Project description:WRKY transcription factors are plant-specific, zinc finger-type transcription factors. The WRKY superfamily is involved in abiotic stress responses in many crops including cotton, a major fiber crop that is widely cultivated and consumed throughout the world. Salinity is an important abiotic stress that results in considerable yield losses. In this study, we identified 109 WRKY genes (GarWRKYs) in a salt-tolerant wild cotton species Gossypium aridum from transcriptome sequencing data to elucidate the roles of these factors in cotton salt tolerance. According to their structural features, the predicted members were divided into three groups (Groups I-III), as previously described for Arabidopsis. Furthermore, 28 salt-responsive GarWRKY genes were identified from digital gene expression data and subjected to real-time quantitative RT-PCR analysis. The expression patterns of most GarWRKY genes revealed by this analysis are in good agreement with those revealed by RNA-Seq analysis. RT-PCR analysis revealed that 27 GarWRKY genes were expressed in roots and one was exclusively expressed in roots. Analysis of gene orthology and motif compositions indicated that WRKY members from Arabidopsis, rice and soybean generally shared the similar motifs within the same subgroup, suggesting they have the similar function. Overexpression-GarWRKY17 and -GarWRKY104 in Arabidopsis revealed that they could positively regulate salt tolerance of transgenic Arabidopsis during different development stages. The comprehensive data generated in this study provide a platform for elucidating the functions of WRKY transcription factors in salt tolerance of G. aridum. In addition, GarWRKYs related to salt tolerance identified in this study will be potential candidates for genetic improvement of cultivated cotton salt stress tolerance.
Project description:Fruit plants are severely constrained by salt stress in the soil due to their sessile nature. Ca2+ sensors, which are known as CBL-interacting protein kinases (CIPKs), transmit abiotic stress signals to plants. Therefore, it is imperative to investigate the molecular regulatory role of CIPKs underlying salt stress tolerance in kiwifruit. In the current study, we have identified 42 CIPK genes from Actinidia. valvata (A.valvata). All the AvCIPKs were divided into four different phylogenetic groups. Moreover, these genes showed different conserved motifs. The expression pattern analysis showed that AvCIPK11 was specifically highly expressed under salt stress. The overexpression of AvCIPK11 in 'Hongyang' (a salt sensitive commercial cultivar from Actinidia chinensis) enhanced salt tolerance by maintaining K+/Na+ homeostasis in the leaf and positively improving the activity of POD. In addition, the salt-related genes AcCBL1 and AcNHX1 had higher expression in overexpression lines. Collectively, our study suggested that AvCIPK11 is involved in the positive regulation of salt tolerance in kiwifruit.
Project description:NAC proteins are plant-specific transcription factors (TFs). Although they play a pivotal role in regulating distinct biological processes, TFs in maize are yet to be investigated comprehensively. Within the maize genome, we identified 152 putative NAC domain-encoding genes (ZmNACs), including eight membrane-bound members, by systematic sequence analysis and physically mapped them onto ten chromosomes of maize. In silico analysis of the ZmNACs and comparison with similar genes in other plants such as Arabidopsis, rice, and soybean, revealed a similar NAC sequence architecture. Phylogenetically, the ZmNACs were arranged into six distinct subgroups (I-VI) possessing conserved motifs. Phylogenetic analysis using stress-related NAC TFs from Arabidopsis, rice, and soybean as seeding sequences identified 24 of the 152 ZmNACs (all from Group II) as putative stress-responsive genes, including one dehydration-responsive ZmSNAC1 gene reported earlier. One drought-tolerant genotype (HKI577) and one susceptible genotype (PC13T-3) were used for studying the expression pattern of the NAC genes during drought stress. qRT-PCR based expression profiles of 11 genes predicted to be related to stress confirmed strong differential gene expression during drought stress. Phylogenetic analyses revealed that ZmNAC18, ZmNAC51, ZmNAC145, and ZmNAC72, which were up-regulated in the tolerant genotype and down-regulated in the susceptible genotype, belonged to the same group to which also belong other drought-responsive genes, namely SNAC1, OsNAC6, ANAC019, and ANAC055, which act as a transcriptional activator and are strongly induced under stress from various abiotic sources. Differentially expressed ZmNAC genes, alone or in combination with each other or with other type(s) of TFs, may control the general cellular machinery and regulate stress-responsive downstream genes. Alternatively, they may serve as a platform to regulate a broad set of genes, which are subsequently fine-tuned by specific regulators. This genome-wide identification and expression profiling opens new avenues for systematic functional analysis of new members of the NAC gene family, which may be exploited in developing lines that are better adapted to drought.
