Evaluation of putative reference genes for gene expression normalization in soybean by quantitative real-time RT-PCR

Area of Science:

• Plant Molecular Biology
• Genomics
• Biotechnology

Background:

• Accurate interpretation of real-time quantitative reverse transcription PCR (RT-qPCR) data necessitates normalization.
• Housekeeping genes are commonly used for normalization, but their expression stability varies with experimental conditions.
• Systematic validation of reference genes is essential for reliable soybean gene expression studies, yet few validated options exist.

Purpose of the Study:

• To systematically compare the expression stability of 14 potential reference genes in soybean.
• To identify the most suitable reference genes for normalizing gene expression data under diverse experimental conditions.

Main Methods:

• Expression stability of 14 candidate reference genes (7 common, 7 new) was analyzed using RT-qPCR.
• Analysis encompassed 116 biological samples across various developmental stages, photoperiod treatments, and soybean cultivars.
• Validation involved assessing relative gene expression of GmFTL3 using selected reference gene panels.

Main Results:

• All 14 genes exhibited some expression variability; SKIP16, UKN1, and UKN2 showed the highest overall stability.
• Optimal reference gene panels were condition-specific: ACT11, UKN1, UKN2 for tissues; SKIP16, UKN1, MTP for development.
• Specific combinations (ACT11, TUA5, TIP41; TIP41, UKN1, UKN2) were stable under altered photoperiod and light quality, respectively.
• ACT11, UKN2, and TUB4 were stable across six cultivars under long day/short day conditions.

Conclusions:

• No single reference gene is universally stable; optimal selection is conditional, tissue-specific, developmental, and cultivar-dependent.
• Newly identified reference genes generally outperformed conventional housekeeping genes.
• These findings provide essential guidance for selecting appropriate reference genes in soybean gene expression research.