Phosphoproteomic analysis reveals that dehydrins ERD10 and ERD14 are phosphorylated by SNF1‐related protein kinase 2.10 in response to osmotic stress

Abstract

SNF1-related protein kinases 2 (SnRK2s) regulate the plant responses to abiotic stresses, especially water deficits. They are activated in plants subjected to osmotic stress, and some of them are additionally activated in response to enhanced concentrations of abscisic acid (ABA) in plant cells. The SnRK2s that are activated in response to ABA are key elements of ABA signalling that regulate plant acclimation to environmental stresses and ABA-dependent development. Much less is known about the SnRK2s that are not activated by ABA, albeit several studies have shown that these kinases are also involved in response to osmotic stress. Here, we show that one of the Arabidopsis thaliana ABA-non-activated SnRK2s, SnRK2.10, regulates not only the response to salinity but also the plant sensitivity to dehydration. Several potential SnRK2.10 targets phosphorylated in response to stress were identified by a phosphoproteomic approach, including the dehydrins ERD10 and ERD14. Their phosphorylation by SnRK2.10 was confirmed in vitro. Our data suggest that the phosphorylation of ERD14 within the S-segment is involved in the regulation of dehydrin subcellular localization in response to stress.

SnRK2 Protein Kinases and mRNA Decapping Machinery Control Root Development and Response to Salt

“…In our in vitro assay SnRK2.6 was able to phosphorylate VCS and VCR at the same residues as SnRK2.10 (Table 3). Phosphorylation of Ser-645, Ser-692, and Ser-1156 of VCS and Ser-680 of VCR has been previously shown to be up-regulated by osmotic and/or salt stress in planta (Stecker et al, 2014;Maszkowska et al, 2019). SnRK2 protein kinases are autophosphorylated upon salt stress.…”

“…S1). Among these, phosphorylation of six sites for VCS and two for VCR have been shown to be up-regulated by osmotic and/or salt stress ( Table 2; Stecker et al, 2014;Maszkowska et al, 2019). No phosphopeptides were identified for the other proteins copurified with SnRK2.4 and SnRK2.10 ( Table 1), suggesting that VCS and VCR are possible phosphorylation targets of SnRK2.4 and SnRK2.10, whereas other identified proteins are likely functioning in the same complex (Table 2).…”

“…Purified recombinant protein kinases SnRK2.4 and SnRK2.10 were used for the in vitro phosphorylation reactions with synthetic peptides from VCS, VCR, and DCP2 proteins. Synthetic peptides were designed to contain the phosphopeptides identified in the TAP experiment and shown previously to be regulated by osmotic and/or salt stress (Table 2; Stecker et al, 2014;Maszkowska et al, 2019). Each protein kinase was incubated with a mixture consisting of three peptides representing the VCS sequence, and one peptide each from VCR and DCP2.…”

Two SnRK2-Interacting Calcium Sensor Isoforms Negatively Regulate SnRK2 Activity by Different Mechanisms

“…Arabidopsis (Arabidopsis thaliana) lines used in this study comprised Col-0 as the wild type background and the following the transfer DNA insertion lines: scs-1 (Salk_051356) and scs-2 (Salk_104688) as described in Bucholc et al (2011); snrk2.6 (Salk_008068) obtained from the Nottingham Arabidopsis Stock Centre (http://nasc.nott.ac.uk); double mutant snrk2.2/2.3 (GABI-Kat 807G04/ Salk_107315) provided by Jian-Kang Zhu (Purdue University); a quadruple knockout mutant snrk2.1/2.4/2.5/2.10 (SAIL_519_C01/Salk_080588/ Salk_075624/WiscDsLox233E9) described by Maszkowska et al (2019); and double mutant abi1-2/pp2ca-1 (Salk_72009/Salk_28132) obtained from Pedro L. Rodriguez (Instituto de Biologia Molecular y Celular de Plantas). The seeds of Arabidopsis were grown under long-day conditions (16-h-light/8-h-dark photoperiod) at 22°C/18°C in soil or in hydroponic culture (Araponics System) as described by Kulik et al (2012).…”

Genome-wide identification and characterization of SnRK family genes in Brassica napus

“…On the other hand, the SnRK2 genes play important roles in responding to abiotic stresses in plants, especially for osmotic and salt stress. For instance, SnRK2.10 phosphorylate several target genes including dehydrins ERD10 and ERD14 to deal with osmotic stress in Arabidopsis thaliana (Maszkowska et al, 2019). SnRK2.1 positivly regulate salt tolerance in Nicotiana tabacum (Diédhiou et al, 2008;Zhang et al, 2014).…”