Sucrose Non-fermenting 1-related Protein Kinase 2 Gene Research Articles

Silencing the CsSnRK2.11 Gene Decreases Drought Tolerance of Cucumis sativus L.

Drought stress restricts vegetable growth, and abscisic acid plays an important role in its regulation. Sucrose non-fermenting1-related protein kinase 2 (SnRK2) is a key enzyme in regulating ABA signal transduction in plants, and it plays a significant role in response to multiple abiotic stresses. Our previous experiments demonstrated that the SnRK2.11 gene exhibits a significant response to drought stress in cucumbers. To further investigate the function of SnRK2.11 under drought stress, we used VIGS (virus-induced gene silencing) technology to silence this gene and conducted RNA-seq analysis. The SnRK2.11-silencing plants displayed increased sensitivity to drought stress, which led to stunted growth and increased wilting speed. Moreover, various physiological parameters related to photosynthesis, chlorophyll fluorescence, leaf water content, chlorophyll content, and antioxidant enzyme activity were significantly reduced. The intercellular CO2 concentration, non-photochemical burst coefficient, and malondialdehyde and proline content were significantly increased. RNA-seq analysis identified 534 differentially expressed genes (DEGs): 311 were upregulated and 223 were downregulated. GO functional annotation analysis indicated that these DEGs were significantly enriched for molecular functions related to host cells, enzyme activity, and stress responses. KEGG pathway enrichment analysis further revealed that these DEGs were significantly enriched in phytohormone signalling, MAPK signalling, and carotenoid biosynthesis pathways, all of which were associated with abscisic acid. This study used VIGS technology and transcriptome data to investigate the role of CsSnRK2.11 under drought stress, offering valuable insights into the mechanism of the SnRK2 gene in enhancing drought resistance in cucumbers.

Identification and expression profile analysis of the SnRK2 gene family in cucumber.

The sucrose non-fermenting-1-related protein kinase 2 (SnRK2) is a plant-specific type of serine/threonine protein kinase that plays an important role in the physiological regulation of stress. The objective of this study was to identify and analyze the members of the SnRK2 gene family in cucumber and lay a foundation for further exploration of the mechanism of CsSnRK2 resistance to stress. Here, 12 SnRK2 genes were isolated from cucumber and distributed on five chromosomes, phylogenetic clustering divided these into three well-supported clades. In addition, collinearity analysis showed that the CsSnRK2 gene family underwent purifying selection pressure during evolution. CsSnRK2 genes of the same group have similar exons and conserved motifs, and intron length may be a specific imprint for the evolutionary amplification of the CsSnRK2 gene family. By predicting cis elements in the promoter, we found that the promoter region of CsSnRK2 gene members had various cis-regulatory elements in response to hormones and stress. Relative expression analysis showed that CsSnRK2.11 (group II) and CsSnRK2.12 (group III) were strongly induced by ABA, NaCl and PEG stress; whereas CsSnRK2.2 (group III) was not activated by any treatment. The response of group I CsSnRK2 to ABA, NaCl and PEG was weak. Furthermore, protein interaction prediction showed that multiple CsSnRK2 proteins interacted with four proteins including protein phosphatase 2C (PP2C), and it is speculated that the CsSnRK2 genes may also an independent role as a third messenger in the ABA signaling pathway. This study provides a reference for analyzing the potential function of CsSnRK2 genes in the future research.

Genome-Wide Identification and Expression Analysis of SnRK2 Gene Family in Dormant Vegetative Buds of Liriodendron chinense in Response to Abscisic Acid, Chilling, and Photoperiod.

