (PPRC), Unigene.16454, and caffeoyl-CoA O methyltransferase 5-like (CCOAOMT) are the top-ranked stable genes across all the samples. The stability of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was the least during all experiments. Furthermore, the reliability of recommended reference gene was validated by the detection of porphobilinogen deaminase (HEMC) expression levels in chimeric leaves. Overall, this study provides appropriate reference genes under three specific experimental conditions and will be useful for future research on spatial and temporal regulation of gene expression and multiple hormone regulation pathways in Ananas comosus var. bracteatus.

Identification and selection of reference genes for gene expression analysis by quantitative real-time PCR in Suaeda glauca's response to salinity

Quantitative real-time polymerase chain reaction (qPCR) using a stable reference gene is widely used for gene expression research. Suaeda glauca L. is a succulent halophyte and medicinal plant that is extensively used for phytoremediation and extraction of medicinal compounds. It thrives under high-salt conditions, which promote the accumulation of high-value secondary metabolites. However, a suitable reference gene has not been identified for gene expression standardization in S. glauca under saline conditions. Here, 10 candidate reference genes, ACT7, ACT11, CCD1, TUA5, UPL1, PP2A, DREB1D, V-H⁺-ATPase, MPK6, and PHT4;5, were selected from S. glauca transcriptome data. Five statistical algorithms (ΔCq, geNorm, NormFinder, BestKeeper, and RefFinder) were applied to determine the expression stabilities of these genes in 72 samples at different salt concentrations in different tissues. PP2A and TUA5 were the most stable reference genes in different tissues and salt treatments, whereas DREB1D was the least stable. The two reference genes were sufficient to normalize gene expression across all sample sets. The suitability of identified reference genes was validated with MYB and AP2 in germinating seeds of S. glauca exposed to different NaCl concentrations. Our study provides a foundational framework for standardizing qPCR analyses, enabling accurate gene expression profiling in S. glauca.

Identification of Ginger (Zingiber officinale Roscoe) Reference Genes for Gene Expression Analysis

Quantitative real-time PCR (qRT-PCR) is widely used in the detection of gene expression level. However, there is no suitable ginger reference gene for qPCR analysis. Therefore, it is the primary task to select and validate the appropriate ginger reference gene to normalize the expression of target genes. In this study, 14 candidate reference genes were selected and analyzed in different tissues (leaf, and rhizome), different development stages, different varieties, and abiotic stress (ABA and salt stress). Expression stability was calculated using geNorm and NormFinder, Bestkeeper, and RefFinder. For abiotic stress and total conditions, 28S and COX were identified as the most stable genes. In addition, RPII was the most stable in the different development stages and different varieties. TEF2 and RPL2 were the least stably expressed in the tissue and all the conditions. In order to verify the feasibility of these genes as reference genes, we used the most stable and least stable reference genes to normalize the expression levels of ZoSPS genes under different conditions. This work can provide theoretical support for future research on ginger gene expression.

Transcriptome-based selection and validation of optimal house-keeping genes for skin research in goats (Capra hircus)

BACKGROUND

In quantitative real-time polymerase chain reaction (qRT-PCR) experiments, accurate and reliable target gene expression results are dependent on optimal amplification of house-keeping genes (HKGs). RNA-seq technology offers a novel approach to detect new HKGs with improved stability. Goat (Capra hircus) is an economically important livestock species and plays an indispensable role in the world animal fiber and meat industry. Unfortunately, uniform and reliable HKGs for skin research have not been identified in goat. Therefore, this study seeks to identify a set of stable HKGs for the skin tissue of C. hircus using high-throughput sequencing technology.

RESULTS

Based on the transcriptome dataset of 39 goat skin tissue samples, 8 genes (SRP68, NCBP3, RRAGA, EIF4H, CTBP2, PTPRA, CNBP, and EEF2) with relatively stable expression levels were identified and selected as new candidate HKGs. Commonly used HKGs including SDHA and YWHAZ from a previous study, and 2 conventional genes (ACTB and GAPDH) were also examined. Four different experimental variables: (1) different development stages, (2) hair follicle cycle stages, (3) breeds, and (4) sampling sites were used for determination and validation. Four algorithms (geNorm, NormFinder, BestKeeper, and ΔCt method) and a comprehensive algorithm (ComprFinder, developed in-house) were used to assess the stability of each HKG. It was shown that NCBP3 + SDHA + PTPRA were more stably expressed than previously used genes in all conditions analysis, and that this combination was effective at normalizing target gene expression. Moreover, a new algorithm for comprehensive analysis, ComprFinder, was developed and released.

