Figure 3.

Priming by methyl jasmonate. MeJA is the most efficient JA compound for chemical priming. Primed P. crispum L. (parsley) suspension culture cells show upon triggering by the elicitor Pmg an augmented secretion of coumarin derivatives as well as cell wall fortification by incorporation of hydroxycinnamic acids and “lignin-like” polymers. NBS-LRR resistance-like protein gene expression is significantly increased in Phaseolus vulgaris L. plants treated with MeJA. This suggests an enhanced signal perception in plants before their infection with Sclerotinia sclerotiorum (Lib.) de Bary. The infection is followed by an elevated expression of the pathogen-related gene PvChit1/PR3, the JA signaling gene PvF-box and the callose deposition-related gene PvCallose. Primed tomato plants show an increased biosynthesis of both SA and JA, together with polyphenols. After the infection with the necrotrophic pathogen R. solani, augmented expression of PR1a, and of the PAD4 gene was observed. MeJA pretreatment further limits the ROS production stimulated by R. solani infection.