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Short Communication

Suppression of MKK5 reduces ozone-induced signal transmission to both MPK3 and MPK6 and confers increased ozone sensitivity in Arabidopsis thaliana

Godfrey P. Miles, Marcus A. Samuel and Brian E. Ellis

In Arabidopsis thaliana, ozone-induced signaling has been shown to involve the mitogen-activated protein kinases (MAPKs) MPK3 and MPK6. To identify a possible ozone-induced mitogen-activated protein kinase kinase (MAPKK) involved in the activation of these specific MAPKs, we employed RNA interference-(RNAi)-based suppression of MKK5, a known cognate
MAPKK to both MPK3 and MPK6. When exposed to ozone, activation of both MPK3 and MPK6 was markedly reduced in the MKK5-suppressed plants compared to WT. Additionally, the
MKK5-suppressed plants were found to be highly sensitive to ozone as determined by visible leaf damage concomitant with elevated levels of leaf-localised H₂O₂. Taken together, our data
suggest MKK5 functions both in ozone-induced activation of MPK3 and MPK6 and in integrating ROS homeostasis during ozone stress.

Authors

Godfrey P. Miles Corresponding author: godfrey.miles@ars.usda.gov

Michael Smith Laboratories; University of British Columbia; Vancouver, BC CA

Marcus A. Samuel

Department of Biological Sciences; University of Calgary; Calgary, AB CA

Brian E. Ellis

Michael Smith Laboratories; University of British Columbia; Vancouver, BC CA