Colorimetric Detection of Class A Soybean Saponins by G-Quadruplex-Based Hybridization Chain Reaction.

Soybean saponin is one of the important secondary metabolites in seeds, which has various beneficial physiological functions to human health. gene is the key enzyme gene for synthesizing class A saponins. It is of great significance to realize the visual and rapid detection of class A saponins at the genetic level. The hybridization chain reaction (HCR) was employed to the visual detection of gene, which was implemented by changing the length of the target fragment to 92 bp and using the hairpin probes we designed to detect the and genes. The best condition of HCR reaction is hemin (1.2 M), Triton X-100 (0.002%), ABTS (3.8 M), and HO (1.5 mM). It was found that HCR has high specificity for gene and could be applied to the visual detection of different soybean cultivars containing Aa type, Ab type, and Aa/Ab type saponins, which could provide technical reference and theoretical basis for molecular breeding of soybean and development of functional soybean products.