Characterization of a cDNA encoding a novel DNA-binding protein, SPF1, that recognizes SP8 sequences in the 5' upstream regions of genes coding for sporamin and beta-amylase from sweet potato

WRKY1-Mediated Interconversion of MeSA and SA in Neighbouring Apple Plants Enhances Defence Against Powdery Mildew

Powdery mildew (PM), caused by the biotrophic fungus Podospharea leucotricha, is a major threat to apple production. Plant-plant communication (PPC) is a crucial strategy for plant communities to enhance their defence against pathogens. The interconversion of methyl salicylate (MeSA) and salicylic acid (SA) is critical for PPC regulation, but the mechanism of MeSA-mediated PPC is not fully understood. This study reveals a significant increase in SA and MeSA levels in neighbouring plants (receivers) following PM attack on emitter plants, activating defence responses in receivers. Notably, the expression of WRKY1, a previously characterized transcription factor, was upregulated in receivers, implicating its role in defence response modulation. WRKY1 was found to promote SA accumulation and enhance PM resistance in receivers. Importantly, WRKY1 positively regulates the expression of SABP2a, which catalysers MeSA to SA conversion, and negatively regulates SAMT1a, which functions in the reverse reaction. Consequently, WRKY1 facilitates the conversion of MeSA to SA in receivers, preventing its reversion and sustaining elevated SA levels. Collectively, our findings clarify the role of WRKY1 in enhancing the defence response to PM in receivers.

Low-temperature stress response: A transcriptomic study of the WRKY family in Prunus davidiana

Low temperature is a crucial environmental factor affecting peach tree growth. The WRKY transcription factor family plays a vital role in plants' responses to low-temperature stress. Understanding the expression patterns and functions of WRKY genes in peach trees under low-temperature stress is essential for uncovering the molecular mechanisms of cold tolerance and guiding the breeding of new cold-tolerant peach varieties. This study analyzed the transcriptome of cold-tolerant peach varieties following low-temperature treatment. Bioinformatics and quantitative real-time PCR were used to systematically analyze the structure, function, and expression characteristics of WRKY family members associated with low-temperature tolerance in peach trees. Results revealed complex transcriptional responses in peach trees under low-temperature stress, with 7029 differentially expressed genes identified and significantly enriched in multiple Gene Ontology terms and Kyoto Encyclopedia of Genes and Genomes pathways, indicating the diverse mechanisms of low-temperature response. Among the transcription factor families, the ERF, MYB, bHLH, NAC, and WRKY families showed significant responses to low-temperature stress. PpWRKY58 exhibited robust and specific upregulation under low-temperature stress, and yeast transformation showed enhanced activity under low-temperature conditions. This suggests a potential role for PpWRKY58 in peach cold hardiness. While WRKY family involvement in plant responses to low-temperature stress is known, our study reveals the specific function of PpWRKY58 in the peach low-temperature response, offering new insights into peach cold tolerance mechanisms, and suggesting PpWRKY58 as a potential target for improving peach cold hardiness.

Plant Signaling Hormones and Transcription Factors: Key Regulators of Plant Responses to Growth, Development, and Stress

Plants constantly encounter a wide range of biotic and abiotic stresses that adversely affect their growth, development, and productivity. Phytohormones such as abscisic acid, jasmonic acid, salicylic acid, and ethylene serve as crucial regulators, integrating internal and external signals to mediate stress responses while also coordinating key developmental processes, including seed germination, root and shoot growth, flowering, and senescence. Transcription factors (TFs) such as WRKY, NAC, MYB, and AP2/ERF play complementary roles by orchestrating complex transcriptional reprogramming, modulating stress-responsive genes, and facilitating physiological adaptations. Recent advances have deepened our understanding of hormonal networks and transcription factor families, revealing their intricate crosstalk in shaping plant resilience and development. Additionally, the synthesis, transport, and signaling of these molecules, along with their interactions with stress-responsive pathways, have emerged as critical areas of study. The integration of cutting-edge biotechnological tools, such as CRISPR-mediated gene editing and omics approaches, provides new opportunities to fine-tune these regulatory networks for enhanced crop resilience. By leveraging insights into transcriptional regulation and hormone signaling, these advancements provide a foundation for developing stress-tolerant, high-yielding crop varieties tailored to the challenges of climate change.

