Validation of Reference Genes for Quantitative Real-Time PCR during Bicolor Tepal Development in Asiatic Hybrid Lilies (Lilium spp.)

Lily (Lilium spp.) LhERF4 negatively affects anthocyanin biosynthesis by suppressing LhMYBSPLATTER transcription

Anthocyanins are among the main pigments involved in the colouration of Asiatic hybrid lily (Lilium spp.). Ethylene, a plant ripening hormone, plays an important role in promoting plant maturation and anthocyanin biosynthesis. However, whether and how ethylene regulates anthocyanin biosynthesis in lily tepals have not been characterized. Using yeast one-hybrid screening, we previously identified an APETALA2 (AP2)/ETHYLENE RESPONSE FACTOR (ERF) named LhERF4 as a potential inhibitor of LhMYBSPLATTER-mediated negative regulation of anthocyanin biosynthesis in lily. Here, transcript and protein analysis of LhERF4, a transcriptional repressor, revealed that LhERF4 directly binds to the promoter of LhMYBSPLATTER. In addition, overexpression of LhERF4 in lily tepals negatively regulates the expression of key structural genes and the total anthocyanin content by suppressing the LhMYBSPLATTER gene. Moreover, the LhERF4 gene inhibits anthocyanin biosynthesis in response to ethylene, affecting anthocyanin accumulation and pigmentation in lily tepals. Collectively, our findings will advance and elucidate a novel regulatory network of anthocyanin biosynthesis in lily, and this research provides new insight into colouration regulation.

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.

Identification and Validation of Reference Genes for qRT-PCR Analysis of Petal-Color-Related Genes in Rosa praelucens

The flower's color is regarded as one of the most outstanding features of the rose. Rosa praelucens Byhouwer, an endemic and critically endangered decaploid wild rose species, is abundant in phenotypic diversity, especially in flower color variation, from white to different degrees of pink. The mechanism underlying this variation, e.g., the level of petal-color-related genes, is worth probing. Seven candidate reference genes for qRT-PCR analysis, including tubulin α chain (TUBA), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), histone H2B (Histone2A), eukaryotic translation elongation factor 1-α (EEF1A), 60S ribosomal protein (RPL37), eukaryotic translation initiation factor 1-α (EIF1A), and aquaporins (AQP), were detected from the transcriptome datasets of full blooming flowers of white-petaled and pink-petaled individuals, and their expression stabilities were evaluated through qRT-PCR analysis. According to stability rankings analysis, EEF1A showed the highest stability and could be chosen as the most suitable reference gene. Moreover, the reliability of EEF1A was demonstrated via qRT-PCR analysis of six petal-color-related target genes, the expression patterns of which, through EEF1A normalization, were found to be consistent with the findings of transcriptome analysis. The result provides an optimal reference gene for exploring the expression level of petal-color-related genes in R. praelucens, which will accelerate the dissection of petal-color-variation mechanisms in R. praelucens.

Exogenously applied zinc improves sugar-acid profile of loquat (Eriobotrya japonica Lindl.) by regulating enzymatic activities and expression of their metabolism-related genes

Soluble sugars and organic acids are the most abundant components in ripe fruits, and they play critical roles in the development of fruit flavor and taste. In this study, loquat trees were sprayed with 0.1, 0.2 and 0.3% zinc sulphate. The contents of soluble sugars and organic acids were determined using HPLC-RID and UPLC-MS, respectively. The activities of key enzymes involved in sugar-acid metabolism were measured and expression profiling of related genes was done using RT-qPCR. The results revealed that 0.1% zinc sulphate was a promising treatment among other Zn applications with respect to the increased levels of soluble sugars and decreased acid contents in loquats. Correlation analysis showed that the enzymes i.e., SPS, SS, FK, and HK were may be involved in the regulation of fructose and glucose metabolism in the fruit pulp of loquat. While, the activity of NADP-ME showed negative and NAD-MDH showed a positive correlation with malic acid content. Meanwhile, EjSPS1-4, EjSS2-4, EjHK1-3, and EjFK1-6 may play an important role in soluble sugar metabolism in the pulp of loquat fruits. Similarly, EjPEPC2, EjPEPC3, EjNAD-MDH1, EjNAD-MDH3-5, EjNAD-MDH6 and EjNAD-MDH13 may have a vital contribution to malic acid biosynthesis in loquat fruits. This study provides new insights for future elucidation of key mechanisms regulating soluble sugars and malic acid biosynthesis in loquats.

