Botanical and biological pesticides elicit a similar Induced Systemic Response in tomato (Solanum lycopersicum) secondary metabolism Luca Pretali a, 1 , Letizia Bernardo a, 1 , Timothy S. Butterfield b , Marco Trevisan a , Luigi Lucini a, * a Institute of Environmental and Agricultural Chemistry, Universit a Cattolica del Sacro Cuore, 29122, Piacenza, Italy b Department of Plant Sciences, University of California, Davis, CA, 95616, USA article info Article history: Received 2 January 2016 Received in revised form 7 March 2016 Accepted 11 April 2016 Available online xxx Keywords: Solanum lycopersicum Solanaceae Bacillus subtilis Azadirachtin Metabolomics Induced Systemic Response abstract Natural pesticides have attracted substantial interest due to the increase in organic agriculture and enhanced attention to environmental pollution. Plant Growth Promoting Bacteria (PGPB) are applied for both disease control and growth enhancement; PGPBs are known to elicit Induced Systemic Response (ISR) in plants. However, less is known about the effect of botanical pesticides, such as the azadirachtin- containing neem extracts, on plant metabolism. This study aimed to investigate the effects of foliar application of the above-mentioned natural pesticides on the metabolic profiling of tomato. Leaf application of Bacillus subtilis fostered Induced Systemic Resistance (ISR) in treated plants via the Jasmonic acid pathway, and enhanced production of secondary metabolites such as flavonoids, phyto- alexins and auxins. Changes in sterols and terpenes, as well as an increase in glucosinolates were also observed. Interestingly, azadirachtin-treated tomatoes also showed an increase in ISR and our results revealed that most of the enriched metabolites are shared with a B. subtilis treatment, suggesting conserved biochemical responses. These (un)expected findings indicate that plants are not insensitive to application of natural pesticide and while Azadirachtin is applied as a direct pesticide, it also stimulates a defense response in tomatoes very similar to B. subtilis induced ISR. © 2016 Elsevier Ltd. All rights reserved. 1. Introduction Plants possess a wide range of active defense mechanisms by which they can respond to the variety of stresses they may encounter during their lives. The period between perception of and response to an attack is critical and may mark the difference be- tween coping or succumbing. During their lifetime, plants encounter numerous herbivorous insects and microbial pathogens. The basal immune response (Systemic acquired resistance, SAR) has evolved to recognize common features of organisms that interact with the plant and induce responses directed against the specific invader encountered (Jones and Dangl, 2006). This basal immune response relies initially upon recognition of microbe- or pathogen-associated molecular patterns (M/PAMPs) by pattern recognition receptors (PRRs) to contain pathogen assault. Circum- vention of initial PAMP-triggered immunity (PTI) by pathogen ef- fectors is recognized R-gene encoded NB-LRR proteins which induce effector-triggered immunity which can involve pro- grammed cell death and the hypersensitive response as well as systemic acquired resistance (SAR) through cell-cell signaling (Jones and Dangl, 2006; Dodds and Rathjen, 2010; Bhuvaneshwari et al., 2015a). Plants can also activate a second line of defense that is referred to as Induced Systemic Resistance (ISR), that differs from SAR on the basis of the nature of the elicitor and the regulatory pathways. This latter type of resistance acts systemically in response to a non-pathogenic organism, and is typically effective against a broad spectrum of biotic stresses (Choudhary et al., 2007). SAR and ISR are two of the inducible defense mechanisms activated in plants, depending upon the nature of the biotic elicitor (path- ogen rather than not pathogen). Plant defense response starts with the production of several secondary metabolites such as antioxidants, phytoalexins, and stress-related plant hormones e.g. salicylic acid (SA), jasmonic acid (JA) and ethylene (ET) (Koornneef and Pieterse, 2008). The plant * Corresponding author. Via Emilia Parmense, 84, 29122, Piacenza, Italy. E-mail addresses: luca.pretali@gmail.com (L. Pretali), l_bernardo@libero.it (L. Bernardo), tsbutterfield@ucdavis.edu (T.S. Butterfield), marco.trevisan@unicatt. it (M. Trevisan), luigi.lucini@unicatt.it (L. Lucini). 1 These authors contributed equally to the work. Contents lists available at ScienceDirect Phytochemistry journal homepage: www.elsevier.com/locate/phytochem http://dx.doi.org/10.1016/j.phytochem.2016.04.002 0031-9422/© 2016 Elsevier Ltd. All rights reserved. Phytochemistry xxx (2016) 1e8 Please cite this article in press as: Pretali, L., et al., Botanical and biological pesticides elicit a similar Induced Systemic Response in tomato (Solanum lycopersicum) secondary metabolism, Phytochemistry (2016), http://dx.doi.org/10.1016/j.phytochem.2016.04.002