Molecular Insights into the Positive Role of Soybean Nodulation by GmWRKY17

Soybean is an important economic oilseed crop, being rich in protein and plant oil, it is widely cultivated around the world. Soybeans have been shown to establish a symbiotic nitrogen fixation (SNF) with their compatible rhizobia, resulting in the formation of nodules. Previous studies have demonstrated the critical roles of phytohormones, such as abscisic acid and cytokinin, in the process of legume nodulation. The present study investigated the role of GmWRKY17, a homolog of Rosa hybrida (Rh)WRKY13 in regulating plant immunity through cytokinin content and abscisic acid signaling in soybean nodulation. Utilizing real-time PCR and histochemical staining, we demonstrated that GmWRKY17 is predominantly expressed in soybean root nodules. Subsequently, we analyzed the function of GmWRKY17-overexpression, RNA interference (RNAi), and the CRISPR/Cas9 system. Overexpression of GmWRKY17 significantly increases soybean nodule number, while RNAi or CRISPR/Cas9-mediated knockout of GmWRKY17 resulted in a dramatic repression of nodule formation in soybeans. These results highlight that GmWRKY17 functions as a positive regulator involved in soybean nodulation. Furthermore, manipulation of GmWRKY17 expression impacts the expression of genes associated with the nod factor (NF) signaling pathway, thereby influencing soybean nodulation. This study demonstrated that WRKY-type transcription factors are involved in the regulation of legume nodulation, offering new light on the molecular basis of the symbiotic interaction between legumes and rhizobia.

Identification of the WRKY gene family in Bergenia purpurascens and functional analysis of BpWRKY13 under cold stress

Bergenia purpurascens, a medicinal alpine plant, exhibits remarkable stress resilience. WRKY transcription factors are central regulators of plant stress responses, yet their family in B. purpurascens remains uncharacterized. Here, we identified 57 BpWRKY genes from B. purpurascens transcriptome data. Expression analysis revealed 11 BpWRKY genes differentially expressed under cold stress, with BpWRKY13 showing the strongest induction. To investigate its function, we overexpressed BpWRKY13 in Arabidopsis thaliana. Transgenic plants displayed significantly enhanced cold tolerance, evidenced by reduced leaf damage, increased survival, and elevated accumulation of proline and soluble proteins. Furthermore, transgenic plants exhibited increased activity of antioxidant enzymes and upregulation of cold-responsive genes. These findings indicate that BpWRKY13 confers cold tolerance by promoting osmoprotection and activating antioxidant defense mechanisms. This study provides a crucial foundation for understanding the BpWRKY gene family and highlights BpWRKY13 as a key regulator of cold resistance in B. purpurascens.

Genome-Wide Identification and Characterization of the WRKY Gene Family and Their Associated Regulatory Elements in Fortunella hindsii

Background

The WRKY gene family is identified as one of the most prominent transcription factor families in plants and is involved in various biological processes such as metabolism, growth and development, and response to biotic and abiotic stresses. In many plant species, the WRKY gene family was widely studied and analyzed but little to no information for Fortunella hindsii. However, the completion of the whole genome sequencing of Fortunella hindsii allowed us to investigate the genome-wide analysis of WRKY proteins.

Objective

The main objective of this study was to analyze and identify the WRKY gene family in Fortunella hindsii genome.

Methodology

Various bioinformatics approaches have been used to conduct this study.

Results

We constituted 46 members of the Fortunella hindsii WRKY gene family, which were unevenly distributed on all nine chromosomes. The phylogenetic relationship of predicted WRKY proteins of Fortunella hindsii with the WRKY proteins of Arabidopsis showed that 46 FhWRKY genes were divided into three main groups (G1, G2, G3) with five subgroups (2A, 2B, 2C, 2D, and 2E) of G2 group. Domain, conserved motif identification, and gene structure were conducted and the results found that these FhWRKY proteins have conserved identical characteristics within groups and maintain differences between groups. In silico subcellular localization, results showed that FhWRKY genes are located in the nucleus. The cis-regulatory element analysis identified several key CREs that are significantly associated with light, hormone responses, and stress. The gene ontology analysis of these predicted FhWRKY genes showed that these genes are significantly enriched in sequence-specific DNA binding, transcriptional activity, cellular biosynthesis, and metabolic processes.

Conclusion

Therefore, overall, our results provided an excellent foundation for further functional characterization of WRKY genes with an aim of Fortunella hindsii citrus crop improvement.

