Metabolic Engineering of Isoflavones: An Updated Overview

Soo In Sohn,Subramani Pandian,Youn Sung Cho,Hyeon Jung Kang,Young Ju Oh,Woo Suk Cho

doi:10.3389/fpls.2021.670103

Abstract

Isoflavones are ecophysiologically active secondary metabolites derived from the phenylpropanoid pathway. They were mostly found in leguminous plants, especially in the pea family. Isoflavones play a key role in plant–environment interactions and act as phytoalexins also having an array of health benefits to the humans. According to epidemiological studies, a high intake of isoflavones-rich diets linked to a lower risk of hormone-related cancers, osteoporosis, menopausal symptoms, and cardiovascular diseases. These characteristics lead to the significant advancement in the studies on genetic and metabolic engineering of isoflavones in plants. As a result, a number of structural and regulatory genes involved in isoflavone biosynthesis in plants have been identified and characterized. Subsequently, they were engineered in various crop plants for the increased production of isoflavones. Furthermore, with the advent of high-throughput technologies, the regulation of isoflavone biosynthesis gains attention to increase or decrease the level of isoflavones in the crop plants. In the review, we begin with the role of isoflavones in plants, environment, and its benefits in human health. Besides, the main theme is to discuss the updated research progress in metabolic engineering of isoflavones in other plants species and regulation of production of isoflavones in soybeans.

Highlights

Isoflavones are a class of flavonoids mostly available in leguminous plants where they play pivotal roles in plant–microbe interactions such as rhizobia–legume symbiosis and defense responses (Sugiyama, 2019)
Overexpression reduced the transcript level, whereas RNAi-mediated gene silencing increased the transcript level of isoflavonoids genes Overexpression increased the isoflavone level in 1.6- to 3.3-fold, whereas RNAi gene silencing decreased the isoflavone content in twofold Overexpression significantly increased the level of isoflavone aglycones, glucosides. and malonylates, whereas knockdown the genes reduced the contents
We have provided an overview of the isoflavone biosynthesis through metabolic engineering in various crop plants

Summary

Introduction

Isoflavones are a class of flavonoids mostly available in leguminous plants where they play pivotal roles in plant–microbe interactions such as rhizobia–legume symbiosis and defense responses (Sugiyama, 2019). The use of transcription factor–driven gene activation combined with the suppression of a competing pathway resulted in increased isoflavone accumulation in soybean seeds. The study resulted in the reduced level of isoflavone accumulation in the gene silenced plants compared to control (Table 2).

Results

Conclusion