CONCLUSION

This study presents the first list of candidate HKGs for C. hircus skin tissues based on an RNA-seq dataset. We propose that the NCBP3 + SDHA + PTPRA combination could be regarded as a triplet set of HKGs in skin molecular biology experiments in C. hircus and other closely related species. In addition, we also encourage researchers who perform candidate HKG evaluations and who require comprehensive analysis to adopt our new algorithm, ComprFinder.

LncRNA HCG11 Suppresses Cell Proliferation and Promotes Apoptosis via Sponging miR-224-3p in Non-Small-Cell Lung Cancer Cells

INTRODUCTION

Studies have found that Lnc-HCG11 is an important regulator of cancer. However, the function of Lnc-HCG11 in NSCLC is not known. Therefore, this experimental design was based on Lnc-HCG11 to explore the pathogenesis of NSCLC.

METHODS

RT-qPCR was used to detect the expression of Lnc-HCG11 and miR-224-3p in NSCLC. The effects of Lnc-HCG11 and miR-224-3p on proliferation and apoptosis of NSCLC cells were detected by CCK-8 assay, Edu assay and Annexin V-FITC/PI assay. Target gene prediction and screening, luciferase reporter assays were used to verify downstream target genes for lnc-HCG11 and miR-224-3p. Western blotting was used to detect the protein expression of caspase-3. The tumor changes in mice were detected by in vivo.

RESULTS

Lnc-HCG11 was significantly reduced in NSCLC. Lnc-HCG11 significantly inhibited cell proliferation of NSCLC cells and induced apoptosis. miR-224-3p was significantly elevated in the NSCLC cell line. Moreover, miR-224-3p significantly increased cell proliferation and inhibited apoptosis of NSCLC cells. Furthermore, Lnc-HCG11 was negatively correlated with miR-224-3p expression. Lnc-HCG11 over-expression was up-regulated the expression levels of c-caspase-3 and caspase-3. Finally, the results of in vivo animal models confirmed that Lnc-HCG11 inhibited tumor growth by modulating the miR-224-3p/c-caspase-3 axis.

CONCLUSION

Lnc-HCG11 could inhibit the progression of NSCLC by modulating the miR-224-3p/caspase-3 axis, and Lnc-HCG11 may be a potential therapeutic target for NSCLC.

Comprehensive transcriptome analysis of reference genes for fruit development of Euscaphis konishii

Background

Quantitativereal-time reverse transcriptase polymerase chain reaction is the common method to quantify relative gene expression. Normalizating using reliable genes is critical in correctly interpreting expression data from qRT-PCR. Euscaphis konishii is a medicinal plant with a long history in China, which has various chemical compounds in fruit. However, there is no report describing the selection of reference genes in fruit development of Euscaphis konishii.

Methods

We selected eight candidate reference genes based on RNA-seq database analysis, and ranked expression stability using statistical algorithms GeNorm, NormFinder, BestKeeper and ReFinder. Finally, The nine genes related to the anthocyanin synthesis pathway of Euscaphis konishii were used to verify the suitability of reference gene.

Results

The results showed that the stability of EkUBC23, EkCYP38 and EkGAPDH2 was better, and the low expression reference genes (EkUBC23 and EkCYP38) were favourable for quantifying low expression target genes, while the high expression reference gene (EkGAPDH2) was beneficial for quantifying high expression genes. In this study, we present the suitable reference genes for fruit development of Euscaphis konishii based on transcriptome data, our study will contribute to further studies in molecular biology and gene function on Euscaphis konishii and other closely related species.