Screening and Validation of Internal Reference Genes for Quantitative Real-Time PCR Analysis of Leaf Color Mutants in Dendrobium officinale

Leaf color mutants (LCMs) are important resources for studying diverse metabolic processes such as chloroplast biogenesis and differentiation, pigments' biosynthesis and accumulation, and photosynthesis. However, in Dendrobium officinale, LCMs are yet to be fully studied and exploited due to the unavailability of reliable RGs (reference genes) for qRT-PCR (quantitative real-time reverse transcription PCR) normalization. Hence, this study took advantage of previously released transcriptome data to select and evaluate the suitability of ten candidate RGs, including Actin (Actin), polyubiquitin (UBQ), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), elongation factor 1-α (EF1α), β-tubulin (β-TUB), α-tubulin (α-TUB), 60S ribosomal protein L13-1 (RPL13AD), aquaporin PIP1-2 (PIP1-2), Intima protein (ALB3) and Cyclin (CYCB1-2) for normalizing leaf color-related genes' expression levels via qRT-PCR. Stability rankings analysis via common software Best-Keeper, GeNorm, and NormFinder disclosed that all ten genes met the requirements of RGs. Of them, EF1α exhibited the highest stability and was selected as the most reliable. The reliability and accuracy of EF1α were confirmed through qRT-PCR analysis of fifteen chlorophyll pathway-related genes. The expression patterns of these genes via EF1α normalization were consistent with the results by RNA-Seq. Our results offer key genetic resources for the functional characterization of leaf color-related genes and will pave the way for molecular dissection of leaf color mutations in D. officinale.

Evaluation of Candidate Reference Genes for Gene Expression Analysis in Wild Lamiophlomis rotata

Lamiophlomis rotata (Benth.) Kudo is a perennial and unique medicinal plant of the Qinghai–Tibet Plateau. It has the effects of diminishing inflammation, activating blood circulation, removing blood stasis, reducing swelling, and relieving pain. However, thus far, reliable reference gene identifications have not been reported in wild L. rotata. In this study, we identified suitable reference genes for the analysis of gene expression related to the medicinal compound synthesis in wild L. rotata subjected to five different-altitude habitats. Based on the RNA-Seq data of wild L. rotata from five different regions, the stability of 15 candidate internal reference genes was analyzed using geNorm, NormFinder, BestKeeper, and RefFinder. TFIIS, EF-1α, and CYP22 were the most suitable internal reference genes in the leaves of L. rotata from different regions, while OBP, TFIIS, and CYP22 were the optimal reference genes in the roots of L. rotata. The reference genes identified here would be very useful for gene expression studies with different tissues in L. rotata from different habitats.

Development of a multiplex RT-PCR assay for simultaneous detection of Lily symptomless virus, Lily mottle virus, Cucumber mosaic virus, and Plantago asiatica mosaic virus in Lilies

BACKGROUND

Viral pathogens causing significant economic losses in lilies (Lilium spp. and hybrids) include Lily symptomless virus (LSV), Lily mottle virus (LMoV), Cucumber mosaic virus (CMV), and Plantago asiatica mosaic virus (PlAMV). Rapid and efficient virus detection methods are pivotal to prevent the spread of these viruses.

RESULTS

In this study, four specific primer pairs designed from conserved regions of genomic sequences of each virus were used to amplify a 116 bp product for LSV, a 247 bp product for LMoV, a 359 bp product for CMV, and a 525 bp product for PlAMV in a multiplex reverse transcription-polymerase chain reaction (multiplex RT-PCR). The amplified products were clearly separated by 2% agarose gel electrophoresis. The optimal reaction annealing temperature and cycle number were 53.8 °C and 35, respectively. The developed multiplex RT-PCR method was then used to test virus infections from lily samples collected from different regions of China.

CONCLUSIONS

An effective multiplex RT-PCR assay was established for the simultaneous detection and differentiation of LSV, LMoV, CMV, and PlAMV in lilies, which offers a useful tool for routine molecular diagnosis and epidemiological studies of these viruses.

