Genome-Wide Identification of the Salvia miltiorrhiza SmCIPK Gene Family and Revealing the Salt Resistance Characteristic of SmCIPK13

Members of the CIPK (CBL-interacting protein kinases) gene family play important roles in calcium (Ca²⁺) signaling pathway-regulated plant resistance to abiotic stresses. Salvia miltiorrhiza, which is widely planted and grown in complex and diverse environments, is mainly focused on the transcriptional regulation of enzyme genes related to the biosynthesis of its bioactive components. However, the excavation of the genes related to the resistance of S.miltiorrhiza and the involved signaling pathways have not been deeply studied. In this study, 20 SmCIPK genes were identified and classified into two families and five subfamilies by biochemical means. Sequence characteristics and conserved motif analysis revealed the conservation and difference of SmCIPK protein in plants. Expression pattern analysis showed that SmCIPKs were mainly expressed in flowers and roots, and more than 90% of gene expression was induced by SA (salicylic acid), and MeJA (methyl jasmonate). Furthermore, the expression level of SmCIPK13 could be significantly increased after stress treatment with NaCl. SmCIPK13 expression in yeast reduces sensitivity to salt, while overexpression of it in Arabidopsis has the same effect and was localized in the cytoplasm, cell membrane and nucleus. In conclusion, the identification of the SmCIPK gene family and the functional characterization of the SmCIPK13 gene provides the basis for clarification of key genes in the Ca²⁺ signaling pathway and abiotic stress in S.miltiorrhiza.

Genome-Wide Identification, Characterization and Expression Analysis of the CIPK Gene Family in Potato (Solanum tuberosum L.) and the Role of StCIPK10 in Response to Drought and Osmotic Stress

The potato (Solanum tuberosum L.), one of the most important food crops worldwide, is sensitive to environmental stresses. Sensor–responder complexes comprising calcineurin B-like (CBL) proteins and CBL-interacting protein kinases (CIPKs) not only modulate plant growth and development but also mediate numerous stress responses. Here, using a Hidden Markov Model and BLAST searches, 27 CIPK genes were identified in potato and divided into five groups by phylogenetic analysis and into two clades (intron-poor and intron-rich) by gene structure analysis. Quantitative reverse-transcription PCR (qRT-PCR) assays revealed that StCIPK genes play important roles in plant growth, development and abiotic stress tolerance. Up-regulated expression of StCIPK10 was significantly induced by drought, PEG6000 and ABA. StCIPK10 enhances both the ability of potato to scavenge reactive oxygen species and the content of corresponding osmoregulation substances, thereby strengthening tolerance to drought and osmotic stress. StCIPK10 is located at the intersection between the abscisic acid and abiotic stress signaling pathways, which control both root growth and stomatal closure in potato. In addition, StCIPK10 interacts with StCBL1, StCBL4, StCBL6, StCBL7, StCBL8, StCBL11 and StCBL12, and is specifically recruited to the plasma membrane by StCBL11.

Identification and comparative analysis of the CIPK gene family and characterization of the cold stress response in the woody plant Prunus mume

Prunus mume is an important ornamental woody plant that grows in tropical and subtropical regions. Freezing stress can adversely impact plant productivity and limit the expansion of geographical locations. Understanding cold-responsive genes could potentially bring about the development of new ways to enhance plant freezing tolerance. Members of the serine/threonine protein kinase (CIPK) gene family play important roles in abiotic stress. However, the function of CIPK genes in P. mume remains poorly defined. A total of 16 CIPK genes were first identified in P. mume. A systematic phylogenetic analysis was conducted in which 253 CIPK genes from 12 species were divided into three groups. Furthermore, we analysed the chromosomal locations, molecular structures, motifs and domains of CIPK genes in P. mume. All of the CIPK sequences had NAF domains and promoter regions containing cis-acting regulatory elements of the related stress response. Three PmCIPK genes were identified as Pmu-miR172/167-targeted sites. Transcriptome data showed that most PmCIPK genes presented tissue-specific and time-specific expression profiles. Nine genes were highly expressed in flower buds in December and January, and 12 genes were up-regulated in stems in winter. The expression levels of 12 PmCIPK genes were up-regulated during cold stress treatment confirmed by qRT-PCR. Our study improves understanding of the role of the PmCIPK gene family in the low temperature response in woody plants and provides key candidate genes and a theoretical basis for cold resistance molecular-assisted breeding technology in P. mume.

Identification of Important Physiological Traits and Moderators That Are Associated with Improved Salt Tolerance in CBL and CIPK Overexpressors through a Meta-Analysis

The CBL-CIPK pathway is a plant-specific Ca2+ sensor relaying pathway that has been shown to be involved in plant response to salt stress. Over-expression of CBL-CIPK network genes has been reported to increase salt tolerance in many studies. The studies on the overexpression of CBL-CIPK network genes, however, have used various indices to evaluate the effect of these genes on salt tolerance and have indicated a variety of roles for the major CBL-CIPK pathway genes. Therefore, it is of great interest to analyze the various effects resulting from the overexpression CBL-CIPK pathway genes and their relation to salt tolerance. The meta-analysis conducted in the present study investigated how over-expression of CBLs or CIPKs in transgenic plants affects the response to salt stress and identified the increase or decrease that occurs in these experimental variables when foreign CIPK or CBL genes are overexpressed in transgenic plants. The data from the collective studies on over-expression of CIPKs indicated that 6 of the 11 examined parameters (main effects) increased by 22% or more, while two of the six examined parameters increased by at least 78% in transgenic plants overexpressing CBL genes. In addition to analyzing the impact of overexpression on the main effects, eight different modifying parameters were also analyzed. Results indicated that several moderators impact the extent to which overexpression of CBLs and CIPKs affect the main parameters. The majority of CBLs have been obtained from dicotyledonous plants and most of the CBLs and CIPKs have been expressed in dicotyledonous plants. In comparison to homologous expression, the meta-analysis indicated that heterogeneous expression of CBLs resulted in greater increases in seed germination. The results of the meta-analysis provide information that could be useful in designing research to examine the mechanisms by which CBL-CIPK pathway genes increase salt tolerance in plants.