Liquiritin elicitation can increase the content of medicinally important glucosinolates and phenolic compounds in Chinese kale plants

Abstract

BACKGROUND: Brassica oleracea var. alboglabra (Chinese kale) is an important vegetable grown in southernChina. This study was aimed at searching for environmentally friendly and affordable approaches to increase the production of medicinally relevant glucosinolates and phenolic compounds in Chinese kale plants. For this purpose, the foliar application of liquiritin at 0 (control), 250, 500 and 750 ppm was tested starting from the four-leaf stage and repeated every two weeks until plants were two months old. RESULTS: Foliar application of liquiritin in Chinese kale plants significantly increased glucosinolates and total phenolic content, in a dose-dependent manner. Compared with control plants, 2.3-and 1.9-fold increases in yields of glucosinolates and total phenolic content, respectively, were corroborated in Chinese kale plants treated with 750 ppm of liquiritin. Along with rises in the content of eight different glucosinolates, liquiritin elicitation effectively increased the concentration of glycosilated and acylated flavonoids and hydroxycinnamic acids. The expression of genes involved in glucosinolate and phenolic biosynthesis was significantly higher in liquiritin-treated plants as compared to controls.CONCLUSIONS: Liquiritin elicitation is a feasible and environmentally friendly practice for increasing the production of medicinally important glucosinolates and phenolic compounds in Chinese kale, which may improve this plant's value as a nutraceutical food. This study also contributes to understanding the molecular mechanisms underlying liquiritin elicitation. This is the first report documenting the use of liquiritin for an elicitation purpose in plants.Liquiritin elicitation increases medicinal properties of Chinese kale www.soci.org Identification and quantification of individual GLSs and PHs Alkaline hydrolysisTo eliminate acid moieties, which generate mass spectra coincident with those of rhamnosyl and hexosyl residues and may lead to miss-assignments during mass spectroscopic analysis, alkaline J Sci Food Agric 2020; 100: 1616-1624

Foliar application of liquiritin protects Chinese flowering cabbage against cucumber mosaic virus and increases health-promoting compounds

“…All these facts refer to the possibility that recognition of animal antigens or elicitor molecules by plants can also trigger immune responses to hinder the invasion of pathogens inside plant body. Liquiritin is a flavanone glycoside that plays a significant role in boosting the immune system of mammals (Cheel et al 2010), and in our recent research, we observed that this compound also has a beneficial effect on the growth of Chinese flowering cabbage plants (Akram et al 2020). Furthermore, we found that a foliar spray of 750 ppm liquiritin enhanced the contents of phenolics and glucosinolates in addition to acylated and glycosylated flavonoids in cabbage plants Akram et al (2020).…”

“…On the basis of aforementioned similarities between animal and plant defense mechanisms and our previous findings with respect to liquiritin (Akram et al 2020), we postulated that the application of this compound might have the effect of eliciting defense responses against the cucumber mosaic virus (CMV) in Chinese flowering cabbage plants.…”

Liquiritoside Alleviated Pb Induced Stress in Brassica rapa subsp. Parachinensis: Modulations in Glucosinolate Content and Some Physiochemical Attributes

“…In the course of our study, foliar application of liquiritoside showed positive effects on the growth of Chinese flowering cabbage plants (data yet not published). Additionally, we observed that liquiritoside mitigated abiotic stress, improved biosynthesis of, glucosinolates besides, flavonoids and phenolics in treated plants (Akram et al, 2020). Yet, the application of exogenously applied liquiritoside in the mitigation of plant stress has never been inspected.…”

“…We used our recently devised method (Akram et al, 2020) for the identification and quantification of different types of glucosinolates from the leaves of Chinese flowering cabbage plants. Leaves from 10 plants were taken from each treatment and pooled together.…”

Effects of Temperature, Relative Humidity, and Carbon Dioxide Concentration on Growth and Glucosinolate Content of Kale Grown in a Plant Factory

“…This crisp and hearty vegetable is often consumed raw in salads and smoothies but can also be consumed in steamed, sautéed, or cooked states. Kale originates from China and has since gained particular attention in other countries due to its constituent cancer-preventive and human-health-promoting phytochemicals (i.e., glucosinolates, carotenoids, phenols, and vitamins) [ 4 , 5 , 6 ]. Glucosinolates are amino-acid-derived, active secondary metabolites that mainly contain sulfur- and nitrogen-related compounds (i.e., β-D-thioglucose, tryptophan, phenylalanine, sulfonated oxime moiety).…”