Search Results (59)

Manganese (Mn) is essential for plants, but its fluctuating soil availability—deficiency in alkaline soils and toxicity in acidic soils—challenges crop productivity. Breakthroughs in Arabidopsis have uncovered Ca²⁺ signaling as a key integrator of Mn status. This review synthesizes these discoveries into an emerging Arabidopsis-centered framework. Under Mn deficiency, sustained Ca²⁺ oscillations activate CPK21/23, which phosphorylate the importer NRAMP1 at Thr498 to enhance Mn uptake. Under Mn excess, a rapid Ca²⁺ transient triggers a multi-layered cascade: CPK4/5/6/11 activates MTP8 (Ser31/32) for vacuolar sequestration, while CBL2/3–CIPK3/9/26 sequentially suppresses MTP8 (Ser35, peak 24 h) and MTP11 (Ser194/201, peak 36 h)—a multi-tiered “brake” system. Concurrently, CBL1/9–CIPK23 induces NRAMP1 endocytosis (Ser20/22) to limit Mn uptake. The IRT1 transporter directly binds cytoplasmic Mn²⁺ and triggers its own degradation via CIPK23, thereby converging with Ca²⁺ signaling. The BRI1–CNGC12 module generates Mn-induced Ca²⁺ signals. By organizing current knowledge into a hierarchical framework, this review provides a working model for future research and outlines translational opportunities for engineering Mn-resilient crops. Full article

Background: The Calcineurin B-like (CBL) and CBL-interacting protein kinase (CIPK) system constitute critical signaling modules mediating plant responses to abiotic stress. Although these families have been studied across various species, their evolutionary dynamics across grasses and the functional plasticity of specific isoforms remain elusive. Methods: A genome-wide analysis of CBL and CIPK families was conducted across five major Poaceae species (Oryza sativa, Triticum aestivum, Zea mays, Sorghum bicolor, and Saccharum spontaneum). Phylogenetic and synteny analyses were analyzed to family expansion and evolution. Cis-regulatory elements analysis in gene promoter regions were examined to predict potential stress-responsive features. Expression profiles of OsCBL and OsCIPK gene families were examined by qRT-PCR under conditions involving PEG-induced osmotic stress, pathogen strain P6 inoculation, and exogenous application of the phytohormones abscisic acid (ABA) and methyl jasmonate (MeJA). Protein–protein interactions between selected CBL (OsCBL4) and CIPK pairs were assessed via Yeast Two-Hybrid (Y2H) and Luciferase Complementation Imaging assays (LCI). Results: Phylogenetic and synteny analyses indicated that segmental duplications have contributed substantially to the expansion of these gene families. Promoter analysis revealed that the majority of CBL and CIPK family members, exemplified by OsCBL4, traditionally characterized as a salt sensor, possesses a cis-element architecture (rich in ABREs and MBS) heavily biased towards dehydration responsiveness. Expression profiling showed that OsCBL4 is significantly hyper-induced by direct osmotic stress (PEG) but exhibits almost no response to exogenous ABA. A subset of kinases genes (e.g., OsCIPK2, 9, 18) displayed PEG-induced expression patterns resembling those of OsCBL4, whereas OsCIPK30 remained transcriptionally unresponsive under the same conditions. Protein interaction assays demonstrated that OsCBL4 physically interacts exclusively with PEG-responsive transcriptionally activated kinases such as OsCIPK9, but failed to interact with the non-responsive OsCIPK30. Conclusions: Our study provides a genomic characterization of CBL and CIPK families across five major Poaceae species. The combined expression and interaction data reveal that OsCBL4-assembles with specific CIPKs into signaling modules during osmotic stress responses in rice, pointing to roles that go beyond salt stress responses. The findings establish a foundation for further functional dissection of CBL-CIPK pathway diversification in abiotic stress adaptation. Full article