Selection and Validation of Appropriate Reference Genes for Quantitative RT-PCR Analysis in Rubia yunnanensis Diels Based on Transcriptome Data

Real-time quantitative polymerase chain reaction (RT-qPCR) has been widely applied in gene expression and transcription abundance analysis because of its high sensitivity, good repeatability, and strong specificity. Selection of relatively stable reference genes is a precondition in order to obtain the reliable analysis results. However, little is known about evaluation of a set of reference genes through scientific experiments in Rubia plants. Here, 15 candidate reference genes were selected from R. yunnanensis transcriptome database and analyzed under abiotic stresses, hormone treatments, and different tissues. Among these 15 candidate reference genes, heterogeneous nuclear ribonucleoprotein (hnRNP), TATA binding protein (TBP), ribosomal protein L5 (RPL5), malate dehydrogenase (MDH), and elongation factor 1-alpha (EF-1α) were indicated as the five most stable reference genes by four statistical programs (geNorm, NormFinder, BestKeeper, and RefFinder). Ultimately, the validity of reference genes was confirmed by normalizing the expression of o-succinylbenzoate-CoA ligase (OSBL) and isochorismate synthase (ICS) involved in the anthraquinone biosynthesis pathway in different tissues and hormone treatments. Meanwhile, four other putative genes involved in the anthraquinone biosynthesis pathway were also normalized with the selected reference genes, which showed similar expression levels with those given by transcriptome data. This work is the first research that aims at a systematic validation on the stability of reference genes selected from R. yunnanensis transcriptome data and will be conducive to analyze gene expression in R. yunnanensis or other Rubia species.

Selection and Validation of Reference Genes for Gene Expression Studies in Codonopsis pilosula Based on Transcriptome Sequence Data

Relative gene expression analyses by RT-qPCR (reverse transcription-quantitative PCR) are highly dependent on the reference genes in normalizing the expression data of target genes. Therefore, inappropriate endogenous control genes will lead to inaccurate target gene expression profiles, and the selection and validation of suitable internal reference genes becomes essential. In this study, we retrieved the commonly used reference genes in transcriptome datasets of Codonopsis pilosula by RNA-Seq (unpublished data), and selected 15 candidate reference genes according to the coefficient of variation (CV) and fold change (FC) value of gene expression. The expression levels of candidate reference genes, which is at different growth stages, undergoing cold stress and drought stress, was determined by RT-qPCR. The expression stability of these genes was evaluated using software packages and algorithms including ΔCt, geNorm, NormFinder and Bestkeeper. Then appropriate reference genes were screened and validated by target gene-UDGPase (UDP glucose pyrophosphorylase). The optimal RGs combinations of C. pilosula, including PP2A59γ, CPY20-1, UBCE32, RPL5B and UBC18 for developmental stage, RPL5B, RPL13 and PP2A59γ for cold treatment, RPL13 and PP2A59γ for drought treatment, were found and proposed as reference genes for future work. This paper laid foundations for both the selection of reference genes and exploration in metabolic mechanism of C. pilosula.

Selection of the Reference Gene for Expression Normalization in Papaver somniferum L. under Abiotic Stress and Hormone Treatment

Papaver somniferum L. is an important medical plant that produces analgesic drugs used for the pain caused by cancers and surgeries. Recent studies have focused on the expression genes involved in analgesic drugs biosynthesis, and the real-time quantitative polymerase chain reaction (RT-qPCR) technique is the main strategy. However, no reference genes have been reported for gene expression normalization in P. somniferum. Herein, nine reference genes (actin (ACT), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), cyclophilin 2 (CYP2), elongation factor 1-alpha (EF-1α), glyceraldehyde-3-phosphate dehydrogenase 2, cytosolic (GAPC2), nuclear cap-binding protein subunit 2 (NCBP2), protein phosphatase 2A (PP2A), TIP41-like protein (TIP41), and tubulin beta chain (TUB)) of P. somniferum were selected and analyzed under five different treatments (cold, drought, salt, heavy metal, and hormone stress). Then, BestKeeper, NormFinder, geNorm, and RefFinder were employed to analyze their gene expression stability. The results reveal that NCBP2 is the most stable reference gene under various experimental conditions. The work described here is the first report regarding on reference gene selection in P. somniferum, which could be used for the accurate normalization of the gene expression involved in analgesic drug biosynthesis.

Evaluation of duplicated reference genes for quantitative real-time PCR analysis in genome unknown hexaploid oat (Avena sativa L.)

BACKGROUND

Oat (Avena sativa L.), a hexaploid crop with unknown genome, has valuable nutritional, medicinal and pharmaceutical uses. However, no suitable RGs (reference genes) for qPCR (quantitative real-time PCR) has been documented for oat yet. Single-copy gene is often selected as RG, which is challengeable or impactable in unexplored polyploids.

