ARABIDOPSIS THALIANA EIF2A KINASE, GCN2 IS ESSENTIAL FOR MEDIATING SURVIVAL RESPONSES TOWARDS METHYL JASMONATE STRESS
Plant growth and productivity rely on rapid energy management strategies designed to cope with dynamic environmental conditions. Among these, cytosolic protein synthesis (translational control) serves as a vital node for the regulation and maintenance of cellular homeostasis. Translational control complements transcriptional control because regulation at the level of translation is faster, rapidly reversible, and energy efficient. Thus, translational control has the potential to explain how plant cells can nimbly adjust to dynamic changes in their environment. In his previous work, Dr. Lokdarshi identified a novel fast-regulatory switch in Arabidopsis thaliana that functions at the nexus of two fundamental processes, cytosolic translation and reactive oxygen species (ROS) signaling. Specifically, the general control of nonderepressible 2 (GCN2), a cytosolic serine/threonine protein kinase, is rapidly activated in response to ROS emanating from chloroplasts under a variety of abiotic and xenobiotic stresses. GCN2 then phosphorylates its target, eukaryotic translation initiation factor (eIF)2 alpha, resulting in readjustments to the active protein synthesis for stress remediation. In the work presented here, we provide new evidence that the plant defense hormone, methyl jasmonate (MeJA), requires light (therefore, chloroplast function) to activate the cytosolic GCN2-eIF2alpha module. Additionally, loss-of-gcn2 mutant seedlings showed increased sensitivity towards MeJA stress supported by a primary root length assay and altered accumulation of MeJA responsive transcripts versus wild-type using quantitative real-time PCR analysis. In conclusion, we provide evidence that the GCN2-eIF2alpha module is critical for mediating survival responses towards MeJA stress and may serve as a missing link in a non-canonical retrograde signaling pathway whereby the status of the photosynthetic machinery feeds back to the cytosolic protein synthesis apparatus for rapid energy management under diverse abiotic, xenobiotic, and biotic stresses.
Diaz, Daniel F.; Lokdarshi, Ansul; and Akuoko, Teressa K.
"ARABIDOPSIS THALIANA EIF2A KINASE, GCN2 IS ESSENTIAL FOR MEDIATING SURVIVAL RESPONSES TOWARDS METHYL JASMONATE STRESS,"
Georgia Journal of Science, Vol. 81, No. 1, Article 43.
Available at: https://digitalcommons.gaacademy.org/gjs/vol81/iss1/43