Background: The ice plant (Mesembryanthemum crystallinum L.) is a typical halophyte with remarkable stress resistance traits, including salinity and alkalinity tolerance. As a crucial signaling transduction pathway for plant responses to environmental stress, the CBL-CIPK signaling system plays a key role in regulating plant stress resistance. Methods: This study systematically analyzed the composition characteristics of the CBL and CIPK gene families across 24 plant species, including the ice plant, using comparative genomics approaches. Results: A total of 297 CBL and 561 CIPK gene family members were identified across the 24 species. Within the ice plant genome, 9 CBL and 18 CIPK genes were identified. Compared to model plants like Arabidopsis thaliana, the ice plant possesses a relatively higher number of CIPK genes, which may be related to its specific adaptation to saline–alkaline environments. Phylogenetic analysis indicated that the ice plant CBL and CIPK genes could be classified into three and four subfamilies, respectively. Expression analysis revealed that several genes (e.g., McCBL1, McCBL4, McCIPK1, McCIPK2) were significantly upregulated under salt stress, suggesting their important roles in the salt stress response. Notably, ice plant CBL and CIPK genes exhibit significant structural diversity. For instance, McCBL3 contains significantly more CDS regions than other members, while CIPK genes can be divided into two types: single-CDS type and multi-CDS type. This structural variation may be associated with functional divergence during the evolution of the gene family. Furthermore, three-dimensional (3D) structure prediction showed that CBL proteins primarily consist of EF-hand domains and α-helices, whereas CIPK proteins additionally contain β-sheet domains, implying that this structural difference may be related to their distinct regulatory mechanisms. Conclusions: This study provides an important theoretical basis for a deeper understanding of the molecular mechanisms underlying the CBL-CIPK signaling pathway in the saline–alkaline stress response of the ice plant. Full article

With the continuous change of climate, drought stress has emerged as the primary constraint on crop growth, posing a significant threat to the stability of global grain reserves. Arbuscular mycorrhizal fungi (AMF), as a kind of widely distributed root endophytes, enhance the drought tolerance of maize (Zea mays L.) through regulating the physiological and molecular responses. However, comprehensive transcriptome analysis to reveal the molecular mechanism of drought tolerance in the symbiotic process between AMF and maize is still limited. In the potted plant experiment, maizes inoculated with and without arbuscular mycorrhizal fungus Funneliformis mosseae were grown under well-watered (WW) or drought-stressed (DS) conditions. By using RNA-Seq and transcriptome analysis on maize roots and leaves, this work aimed to investigate the differential expressed genes (DEGs) related to the Ca²⁺ signaling pathway induced by AMF symbiosis under drought stress. Our findings indicated that F. mosseae inoculation resulted in a decrease in the net fluxes of Ca²⁺, while simultaneously elevating Ca²⁺ contents in the maize roots and leaves under well-watered or drought-stressed conditions. Notably, 189 DEGs were regulated not only by AMF symbiosis and drought stress, but also exhibited preferential expression in either leaves or roots. The annotation and enrichment of Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) showed that most of the DEGs were significantly enriched in Ca²⁺ signaling pathway genes, related to signal transduction, cellular process, and defense response. A high number of DEGs with this function (including calcineurin B-like protein (CBL), CBL-interacting protein kinase (CIPK), mitogen-activated protein kinase (MAPK), and calcium-dependent protein kinase (CDPK) receptor kinases) were upregulated-DEGs or downregulated-DEGs in F. mosseae-inoculated maizes under drought stress. Furthermore, some DEGs belong to transcription factor (TF) families, including bHLH ERF, and, MYB, were speculated to play key roles in improving the drought tolerance of maize. Based on the expression data and co-expression analysis between TF and Ca²⁺ signaling pathway genes, Whirly1 with CBL11, and BRI1-EMS-SUPPRESSOR 1 (BES1) with CBL10, CIPK24, CDPK1, CDPK14, CDPK19, and MAPK9 genes showed significant positive correlations, while B3 domain-containing transcription factors (B3 TFs) with MAPK1 and both CBL9 genes showed significant negative correlations in response to both F. mosseae inoculation and drought stress. The regulation of Ca²⁺ signaling pathways by AMF symbiosis was an important response mechanism of maize to improve their drought resistance. This study provides insightful perspectives on how AMF-induced modulation of gene expression within the Ca²⁺ signaling pathway can enhance the drought tolerance of mycorrhizal maize in the future. Full article