RESULTS

In this study, eleven candidate RGs, including four duplicated genes, were selected from oat transcriptome. The stability and the optimal combination of these candidate RGs were assessed in 18 oat samples by using four statistical algorithms including the ΔCt method, geNorm, NormFinder and BestKeeper. The most stable RGs for "all samples", "shoots and roots of seedlings", "developing seeds" and "developing endosperms" were EIF4A (Eukaryotic initiation factor 4A-3), UBC21 (Ubiquitin-Conjugating Enzyme 21), EP (Expressed protein) and EIF4A respectively. Among these RGs, UBC21 was a four-copy duplicated gene. The reliability was validated by the expression patterns of four various genes normalized to the most and the least stable RGs in different sample sets.

CONCLUSIONS

Results provide a proof of concept that the duplicated RG is feasible for qPCR in polyploids. To our knowledge, this study is the first systematic research on the optimal RGs for accurate qPCR normalization of gene expression in different organs and tissues of oat.

Screening and Evaluation of Stable Reference Genes for Quantitative Real-Time Polymerase Chain Reaction (qRT-PCR) Analysis in Chinese Fir Roots under Water, Phosphorus, and Nitrogen Stresses

Chinese fir (Cunninghamia lanceolata) is an economical important timber species widely planted in southeastern Asia. Decline in yield and productivity during successive rotation is believed to be linked with abiotic stress, such as drought stress and nitrogen (N) and phosphorus (P) starvation. Molecular breeding could be an option to develop tolerant genotypes. For gene expression studies using quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR), stable reference genes are needed for normalization of gene expression under different experimental conditions. However, there is no internal reference genes identified for Chinese fir under abiotic stresses. Thus, nine internal reference genes based on transcriptome data were selected and analyzed in the root of Chinese fir under drought stress and N and P starvation. Data were analyzed using geNorm, NormFinder, and BestKeeper, to screen and identify the best reference genes. The results showed that the UBQ and GAPDH genes were the two most stable genes under drought stress and the Actin1 and GAPDH were the two most stable genes under P starvation. Further, it was discovered that the Actin1 and UBC were the two most stable genes under N starvation among nine candidate reference genes. The gene expression of drought stress induced expression protein 14-3-3-4, the P transporter gene ClPht1;3, and the nitrate transporter gene NRT1.1 were used to verify the stability of the selected reference genes under drought stress and P and N starvation, respectively, and the results revealed that the screened reference genes were sufficient to normalize expression of the target genes. In conclusion, the results demonstrate that the stability of reference genes was closely related to the external conditions and reference genes applied to the roots of Chinese fir under different abiotic stress treatments were different. Our data will facilitate further studies on stress ecology and gene function analysis in Chinese fir.

Identification and evaluation of reference genes for quantitative real-time PCR analysis in Polygonum cuspidatum based on transcriptome data

BACKGROUND

Polygonum cuspidatum of the Polygonaceae family is a traditional medicinal plant with many bioactive compounds that play important roles in human health and stress responses. Research has attempted to identify biosynthesis genes and metabolic pathways in this species, and quantitative real-time PCR (RT-qPCR) has commonly been used to detect gene expression because of its speed, sensitivity, and specificity. However, no P. cuspidatum reference genes have been identified, which hinders gene expression studies. Here, we aimed to identify suitable reference genes for accurate and reliable normalization of P. cuspidatum RT-qPCR data.

RESULTS

Twelve candidate reference genes, including nine common (ACT, TUA, TUB, GAPDH, EF-1γ, UBQ, UBC, 60SrRNA, and eIF6A) and three novel (SKD1, YLS8, and NDUFA13), were analyzed in different tissues (root, stem, and leaf) without treatment and in leaves under abiotic stresses (salt, ultraviolet [UV], cold, heat, and drought) and hormone stimuli (abscisic acid [ABA], ethylene [ETH], gibberellin [GA₃], methyl jasmonate [MeJA], and salicylic acid [SA]). Expression stability in 65 samples was calculated using the △CT method, geNorm, NormFinder, BestKeeper, and RefFinder. Two reference genes (NDUFA13 and EF-1γ) were sufficient to normalize gene expression across all sample sets. They were also the two most stable genes for abiotic stresses and different tissues, whereas NDUFA13 and SKD1 were the top two choices for hormone stimuli. Considering individual experimental sets, GAPDH was the top-ranked gene under ABA, ETH, and GA₃ treatments, while 60SrRNA showed good stability under MeJA and cold treatments. ACT, UBC, and TUB were suitable genes for drought, UV, and ABA treatments, respectively. TUA was not suitable because of its considerable variation in expression under different conditions. The expression patterns of PcPAL, PcSTS, and PcMYB4 under UV and SA treatments and in different tissues normalized by stable and unstable reference genes demonstrated the suitability of the optimal reference genes.

