Contents lists available at ScienceDirect Scientia Horticulturae journal homepage: www.elsevier.com/locate/scihorti Olive tree pruning derived biochar increases glucosinolate concentrations in broccoli Paula Garcia-Ibañez a,1 , Maria Sanchez-Garcia b,1 , Miguel A. Sánchez-Monedero b , María Luz Cayuela b , Diego A. Moreno a, * a Phytochemistry and Healthy Foods Lab, Departments of Food Science and Technology, Centro de Edafología y Biología Aplicada del Segura, CEBAS-CSIC, Campus de Espinardo-25, E-301000, Murcia, Spain b Department of Soil and Water Conservation and Organic Waste Management, Centro de Edafología y Biología Aplicada del Segura, CEBAS-CSIC, Campus de Espinardo- 25, E-30100, Murcia, Spain ARTICLE INFO Keywords: Charcoal Brassica oleracea Amino acid fertilizer Glucosinolates ABSTRACT Biochar has attracted great attention in the soil scientific community for its interaction with different biogeo- chemical cycles and its potential environmental and agronomical benefits. However, there is only limited in- formation about its effect on plant secondary metabolism. In this manuscript, a biochar produced from olive tree pruning by slow pyrolysis at 600 °C was selected to analyze its impact on the concentration of the health- promoting compounds glucosinolates (GLSs) in broccoli. The biochar was applied as soil amendment, alone or combined with organic and mineral fertilization, in a broccoli cultivar in the field. We found that this particular biochar caused an enrichment in GLSs concentration in broccoli amended with biochar alone. Meanwhile, the fertilized treatments caused a decrease in the GLSs concentration in broccoli inflorescence, particularly mineral fertilization originated the lowest concentration of neoglucobrassicin and glucoraphanin. When biochar was combined with mineral fertilization it increased the concentration of GLS to similar levels as the untreated plants, probably as a physiological response of the plant to the enhanced physicochemical properties of biochar amended soils. These findings highlight the importance of agronomical practices in achieving a balance between a good performance in production and the presence of beneficial phytochemicals. 1. Introduction One of the most cultivated vegetables is broccoli (Brassica oleracea var. italica), which is receiving attention not only because of its nu- tritive value but also as a source of diverse bioactive compounds, such as flavonoids and phenolics (Koh et al., 2009). Recent studies have linked the consumption of Brassica vegetables to a protective or pre- ventive effect on some types of cancer, such as colon or breast cancer (Bessler and Djaldetti, 2018; Dias, 2012). In particular, there is an in- creasing interest in the study of Glucosinolates (GLSs), which are the main responsible for the health-promoting effects of broccoli and other brassicas (Axelsson et al., 2017; Mohammadi et al., 2018). These phy- tochemicals are sulfur- and nitrogen-containing secondary metabolites derived from amino acids, predominantly found in Brassicaceae family (Prieto et al., 2019). GLSs are very stable compounds but after me- chanical damage or insect attack, they are hydrolyzed by a β-thioglu- cosidase known as myrosinase, forming bioactive derivate compounds such as isothiocyanates and other hydrolysis products involved in the plant defense against herbivores and pathogens (Bhat and Vyas, 2019; Halkier and Gershenzon, 2006). The content of GLSs in broccoli plants are mostly determined by the genotype, but their metabolism in the plant can be regulated by a range of environmental factors such as climate and agricultural practices (Farnham et al., 2004; Yan and Chen, 2007). For example Rios et al. (2020) demonstrated that indole GLSs were highly affected by salinity, showing higher concentrations in spring and autumn in inflorescences and leaves. Among them, fertilization is a key factor driving both plant nutritional status and secondary metabolism (Francisco et al., 2017). The concentration of GLS is known to be affected by N and S fertili- zation and also by the balance between them (Björkman et al., 2011). S fertilization seems to increase the glucosinolate content in broccoli (Falk et al., 2007), whereas an increase in N/S usually lowers GLSs concentration as a consequence of a dilution effect caused by the en- hanced vegetative growth (Francisco et al., 2017). Another factor https://doi.org/10.1016/j.scienta.2020.109329 Received 26 September 2019; Received in revised form 27 February 2020; Accepted 28 February 2020 ⁎ Corresponding author. E-mail address: dmoreno@cebas.csic.es (D.A. Moreno). 1 Equal contribution. Scientia Horticulturae 267 (2020) 109329 0304-4238/ © 2020 Elsevier B.V. All rights reserved. T