Potassium cation (K⁺) is essential for wheat (Triticum aestivum L.) growth, but the regulatory mechanisms of root response to K⁺ deficiency are not well understood. This study examines how varying durations of K⁺-deprivation affect root K⁺ transport and homeostasis in two wheat varieties, XN979 and YM68. Field pot experiments over three growing seasons showed that XN979 has significantly higher K uptake and productive efficiency than YM68 at a K fertilizer application rate of 60 kg hm⁻². Hydroponic experiments revealed that XN979 has a lower K_m (K⁺ concentrations at which 1/2 of V_max) and a higher V_max (maximum rate of K⁺ uptake) in K⁺ uptake kinetics, indicating better adaptation to K⁺-deficient environments. RNA-seq analysis after different durations of K⁺ deficiency (0, 6, 12, 24, 48 h) showed that genes encoding the Arabidopsis K⁺ Transporter 1 (AKT1) K⁺-channel in both varieties were not significantly upregulated. Instead, K⁺ transport in root primarily depended on high-affinity K⁺ (HAK) transporters. Genes encoding the Arabidopsis K⁺ Transporter 2 (AKT2) K⁺-channel in phloem cells were significantly upregulated under K⁺-deprivation. KOR1 and KOR2, encoding the Stelar K⁺ Outward Rectifier (SKOR) K⁺-channel in xylem cells, were significantly downregulated after 6 h and 12 h of K⁺-deprivation, respectively. Significant changes in the expression levels of the Calcineurin B-Like protein–CBL-Interacting Protein Kinase (CBL-CIPK) signaling system and phytohormones synthesis-related genes suggest their involvement in the root response to K⁺-deprivation. These findings clarify the regulation of wheat root responses to K deficiency. Full article

The potato (Solanum tuberosum L.) plays an important role in ensuring global food security. Potato tubers store abundant nutrients and are also reproductive organs. The adjustment of tuber sprouting plays a vital role in timely sowing and improving tuber product quality. CBL-interacting protein kinases (CIPKs) exert an important function in the entire life cycle of plants and in coping with stress. In our present study, we found that the StCIPK23 expression level increased during storage and that overexpression of StCIPK23 can accelerate tuber sprouting. Physiological assays indicated that overexpressing StCIPK23 altered carbohydrate metabolism and antioxidant-related enzyme activities during storage. Starch branching enzyme (SBEI) gene expression was upregulated, while sucrose synthase (SS), 3-phosphoglyceric phosphokinase (PGK), and glyceraldehyde-3-phosphate dehydrogenase 1 (GAPC1) gene expression were downregulated in StCIPK23-overexpressing potato. High gibberellin (GA) content and low abscisic acid (ABA) content were also detected in transgenic tubers. We conducted metabolomics analysis on bud eyes, and the results showed a total of 94 differential metabolites were found. Among them, 61 metabolites were increased, the top three metabolites were coumaryl alcohol, glutathione and quercetin–glucoside–glucoside–rhamnoside. Our results suggest that StCIPK23 is a positive regulator of potato tuber sprouting. Full article

Calcium ions (Ca²⁺) play a crucial role as a key messenger in various adaptive and developmental processes. In plants, the calcineurin B-like protein (CBL) family is a unique calcium sensor, which plays a key role in regulating plant growth and development as well as responding to external environmental stimuli throughout the Ca²⁺ signaling pathway. However, the CBL gene family in poplar has not been systematically described. In this study, thirteen CBL genes were identified from the Populus trichocarpa genome using bioinformatics methods. Multiple sequence alignment showed that all PtrCBLs contained four conserved EF-hand domains. Promoter cis-acting elements revealed that PtrCBL promoters contained at least one abiotic-related or hormone response element. A protein–protein interaction network revealed that PtrCBLs interacted with various CIPK proteins to participate in growth and development or respond to environmental stimuli in poplar. Transcriptome data demonstrated that numerous PsnCBLs were involved in the response to alkaline stress in Populus simonii × Populus nigra. RT-qPCR and RNA-seq analyses implied that PsnCBLs exhibited complex expression patterns in poplar under alkaline stress at different time points. These results provide comprehensive information for future research on the CBL gene function and lay a research foundation for studying alkaline stress in poplar. Full article

