The Calcium-Dependent Protein Kinase TaCDPK27 Positively Regulates Salt Tolerance in Wheat

Abstract

As essential calcium ion (Ca2+) sensors in plants, calcium-dependent protein kinases (CDPKs) function in regulating the environmental adaptation of plants. However, the response mechanism of CDPKs to salt stress is not well understood. In the current study, the wheat salt-responsive gene TaCDPK27 was identified. The open reading frame (ORF) of TaCDPK27 was 1875 bp, coding 624 amino acids. The predicted molecular weight and isoelectric point were 68.905 kDa and 5.6, respectively. TaCDPK27 has the closest relationship with subgroup III members of the CDPK family of rice. Increased expression of TaCDPK27 in wheat seedling roots and leaves was triggered by 150 mM NaCl treatment. TaCDPK27 was mainly located in the cytoplasm. After NaCl treatment, some of this protein was transferred to the membrane. The inhibitory effect of TaCDPK27 silencing on the growth of wheat seedlings was slight. After exposure to 150 mM NaCl for 6 days, the NaCl stress tolerance of TaCDPK27-silenced wheat seedlings was reduced, with shorter lengths of both roots and leaves compared with those of the control seedlings. Moreover, silencing of TaCDPK27 further promoted the generation of reactive oxygen species (ROS); reduced the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT); aggravated the injury to photosystem II (PS II); and increased programmed cell death (PCD) in wheat leaves under NaCl treatment, confirming that the TaCDPK27-silenced seedlings exhibited more NaCl injury than control seedlings. Taken together, the decrease in NaCl tolerance in TaCDPK27-silenced seedlings was due to excessive ROS accumulation and subsequent aggravation of the NaCl-induced PCD. TaCDPK27 may be essential for positively regulating salt tolerance in wheat seedlings.

Insights into Salinity Tolerance in Wheat

“…These proteins aid in stress resistance in wheat by participating in H 2 O 2 and ABA responses [68]. Silencing of the TaCDPK27 gene in wheat leads to the accumulation of excess ROS and increased salt-induced programmed cell death (PCD), demonstrating that TaCDPK27 is necessary for salt-tolerance regulation in wheat seedlings [69]. TaCDPK5/TaCDPK9-1 can be auto-phosphorylated and phosphorylate the TabZIP60 protein in a Ca 2+ dependent manner.…”

Improving Wheat Salt Tolerance for Saline Agriculture

“…Recently, 18 TaCaM and 230 TaCML genes were identified in wheat genome . Most of the reported wheat Ca 2+ signaling proteins positively regulated plant salt tolerance, such as TaCAM2-D, TaCRT1, TaCDPK27, and TaCIPK24, with exception of TaCIPK25, which negatively regulates salt response in wheat …”

“…15 Recently, 18 TaCaM and 230 TaCML genes were identified in wheat genome. 16 Most of the reported wheat Ca 2+ signaling proteins positively regulated plant salt tolerance, such as TaCAM2-D, 17 TaCRT1, 18 TaCDPK27, 19 and TaCIPK24, 15 with exception of TaCIPK25, which negatively regulates salt response in wheat. 20 Besides Ca 2+ mediated signal, the synthesis of osmolytes (such as sugars, proline, glycine betaine), which promote osmotic balance at the cellular level, can alleviate the osmotic stress.…”

Transcriptomic analysis reveals that methyl jasmonate confers salt tolerance in alfalfa by regulating antioxidant activity and ion homeostasis

“…When plants are subjected to salt stress, Ca 2+ is stimulated as the initial signal molecule ( Yang et al., 2019 ). Elevation in intracellular Ca 2+ level triggers the expression of genes encoding Ca 2+ sensors including calmodulin (CaM), CaM-like protein (CML), calcineurin B-like protein (CBL), and calcium-dependent protein kinase (CDPK) ( Wang et al., 2018 ; Yue et al., 2022 ). Subsequently, genes related to osmoregulation, antioxidants, and ion exclusion/sequestration responded to salt stimuli.…”