“…Another important mechanism involved in H 2 O 2 production in guard cell is mediated by class III peroxidases (PRXs; Figure 1 ). Both internal factors, such as SA ( Mori et al, 2001 ; Khokon et al, 2011 ), isothiocyanates (ITCs; Hossain et al, 2013 ; Sobahan et al, 2015 ) and methylglyoxal ( Hoque et al, 2012 ), and external factors, such as YEL ( Khokon et al, 2010a ), chitosan ( Khokon et al, 2010b ), flg22 ( O’Brien et al, 2012 ), and elf26 ( O’Brien et al, 2012 ), induce H 2 O 2 production mediated by PRXs. Pharmacological and genetic studies further showed that salicylhydroxamic acid (SHAM)-sensitive PRXs but not RBOHD or RBOHF are essential for stomatal closure and H 2 O 2 production in guard cells induced by SA, ITCs, methylglyoxal, chitosan and YEL ( Khokon et al, 2010a , b , 2011 ; Hoque et al, 2012 ; Hossain et al, 2013 ).…”