Elicitor-responses in rice cells are differentially potentiated by plant defense activators.

We examined the priming effects of four plant defense activators (probenazole [PBZ], methyl jasmonate [MeJA], acibenzolar-S-methyl [ASM], and carpropamid [CRP]) in rice cells. Activators potentiated the elicitor-responsive expression of Cht-1 gene by 4-to 7-fold. MeJA greatly activated PBZ1 and Os PAL1 gene expression by over 50-fold, and CRP also enhanced PBZ1 gene expression to the same degree. On the other hand, activators accelerated the elicitor-responsive photon emission and augmented its peak intensity by 2- to 3-fold. These results indicated that each elicitor response was potentiated by plant defense activators in different but overlapping manners. Among elicitor responses, photon emission can be a useful marker for priming because of its sensitivity to various kinds of activators and a simple strategy for its estimation.