Project description:Salinity stress has become a significant concern to global food security. Revealing the mechanisms that enable plants to survive under salinity has immense significance. Sorghum has increasingly attracted researchers interested in understanding the survival and adaptation strategies to high salinity. However, systematic analysis of the DEGs (differentially expressed genes) and their relative expression has not been reported in sorghum under salt stress. The de novo transcriptomic analysis of sorghum under different salinity levels from 60 to 120 mM NaCl was generated using Illumina HiSeq. Approximately 323.49 million high-quality reads, with an average contig length of 1145 bp, were assembled de novo. On average, 62% of unigenes were functionally annotated to known proteins. These DEGs were mainly involved in several important metabolic processes, such as carbohydrate and lipid metabolism, cell wall biogenesis, photosynthesis, and hormone signaling. SSG 59-3 alleviated the adverse effects of salinity by suppressing oxidative stress (H2O2) and stimulating enzymatic and non-enzymatic antioxidant activities (SOD, APX, CAT, APX, POX, GR, GSH, ASC, proline, and GB), as well as protecting cell membrane integrity (MDA and electrolyte leakage). Significant up-regulation of transcripts encoding the NAC, MYB, and WRYK families, NHX transporters, the aquaporin protein family, photosynthetic genes, antioxidants, and compatible osmolyte proteins were observed. The tolerant line (SSG 59-3) engaged highly efficient machinery in response to elevated salinity, especially during the transport and influx of K+ ions, signal transduction, and osmotic homeostasis. Our data provide insights into the evolution of the NAC TFs gene family and further support the hypothesis that these genes are essential for plant responses to salinity. The findings may provide a molecular foundation for further exploring the potential functions of NAC TFs in developing salt-resistant sorghum lines.
Project description:The NAC (NAM, ATAF1/2, and CUC2), is a large family of plant-specific transcription factors (TFs) that exert crucial regulatory roles in various physiological processes and abiotic stresses. There is scanty information on the role of the NAC family in sunflower (Helianthus annuus L.). In this study, we conducted a genome-wide survey and expression analysis of the NAC family in sunflower. A total of 150 HaNACs were identified in sunflower. Phylogenetic analysis to compare HaNACs with Arabidopsis NACs generated 15 clusters. Among them, eight membrane-bound NAC TFs with transmembrane helixes were found (designated as NTLs), which were suggested to be localized in the membrane and transferred to the nucleus through proteolysis. Notably, 12 HaNACs were potentially regulated via miR164 cleavage or translational inhibition. By analyzing RNA-seq data from Sequence Read Archive (SRA), the expression of HaNACs showed tissue specificity and strong response to drought stress. Additionally, phylogenetic analysis of 150 HaNACs with the previously reported NACs related to abiotic stress revealed that 75% of the abiotic stress-related NACs were clustered into the SNAC (abiotic stress-related NAC) group, and only 25% were in the Non-SNAC group. qRT-PCR further demonstrated that about 75% of the HaNACs in the SNAC subgroup were induced by salt and drought stress, and the expression of some HaNACs showed tissue specificity. These findings provide valuable information that can deepen the understanding of how NAC TFs in sunflower respond to abiotic stress.
Project description:BackgroundThe NAC TF family is widely involved in plant responses to various types of stress. Red clover (Trifolium pratense) is a high-quality legume, and the study of NAC genes in red clover has not been comprehensive. The aim of this study was to analyze the NAC gene family of red clover at the whole-genome level and explore its potential role in the Pb stress response.ResultsIn this study, 72 TpNAC genes were identified from red clover; collinearity analysis showed that there were 5 pairs of large fragment replicators of TpNAC genes, and red clover was found to be closely related to Medicago truncatula. Interestingly, the TpNAC genes have more homologs in Arabidopsis thaliana than in soybean (Glycine max). There are many elements in the TpNAC genes promoters that respond to stress. Gene expression analysis showed that all the TpNAC genes responded to Pb stress. qRT-PCR showed that the expression levels of TpNAC29 and TpNAC42 were significantly decreased after Pb stress. Protein interaction network analysis showed that 21 TpNACs and 23 other genes participated in the interaction. In addition, the TpNAC proteins had three possible 3D structures, and the secondary structure of these proteins were mainly of other types. These results indicated that most TpNAC members were involved in the regulation of Pb stress in red clover.ConclusionThese results suggest that most TpNAC members are involved in the regulation of Pb stress in red clover. TpNAC members play an important role in the response of red clover to Pb stress.