A novel mode of WRKY1 regulating PR1-mediated immune balance to defend against powdery mildew in apple

Powdery mildew (PM), caused by the biotrophic fungus Podospharea leucotricha, poses a significant threat to apple production. Salicylic acid (SA) signaling plays a crucial role in enhancing resistance to biotrophic pathogens. While PR1, a defense protein induced by SA, is essential for plant immunity, its excessive accumulation can be detrimental. However, the mechanism of PR1-mediated immune balance remains unclear. This study identified a key transcription factor, WRKY1, which enhances the SA accumulation by modulating the SA biosynthesis gene EPS1, while simultaneously regulating the WRKY40-NPR3g module to prevent sustained PR1 expression caused by continuous SA accumulation. Specifically, the transcription factor WRKY40 upregulates NPR3g expression, and NPR3g interacts with NPR1 in an SA-dependent manner. Then, two TGA2c variants that interact with NPR1 to activate PR1 expression were identified: canonical TGA2c-1 and alternative splicing of TGA2c-2 with an exon deletion. SA does not influence the NPR1-TGA2c-1 interaction but is essential for the NPR1-TGA2c-2 interaction. Notably, NPR3g reduces PR1 levels by selectively disrupting the NPR1-TGA2c-2 complex through competition for the BTB-POZ domain of NPR1. In conclusion, this study identifies a novel mechanism by which WRKY1 modulates PR1-mediated immune balance to defend against PM.

Genome-wide identification and expression profiling of WRKY gene family in grain Amaranth (Amaranthus hypochondriacus L.) under salinity and drought stresses

BACKGROUND

The WRKY gene family plays a significant role in plant growth, development, and responses to biotic and abiotic stresses. However, the role of the WRKY gene family has not been reported in Amaranthus hypochondriacus. This study presents a comprehensive genome-wide analysis of the WRKY gene family in grain amaranth (A. hypochondriacus L.), a resilient crop known for its high nutritional value and adaptability to challenging environments.

RESULTS

In this study, 55 WRKY genes (AhyWRKY1-55) were identified in A. hypochondriacus and distributed unevenly across 16 scaffolds. Of these, 50 contained conserved WRKY domains and were classified into three main groups. Group II was further divided into five subgroups (IIa-IIe) based on phylogenetic analysis, with each clade being well supported by conserved motifs. Additionally, the gene structure analysis revealed variations in exon-intron organization. In contrast, motif analysis showed the presence of conserved domains that were similar within the group but differed between groups, suggesting their functional diversity. Cis-acting elements related to plant growth and development and light, hormones, and stress responses were identified. Synteny analysis revealed that 34 (61.8%) of the genes originated from tandem duplication, indicating the role of tandem duplication in the expansion of the A. hypochondriacus WRKY gene family. Protein-protein interaction analysis suggested that AhyWRKY3, AhyWRKY27, AhyWRKY28, AhyWRKY36, and AhyWRKY52 were hub genes involved in the complex protein interaction network. Using in silico and real-time quantitative PCR, expression analysis revealed tissue- and condition-specific expression patterns of AhyWRKY genes. Notably, under drought stress, AhyWRKY39, AhyWRKY40, AhyWRKY54, and AhyWRKY01 showed increased expression, while under salt stress, AhyWRKY40, AhyWRKY54, AhyWRKY39, AhyWRKY49, and AhyWRKY8 were upregulated at 30 days, suggesting that these genes may play key role in response to salinity stress.

CONCLUSIONS

The present study provides valuable insights into the organization and evolutionary patterns of the WRKY gene family in amaranth. It also identifies putative candidate WRKY genes that may play a role in conferring drought and salt tolerance. Overall, this study lays a foundation for further functional validation of these WRKY candidate genes, facilitating their exploitation in the amaranth genetic improvement programs to develop stress-resilient varieties.

The physiological and molecular mechanisms of WRKY transcription factors regulating drought tolerance: A review

WRKY transcription factors (TFs) play crucial roles in responses to abiotic and biotic stresses that significantly impact plant growth and development. Advancements in molecular biology and sequencing technologies have elevated WRKY TF studies from merely determining expression patterns and functional characterization to uncovering molecular regulatory networks. Numerous WRKY TFs regulate drought tolerance in plants through various regulatory networks. This review details the physiological and molecular mechanisms of WRKY TFs regulating drought tolerance. The review focuses on the WRKY TFs involved in the phytohormone and metabolic pathways associated with the drought stress response and the multiple functions of these WRKY TFs, including biotic and abiotic stress responses and their participation in plant growth and development.

