Growth under high light and elevated temperature affects metabolic responses and accumulation of health-promoting metabolites in kale varieties

Abstract

19Plants are highly sensitive to changes in the light environment and respond to alternating light 20 conditions by coordinated adjustments in foliar gene expression and metabolism. Here we 21 assessed how long-term growth under high irradiance and elevated temperature, a scenario 22 increasingly associated with the climate change, affects foliar chemical composition of 23 Brassicaceous plants. Transcript profiling of Arabidopsis suggested up-regulation of 24 phenylpropanoid metabolism and down-regulation of processes related to biotic stress 25 resistance and indole glucosinolates (GSL). These observations prompted metabolite profiling 26 of purple (Black Magic) and pale green (Half Tall) varieties of kale, an economically important 27 crop species. Long-term acclimation to high light and elevated temperature resulted in reduced 28 levels of 4-methoxy-indol-3-yl-methyl GSL in both kale varieties. The total levels of aliphatic 29 GSLs increased under these conditions, although the profiles of individual GSL structures 30 showed cultivar-dependent differences. Black Magic became rich in 4-methylsulfinylbutyl 31 GSL and 2-phenylethyl GSL, which have health-promoting effects in human diet. Additionally, 32 the purple pigmentation of Black Magic became intensified due to increased accumulation 33 anthocyanins, especially derivatives of cyanidin. These findings demonstrate that the 34 potentially stressful combination of high light and elevated temperature can have beneficial 35 effects on the accumulation of health-promoting metabolites in leafy vegetables. 36 37 Key words 38 Arabidopsis, Brassica, high light acclimation, transcriptome, metabolite profiling, 39 glucosinolate, anthocyanins 40 41 42 43 3 Acknowledgements 44

Improving the Health-Benefits of Kales (Brassica oleracea L. var. acephala DC) through the Application of Controlled Abiotic Stresses: A Review

“…In kale plants, the accumulation of glucosinolates, total phenolics, and flavonoids has is stimulated by exposure to radiation. Alegra et al [135] reported a significant increase in aliphatic glucosinolates in Half Tall and Black Magic kale radiated after two days of germination with high light (800 µmol photons/m 2 s). Black Magic showed an increase in glucoraphanin (150%, 100 nmol/g FW), glucoerucin (350%, 1.8 nmol/g FW), and total aliphatic glucosinolates (175%, 110 nmol/g FW) by high light treatment, while Half Tall displayed the same response to treatment in glucoberverin (2%, 6 nmol/g FW), glucoraphanin (400%, 20 nmol/g FW), glucoerucin (100%, 0.5 nmol/g FW), and total aliphatic glucosinolates (66%, 100 nmol/g FW).…”

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

“…The deposition of glucosinolates in growing plants and their distribution to plant organs are significantly affected by environmental factors [ 26 ], with temperature being one of the key factors. Several studies have been conducted to determine the process and effects of temperature on seed germination, physical development, flower formation, and yield [ 27 , 28 , 29 , 30 ]. However, physiological processes and their integration are sped up under higher temperatures with both positive and negative effects.…”