Systematic Identification and Validation of Suitable Reference Genes for the Normalization of Gene Expression in Prunella vulgaris under Different Organs and Spike Development Stages

The quantitative real-time PCR (qRT-PCR) is an efficient and sensitive method for determining gene expression levels, but the accuracy of the results substantially depends on the stability of the reference gene (RG). Therefore, choosing an appropriate reference gene is a critical step in normalizing qRT-PCR data. Prunella vulgaris L. is a traditional Chinese medicine herb widely used in China. Its main medicinal part is the fruiting spike which is termed Spica Prunellae. However, thus far, few studies have been conducted on the mechanism of Spica Prunellae development. Meanwhile, no reliable RGs have been reported in P. vulgaris. The expression levels of 14 candidate RGs were analyzed in this study in various organs and at different stages of Spica Prunellae development. Four statistical algorithms (Delta Ct, BestKeeper, NormFinder, and geNorm) were utilized to identify the RGs' stability, and an integrated stability rating was generated via the RefFinder website online. The final ranking results revealed that eIF-2 was the most stable RG, whereas VAB2 was the least suitable as an RG. Furthermore, eIF-2 + Histon3.3 was identified as the best RG combination in different periods and the total samples. Finally, the expressions of the PvTAT and Pv4CL2 genes related to the regulation of rosmarinic acid synthesis in different organs were used to verify the stable and unstable RGs. The stable RGs in P. vulgaris were originally identified and verified in this work. This achievement provides strong support for obtaining a reliable qPCR analysis and lays the foundation for in-depth research on the developmental mechanism of Spica Prunellae.

Sugar and acid profile of loquat (Eriobotrya japonica Lindl.), enzymes assay and expression profiling of their metabolism-related genes as influenced by exogenously applied boron

Soluble sugars and organic acids are the most abundant components in ripe fruits, and they play critical roles in the development of fruit flavor and taste. Some loquat cultivars have high acid content which seriously affect the quality of fruit and reduce the value of commodity. Consequently, studying the physiological mechanism of sugar-acid metabolism in loquat can clarify the mechanism of their formation, accumulation and degradation in the fruit. Minerals application has been reported as a promising way to improve sugar-acid balance of the fruits. In this study, loquat trees were foliar sprayed with 0.1, 0.2 and 0.3% borax, and changes in soluble sugars and organic acids were recorded. The contents of soluble sugars and organic acids were determined using HPLC-RID and UPLC-MS, respectively. The activities of enzymes responsible for the metabolism of sugars and acids were quantified and expressions of related genes were determined using quantitative real-time PCR. The results revealed that 0.2% borax was a promising treatment among other B applications for the increased levels of soluble sugars and decreased acid contents in loquats. Correlation analysis showed that the enzymes i.e., SPS, SS, FK, and HK were may be involved in the regulation of fructose and glucose metabolism in the fruit pulp of loquat. While the activity of NADP-ME showed negative and NAD-MDH showed a positive correlation with malic acid content. Meanwhile, EjSPS1, EjSPS3, EjSS3, EjHK1, EjHK3, EjFK1, EjFK2, EjFK5, and EjFK6 may play an important role in soluble sugars metabolism in fruit pulp of loquat. Similarly, EjPEPC2, EjPEPC3, EjNAD-ME1, EjNAD-MDH1, EjNAD-MDH5-8, EjNAD-MDH10, and EjNAD-MDH13 may have a vital contribution to malic acid biosynthesis in loquat fruits. This study provides new insights for future elucidation of key mechanisms regulating soluble sugars and malic acid biosynthesis in loquats.

WUSCHEL-related homeobox genes cooperate with cytokinin to promote bulbil formation in Lilium lancifolium

The bulbil is an important vegetative reproductive organ in triploid tiger lily (Lilium lancifolium). Based on our previously obtained transcriptome data, we screened two WUSCHEL-related homeobox (WOX) genes closely related to bulbil formation, LlWOX9 and LlWOX11. However, the biological functions and regulatory mechanisms of LlWOX9 and LlWOX11 are unclear. In this study, we cloned the full-length coding sequences of LlWOX9 and LlWOX11. Transgenic Arabidopsis (Arabidopsis thaliana) showed increased branch numbers, and the overexpression of LlWOX9 and LlWOX11 in stem segments promoted bulbil formation, while the silencing of LlWOX9 and LlWOX11 inhibited bulbil formation, indicating that LlWOX9 and LlWOX11 are positive regulators of bulbil formation. Cytokinin type-B response regulators could bind to the promoters of LlWOX9 and LlWOX11 and promote their transcription. LlWOX11 could enhance cytokinin pathway signaling by inhibiting the transcription of type-A LlRR9. Our study enriches the understanding of the regulation of plant development by the WOX gene family and lays a foundation for further research on the molecular mechanism of bulbil formation in lily.

