Protein kinase CK2α subunits constitutively activate ABA signaling in Arabidopsis

Abstract

Protein kinase CK2 (formerly known as casein kinase II), a Ser/Thr protein kinase highly conserved in eukaryotes, is essential for cell survival by regulating a wide range of plant growth, development, and stress responses. A growing body of evidence has shown a link between CK2 and abscisic acid (ABA) signaling in response to abiotic stress. However, the roles of CK2 subunits in ABA signaling remain unclear in plants. Our recent work in Arabidopsis thaliana has revealed that CK2α and CK2β subunits inversely modulate ABA signal output. Here, we examine the roles of CK2αs, by assessing how CK2αs affect ABA signaling. Together with the previous findings, our mutant and transient expression analyses demonstrate that CK2αs positively modulate ABA signaling through the core ABA signaling pathway in the presence of ABA, though the positive effect of CK2αs are much smaller than that of core ABA signaling components in ABA response. In addtion, our current and previous findings also suggest that CK2αs play a role in maintaining constitutively active ABA signaling even in the absence of ABA independently of the core ABA signaling pathway. Thus, we found that CK2αs constitutively activate ABA signaling in the presence or absence of ABA in a different manner in Arabidopsis plants.

CRISPR/Cas9-targeted mutagenesis of OsERA1 confers enhanced responses to abscisic acid and drought stress and increased primary root growth under nonstressed conditions in rice

“…Thus, the increased primary root growth of the osera1 mutant under nonstressed conditions may be due to an enhanced sensitivity to ABA. The basal role of ABA signaling under nonstressed conditions has been the focus of recent research [45,46], and further research is required to clarify the roles of OsERA1 in this context. This is the first report of CRISPR/Cas9-targeted mutagenesis being used to functionally characterize the role of ERA1 in plants.…”