Plants frequently encounter relatively low and fluctuating potassium (K⁺) concentrations in soil, with roots serving as primary responders to this stress. Histone modifications, such as de-/acetylation, can function as epigenetic markers of stress-inducible genes. However, the signaling network between histone modifications and low-K⁺ (LK) response pathways remains unclear. This study investigated the regulatory role of Histone Deacetylase Complex 1 (HDC1) in primary root growth of Arabidopsis thaliana under K⁺ deficiency stress. Using a hdc1-2 mutant line, we observed that HDC1 positively regulated root growth under LK conditions. Compared to wild-type (WT) plants, the hdc1-2 mutant exhibited significantly inhibited primary root growth under LK conditions, whereas HDC1-overexpression lines displayed opposite phenotypes. No significant differences were observed under HK conditions. Further analysis revealed that the inhibition of hdc1-2 on root growth was due to reduced apical meristem cell proliferation rather than cell elongation. Notably, the root growth of hdc1-2 showed reduced sensitivity compared to WT after auxin treatment under LK conditions. HDC1 may regulate root growth by affecting auxin polar transport and subsequent auxin signaling, as evidenced by the altered expression of auxin transport genes. Moreover, the organ-specific RT-qPCR analyses unraveled that HDC1 negatively regulates the expression of CBL-CIPK-K⁺ channel-related genes such as CBL1, CBL2, CBL3, AKT1, and TPK1, thereby establishing a molecular link between histone deacetylation, auxin signaling, and CBLs-CIPKs pathway in response to K⁺ deficiency. Full article

Various CBL-interacting protein kinases (CIPKs) are involved in abiotic stress responses in plants. Despite the economic importance of jasmine (Jasminum sambac L. Aiton) and the availability of genome data, there are few reports analyzing the CIPK gene family. In this study, genome-wide identification of the CIPK gene family in jasmine was conducted, which would provide valuable information for the function analysis of JsCIPKs regarding participation in growth and development and response to salt stress. In the present study, a total of 17 CIPKs were identified, which were unevenly distributed on eight chromosomes. The JsCIPK protein sequences contained 311–781 amino acids, with a molecular weight of 35.05–87.58 kDa. Phylogenetic analysis revealed that the 17 JsCIPKs could be divided into five classical branches. JsCIPK genes with higher homology showed greater similarity between conserved protein motifs. Collinearity analysis demonstrated that 13 gene pairs in Arabidopsis were collinear with the jasmine sequences. Various hormone-related response- and stress-induced elements were observed in the promoter region of JsCIPK genes, such as TC-rich repeats, CARE, etc. Furthermore, the expression of JsCIPK genes varied in different organs. Finally, the expression analyses of eight JsCIPKs under salt stress were performed. A systematic analysis of the CIPK gene family and the effect of salt stress on the expression of eight JsCIPK genes in leaves of jasmine was carried out. The expression of JsCIPK6 and JsCIPK8 was significantly down-regulated and up-regulated by salt treatment, respectively. These findings would lay a foundation for future functional studies of these two genes in jasmine related to salt stress and provide useful resistance genes for the molecular breeding of new varieties of salt-tolerant jasmine. Full article