Selection and validation of reference genes for quantitative real-time PCR of Quercus mongolica Fisch. ex Ledeb under abiotic stresses

Quercus mongolica Fisch. ex Ledeb is the main species of coniferous and broadleaved mixed forests in northeast and north China, which has high ornamental, economic, and ecological value. The appropriate reference genes must be selected for quantitative real-time PCR to reveal the molecular mechanisms of stress responses and their contribution to breeding of Q. mongolica. In the present study, we chose 11 candidate reference genes (TUA, CYP18, HIS4, RPS13, ACT97, TUB1, UBQ10, UBC5, SAND, PP2A, and SAMDC) and used four programs (GeNorm, NormFinder, BestKeeper, and RefFinder) to assess the expression stability of the above genes in roots, stems, and leaves under five abiotic stress factors (cold, salt, drought, weak light, and heavy metal). The findings revealed that under various experimental environments, the most stable genes were different; CYP18, ACT97, and RPS13 ranked the highest under most experimental environments. Moreover, two genes induced by stress, CMO and P5CS2, were chosen to demonstrate the reliability of the selected reference genes in various tissues under various stress conditions. Our research provides a significant basis for subsequent gene function studies of Q. mongolica.

Construction of yeast one-hybrid library and screening of transcription factors regulating LhMYBSPLATTER expression in Asiatic hybrid lilies (Lilium spp.)

BACKGROUND

Anthocyanins, which belong to flavonoids, are widely colored among red-purple pigments in the Asiatic hybrid lilies (Lilium spp.). Transcription factor (TF) LhMYBSPLATTER (formerly known as LhMYB12-Lat), identified as the major kernel protein, regulating the anthocyanin biosynthesis pathway in 'Tiny Padhye' of Tango Series cultivars, which the pigmentation density is high in the lower half of tepals and this patterning is of exceptional ornamental value. However, the research on mechanism of regulating the spatial and temporal expression differences of LhMYBSPLATTER, which belongs to the R2R3-MYB subfamily, is still not well established. To explore the molecular mechanism of directly related regulatory proteins of LhMYBSPLATTER in the anthocyanin pigmentation, the yeast one-hybrid (Y1H) cDNA library was constructed and characterized.

RESULTS

In this study, we describe a yeast one-hybrid library to screen transcription factors that regulate LhMYBSPLATTER gene expression in Lilium, with the library recombinant efficiency of over 98%. The lengths of inserted fragments ranged from 400 to 2000 bp, and the library capacity reached 1.6 × 10⁶ CFU of cDNA insert, which is suitable to fulfill subsequent screening. Finally, seven prey proteins, including BTF3, MYB4, IAA6-like, ERF4, ARR1, ERF WIN1-like, and ERF061 were screened by the recombinant bait plasmid and verified by interaction with the LhMYBSPLATTER promoter. Among them, ERFs, AUX/IAA, and BTF3 may participate in the negative regulation of the anthocyanin biosynthesis pathway in Lilium.

CONCLUSION

A yeast one-hybrid library of lily was successfully constructed in the tepals for the first time. Seven candidate TFs of LhMYBSPLATTER were screened, which may provide a theoretical basis for the study of floral pigmentation.

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.

Validation of Reference Genes for Quantitative PCR in Johnsongrass (Sorghum halepense L.) under Glyphosate Stress

Weeds are one of the main causes of the decrease in crop yields, with Johnsongrass (Sorghum halepense L.) being one of the most significant. Weeds can be controlled by herbicides, but some have developed resistance. Quantitative PCR is the technique of choice for studying gene expression related to herbicide resistance because of its high sensitivity and specificity, although its quantitative accuracy is highly dependent on the stability of the reference genes. Thus, in this study we evaluated the stability of different reference genes of glyphosate-resistant S. halepense. Nine genes frequently used as reference genes were selected: MDH, ADP, PP2A, EIF4α, ACT, ARI8, DnaJ, Hsp70, and ALS1, and their expression analyzed in susceptible and resistant biotypes at 0, 24 and 72 h post-application of glyphosate. The stability was analyzed with the geNorm, NormFinder, and BestKeeper software programs and using the ΔCt method. RefFinder was used to generate a comprehensive stability ranking. The results showed that PP2A and ARI8 were the most stable genes under the test conditions. EPSPS expression was also verified against the best two and the worst two reference genes. This study provides useful information for gene expression analysis under glyphosate stress and will facilitate resistance mechanism studies in this weed species.

