Waheed Akram1,2, Taiba Saeed1,2, Aqeel Ahmad1,2, Nasim A Yasin3, Muhammad Akbar4, Waheed U Khan5, Shakeel Ahmed6, Juxian Guo1,2, Wenlong Luo1,2, Tingquan Wu1,2, Guihua Li1,2. 1. Guangdong Key Laboratory for New Technology Research of Vegetables, Guangdong Academy of Agricultural Sciences, Guangzhou, China. 2. Vegetable Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, China. 3. Institute of Agricultural Sciences, University of the Punjab, Lahore, Pakistan. 4. Department of Botany, University of Gujrat, Gujrat, Pakistan. 5. College of Earth and Environmental Sciences, University of the Punjab, Lahore, Pakistan. 6. Instituto de Farmacia, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile.
Abstract
BACKGROUND: Brassica oleracea var. alboglabra (Chinese kale) is an important vegetable grown in southern China. 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.
BACKGROUND:Brassica oleracea var. alboglabra (Chinese kale) is an important vegetable grown in southern China. 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.