CONCLUSIONS

We propose NDUFA13 and EF-1γ as reference genes to normalize P. cuspidatum expression data. To our knowledge, this is the first systematic study of reference genes in P. cuspidatum which could help advance molecular biology research in P. cuspidatum and allied species.

Multivariate analysis reveals phenotypic diversity of Euscaphis japonica population

Fruit traits affect population genetic diversity by affecting seed protection and dispersal strategies, thereby comprising important components of phenotypic variation. Understanding of the phenotypic variation is an indispensable first step for developing breeding strategies. However, little information is known about the genetic variation in E. japonica-a monotypic species with abundant phenotypes that is mainly distributed in southern China. In this study, we evaluated the phenotypic diversity of 67 E. japonica using 23 phenotypic traits. Our results showed that the Shannon-Wiener (I) index of qualitative traits ranged from 0.55 to 1.26, and the color traits had a relatively high I. The average coefficient of variation of compound leaf traits (14.74%) was higher than that of fruit and seed traits (12.77% and 11.47%, respectively). Principal component analysis also showed that compound leaf and fruit traits were important components of total variation. Furthermore, correlation analysis revealed a significant difference in elevation and fruit color, irregular ribs, leaf margin and texture. The F value within populations was smaller than among populations, indicating the variation in phenotypic traits among populations was much greater than within populations. Dehua and Zunyi populations had the highest coefficients of variation, whereas Wenzhou population had the smallest-which may be attributed to habitat destruction. According to Q-type clustering, 67 samples clustered into four groups, with those having similar phenotypes clustering into the same group. In general, leaf and fruit traits had abundant phenotypic diversity, representing the main sources of phenotypic variation. Combined with clustering results and field surveys, this study suggests that the phenotypes of E. japonica are classified into two main categories: The deciduous E. japonica present at high altitudes; and the evergreen E. japonica present at low altitudes. Excavating E. japonica variations provides a theoretical reference for its classification and diversity, and is of great significance for planning genetic resources and establishing conservation strategies.

Identification of reliable reference genes for quantitative real-time PCR normalization in pitaya

BACKGROUND

A suitable reference gene is an important prerequisite for guarantying accurate and reliable results in quantitative real-time PCR (qRT-PCR) analyses. However, there is no absolute universality in reference genes among different species. It's hard to find an ideal reference gene to fit for different tissues and growth periods. Pitaya (Hylocereus) is commercially produced as a new fruit crop at a large scale in tropical and subtropical regions. To date, there is no report on the identification of the most reliable reference genes for qRT-PCR normalization in pitaya.

RESULTS

In this study, six candidate reference genes i.e. Actin(1), GAPDH, UBC(1), UBC(2) EF1-α(1) and histone(1) were selected from thirty-nine typical candidate reference genes to determine the most stable reference genes for qRT-PCR normalization in different tissues, temperature stresses and fruit developmental stages of pitaya. Among the six candidate reference genes, Actin(1) and EF1-α(1) were the most stable gene according to calculations of three statistical methods (GeNorm, NormFinder and BestKeeper) while UBC(1) and UBC(2) showed the lowest expression stability. The six candidate reference genes were further validated by comparing expression profiles of key genes related to betalain biosynthesis at flesh coloration stages of Guanhuahong (Hylocereus monacanthus) and Guanhuabai (H. undatus) pitayas. Actin(1) was recommended the best reference gene for accurate normalization of qRT-PCR data.

CONCLUSIONS

In this study, the stability of the selected reference genes for normalizing the qRT-PCR data were identified from pitaya. Actin(1) was the most stably expressed genes in different tissues and fruit developmental stages in pitaya. The present work provides the first data of reference gene identification for pitaya and will facilitate further studies in molecular biology and gene function on Hylocereus and other closely related species.