Identification and Validation of Reference Genes for Gene Expression Analysis in Schima superba

Real-time quantitative PCR (RT-qPCR) is a reliable and high-throughput technique for gene expression studies, but its accuracy depends on the expression stability of reference genes. Schima superba is a fast-growing timber species with strong resistance. However, thus far, reliable reference gene identifications have not been reported in S. superba. In this study, 19 candidate reference genes were selected and evaluated for their expression stability in different tissues of S. superba. Three software programs (geNorm, NormFinder, and BestKeeper) were used to evaluate the reference gene transcript stabilities, and comprehensive stability ranking was generated by the geometric mean method. Our results show that SsuACT was the most stable reference gene and that SsuACT + SsuRIB was the best reference gene combination for different tissues. Finally, the stable and less stable reference genes were verified using SsuSND1 expression in different tissues. To our knowledge, this is the first report to verify appropriate reference genes for normalizing gene expression in S. superba for different tissues, which will facilitate the future elucidation of gene regulations in this species and useful references for relative species.

Cytokinin Type-B Response Regulators Promote Bulbil Initiation in Lilium lancifolium

The bulbil is an important vegetative reproductive organ in triploid Lilium lancifolium whose development is promoted by cytokinins. Type-B response regulators (RRs) are critical regulators that mediate primary cytokinin responses and promote cytokinin-induced gene expression. However, the function of cytokinin type-B Arabidopsis RRs (ARRs) in regulating bulbil formation is unclear. In this study, we identified five type-B LlRRs, LlRR1, LlRR2, LlRR10, LlRR11 and LlRR12, in L. lancifolium for the first time. The five LlRRs encode proteins of 715, 675, 573, 582 and 647 amino acids. All of the regulators belong to the B-I subfamily, whose members typically contain a conserved CheY-homologous receiver (REC) domain and an Myb DNA-binding (MYB) domain at the N-terminus. As transcription factors, all five type-B LlRRs localize at the nucleus and are widely expressed in plant tissues, especially during axillary meristem (AM) formation. Functional analysis showed that type-B LlRRs are involved in bulbil formation in a functionally redundant manner and can activate LlRR9 expression. In summary, our study elucidates the process by which cytokinins regulate bulbil initiation in L. lancifolium through type-B LlRRs and lays a foundation for research on the molecular mechanism of bulbil formation in the lily.

LhGST is an anthocyanin-related glutathione S-transferase gene in Asiatic hybrid lilies (Lilium spp.)

LhGST, an anthocyanin-related GST gene, was identified from Asiatic hybrid lilies. Expression and functional analyses demonstrated that LhGST might be involved in anthocyanin sequestration in lily tepals. Anthocyanins are responsible for the pink, red and purple pigmentation of flowers in Asiatic hybrid lilies, synthesized at the cytoplasmic surface of the endoplasmic reticulum (ER) and then transported to the vacuole. To date, the mechanism involved in the intracellular transport of anthocyanins in lilies has not been well elucidated. Here, full-length glutathione S-transferase gene (LhGST) was identified from lilies. Expression analysis revealed that LhGST was positively correlated with anthocyanin accumulation. Phylogenetic tree analysis showed that LhGST clustered with other anthocyanin-related GSTs in the same phi clade. Moreover, functional complementation of an Arabidopsis tt19 mutant demonstrated that LhGST might be involved in anthocyanin accumulation in lily tepals. Additionally, according to phenotype analysis, LhGST was found to be correlated with the transport of anthocyanin in lilies by virus-induced gene silencing (VIGS) assay. In addition, cis-element analysis of the LhGST promoter showed the presence of ABA-, auxin-, MeJA-, gibberellin-, light-, and stress-responsive elements and an MYB recognition site (MRS, CCGTTG). Yeast one-hybrid and dual-luciferase report assays revealed that the promoter of LhGST was activated by LhMYB12-lat, which is a key R2R3-MYB transcription factor that regulates anthocyanin biosynthesis in lilies. In conclusion, our results revealed that LhGST plays a key role in anthocyanin transport and accumulation in the tepals of lilies.

