“…Polyamines correlate with numerous vital biochemical functions, including protein regulation (Takahashi and Kakehi, 2010; Sayas et al., 2019), regulation of chemiosmosis and photoprotection in chloroplasts (Ioannidis et al., 2016), ATP synthesis (Ioannidis et al., 2006), ion channeling (Pottosin et al., 2014a; Shabala et al., 2016), membrane fluidity (Paschalidis et al., 2010; Bleackley et al., 2014; Shabala et al., 2016; Dorighetto Cogo et al., 2018), and control of N/C balance (Moschou et al., 2012; Gupta et al., 2013; Majumdar et al., 2016). Exogenous PA application enhanced plant tolerance/resistance to several abiotic stress conditions, such as salinity, drought, water logging/flooding, osmotic stress, heavy metals, and extreme temperatures (Liu et al., 2006, 2015; Moschou et al., 2008c, 2012; Paschalidis et al., 2009a; Toumi et al., 2010; Moschou and Roubelakis-Angelakis, 2014; Gupta et al., 2016; Handa et al., 2018; Nguyen et al., 2018; Tiburcio and Alcazar, 2018; Pal et al., 2019; Yin et al., 2019). Polyamine application also enhanced tolerance to a few phytopathogenic infections in planta , such as Alternaria alternata (Estiarte et al., 2017), Phytophthora capsici (Koç, 2015), and Pseudomonas viridiflava (Rossi et al., 2015, 2018), and in vitro , such as Fusarium strains (Wojtasik et al., 2015) and Sclerotinia sclerotiorum (Garriz et al., 2003).…”