Reference genes selection for quantitative gene expression studies in tea green leafhoppers, Empoasca onukii Matsuda

Reference Genes for Expression Analysis Using RT-qPCR in Cnaphalocrocis medinalis (Lepidoptera: Pyralidae)

Cnaphalocrocis medinalis is a destructive migratory rice pest. Although many studies have investigated its behavioral and physiological responses to environmental changes and migration-inducing factors, little is known about its molecular mechanisms. This study was conducted to select suitable RT-qPCR reference genes to facilitate future gene expression studies. Here, thirteen candidate housekeeping genes (EF1α, AK, EF1β, GAPDH, PGK, RPL13, RPL18, RPS3, 18S rRNA, TBP1, TBP2, ACT, and UCCR) were selected to evaluate their stabilities under different conditions using the ∆CT method; the geNorm, NormFinder, BestKeeper algorithms; and the online tool RefFinder. The results showed that the most stable reference genes were EF1β, PGK, and RPL18, related to developmental stages; RPS3 and RPL18 in larval tissues; EF1β and PGK in larvae feeding on different rice varieties; EF1α, EF1β, and PGK in larvae temperature treatments; PGK and RPL13, related to different adult ages; PGK, EF1α, and ACT, related to adult nutritional conditions; RPL18 and PGK, related to adult mating status; and, RPS3 and PGK, related to different adult take-off characteristics. Our results reveal reference genes that apply to various experimental conditions and will greatly improve the reliability of RT-qPCR analysis for the further study of gene function in this pest.

Exploring tea (Camellia sinensis) microbiome: Insights into the functional characteristics and their impact on tea growth promotion

Tea (Camellia sinensis) is perhaps the most popular and economic beverage in the globe due to its distinctive fragrance and flavour generated by the leaves of commercially farmed tea plants. The tea microbiome has now become a prominent topic of attention for microbiologists in recent years as it can help the plant for soil nutrient acquisition as well as stress management. Tea roots are well known to be colonized by Arbuscular Mycorrhizal Fungi (AMF) and many other beneficial microorganisms that boost the growth of the tea which increases leaf amino acids, protein, caffeine, and polyphenols content. One of the primary goals of rhizosphere microbial biology is to aid in the establishment of agricultural systems that provide high quantities of the food supply while minimizing environmental effects and anthropogenic activities. The present review is aimed to highlight the importance of microbes (along with their phylogeny) derived from cultivated and natural tea rhizospheres to understand the role of AMF and rhizospheric bacterial population to improve plant growth, enhancement of tea quality, and protecting tea plants from pathogens. This review also summarizes recent advances in our understanding of the diversity and profile of tea-associated bacteria. The utilization of the tea microbiome as a "natural resource" could provide holistic development in tea cultivation to ensure sustainability, highlighting knowledge gaps and future microbiome research.

Selection of reference genes for normalization of RT-qPCR data in gene expression studies in Anthonomus eugenii Cano (Coleoptera: Curculionidae)

The pepper weevil, Anthonomus eugenii Cano (Coleoptera: Curculionidae), is the main insect pest of peppers (Capsicum spp.) throughout the southern U.S. and a potential target for novel control methods that may require gene expression analyses. Careful selection of adequate reference genes to normalize RT-qPCR data is an important prerequisite for gene expression studies since the expression stability of reference genes can be affected by the experimental conditions leading to biased or erroneous results. The lack of studies on validation of reference genes for RT-qPCR analysis in A. eugenii limits the investigation of gene expression, therefore it is needed a systematic selection of suitable reference genes for data normalization. In the present study, three programs (BestKeeper, geNorm and NormFinder) were used to analyze the expression stability of candidate reference genes (β-ACT, ArgK, EF1-α, GAPDH, RPL12, RPS23, α-TUB, 18S and 28S) in A. eugenii under different experimental conditions. Our results revealed that the most stably expressed reference genes in A. eugenii varied according to the experimental condition evaluated: developmental stages (EF1-α, 18S and RPL12), sex (RPS23 and RPL12), low temperature (GAPDH and α-TUB), high temperature (α-TUB and RPS23), all temperatures (α-TUB and GAPDH), starvation (RPL12 and α-TUB), and dsRNA exposure (α-TUB and RPL12). Our study provides for the first time valuable information on appropriate reference genes that can be used in the analysis of gene expression by RT-qPCR in biological experiments involving A. eugenii.

Identification and evaluation of reliable reference genes for quantitative real-time PCR analysis in tea plants under differential biotic stresses

The selection of reliable reference genes (RGs) for normalization under given experimental conditions is necessary to develop an accurate qRT-PCR assay. To the best of our knowledge, only a small number of RGs have been rigorously identified and used in tea plants (Camellia sinensis (L.) O. Kuntze) under abiotic stresses, but no critical RG identification has been performed for tea plants under any biotic stresses till now. In the present study, we measured the mRNA transcriptional levels of ten candidate RGs under five experimental conditions; these genes have been identified as stable RGs in tea plants. By using the ΔCt method, geNorm, NormFinder and BestKeeper, CLATHRIN1 and UBC1, TUA1 and SAND1, or SAND1 and UBC1 were identified as the best combination for normalizing diurnal gene expression in leaves, stems and roots individually; CLATHRIN1 and GAPDH1 were identified as the best combination for jasmonic acid treatment; ACTIN1 and UBC1 were identified as the best combination for Toxoptera aurantii-infested leaves; UBC1 and GAPDH1 were identified as the best combination for Empoasca onukii-infested leaves; and SAND1 and TBP1 were identified as the best combination for Ectropis obliqua regurgitant-treated leaves. Furthermore, our results suggest that if the processing time of the treatment was long, the best RGs for normalization should be recommended according to the stability of the proposed RGs in different time intervals when intragroup differences were compared, which would strongly increase the accuracy and sensitivity of target gene expression in tea plants under biotic stresses. However, when the differences of intergroup were compared, the RGs for normalization should keep consistent across different time points. The results of this study provide a technical guidance for further study of the molecular mechanisms of tea plants under different biotic stresses.

Reference gene selection for quantitative gene expression analysis in black soldier fly (Hermetia illucens)

Hermetia illucens is an important resource insect for the conversion of organic waste. Quantitative PCR (qPCR) is the primary tool of gene expression analysis and a core technology of molecular biology research. Reference genes are essential for qPCR analysis; however, a stability analysis of H. illucens reference genes has not yet been carried out. To find suitable reference genes for normalizing gene expression data, the stability of eight housekeeping genes (including ATP6V1A, RPL8, EF1, Tubulin, TBP, GAPDH, Actin and RP49) was investigated under both biotic (developmental stages, tissues and sex) and abiotic (heavy metals, food, antibiotics) conditions. Gene expression data were analysed by geNorm, NormFinder, BestKeeper, and ΔCt programs. A set of specific reference genes was recommended for each experimental condition using the results of RefFinder synthesis analysis. This study offers a solid foundation for further studies of the molecular biology of H. illucens.