| Title: | Regulation of Arabidopsis defense responses against Spodoptera littoralis by CPK-mediated calcium signaling |
| Author(s): | Kanchiswamy CN; Takahashi H; Quadro S; Maffei ME; Bossi S; Bertea C; Zebelo SA; Muroi A; Ishihama N; Yoshioka H; Boland W; Takabayashi J; Endo Y; Sawasaki T; Arimura G; |
| Address: | "Global COE Program: Evolution and Biodiversity, Graduate School of Science, Kyoto University, Kyoto, Japan" |
| ISSN/ISBN: | 1471-2229 (Electronic) 1471-2229 (Linking) |
| Abstract: | "BACKGROUND: Plant Ca2+ signals are involved in a wide array of intracellular signaling pathways after pest invasion. Ca2+-binding sensory proteins such as Ca2+-dependent protein kinases (CPKs) have been predicted to mediate the signaling following Ca2+ influx after insect herbivory. However, until now this prediction was not testable. RESULTS: To investigate the roles CPKs play in a herbivore response-signaling pathway, we screened the characteristics of Arabidopsis CPK mutants damaged by a feeding generalist herbivore, Spodoptera littoralis. Following insect attack, the cpk3 and cpk13 mutants showed lower transcript levels of plant defensin gene PDF1.2 compared to wild-type plants. The CPK cascade was not directly linked to the herbivory-induced signaling pathways that were mediated by defense-related phytohormones such as jasmonic acid and ethylene. CPK3 was also suggested to be involved in a negative feedback regulation of the cytosolic Ca2+ levels after herbivory and wounding damage. In vitro kinase assays of CPK3 protein with a suite of substrates demonstrated that the protein phosphorylates transcription factors (including ERF1, HsfB2a and CZF1/ZFAR1) in the presence of Ca2+. CPK13 strongly phosphorylated only HsfB2a, irrespective of the presence of Ca2+. Furthermore, in vivo agroinfiltration assays showed that CPK3-or CPK13-derived phosphorylation of a heat shock factor (HsfB2a) promotes PDF1.2 transcriptional activation in the defense response. CONCLUSIONS: These results reveal the involvement of two Arabidopsis CPKs (CPK3 and CPK13) in the herbivory-induced signaling network via HsfB2a-mediated regulation of the defense-related transcriptional machinery. This cascade is not involved in the phytohormone-related signaling pathways, but rather directly impacts transcription factors for defense responses" |
| Keywords: | Animals Arabidopsis/*enzymology/genetics Arabidopsis Proteins/genetics/*metabolism Calcium/metabolism *Calcium Signaling Calcium-Calmodulin-Dependent Protein Kinases/genetics/*metabolism Cyclopentanes/metabolism Cytosol/metabolism Ethylenes/metabolism Gen; |
| Notes: | "MedlineKanchiswamy, Chidananda Nagamangala Takahashi, Hirotaka Quadro, Stefano Maffei, Massimo E Bossi, Simone Bertea, Cinzia Zebelo, Simon Atsbaha Muroi, Atsushi Ishihama, Nobuaki Yoshioka, Hirofumi Boland, Wilhelm Takabayashi, Junji Endo, Yaeta Sawasaki, Tatsuya Arimura, Gen-ichiro eng Research Support, Non-U.S. Gov't England 2010/05/28 BMC Plant Biol. 2010 May 26; 10:97. doi: 10.1186/1471-2229-10-97" |