Protein kinases play an essential role in plants’ responses to environmental stress signals. SnRK2 (sucrose non-fermenting 1-related protein kinase 2) is a plant-specific protein kinase that plays a crucial role in abscisic acid and abiotic stress responses in some model plant species. In apple, corn, rice, pepper, grapevine, Arabidopsis thaliana, potato, and tomato, a genome-wide study of the SnRK2 protein family was performed earlier. The genome-wide comprehensive investigation was first revealed to categorize the SnRK2 genes in the Liriodendron chinense (L. chinense). The five SnRK2 genes found in the L. chinense genome were highlighted in this study. The structural gene variants, 3D structure, chromosomal distributions, motif analysis, phylogeny, subcellular localization, cis-regulatory elements, expression profiles in dormant buds, and photoperiod and chilling responses were all investigated in this research. The five SnRK2 genes from L. chinense were grouped into groups (I–IV) based on phylogeny analysis, with three being closely related to other species. Five hormones-, six stress-, two growths and biological process-, and two metabolic-related responsive elements were discovered by studying the cis-elements in the promoters. According to the expression analyses, all five genes were up- and down-regulated in response to abscisic acid (ABA), photoperiod, chilling, and chilling, as well as photoperiod treatments. Our findings gave insight into the SnRK2 family genes in L. chinense and opened up new study options.

Genome-wide survey of sucrose non-fermenting 1-related protein kinase 2 in Rosaceae and expression analysis of PbrSnRK2 in response to ABA stress

BackgroundThe members of the sucrose non-fermenting 1-related protein kinase 2 (SnRK2) family are specific serine/threonine protein kinases in plants that play important roles in stress signal transduction and adaptation. Because of their positive regulatory roles in response to adverse conditions, the genes encoding thes proteins are considered potential candidates for breeding of plants for disease resistance and genetic improvement. However, there is far less information about this kinase family, and the function of these genes has not been explored in Rosaceae.ResultsA genome-wide survey and analysis of the genes encoding members of the SnRK2 family were performed in pear (Pyrus bretschneideri) and seven other Rosaceae species. A total of 71 SnRK2 genes were identified from the eight Rosaceae species and classified into three subgroups based on phylogenetic analysis and structural characteristics. Purifying selection played a crucial role in the evolution of SnRK2 genes, and whole-genome duplication and dispersed duplication were the primary forces underlying the characteristics of the SnRK2 gene family in Rosaceae. Transcriptome data and qRT-PCR assay results revealed that the distribution of PbrSnRK2s was very extensive, including across the roots, leaves, pollen, styles, and flowers, although most of them were mainly expressed in leaves. In addition, under stress conditions, the transcript levels of some of the genes were upregulated in leaves in response to ABA treatment.ConclusionsThis study provides useful information and a theoretical introduction for the study of the evolution, expression, and functions of the SnRK2 gene family in plants.

Heterologous expression of an Agropyron cristatum SnRK2 protein kinase gene (AcSnRK2.11) increases freezing tolerance in transgenic yeast and tobacco.

The sucrose non-fermenting-1 related protein kinase 2 (SnRK2) family plays an important role in the response to abiotic stress. To characterize the function of the SnRK2 gene from Agropyron cristatum in stress protection, we cloned the complete coding sequence of the AcSnRK2.11 gene from A. cristatum and generated AcSnRK2.11-overexpressing tobacco lines. The open reading frame of AcSnRK2.11 was 1083bp in length and encoded a polypeptide of 360 amino acid residues. The sequence analysis results showed that AcSnRK2.11 contained conserved domains typified in SnRK2 protein kinases. Subcellular localization analysis showed that AcSnRK2.11 was located in the nucleus. AcSnRK2.11 was constitutively expressed in all of the examined tissues, and its transcription was induced by cold, dehydration, and salt stress, but not by abscisic acid treatment. Overexpression of the AcSnRK2.11 gene conferred freezing tolerance in yeast. AcSnRK2.11-overexpressing tobacco lines showed higher tolerance to freezing stress than did wild-type (WT) based on higher survival rates, lower malondialdehyde content and increased relative water content retention, chlorophyll yields, superoxide dismutase activities, reactive oxygen species content, peroxidase levels, and soluble carbohydrates under low-temperature conditions. The transcripts of NtDREB1, NtDREB2, NtERD10A, NtERD10B, NtERD10C, NtERD10D, NtMnSOD, NtCDPK15, and NtMPK9 in AcSnRK2.11-overexpressing tobacco lines were more abundant than in WT plants under low-temperature stress. These results suggest that AcSnRK2.11 may function as a regulatory factor associated with a cold-response pathway and could be used in plant breeding for cold resistance.