Phyllostachys edulis, an economically and ecologically significant bamboo species, has substantial research value in applications as a bamboo substitute for plastic and in forest carbon sequestration. However, frequent seasonal low-temperature events due to global climate change affect the growth, development, and productivity of P. edulis. Calcium signaling, serving as a versatile second messenger, is involved in various stress responses and nitrogen metabolism. In this study, we analyzed the calcium signaling dynamics and regulatory strategies in P. edulis under chilling stress. Differentially expressed genes (DEGs) from the CBF families, AMT families, NRT families, and Ca²⁺ sensor families, including CaM, CDPK, and CBL, were identified using transcriptomics. Additionally, we explored the law of Ca²⁺ flux and distribution in the roots of P. edulis under chilling stress and validated these findings by assessing the content or activity of Ca²⁺ sensor proteins and nitrogen transport proteins in the roots. The results indicated that the Ca²⁺ sensor families of CaM, CDPK, and CBL in P. edulis exhibited significant transcriptional changes under chilling stress. Notably, PH02Gene03957, PH02Gene42787, and PH02Gene19300 were significantly upregulated, while the expressions of PH02Gene08456, PH02Gene01209, and PH02Gene37879 were suppressed. In particular, the expression levels of the CBF family gene PH02Gene14168, a downstream target gene of the calcium channels, increased significantly. P. edulis exhibited an influx of Ca²⁺ at the root, accompanied by oscillating negative peaks under chilling stress. Spatially, the cytosolic calcium concentration ([Ca²⁺]_cyt) within the root cells increased. The CIPK family genes, interacting with Ca²⁺-CBL in downstream signaling pathways, showed significant differential expressions. In addition, the expressions of the NRT and AMT family genes changed correspondingly. Our study demonstrates that Ca²⁺ signaling is involved in the regulatory network of P. edulis under chilling stress. [Ca²⁺]_cyt fluctuations in the roots of P. edulis are induced by chilling stress, reflecting an influx of extracellular Ca²⁺. Upon binding to Ca²⁺, downstream target genes from the CBF family are activated. Within the Ca²⁺–CBL–CIPK signaling network, the CIPK family plays a crucial role in nitrogen metabolism pathways. Full article

Background/Objectives: Nitrogen is an essential macroelement for plant growth and productivity. Calcium (Ca²⁺) acts as a critical second messenger in numerous adaptations and developmental processes in plants. The Calcineurin B-like protein (CBL)-interacting protein kinase (CIPK) signaling pathway has been demonstrated to be involved in multiple intracellular ion homeostasis of plants in response to stresses. However, whether CIPKs are involved in nitrate deficiency stress remains largely unknown. Methods: In this study, we screened Arabidopsis thaliana T-DNA insertion mutants of the CIPK family under nitrate deficiency conditions by a reverse genetic strategy. Results: We found that the cipk1 mutant showed a shorter primary root and had a lower fresh weight and total N content compared with wildtype (WT) plants under nitrate deficiency. The CIPK1 complementation lines completely rescued the sensitive phenotype. Additionally, CIPK1 mutation caused nitrogen-starvation marker genes to be decreased under nitrate deficiency. We further found that CIPK1 interacted with teosintebranched 1/cycloidea/proliferating cell factor 1-20 (TCP20) in a yeast two-hybrid system. Conclusions: Collectively, our results reveal a novel role of CIPK1 in response to nitrate deficiency in Arabidopsis. Full article

CBL-interacting protein kinases (CIPKs) play important regulatory roles in plant growth development and abiotic stress tolerance. However, the biological roles of these genes in response to low-nitrate (LN) stress in potato plants have not been determined. Here, we reported that StCIPK23 was expressed mainly in roots and leaves. StCIPK23 was located mainly in the cell membrane, nucleus, and cytoplasm. Further research suggested that, compared with wild-type (WT) plants, StCIPK23-overexpressing plants were taller and had significantly greater nitrate and ammonium nitrogen contents under LN stress. StCIPK23 overexpression can increase StAT, StNRT2.1, StNR, StGS1-3, and StGOGAT expression levels in StCIPK23 transgenic seedlings compared to those in WT plants under LN stress. The results of yeast two-hybrid and luciferase complementation imaging experiments suggested that StCIPK23 could interact with StCBL3. Real-time reverse transcription–PCR revealed the StCIPK23 expression level peaked at 6 h and the StCBL3 expression level peaked at 9 h in the roots under LN stress. In conclusion, we found that StCIPK23 and StCBL3 form a complex to regulate the expression of key genes in the nitrogen metabolism pathway to improve LN tolerance in potato plants. Full article

