Halophyte Nitraria billardieri CIPK25 mitigates salinity-induced cell damage by alleviating H2O2 accumulation

Abstract

The plant-specific module of calcineurin B-like proteins (CBLs) and CBL-interacting protein kinases (CIPKs) play a crucial role in plant adaptation to different biotic and abiotic stresses in various plant species. Despite the importance of the CBL-CIPK module in regulating plant salt tolerance, few halophyte CIPK orthologs have been studied. We identified NbCIPK25 in the halophyte Nitraria billardieri as a salt-responsive gene that may improve salt tolerance in glycophytes. Sequence analyses indicated that NbCIPK25 is a typical CIPK family member with a conserved NAF motif, which contains the amino acids: asparagine, alanine, and phenylalanine. NbCIPK25 overexpression in salt-stressed transgenic Arabidopsis seedlings resulted in enhanced tolerance to salinity, a higher survival rate, longer newly grown roots, more root meristem cells, and less damaged root cells in comparison to wild-type (WT) plants. H2O2 accumulation and malondialdehyde (MDA) content were both deceased in NbCIPK25-transgenic plants under salt treatment. Furthermore, their proline content, an important factor for scavenging reactive oxygen species, accumulated at a significantly higher level. In concordance, the transcription of genes related to proline accumulation was positively regulated in transgenic plants under salt condition. Finally, we observed a stronger auxin response in salt-treated transgenic roots. These results provide evidence for NbCIPK25 improving salt tolerance by mediating scavenging of reactive oxygen species, thereby protecting cells from oxidation and maintaining plant development under salt stress. These findings suggest the potential application of salt-responsive NbCIPK25 for cultivating glycophytes with a higher salt tolerance through genetic engineering.

A meta‐analysis highlights the cross‐resistance of plants to drought and salt stresses from physiological, biochemical, and growth levels

“…The H 2 O 2 and MDA contents in halophytes increased less than those in non‐halophytes under drought, salt, and combined stresses (Figures 3 and 7c). Previous studies have also shown that Arabidopsis plants overexpressing genes from halophytes exhibit lower H 2 O 2 and MDA contents in response to osmotic and salt stresses compared to wild‐type plants (Dabbous et al, 2017; Lu et al, 2022). The SOD activities and ascorbate contents in halophytes increased more significantly, whereas the POD, APX activities and glutathione contents in non‐halophytes showed greater increases under drought, salt, and combined stresses (Figures 3 and 7c).…”

Halophyte Nitraria billardieri CIPK25 promotes photosynthesis in Arabidopsis under salt stress

“…However, the underlying molecular and physiological mechanisms that explain how halophyte-derived CIPKs work against salt stress are not well understood. In our previous study, we found that CIPK25 positively responded to salt stress (500 mM NaCl) in N. billardieri (Lu et al, 2022). To explore the potential mechanism of a halophyte CIPK gene in salt adaptability, here, we overexpressed NbCIPK25 in Arabidopsis and analyzed its transcriptome data under normal or salt condition.…”

“…Due to their unique physiological characteristics that allow them to grow on saline soils, Nitraria species are ideal plants for studying the mechanisms of salt tolerance (Li et al, 2021). Therefore, we used N. billardieri to identify genes that are involved in salt tolerance and isolated NbCIPK25 from this halophyte, which gene was found to positively respond to salt stress (Lu et al, 2022). To explore the molecular mechanism of NbCIPK25 function in salt response, we overexpressed NbCIPK25 in Arabidopsis and found it affects the expression of different genes under normal or salt condition.…”

PYL Family Genes from Liriodendron chinense Positively Respond to Multiple Stresses

“…Prediction of 3D structures for LcPYL proteins was conducted using SWISS-MODEL online software ( , accessed on 25 August 2022) and PyMOL ( , accessed on 25 August 2022) [ 43 , 44 ]. The conserved motifs of 5 LcPYLs and 14 AtPYLs were analyzed by MEME online software ( , accessed on 7 August 2022) with 10 as the maximum motif number setting and keeping default values for the remaining parameters [ 45 , 46 ].…”