TaSnRK2.9, a Sucrose Non-fermenting 1-Related Protein Kinase Gene, Positively Regulates Plant Response to Drought and Salt Stress in Transgenic Tobacco.

Sucrose non-fermenting 1-related protein kinase 2 (SnRK2) family members play crucial roles in plant abiotic stress response. However, the precise mechanism underlying the function of SnRKs has not been thoroughly elucidated in plants. In this research, a novel SnRK2 gene, TaSnRK2.9 was cloned and characterized from common wheat. The expression of TaSnRK2.9 was upregulated by polyethylene glycol (PEG), NaCl, H2O2, abscisic acid (ABA), methyl jasmonate (MeJA), and ethrel treatments. TaSnRK2.9 was mainly expressed in wheat young root, stamen, pistil, and lemma. Overexpressing TaSnRK2.9 in transgenic tobacco enhanced plants’ tolerance to drought and salt stresses both in young seedlings and mature plants with improved survival rate, seed germination rate, and root length. Physiological analyses suggest that TaSnRK2.9 improved antioxidant system such as superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and glutathione (GSH) to reduce the H2O2 content under drought or salt stress. Additionally, TaSnRK2.9 overexpression plants had elevated ABA content, implying that the function of TaSnRK2.9 may be ABA-dependent. Moreover, TaSnRK2.9 increased the expression of some ROS-related, ABA-related, and stress-response genes under osmotic or salt treatment. TaSnRK2.9 could interact with NtABF2 in yeast two-hybrid assay, and increased the expression of NtABF2 under mannitol or NaCl treatment in transgenic tobacco plants. In conclusion, overexpression of TaSnRK2.9 in tobacco conferred plants tolerance to drought and salt stresses through enhanced ROS scavenging ability, ABA-dependent signal transduction, and specific SnRK-ABF interaction.

Overexpression of a protein kinase gene MpSnRK2.10 from Malus prunifolia confers tolerance to drought stress in transgenic Arabidopsis thaliana and apple

Members of the sucrose non-fermenting-1-related protein kinase 2 (SnRK2) family play central roles in the abscisic acid (ABA) signaling pathway and in mediating osmotic stress signaling and tolerance in plants. Previously, 12 full-length coding sequences that belong to SnRK2 gene family were identified and cloned in wild apple species Malus prunifolia. In this study, one of the members, MpSnRK2.10, was overexpressed in Arabidopsis and apple to investigate its potential function in response to drought stress. The results showed that overexpression of this gene did not affect plant growth under normal conditions. However, the transgenic plants showed enhanced tolerance to drought, as indicated by the amelioration in phenotype appearance and physiological indices related to drought stress damage. Additionally, transgenic apple plants overexpressing MpSnRK2.10 exhibited greater sensitivity to ABA compared to wild-type (WT) plants. Moreover, expressions of three stress response genes, MdRAB18, MdRD22, and MdRD29B, were more strongly induced in transgenic apple plants than in the WT when subjected to ABA and mannitol treatments. Taken as a whole, our study suggests that MpSnRK2.10 has a role in the enhancement of ABA signal transduction in response to stress, and that the manipulation of MpSnRK2.10 expression could be a feasible approach for improving abiotic stress tolerance in apple and other important crops.

Molecular Characterization and Co-expression Analysis of the SnRK2 Gene Family in Sugarcane (Saccharum officinarum L.)