Calcium ions function as key messengers in the context of intracellular signal transduction. The ability of plants to respond to biotic and abiotic stressors is highly dependent on the calcineurin B-like protein (CBL) and CBL-interacting protein kinase (CIPK) signaling network. Here, a comprehensive effort was made to identify all members of the soybean CBL gene family, leading to the identification of 15 total genes distributed randomly across nine chromosomes, including 13 segmental duplicates. All the GmCBL gene subfamilies presented with similar gene structures and conserved motifs. Analyses of the expression of these genes in different tissues revealed that the majority of these GmCBLs were predominantly expressed in the roots. Significant GmCBL expression and activity increases were also observed in response to a range of stress-related treatments, including salt stress, alkaline stress, osmotic stress, or exposure to salicylic acid, brassinosteroids, or abscisic acid. Striking increases in GmCBL1 expression were observed in response to alkaline and salt stress. Subsequent analyses revealed that GmCBL1 was capable of enhancing soybean salt and alkali tolerance through the regulation of redox reactions. These results offer new insight into the complex mechanisms through which the soybean CBL gene family regulates the responses of these plants to environmental stressors, highlighting promising targets for efforts aimed at enhancing soybean stress tolerance. Full article

Soil salinization poses a threat to the sustainability of agricultural production and has become a global issue. Cotton is an important cash crop and plays an important role in economic development. Salt stress has been harming the yield and quality of many crops, including cotton, for many years. In recent years, soil salinization has been increasing. It is crucial to study the mechanism of cotton salt tolerance and explore diversified materials and methods to alleviate the salt stress of cotton for the development of the cotton industry. Nanoparticles (NPs) are an effective means to alleviate salt stress. In this study, zinc oxide NPs (ZnO NPs) were sprayed on cotton leaves with the aim of investigating the intrinsic mechanism of NPs to alleviate salt stress in cotton. The results show that the foliar spraying of ZnO NPs significantly alleviated the negative effects of salt stress on hydroponic cotton seedlings, including the improvement of above-ground and root dry and fresh weight, leaf area, seedling height, and stem diameter. In addition, ZnO NPs can significantly improve the salt-induced oxidative stress by reducing the levels of MDA, H₂O₂, and O₂⁻ and increasing the activities of major antioxidant enzymes, such as superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT). Furthermore, RNA-seq showed that the foliar spraying of ZnO NPs could induce the expressions of CNGC, NHX2, AHA3, HAK17, and other genes, and reduce the expression of SKOR, combined with the CBL-CIPK pathway, which alleviated the toxic effect of excessive Na⁺ and reduced the loss of excessive K⁺ so that the Na⁺/K⁺ ratio was stabilized. In summary, our results indicate that the foliar application of ZnO NPs can alleviate high salt stress in cotton by adjusting the Na⁺/K⁺ ratio and regulating antioxidative ability. This provides a new strategy for alleviating the salt stress of cotton and other crops, which is conducive to the development of agriculture. Full article

Abiotic stressors, including drought, salt, cold, and heat, profoundly impact plant growth and development, forcing elaborate cellular responses for adaptation and resilience. Among the crucial orchestrators of these responses is the CBL-CIPK pathway, comprising calcineurin B-like proteins (CBLs) and CBL-interacting protein kinases (CIPKs). While CIPKs act as serine/threonine protein kinases, transmitting calcium signals, CBLs function as calcium sensors, influencing the plant’s response to abiotic stress. This review explores the intricate interactions between the CBL-CIPK pathway and plant hormones such as ABA, auxin, ethylene, and jasmonic acid (JA). It highlights their role in fine-tuning stress responses for optimal survival and acclimatization. Building on previous studies that demonstrated the enhanced stress tolerance achieved by upregulating CBL and CIPK genes, we explore the regulatory mechanisms involving post-translational modifications and protein–protein interactions. Despite significant contributions from prior research, gaps persist in understanding the nuanced interplay between the CBL-CIPK system and plant hormone signaling under diverse abiotic stress conditions. In contrast to broader perspectives, our review focuses on the interaction of the pathway with crucial plant hormones and its implications for genetic engineering interventions to enhance crop stress resilience. This specialized perspective aims to contribute novel insights to advance our understanding of the potential of the CBL-CIPK pathway to mitigate crops’ abiotic stress. Full article