Characterization of Maize Near-Isogenic Lines With Enhanced Flavonoid Expression to Be Used as Tools in Diet-Health Complexity

Binning Wu,Surinder Chopra,Haotian Chang,Rich Marini,Lavanya Reddivari

doi:10.3389/fpls.2020.619598

Binning Wu, Surinder Chopra + Show 3 more

Open Access

https://doi.org/10.3389/fpls.2020.619598

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Abstract

Increasing incidence of chronic diseases in the 21st century has emphasized the importance of developing crops with enhanced nutritional value. Plant-based diets are associated with reduced incidence of many chronic diseases. The growing population and increased food demand have prioritized the development of high-yielding commercial crop varieties at the expense of natural flavors as well as health-benefiting compounds including polyphenols. Flavonoids are a large subfamily of polyphenols abundant in the plant kingdom with known health-promoting effects, making them a promising trait to be re-introduced into elite lines. Given the vast array of flavonoids and the complexity of plant food metabolome interactions, it is difficult to identify with certainty the specific class(es) of flavonoids in the food matrix that are anti-inflammatory. To address this, we have developed four maize near-isogenic lines (NILs); a line that lacked both anthocyanins and phlobaphenes, a second NIL containing phlobaphenes, a third line had anthocyanins, and a fourth line that contained both anthocyanins and phlobaphenes. The phytochemical profiles and the antioxidant potential of the NILs were characterized. The accumulation of anthocyanins and phlobaphenes contributed significantly to antioxidant capacity compared to maize lines that lacked one or both of the compounds (p < 0.05). Pilot study showed that intake of flavonoid-rich maize diets were able to alleviate experimental colitis in mice. These NILs offer novel materials combining anthocyanins and phlobaphenes and can be used as powerful tools to investigate the disease-preventive effects of specific flavonoid compound in diet/feeding experiments.

Highlights

The prevalence of chronic diseases globally is a major challenge in the 21st century
To verify whether the observed phenotypic differences were due to varying expression levels of the regulating transcription factors, gene expression assays were performed on c1, r1, and p1 by quantitative real-time PCR (qRT-PCR)
The expression level of r1 was remarkably higher in line ‘C’ than in ‘D.’ On the other hand, as expected, the expression level of p1 was significantly higher in line ‘B’ and ‘D’ than in ‘A’ and ‘C’ (Figure 3C)

Summary

Introduction

The prevalence of chronic diseases globally is a major challenge in the 21st century. Flavonoids, a subclass of polyphenols, are being studied extensively to explore their disease-preventing effects and mechanisms of their actions. These compounds are capable of interfering with electron-transfer reaction pathways to scavenge free radicals (Sarker and Oba, 2019b, 2020b; Sarker et al, 2020a), making them promising candidates to counteract inflammationassociated chronic diseases. In a study with atrophic gastritis patients, daily consumption of vitamin C for 5 years was not effective in ameliorating high blood pressure (Kim et al, 2002) These observations raise the question do purified phytochemicals confer the same health benefits as they do in their naturally occurring forms?

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