In plants, both abscisic acid (ABA) dependent and independent pathways form the basis for the response to environmental stresses. Sucrose non-fermenting 1-related protein kinase 2 (SnRK2) plays a central role in plant stress signal transduction. However, complete annotation and specific expression patterns of SnRK2s in sugarcane remain unclear. For the present study, we performed a full-length cDNA library survey of sugarcane, thus identifying ten SoSnRK2 genes via phylogenetic, local BLAST methods, and various bioinformatics analyses. Phylogenetic analysis indicated division of SoSnRK2 genes into three subgroups, similar to other plant species. Gene structure comparison with Arabidopsis suggested a unique evolutionary imprint of the SnRK2 gene family in sugarcane. Both sequence alignment and structural annotation provided an overview of the conserved N-terminal and variations of the C-terminal, suggesting functional divergence. Transcript and transient expression assays revealed SoSnRK2s to be involved in the responses to diverse stress signals, and strong ABA induction of SoSnRK2s in subgroup III. Co-expression network analyses indicated the existence of both conserved and variable biological functions among different SoSnRK2s members. In summary, this comprehensive analysis will facilitate further studies of the SoSnRK2 family and provide useful information for the functional validation of SoSnRK2s.

Genome-wide identification, characterization, and expression analysis of SnRK2 family in Hevea brasiliensis

The sucrose non-fermenting 1-related protein kinase 2 (SnRK2) gene family belongs to a group of plant-specific serine/threonine kinase family involved in abscisic acid (ABA) signaling and biotic and abiotic stress response. Although genome-wide analyses of the SnRK2 gene family have been conducted in some species, little is known about the SnRK2 gene family in rubber tree (Hevea brasiliensis). In this study, we identified 10 SnRK2s designated as HbSnRK2.1 to HbSnRK2.10 in the rubber tree genome. The subsequently constructed phylogenetic tree demonstrated that HbSnRK2s have three subfamilies that correlate well with those of Arabidopsis sp. and rice subfamilies. All SnRK2 genes contained nine exons and eight introns. Although the C-terminus was divergent, eight conserved motifs were found. Motifs 1–6 were common to all HbSnRK2s. Expression analysis results showed that 7 of the 10 HbSnRK2s were highly expressed in latex. HbSnRK2.7 was predominantly expressed and simultaneously regulated by abscisic acid, jasmonic acid, and ethylene treatment in laticifers. HbSnRK identification and characterization provided further understanding on the role of ABA signal in the rubber tree.

Genome-wide identification, annotation and expression profile analysis of SnRK2 gene family in grapevine

Background and Aims Protein kinases are widely involved in the response in plants to external environment stress signals. Sucrose non-fermenting 1-related protein kinase 2 (SnRK2) is an important class of plant-specific protein kinases that plays a crucial role in abscisic acid responses and abiotic stresses across some model plant species. Genome-wide annotation, however, and specific expression patterns of SnRK2s in grapevine remain unclear. Methods and Results From a genome-wide survey of grapevine, we identified eight VviSnRK2 genes through phylogenetic and local BLAST methods and various bioinformatics analyses. Phylogenetic analysis indicated that these VviSnRK2s could be classified into three subgroups as found in Arabidopsis. Comparison of the structure of the genes with those of Arabidopsis suggests that intron length may be a special evolutionary imprint of the SnRK2 gene family in grapevine. Sequence alignment and structural annotation provided an overview of variations that may contribute to functional divergence from Arabidopsis SnRK2s. Expressional analyses based on public microarray data and quantitative real-time polymerase chain reaction and co-expression network analyses suggest both conserved and variant biological functions exist in SnRK2s across different species. Conclusions Our thorough analysis of the SnRK2 gene family in the grapevine genome revealed functional conservation and diversity synchronously existed in grapevine SnRK2 gene family. Significance of the Study Our research provides a comprehensive overview of both the expression pattern and functional diversity of the grapevine SnRK2 gene family, which will facilitate the future functional characterisation of individual VviSnRK2 genes.