Project description:The senescence process of plants is important for the completion of their life cycle, particularly for crop plants, it is essential for efficient nutrient remobilization during seed filling. It is a highly regulated process, and in order to address the regulatory aspect, the role of genes in the NAC transcription factor family during senescence of barley flag leaves was studied. Several members of the NAC transcription factor gene family were up-regulated during senescence in a microarray experiment, together with a large range of senescence-associated genes, reflecting the coordinated activation of degradation processes in senescing barley leaf tissues. This picture was confirmed in a detailed quantitative reverse transcription-PCR (qRT-PCR) experiment, which also showed distinct gene expression patterns for different members of the NAC gene family, suggesting a group of ~15 out of the 47 studied NAC genes to be important for signalling processes and for the execution of degradation processes during leaf senescence in barley. Seven models for DNA-binding motifs for NAC transcription factors were designed based on published motifs, and available promoter sequences of barley genes were screened for the motifs. Genes up-regulated during senescence showed a significant over-representation of the motifs, suggesting regulation by the NAC transcription factors. Furthermore, co-regulation studies showed that genes possessing the motifs in the promoter in general were highly co-expressed with members of the NAC gene family. In conclusion, a list of up to 15 NAC genes from barley that are strong candidates for being regulatory factors of importance for senescence and biotic stress-related traits affecting the productivity of cereal crop plants has been generated. Furthermore, a list of 71 senescence-associated genes that are potential target genes for these NAC transcription factors is presented.
Project description:In plants, the NAC (NAM-ATAF1/2-CUC) family of proteins constitutes several transcription factors and plays vital roles in diverse biological processes, such as growth, development, and adaption to adverse factors. Tea, as a non-alcoholic drink, is known for its bioactive ingredients and health efficacy. Currently, knowledge about NAC gene family in tea plant remains very limited. In this study, a total of 45 CsNAC genes encoding NAC proteins including three membrane-bound members were identified in tea plant through transcriptome analysis. CsNAC factors and Arabidopsis counterparts were clustered into 17 subgroups after phylogenetic analysis. Conserved motif analysis revealed that CsNAC proteins with a close evolutionary relationship possessed uniform or similar motif compositions. The distribution of NAC family MTFs (membrane-associated transcription factors) among higher plants of whose genome-wide has been completed revealed that the existence of doubled TMs (transmembrane motifs) may be specific to fabids. Transcriptome analysis exhibited the expression profiles of CsNAC genes in different tea plant cultivars under non-stress conditions. Nine CsNAC genes, including the predicted stress-related and membrane-bound genes, were examined through qRT-PCR (quantitative real time polymerase chain reaction) in two tea plant cultivars, namely, 'Huangjinya' and 'Yingshuang'. The expression patterns of these genes were investigated in different tissues (root, stem, mature leaf, young leaf and bud) and under diverse environmental stresses (drought, salt, heat, cold and abscisic acid). Several CsNAC genes, including CsNAC17 and CsNAC30 that are highly orthologous to known stress-responsive ANAC072/RD26 were identified as highly responsive to abiotic stress. This study provides a global survey of tea plant NAC proteins, and would be helpful for the improvement of stress resistance in tea plant via genetic engineering.
Project description:NAC (NAM, ATAF1/2, and CUC2) transcription factors compose one of the largest families of plant-specific transcription factors; they are widely involved in plant growth and development and have especially important roles in improving stress resistance in plants. However, NAC gene family members in alfalfa (Medicago sativa L.) have not been systematically identified and analyzed genome-wide due to the complexity of the alfalfa reference genome. In this study, a total of 421 M. sativa NAC genes (MsNACs) were identified from the alfalfa “Xinjiangdaye” reference genome. Basic bioinformatics analysis, including characterization of sequence length, protein molecular weight and genome position and conserved motif analysis, was conducted. Expression analysis showed that 47 MsNACs had tissue-specific expression, and 64 MsNACs were expressed in all tissues. The transcriptomic profiles of the genes were very different, indicating that these MsNACs have various functions in alfalfa growth and development. We identified 25, 42 and 47 MsNACs that respond to cold, drought and salt stress based on transcriptome data analysis and real-time quantitative PCR (RT−qPCR). Furthermore, 22 MsNACs were found to respond to both salt and drought stress, and 15 MsNACs were found to respond to cold, salt and drought stress. The results of this study could provide valuable information for further functional analysis of MsNACs and for the improvement of stress resistance in alfalfa.