Identification of Suitable Reference Genes for RT-qPCR Assays in Liriodendron chinense (Hemsl.) Sarg

The precision and reliability of reverse transcription quantitative polymerase chain reaction (RT-qPCR) depend mainly on suitable reference genes; however, reference genes have not yet been identified for Liriodendron chinense (Hemsl.) Sarg. In this study, the expression stability of 15 candidate reference genes, ACT7, ACT97, UBQ1, eIF2, eIF3, HIS, BIG, AGD11, EFG, GAPDH, CYP, RPL25, UBC, RPB1, and TUB, was tested across multiple organs of L. chinense using four algorithms, geNorm, NormFinder, BestKeeper, and RefFinder. To understand the difference between the selected reference genes and the unsuitable candidate reference genes, the expression level of a target gene, LcPAT7, was normalized across various plant samples. ACT97 and eIF3 represented the best combination across all samples tested, while AGD11 and UBQ1 were unsuitable for normalization in this case. In the vegetative organ subset, ACT97, ACT7, and GAPDH showed the highest expression stability. For floral organs, UBC and eIF3 were the most stable reference genes. Unsuitable reference genes underestimated the expression levels of a target gene, LcPAT7. This study identified two reference genes (ACT97 and eIF3) for the precise and reliable normalization of L. chinense RT-qPCR data across various organs. Our work provides an effective framework for quantifying gene expression in L. chinense.

Protective Effect of the Total Triterpenes of Euscaphis konishii Hayata Pericarp on Bacillus Calmette-Guérin Plus Lipopolysaccharide-Induced Liver Injury

BACKGROUND

Liver injury has been recognized as a primary cause of hepatic morbidity and mortality. Euscaphis konishii Hayata, also called Euscaphis fukienensis Hsu, is usually used as a detumescent and analgesic agent to improve liver function in South China, but its mechanism of action and chemical composition are unclear.

OBJECTIVE

The main aim of the study was to investigate the constituent and potential hepatoprotective mechanism of the total triterpenes of E. konishii pericarp (TTEP).

METHODS

The constituent of TTEP was analyzed by a series of silica gel column to get single compounds and then identified by NMR and MS. In vitro assays were conducted to test the free radical scavenging activity of TTEP. The BCG/LPS-induced immunological livery injury mice model was established to clarify the hepatoprotective effect of TTEP in vivo.

RESULTS

8 pentacyclic triterpene acids were separated and identified by NMR and MS. TTEP treatment (50, 100, and 200 mg/Kg) improved the immune function of the BCG/LPS-infected mice, dose-dependently alleviated the BCG/LPS-induced inflammation and oxidative stress, and ameliorated the hepatocyte apoptosis in the liver tissue.

CONCLUSION

The pericarp of E. konishii may be further considered as a potent natural food for liver disease treatment.

Evaluation of reference genes for normalizing RT-qPCR in leaves and suspension cells of Cephalotaxus hainanensis under various stimuli

BACKGROUND

Reverse transcription quantitative real-time PCR (RT-qPCR) is a widely used approach for investigating gene expression levels in plants because of its high reproducibility, sensitivity, accuracy and rapidness. Evaluation of reference genes for normalizing RT-qPCR data is a necessary step, especially in new plant varieties. Cephalotaxus hainanensis is a precious medicinal plant belonging to the family of Cephalotaxaceae and no RT-qPCR studies have been reported on it.

RESULTS

In this study, 9 candidate reference genes were selected from the transcriptome data of C. hainanensis; 3 statistical algorithms (geNorm, NormFinder, BestKeeper) were applied to evaluate their expression stabilities through 180 samples under 6 stimuli treatments in leaves and leaf-derived suspension cultured cells; a comprehensive stabilities ranking was also performed by RefFinder. The results showed that suitable reference genes in C. hainanensis should be selected for normalization relative to different experimental sets. 18S showed a higher stability than other candidate reference genes which ranked at the top two suitable genes under all experimental setups in this study.

CONCLUSION

This study is the first to evaluate the stability of reference genes in C. hainanensis and supply an important foundation to use the RT-qPCR for an accurate and far-reaching gene expression analysis in C. hainanensis.

