Selection and validation of optimal reference genes for RT-qPCR analyses in Aphidoletes aphidimyza Rondani (Diptera: Cecidomyiidae)

Selection of Bactrocera tau (Walker) Reference Genes for Quantitative Real-Time PCR

The selection of appropriate reference genes is critical for standardizing quantitative real-time reverse transcription polymerase chain reaction (RT-qPCR) data, thereby ensuring accurate and reliable results of gene expression analysis. In this study, we identified 10 candidate reference genes (encoding α-tubulin, G6PDH, Rab1, RT, RPS13, β-tubulin, DPH1, HSP90, GAPDH, and CP) and evaluated their suitability for use as reference genes in the pest insect, Bactrocera tau. Analysis was conducted using three software-based methods-Delta CT, NormFinder, and BestKeeper-alongside the online tool RefFinder. Expression levels of these genes were analyzed across various B. tau developmental stages and body parts. The overall ranking of reference gene stability scores was as follows: α-tubulin > G6PDH > CP > β-tubulin > RT > HSP90 > GAPDH > DPH1 > RPS13 > Rab1. Ultimately, α-tubulin and G6PDH were identified as the most stable reference genes for B. tau.

Screening and Validation of Stable Reference Genes for qRT-PCR Analysis in Epicauta gorhami (Coleoptera: Meloidae)

Epicauta gorhami is a hypermetamorphic insect that mainly forage soybeans during the adult stage. However, the lack of appropriate references hinders our studying of the gene function in E. gorhami. In this study, referring to five computational tools (Ct value, geNorm, NormFinder, BestKeeper and RefFinder), the stability of 10 housekeeping genes (GAPDH, ACT, RPL4, RPL27, α-TUB, RPS18, EF1α, RPS28, RPL13 and SOD) was assessed by qRT-PCR under three different conditions (adult ages, tissues/organs and temperatures). The findings suggested that SOD and RPS18 were the most ideal references for examine gene transcripts among diverse adult ages and at various temperatures; a pair of RPS18 and RPS28 was the most reliable genes to assess gene expressions in diverse adult tissues. Finally, the relative expression levels of EgUAP were computed after normalization RPS18 and RPS28 with across diverse adult tissues. As expected, EgUAP expression was abundant in the foregut, trachea and antenna and scarce in the midgut, hindgut and epidermis. These findings will lay a solid foundation for analyzing the gene expression of E. gorhami.

The Selection and Validation of Reference Genes for RT-qPCR Analysis of the Predatory Natural Enemy Orius nagaii (Hemiptera: Anthocoridae)

Orius nagaii is a highly effective natural enemy for controlling thrips, tetranychids, aphids, and various Lepidoptera pests. Nevertheless, the molecular mechanisms underlying its interactions with host pests remain unclear. Screening for optimal reference genes is a prerequisite for using reverse transcription-quantitative polymerase chain reaction (RT-qPCR) to investigate the interrelationship. Here, ten commonly used reference genes (Act, GAPDH, β-Tub, EF1-α, RPS10, RPS15, RPL6, RPL13, RPL32, and HSP90) were selected, and their expression stability across developmental stages, tissues, temperatures, and host conditions were evaluated using RefFinder, which uses multiple analytical approaches (NormFinder, geNorm, the ΔCt method, and BestKeeper). The findings suggested that the most reliable normalization can be achieved by selecting the two reference genes for all conditions, with the optimal pairs being RPS10 and RPL32 for the developmental stage, RPS10 and RPS15 for tissue, RPS10 and RPS15 for the host, and EF1-α and RPL13 for temperature. Also, the best and least stable reference genes were chosen to compare the relative transcript levels of the TBX1 in various tissues, which exhibited considerable variation. Our findings will significantly enhance the reliability of RT-qPCR and provide a foundation for further research on the expression patterns of crucial genes that are implicated in the interaction between O. nagaii and its host pests.

Evaluation and Validation of Reference Genes for Gene Expression Analysis Using qRT-PCR in the Sugarcane Stem Borer Chilo sacchariphagus (Lepidoptera: Pyralidae)

Chilo sacchariphagus (Lepidoptera: Pyralidae) is an economically important sugarcane pest. Although numerous studies were conducted on the physiological responses in C. sacchariphagus, little is known regarding the genes regulating these physiological processes. Gene expression analysis by qRT-PCR can offer a significant indication for functional gene studies. To our knowledge, the reference genes of C. sacchariphagus have not been screened or evaluated, which hinders the functional gene study. In the present study, the stability of seven reference genes (β-ACT, GAPDH, BTF3, 28S, RPL7, EF1α, and SDHA) was evaluated in C. sacchariphagus under different experimental conditions, including tissues (antenna, head, thorax, abdomen, leg, and wing), temperatures (4 °C, 25 °C, and 37 °C) and sexes (male and female), through RefFinder, which integrates four algorithms (Normfinder, BestKeeper, ΔCt method, and geNorm). The findings suggested that the combination of β-ACT and RPL7 is ideal to analyze gene expressions in different tissues and at distinct temperatures, and EF1α and SDHA were suitable reference genes for comparing gene expressions between sexes. Finally, the expression profiles of CsacPBP1 gene were evaluated, and the outcomes further confirm the importance of selecting fitting reference genes for normalization of qRT-PCR data. This study represents the first kind in screening out suitable reference genes for gene expression analysis in C. sacchariphagus. Information from this study is poised to galvanize future inquiry into the gene expression of C. sacchariphagus, an economically important pest of sugarcane.

Evaluation of reference genes for quantitative expression analysis in Mylabris sibirica (Coleoptera, Meloidae)

Mylabris sibirica is a hypermetamorphic insect whose adults feed on oilseed rape. However, due to a shortage of effective and appropriate endogenous references, studies on molecular functional genes in Mylabris sibirica, have been tremendously limited. In this study, ten internal reference genes (ACT, ARF1, AK, EF1α, GAPDH, α-TUB, RPL6, RPL13, RPS3 and RPS18) were tested and assessed under four selected treatments including adult ages, adult tissues, temperatures, and sex by RT-qPCR based on five methods (Ct value, geNorm, NormFinder, BestKeeper and RefFinder). Our findings showed that RPL6 and RPL13 were the most optimal internal reference gene combination for gene expression during various adult ages and under diverse temperatures; The combination of RPL6 and RPS18 was recommended to test gene transcription levels under different adult tissues. AK and RPL6 were the best reference genes in male and female adults. RPL6 and RPL13 were the most appropriate reference gene pair to estimate gene expression levels under four different tested backgrounds. The relative transcript levels of a uridine diphosphate (UDP)-N-acetylglucosamine-pyrophosphorylase (MsUAP), varied greatly according to normalization with the two most- and least-suited reference genes. This study will lay the basis for further molecular physiology and biochemistry studies in M. sibirica, such as development, reproduction, sex differentiation, cold and heat resistance.