Selection and validation of appropriate reference genes for gene expression studies in Forsythia

The qRT-PCR method has been widely used to detect gene expression level in plants, helping to understand the molecular mechanisms. However, there are few researches which focus on the selection of the internal reference genes in Forsythia. To select the appropriate reference genes of Forsythia aimed at qRT-PCR normalization, twelve candidate reference genes were selected from our transcriptome data. Their expression was assessed by RT-PCR analysis in 47 Forsythia samples, including 12 species cultivars, different organs and tissues. GeNorm, NormFinder, and BestKeeper software were used to select the appropriate reference genes, AG and PSY were used to verify the accuracy of the outcome. The results showed that UKN1 was a stable reference gene in leaves of twelve Forsythia germplasms and in different developmental stages of fruits. MTP, ABCT + MTP, and ABCT + MTP + TIP were stable reference genes in different organs. ACT and SDH were stable reference genes in different flower tissues and different developmental stages of the flower buds. When Forsythia plants were stressed with PEG or ABA, SDH + UKN1 + G6PD was the stable reference gene group for qRT-PCR. The results provided the basis for investigating the physiological and biochemical processes of Forsythia related to medicinal and ornamental properties, and drought-resistance in the level of gene expression.

Selection of reference genes for quantitative real-time PCR analysis of photosynthesis-related genes expression in Lilium regale

Photosynthesis is closely related to the growth of plants. A stable reference gene is fundamental for studies of the molecular mechanism of photosynthesis in Lilium regale. Therefore, it is very important to select a suitable reference gene for qRT-PCR analysis on genes of photosynthetic system, chlorophyll biosynthetic pathway and chloroplast development in Lilium regale. Three kinds of tissues, leaves and bulbs (abnormal leaves) of tissue culture plantlets and cotyledons of seedlings of the wild-type and mutant Lilium regale were selected as materials for qRT-PCR. Six housekeeping genes were selected as candidate genes from transcriptome sequencing data of the wild-type and yellow seedling lethal mutant of Lilium regale. Finally, the expression stability of six candidate reference genes was analyzed using geNorm, NormFinder, and BestKeeper software, the comparative ∆Ct method, and the RefFinder program. The results showed that LrActin2 was the best reference gene for qRT-PCR analysis of photosynthesis-related genes expression in leaves of tissue culture plantlets and seedlings of Lilium regale. This study provided useful data for further research on molecular mechanism of photosynthesis in the Lilium.

Neuroprotective effects of lovastatin in the pilocarpine rat model of epilepsy according to the expression of neurotrophic factors

Studies have suggested that neurotrophic factors (NTFs) are involved in the status epilepticus development. This indicates their essential role in mediating acquired epileptic conditions. Therefore, modulating the expression of NTFs may inhibit seizure-induced cell loss in the epileptic lesions. In this study, we examined the anti-apoptotic, anti-necrotic and regulatory effects of lovastatin on the expression of NTFs in the pilocarpine rat model of temporal lobe epilepsy (TLE). A total of 32 male Wistar rats were divided into 4 groups (n = 8 per group): i) normal; ii) non-treated epileptic group [intraperitoneal (i.p.) administration of 350-400 mg/kg pilocarpine]; iii) treatment group (pilocarpine-treated rats treated followed by 5 mg/kg lovastatin); and iv) vehicle epileptic rats treated with Carboxymethyl cellulose (CMC). Animals that had a behavioral score of 4-5 according to the Racine scale were selected for study participation. Three days after the first seizure, pilocarpine-treated rats received i.p. injections of lovastatin for 14 days. The rats were killed and prepared for histopathologic analysis as well as real-time RT-PCR 17 days after the first seizure. The results of this study showed increased mRNA expression of glial cell line-derived neurotrophic factor (GDNF) and Ciliary neurotrophic factor (CNTF) and decreased expressions of Brain-derived neurotrophic factor (BDNF), Neurotrophin-3 (NT-3), and Neurotrophin-4 (NT-4) mRNA in the epileptic rats treated with lovastatin. Histological analysis of neurodegeneration in the brain sections showed that the number of hippocampal apoptotic and necrotic cells significantly decreased in the treatment groups. Furthermore, numerical density of neurons per area was significantly higher in the treated groups compared with the untreated groups. Collectively, the results of this study have shown that lovastatin could attenuate seizure-induced expression of neurotrophic factors and consequently reduce hippocampal cell death in the pilocarpine rat model of TLE.

