Abstract
There is strong evidence that phytohormones such as abscisic acid, auxin, salicylic acid, and jasmonates might play a role in defense of the host plants during phytoplasma infections. However, these compounds are usually present at low concentration in complex matrixes, requiring a sensitive and selective method to analyze and quantify them. Here, we present a HPLC-MS/MS method to quantify phytohormones in different infected and noninfected plant tissues.