Optimal reference genes for gene expression analysis in polyploid of Cyprinus carpio and Carassius auratus

Screening and Stability Analysis of Reference Genes for Gene Expression Normalization in Hybrid Yellow Catfish (Pelteobagrus fulvidraco ♀ × Pelteobagrus vachelli ♂) Fed Diets Containing Different Soybean Meal Levels

In this study, we screened the expression stability of six reference genes (18S rRNA, β-actin, GAPDH, EF1a, B2M, and HPRT1) in hybrid yellow catfish (n = 6), considering the SBM levels, sampling time points, and different tissues. Four different statistical programs, BestKeeper, NormFinder, Genorm, and Delta Ct, combined with a method that comprehensively considered all results, were used to evaluate the expression stability of these reference genes systematically. The results showed that SBM levels significantly impacted the expression stability of most of the reference genes studied and that this impact was time-, dose-, and tissue-dependent. The expression stability of these six reference genes varied depending on tissue, sampling time point, and SBM dosage. Additionally, more variations were found among different tissues than among different SBM levels or sampling time points. Due to its high expression, 18S rRNA was excluded from the list of candidate reference genes. β-actin and GAPDH in the liver and β-actin, HPRT1 and EF1a in the intestine were the most stable reference genes when SBM levels were considered. HPRT1, and EF1a in tissues sampled at 2 W and EF1a and β-actin in tissues sampled at 4 and 6 W were proposed as two stable reference genes when different tissues were considered. When the sampling time points were considered, β-actin, EF1a, and HPRT1 were the top three stable reference genes in the intestine. In contrast, β-actin and B2M are the most stable reference genes in the liver. In summary, β-actin, EF1a, and HPRT1 were the more stable reference genes in this study. The stability of reference genes depends on the tissues, sampling time points, and SBM diet levels in hybrid yellow catfish. Therefore, attention should be paid to these factors before selecting suitable reference genes for normalizing the target genes.

Identification of Reliable Reference Genes under Different Stresses and in Different Tissues of Toxicodendron succedaneum

Toxicodendron succedaneum (L.) Kuntze (T. succedaneum) is an economic tree species that produces urushiol and urushi wax, and it is of great value in industry and medicine. However, the stability of reference genes (RGs) has not been systematically reported in T. succedaneum to date. In this study, the expression of 10 candidate RGs was analyzed by RT-qPCR in different tissues (roots, stems, leaves), stress treatments (high/low temperature, drought), and hormone stimulation (jasmonic acid, JA). Then, the stability ranking of 10 candidate genes was evaluated by ∆Ct analysis and three software programs: geNorm, NormFinder, and BestKeeper. Finally, RefFinder was used to comprehensively analyze the expression stability of 10 candidate genes. The comprehensive analysis showed that TsRG05/06, TsRG01/06, and TsRG03/ACT were stable under high/low-temperature stress, drought stress, and JA treatment, respectively. TsRG03 and ACT had stable expression in different tissues. While the TsRG03 and ACT were recommended as the suitable RGs for T. succedaneum in all samples. Meanwhile, UBQ was the least suitable as a reference gene for T. succedaneum. In addition, the results of geNorm showed that the combination of two stable RGs could make the results of gene expression more accurate. These results provide alternative RGs for the study of gene function, correction, and normalization of target gene expression and directed molecular breeding in T. succedaneum.