How Natural Extracts Activate Defenses Against Pathogens In Tomato Plants

Tomato is an agronomically valuable crop in many countries, either grown in fields or greenhouses and therefore has been bred and genetically improved for centuries. Nonetheless, it remains vulnerable to diseases, consequently requiring the use of chemical pesticides, mainly in greenhouses. On the other hand, it is vital to diminish the usage of environmental-unfriendly phytochemicals and prefer less harmful tools to fight pathogens. Plants respond to pathogens by means of elaborated mechanisms. In many cases, these responses can result in resistance. Besides constitutive defenses, plant tissues can counteract pathogens assault thru inducible responses (Frost et al. 2008). These require the specific recognition of the attacker, which in turn triggers a multileveled defense (Dangl et al. 2013) that can result in resistance. If the plant is unable to recognize the pathogen it will not activate the resistance machinery. Different actors are involved in this phenomenon specifically phytohormones, such as salicylic acid (SA) and jasmonic acid (JA) (Dangl et al. 2013), small signaling molecules, proteins, enzymes and protective molecules (for example: reactive oxygen species, the cell wall component callose and pathogenesis-associated proteins, PR; Borges and Sandalio 2015; Dangl et al. 2013). The latter forms a heterogeneous group of proteins (17 members) with specific capabilities and systems (Sels et al. 2008)