Neuroprotective effect of lovastatin through down-regulation of pro-apoptotic Mst1 gene expression in rat model pilocarpine epilepsy

OBJECTIVE

Statins as inhibitors of HMG-CoA reductase have been recently recognized as anti-inflammatory and neuroprotective drugs. In this paper, we studied anti-apoptotic and regulatory effects of lovastatin using Pilocarpine rat model through downregulation of Mst1 (Mammalian sterile 20-like kinase 1) as a novel pro-apoptotic gene.

METHODS

The rats were divided into four groups: non-treated epileptic rats, lovastatin treated, and two vehicle groups. Racine scale was used for behavioral assessment and animals with a score of 4-5 were selected for the study. After 3 days, epileptic rats received intraperitoneal injections of lovastatin, followed by treating for 14 days. Next, they were sacrificed (28 post-first seizure) and prepared for histopathological analysis and Real-time RT-PCR.

RESULTS

The results showed that lovastatin protects Pilocarpine-induced cell death via a regulatory effect on pro-apoptotic and anti-apoptotic gene expression. The real-time PCR results showed that in the epileptic lovastatin treated group, the expression level of Mst1 significantly decreased while Nrf2 and Bcl-2 genes increased. Furthermore, histological analysis of neurodegeneration in the brain sections showed that the number of hippocampal apoptotic cells significantly decreased in the treatment groups. The results showed that the numerical density of neurons per area was significantly higher in the treated than the untreated group.

CONCLUSION

Overall, the results of this study showed that lovastatin attenuates hippocampal cell death in Pilocarpine-induced status epilepticus rat model through downregulation of the pro-apoptotic Mst1 gene.

ABBREVIATIONS

Mst1: Mammalian sterile 20-like kinase 1; Nrf2: nuclear factor erythroid 2-related factor 2; Bcl-2: B-cell lymphoma 2; HMG-CoA: 3-hydroxy-3-methylglutaryl-coenzyme A; RT-PCR: reverse transcription-polymerase chain reaction; TLE: Temporal Lobe Epilepsy; SE: status epilepticus.

Adenosine decreases oxidative stress and protects H2O2-treated neural stem cells against apoptosis through decreasing Mst1 expression

Overproduction of free radicals during oxidative stress induces damage to key biomolecules and activates programed cell death pathways. Neuronal cell death in the nervous system leads to a number of neurodegenerative diseases. The aim of the present study was to evaluate the neuroprotective effect of adenosine on inhibition of apoptosis induced by hydrogen peroxide (H₂O₂) in bone marrow-derived neural stem cells (B-dNSCs), with focus on its regulatory effect on the expression of mammalian sterile 20-like kinase 1 (Mst1), as a novel proapoptotic kinase. B-dNSCs were exposed to adenosine at different doses (2, 4, 6, 8 and 10 µM) for 48 h followed by 125 µM H₂O₂ for 30 min. Using MTT, terminal deoxynucleotidyl transferase dUTP nick-end labeling and real-time reverse transcription polymerase chain reaction assays, the effects of adenosine on cell survival, apoptosis and Mst1, nuclear factor (erythroid-derived 2)-like 2 and B-cell lymphoma 2 and adenosine A1 receptor expression were evaluated in pretreated B-dNSCs compared with controls (cells treated with H₂O₂ only). Firstly, results of the MTT assay indicated 6 µM adenosine to be the most protective dose in terms of promotion of cell viability. Subsequent assays using this dosage indicated that apoptosis rate and Mst1 expression in B-dNSCs pretreated with 6 µM adenosine were significantly decreased compared with the control group. These findings suggest that adenosine protects B-dNSCs against oxidative stress-induced cell death, and therefore, that it may be used to promote the survival rate of B-dNSCs and as a candidate for the treatment of oxidative stress-mediated neurological diseases.