Molecular evolution, characterization, and expression analysis of SnRK2 gene family in Pak-choi (Brassica rapa ssp. chinensis).

The sucrose non-fermenting 1-related protein kinase 2 (SnRK2) family members are plant-specific serine/threonine kinases that are involved in the plant response to abiotic stress and abscisic acid (ABA)-dependent plant development. Further understanding of the evolutionary history and expression characteristics of these genes will help to elucidate the mechanisms of the stress tolerance in Pak-choi, an important green leafy vegetable in China. Thus, we investigated the evolutionary patterns, footprints and conservation of SnRK2 genes in selected plants and later cloned and analyzed SnRK2 genes in Pak-choi. We found that this gene family was preferentially retained in Brassicas after the Brassica-Arabidopsis thaliana split. Next, we cloned and sequenced 13 SnRK2 from both cDNA and DNA libraries of stress-induced Pak-choi, which were under conditions of ABA, salinity, cold, heat, and osmotic treatments. Most of the BcSnRK2s have eight exons and could be divided into three groups. The subcellular localization predictions suggested that the putative BcSnRK2 proteins were enriched in the nucleus. The results of an analysis of the expression patterns of the BcSnRK2 genes showed that BcSnRK2 group III genes were robustly induced by ABA treatments. Most of the BcSnRK2 genes were activated by low temperature, and the BcSnRK2.6 genes responded to both ABA and low temperature. In fact, most of the BcSnRK2 genes showed positive or negative regulation under ABA and low temperature treatments, suggesting that they may be global regulators that function at the intersection of multiple signaling pathways to play important roles in Pak-choi stress responses.

Overexpression of a maize SNF-related protein kinase gene, ZmSnRK2.11, reduces salt and drought tolerance in Arabidopsis

Sucrose non-fermenting-1 related protein kinase 2 (SnRK2) is a unique family of protein kinases associated with abiotic stress signal transduction in plants. In this study, a maize SnRK2 gene ZmSnRK2.11 was cloned and characterized. The results showed that ZmSnRK2.11 is up-regulated by high-salinity and dehydration treatment, and it is expressed mainly in maize mature leaf. A transient expression assay using onion epidermal cells revealed that ZmSnRK2.11-GFP fusion proteins are localized to both the nucleus and cytoplasm. Overexpressing-ZmSnRK2.11 in Arabidopsis resulted in salt and drought sensitivity phenotypes that exhibited an increased rate of water loss, reduced relative water content, delayed stoma closure, accumulated less free proline content and increased malondialdehyde (MDA) content relative to the phenotypes observed in wild-type (WT) control. Furthermore, overexpression of ZmSnRK2.11 up-regulated the expression of the genes ABI1 and ABI2 and decreased the expression of DREB2A and P5CS1. Taken together, our results suggest that ZmSnRK2.11 is a possible negative regulator involved in the salt and drought stress signal transduction pathways in plants.

Genome-wide identification and expression profiling of the SnRK2 gene family in Malus prunifolia

Sucrose non-fermenting-1-related protein kinase 2 (SnRK2) constitutes a small plant-specific serine/threonine kinase family with essential roles in the abscisic acid (ABA) signal pathway and in responses to osmotic stress. Although a genome-wide analysis of this family has been conducted in some species, little is known about SnRK2 genes in apple (Malus domestica). We identified 14 putative sequences encoding 12 deduced SnRK2 proteins within the apple genome. Gene chromosomal location and synteny analysis of the apple SnRK2 genes indicated that tandem and segmental duplications have likely contributed to the expansion and evolution of these genes. All 12 full-length coding sequences were confirmed by cloning from Malus prunifolia. The gene structure and motif compositions of the apple SnRK2 genes were analyzed. Phylogenetic analysis showed that MpSnRK2s could be classified into four groups. Profiling of these genes presented differential patterns of expression in various tissues. Under stress conditions, transcript levels for some family members were up-regulated in the leaves in response to drought, salinity, or ABA treatments. This suggested their possible roles in plant response to abiotic stress. Our findings provide essential information about SnRK2 genes in apple and will contribute to further functional dissection of this gene family.

