Arabidopsis thaliana AtGCN2 kinase coordinates translational regulation and plant immune responses
X. LIU (1), K. Pajerowska-Mukhtar (1) (1) University of Alabama at Birmingham, U.S.A.

Upon biotic stress, plant may accumulate excessive amounts of misfolded or unfolded proteins within the Endoplasmic Reticulum (ER). In response to that, Unfolded Protein Response (UPR) is activated to alleviate the stress condition and restore homeostasis. TBF1, a heat-shock-like transcription factor, which has been shown to induce the transcription of ER-resident genes, contains two upstream open reading frames (uORFs) that can exert inhibitory effects on translation of the main ORF. Interestingly, the repressive effects of uORFs on TBF1 translation can be alleviated by AtGCN2-mediated phosphorylation of a regulatory molecule eIF2α (eukaryotic initiation factor 2α). Previous work in our lab found that AtGCN2 kinase is involved in immune signaling pathways mediated by the phytohormones salicylic acid and jasmonic acid. Though immune signaling pathways mediated by these two phytohormones are antagonistic, the AtGCN2 kinase seems to function as a central node that is targeted by pathogens with various nutritional strategies to jeopardize the host immune response. Recently, we determined that the AtGCN2 kinase plays differential roles in two additional forms of the plant immune responses: MAMP (Microbe-Associated Molecular Patterns)-Triggered Immunity and Effector-Triggered Immunity. More interestingly, we identified that AtGCN2 has a role in MAMP-induced stomatal closure and phytotoxin coronatine-triggered stomatal reopening. Current research focuses on determining the molecular mechanism underlying the involvement of AtGCN2 kinase in the stomatal immunity.

Abstract Number: P7-185
Session Type: Poster