Comparative transcriptome among Euscaphis konishii Hayata tissues and analysis of genes involved in flavonoid biosynthesis and accumulation

BACHGROUND

Euscaphis konishii Hayata, a member of the Staphyleaceae Family, is a plant that has been widely used in Traditional Chinese Medicine and it has been the source for several types of flavonoids. To identify candidate genes involved in flavonoid biosynthesis and accumulation, we analyzed transcriptome data from three E. konishii tissues (leaf, branch and capsule) using Illumina Hiseq 2000 platform.

RESULTS

A total of 91.7, 100.3 and 100.1million clean reads were acquired for the leaf, branch and capsule, respectively; and 85,342 unigenes with a mean length of 893.60 bp and N50 length of 1307 nt were assembled using Trinity program. BLASTx analysis allowed to annotate 40,218 unigenes using public protein databases, including NR, KOG/COG/eggNOG, Swiss-Prot, KEGG and GO. A total of 14,291 (16.75%) unigenes were assigned to 128 KEGG pathways, and 900 unigenes were annotated into 22 KEGG secondary metabolites, including flavonoid biosynthesis. The structure enzymes involved in flavonoid biosynthesis, such as phenylalanine ammonia lyase, cinnamate 4-hydroxylase, 4-coumarate CoA ligase, shikimate O-hydroxycinnamoyltransferase, coumaroylquinate 3'-monooxygenase, caffeoyl-CoA O-methyltransferase, chalcone synthase, chalcone isomerase, flavanone 3-hydroxylase, flavonoid 3'-hydroxylase, flavonoid 3',5'-hydroxylase, flavonolsynthese, dihydroflavonol 4-reductase, anthocyanidinreductase, leucoanthocyanidin dioxygenase, leucoanthocyanidin reductase, were identified in the transcriptome data, 40 UDP-glycosyltransferase (UGT), 122 Cytochrome P450 (CYP) and 25 O-methyltransferase (OMT) unigenes were also found. A total of 295 unigenes involved in flavonoid transport and 220 transcription factors (97 MYB, 84 bHLH and 39 WD40) were identified. Furthermore, their expression patterns among different tissues were analyzed by DESeq, the differentially expressed genes may play important roles in tissues-specific synthesis, accumulation and modification of flavonoids.

CONCLUSION

We present here the de novo transcriptome analysis of E. konishii and the identification of candidate genes involved in biosynthesis and accumulation of flavonoid. In general, these results are an important resource for further research on gene expression, genomic and functional genomics in E. konishii and other related species.

Reference genes identification for normalization of qPCR under multiple stresses in Hordeum brevisubulatum

BACKGROUND

Real-time quantitative PCR has been widely used as the most reliable method to measure gene expression, due to its high accuracy and specificity. Wild barley (Hordeum brevisubulatum (Trin.) Link) is a wild relative species in Triticeae that has strong tolerance to abiotic stresses and extremely wide adaptation. However, suitable references gene have not been documented for standardization of gene expression in wild barley under abiotic stress.

RESULTS

Here we report the first systematic and comprehensive analysis of reference genes for quantitative real-time PCR standardization in wild barley. We selected 11 genes, including ACT (Actin), ADP (ADP-ribosylation factor 1), CYP2 (Cyclophilin 2), EF-1α (Elongation factor 1-alpha), GAPDH (Glyceraldehyde 3-phosphate dehydrogenase), HSP90 (Heat shock protein 90), TUBα (Alpha-tubulin), TUBβ6 (Beta-tubulin 6), UBI (Ubiquitin), 18SrRNA-1 (guanine1575-N7-methyltransferase) and 18SrRNA-3 (adenine1779-N6-dimethyltransferase) from a wild barley transcriptome database and analyzed their expression stabilities in shoots and roots of wild barley seedling under various stress conditions using comparative ΔCt, BestKeeper, Normfinder and geNorm software. The results demonstrated that ADP was the most suitable reference gene in salt stress while UBI showed peak stability under mannitol and ABA stress; EF-1α was the most appropriate reference gene for PEG, GA₃, ethylene and heat stress; 18SrRNA-3 was the best choice for cold stress; and TUBα was the first stable gene across different tissues.

CONCLUSIONS

Our main contribution was to identify reference genes with suitable and stable expression in wild barley under various stress conditions and in different tissues to provide a useful resource for future studies. The results demonstrate the importance of transcriptome data as a useful resource for the screening of candidate reference genes and highlight the need for specific reference genes for specific conditions. Furthermore, these findings will provide valuable information for wild barley and relative species for future research.