Genome-wide analysis and evolutionary study of sucrose non-fermenting 1-related protein kinase 2 (SnRK2) gene family members in Arabidopsis and Oryza

The over-expression of plant specific SnRK2 gene family members by hyperosmotic stress and some by abscisic acid is well established. In this report, we have analyzed the evolution of SnRK2 gene family in different plant lineages including green algae, moss, lycophyte, dicot and monocot. Our results provide some evidences to indicate that the natural selection pressure had considerable influence on cis-regulatory promoter region and coding region of SnRK2 members in Arabidopsis and Oryza independently through time. Observed degree of sequence/motif conservation amongst SnRK2 homolog in all the analyzed plant lineages strongly supported their inclusion as members of this family. The chromosomal distributions of duplicated SnRK2 members have also been analyzed in Arabidopsis and Oryza. Massively Parallel Signature Sequencing (MPSS) database derived expression data and the presence of abiotic stress related promoter elements within the 1kb upstream promoter region of these SnRK2 family members further strengthen the observations of previous workers. Additionally, the phylogenetic relationships of SnRK2 have been studied in all plant lineages along with their respective exon–intron structural patterns. Our results indicate that the ancestral SnRK2 gene of land plants gradually evolved by duplication and diversification and modified itself through exon–intron loss events to survive under environmental stress conditions.

Cloning and characterization of TaSnRK2.3, a novel SnRK2 gene in common wheat.

Environmental stresses such as drought, salinity, and cold are major adverse factors that significantly affect agricultural productivity. Protein phosphorylation/dephosphorylation is a major signalling event induced by osmotic stress in higher plants. Sucrose non-fermenting 1-related protein kinase 2 (SnRK2) family members play essential roles in the response to hyperosmotic stresses in plants. In this study, the TaSnRK2.3 gene, a novel SnRK2 member was cloned, and three copies located on chromosomes 1A, 1B, and 1D were identified in common wheat. TaSnRK2.3 was strongly expressed in leaves, and responded to polyethylene glycol, NaCl, abscisic acid, and cold stresses. To characterize its function, transgenic Arabidopsis overexpressing TaSnRK2.3–GFP controlled by the cauliflower mosaic virus 35S promoter was generated and subjected to severe abiotic stresses. Overexpression of TaSnRK2.3 resulted in an improved root system and significantly enhanced tolerance to drought, salt, and freezing stresses, simultaneously demonstrated by enhanced expression of abiotic stress-responsive genes and ameliorative physiological indices, including a decreased rate of water loss, enhanced cell membrane stability, improved photosynthetic potential, and significantly increased osmotic potential and free proline content under normal and/or stressed conditions. These results demonstrate that TaSnRK2.3 is a multifunctional regulator, with potential for utilization in transgenic breeding for improved abiotic stress tolerance in crop plants.

Sucrose non-fermenting 1-related protein kinase 2 (SnRK2): a family of protein kinases involved in hyperosmotic stress signaling

Our understanding of plant adaptation to abiotic stresses, which include drought, salinity, non-optimal temperatures and poor soil nutrition, is limited, although significant strides have been made in identifying some of the gene players and signaling partners. Several protein kinases get activated in plants in response to osmotic stress and the stress hormone abscisic acid (ABA). Among these is a superfamily of sucrose non-fermenting protein kinase genes (SnRK2). This review focuses on the developments related to the activity, substrates, interacting proteins and gene regulation of SnRK2 gene family members. Reversible phosphorylation as a crucial regulatory mechanism turns out to be a rule rather than an exception in plant responses to abiotic stress. Nine out of thirteen bZIP transcription factors (ABI5/ABF/AREB family) share the recognition motif, R-Q-X-S/T, suggesting that likely SnRK2 kinases have a major role in regulating gene expression during hyperosmotic stress.