Changes in SeMSC, Glucosinolates and Sulforaphane Levels, and in Proteome Profile in Broccoli (Brassica oleracea var. Italica) Fertilized with Sodium Selenate

Abstract

The aim of this work was to analyze the effect of sodium selenate fortification on the content of selenomethyl selenocysteine (SeMSC), total glucosinolates and sulforaphane, as well as the changes in protein profile of the inflorescences of broccoli (Brassica oleracea var. Italica). Two experimental groups were considered: plants treated with 100 μmol/L sodium selenate (final concentration in the pot) and control plants treated with water. Fortification began 2 weeks after transplantation and was repeated once a week during 10 weeks. Broccoli florets were harvested when they reached appropriate size. SeMSC content in broccoli florets increased significantly with sodium selenate fortification; but total glucosinolates and sulforaphane content as well as myrosinase activity were not affected. The protein profile of broccoli florets changed due to fortification with sodium selenate. Some proteins involved in general stress-responses were up-regulated, whereas down-regulated proteins were identified as proteins involved in protection against pathogens. This is the first attempt to evaluate the physiological effect of fortification with sodium selenate on broccoli at protein level. The results of this work will contribute to better understanding the metabolic processes related with selenium uptake and accumulation in broccoli.

Effect of Se treatment on glucosinolate metabolism and health-promoting compounds in the broccoli sprouts of three cultivars

“…In particular, selenate treatment increased the GSL content by 15.2% compared to the control. Previous studies reported that the total GSL content is minimally affected by selenate treatment in broccoli sprouts and mature broccoli (25 and 100 lmol/L) (Avila et al, 2013;Sepúlveda, Barrientos, Mahn, & Moenne, 2013). In the present study, the total GSL content was not affected after Se fertilization in cultivars FL60 and SL120, agreeing with previously reported values.…”

“…In the present study, selenite and selenate treatments did not significantly influence the production of sulforaphane. The sulforaphane content in broccoli is minimally different between the control and selenate treatments (Sepúlveda et al, 2013). A similar result was also obtained in the present study for cultivar FL60.…”

“…The variation in myrosinase activity between the cultivars and different treatments was consistent with the variation trend of sulforaphane. Sepúlveda et al (2013) reported that the myrosinase activity in mature broccoli is minimally affected by Se treatment. Piekarska et al (2014) also reported that the myrosinase activity in Brassica crops and rye decreases when treated with SeO 2 water solution (10 mg/L).…”

Recent progress in the use of ‘omics technologies in brassicaceous vegetables

“…The plants responded to glycine supply by altering the expression of proteins involved in protein processing, amino acid metabolism and redox homeostasis. A similar experiment involving broccoli investigated the effect of supplying the plants with a non-limiting concentration of the essential trace element selenium ( Sepúlveda et al, 2013 ), resulting in an enhanced accumulation in the inflorescence of a number of proteins associated with the general stress response, while that of pathogen defense-related proteins was reduced. The effect of an organic farming regime on the cabbage proteome has shown that the cropping system had a measurable effect on the accumulation of proteins involved in glycolysis, the Krebs cycle, amino acid metabolism and various detoxification processes ( Nawrocki et al, 2011 ).…”

Accumulation of Glucosinolates in Broccoli

“…In addition, selenoglucosinolates displayed a higher anticarcinogenic activity than thioglucosinolates [162]. Se fertilization has been reported to exert no significant influence on glucosinolate levels in both broccoli sprouts [163][164][165] and florets [166]. Hence, Se fertilization is a good approach to accumulating selenium while maintaining glucosinolate content.…”