Tobacco rattle virus-induced PHYTOENE DESATURASE (PDS) and Mg-chelatase H subunit (ChlH) gene silencing in Solanum pseudocapsicum L

Virus-induced gene silencing (VIGS) is an attractive tool for determining gene function in plants. The present study constitutes the first application of VIGS in S. pseudocapsicum, which has great ornamental and pharmaceutical value, using tobacco rattle virus (TRV) vectors. Two marker genes, PHYTOENE DESATURASE (PDS) and Mg-chelatase H subunit (ChlH), were used to test the VIGS system in S. pseudocapsicum. The photobleaching and yellow-leaf phenotypes of the silenced plants were shown to significantly correlate with the down-regulation of endogenous SpPDS and SpChlH, respectively (P ≤ 0.05). Moreover, the parameters potentially affecting the efficiency of VIGS in S. pseudocapsicum, including the Agrobacterium strain and the inoculation method (leaf syringe-infiltration, sprout vacuum-infiltration and seed vacuum-infiltration), were compared. The optimized VIGS parameters were the leaf syringe-infiltration method, the Agrobacterium strain GV3101 and the growth of agro-inoculated plants at 25°. With these parameters, the silencing efficiency of SpPDS and SpChlH could reach approximately 50% in S. pseudocapsicum. Additionally, the suitability of various reference genes was screened by RT-qPCR using three candidate genes, and the results demonstrated that glyceraldehyde 3-phosphate dehydrogenase (GAPDH) can serve as a suitable reference for assessing the gene expression levels of VIGS systems in S. pseudocapsicum. The proven application of VIGS in S. pseudocapsicum and the characterization of a suitable reference gene in the present work will expedite the functional characterization of novel genes in S. pseudocapsicum.

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

BACKGROUND

Quantitative real-time reverse transcription-polymerase chain reaction has been widely used in gene expression analysis, however, to have reliable and accurate results, reference genes are necessary to normalize gene expression under different experimental conditions. Several reliable reference genes have been reported in plants of Traditional Chinese Medicine, but none have been identified for Euscaphis konishii Hayata.

RESULTS

In this study, 12 candidate reference genes, including 3 common housekeeping genes and 9 novel genes based on E. konishii Hayata transcriptome data were selected and analyzed in different tissues (root, branch, leaf, capsule and seed), capsule and seed development stages. Expression stability was calculated using geNorm and NormFinder, the minimal number of reference genes required for accurate normalization was calculated by Vn/Vn + 1 using geNorm. EkEEF-5A-1 and EkADF2 were the two most stable reference genes for all samples, while EkGSTU1 and EkGAPDH were the most stable reference genes for tissue samples. For seed development stages, EkGAPDH and EkEEF-5A-1 were the most stable genes, whereas EkGSTU1 and EkGAPDH were identified as the two most stable genes in the capsule development stages. Two reference genes were sufficient to normalize gene expression across all sample sets.

CONCLUSION

Results of this study revealed that suitable reference genes should be selected for different experimental samples, and not all the common reference genes are suitable for different tissue samples and/or experimental conditions. In this study, we present the first data of reference genes selection for E. konishii Hayata based on transcriptome data, our data will facilitate further studies in molecular biology and gene function on E. konishii Hayata and other closely related species.

Identification of reference genes for qRT-PCR in granulosa cells of healthy women and polycystic ovarian syndrome patients

Comparative gene expression analysis by qRT-PCR is commonly used to detect differentially expressed genes in studies of PCOS pathology. Impaired GC function is strongly associated with PCOS pathogenesis, and a growing body of studies has been dedicated to identifying differentially expressed genes in GCs in PCOS patients and healthy women by qRT-PCR. It is necessary to validate the expression stability of the selected reference genes across the tested samples for target gene expression normalization. We examined the variability and stability of expression of the 15 commonly used reference genes in GCs from 44 PCOS patients and 45 healthy women using the GeNorm, BestKeeper, and NormFinder statistical algorithms. We combined the rankings of the three programs to produce a final ranking based on the geometric means of their stability scores. We found that HPRT1, RPLP0, and HMBS out of 15 examined commonly used reference genes are stably expressed in GCs in both controls and PCOS patients and can be used for normalization in gene expression profiling by qRT-PCR. Future gene-expression studies should consider using these reference genes in GCs in PCOS patients for more accurate quantitation of target gene expression and data interpretation.