The Mulberry WRKY Transcription Factor MaWRKYIIc7 Participates in Regulating Plant Drought Stress Tolerance

The sericulture industry is an important component of the agricultural industry. Drought stress can cause yellowing, premature ageing, and the shrinkage of mulberry (Morus alba L.) leaves, greatly damaging their quality and restricting the high-quality development of the sericulture industry. WRKY transcription factors play important roles in the plant drought stress response. In this study, we found that MaWRKYIIc7 of the mulberry WRKY TFs, had significantly higher expression levels in leaves than in other tissues and was induced to be expressed under drought stress. The MaWRKYIIc7 protein is located in the nucleus and plasma membrane, and its transcriptional activity depends mainly on the N-terminal sequence. The overexpression of MaWRKYIIc7 in Arabidopsis resulted in better drought tolerance. An analysis of the transient overexpression of MaWRKYIIc7 in mulberry seedlings under drought stress revealed that the transgenic seedlings presented decreased stomatal opening, decreased MDA content, increased ROS clearance ability, and increased the expression of ABA biosynthesis-related genes. The Y1H and Dual-luc results indicate that MaWRKYIIc7 can bind W-boxes to positively regulate MaNCED1 and MaRD29A, synergistically regulating the drought tolerance of mulberry. Overall, our research suggests that MaWRKYIIc7 can increase plant drought tolerance by promoting ROS clearance, adjusting stomatal opening, and activating the ABA signalling pathway.

Genome-wide identification and characterization of WRKYs family involved in responses to Cylindrocarpon destructans in Panax notoginseng

BACKGROUND

WRKY transcription factors (TFs) are key regulators of plant responses to biotic and abiotic stresses. Previous studies demonstrated that the role of WRKY TFs play in the disease resistance of Panax notoginseng, the causal agent of root rot disease. However, comprehensive genome-wide analyses of WRKY genes in this species remain scarce.

RESULT

We identified 79 WRKY genes in the P. notoginseng genome, classifing them into three groups based on structural features and phylogenetic relationships: Class I (14 genes), Class II (55 genes), and Class III (10 genes). Of these, 58 PnWRKY genes were mapped to the P. notoginseng chromosomes and showed collinearity with Arabidopsis thaliana, Daucus carota, and three Solanaceae species. Expression analysis revealed that 53 PnWRKY genes were actively transcribed across various tissues, including roots, flowers, stems, rhizomes, and different root parts. Furthermore, PnWRKY genes responded to Cylindrocarpon destructans infection and were induced by jasmonic acid (JA) and salicylic acid (SA). Notably, the ectopic expression of PnWRKY35 in tobacco enhanced resistance to C. destructans, accompanied by increased levels of gibberellins (GA24, GA3, GA8), JA, SA, and brassinolide. KEGG enrichment analysis of 547 differentially expressed genes (DEGs) indicated their involvement pathways related to disease resistance, including the biosynthesis of sesquiterpenes and triterpenes, JA biosynthesis, plant-pathogen interactions and the MAPK signaling pathway.

CONCLUSION

This study demonstrated that the WRKY family in P. notoginseng plays a significant role in resistance to root rot disease. PnWRKY genes are responsive to MeJA and SA induction as well as C. destructans infection. Moreover, ectopic expression of PnWRKY35 activates multiple plant disease resistance pathways, increases phytohormone levels, and enhance resistance to C. destructans. These findings provide a foundation for future exploration of the mechanism underlying P. notoginseng resistance to root rot disease.

WRKY45 positively regulates salinity and osmotic stress responses in Arabidopsis

Salt damage is a major issue that causes a decline in crop yield. WRKY transcription factors (TFs) extensively regulate plant biotic and abiotic stress responses, growth, and development. WRKY45 is crucial in regulating leaf senescence, low phosphorus responses, and cadmium stress response in Arabidopsis. However, the involvement of WRKY45 in salinity and osmotic stress responses is unclear. Here, we report that WRKY45 plays a vital role in responding to salinity and osmotic stress. NaCl and sorbitol treatments upregulate WRKY45 expression. Furthermore, the overexpression of WRKY45 (WRKY45-OXs) may enhance the tolerance of Arabidopsis to salinity and osmotic stress. Moreover, the root length, fresh weight, chlorophyll, and proline content were significantly higher in WRKY45-OXs than in the wide type (WT) Col-0 plants after salt or PEG treatment, whereas malondialdehyde and reactive oxygen species (ROS) levels were significantly lower than in the WT plants. Correspondingly, the overexpression of WRKY45 modulated the expression of stress-responsive genes. Dual luciferase assay and electrophoretic mobility shift assay further confirmed that WRKY45 can activate the promoter of RD29A by directly binding to specific W-box cis-acting elements. Overall, our experimental evidence suggesting that WRKY45 mainly acts as a key regulator coordinating the response to high salinity and osmotic stress through mechanisms dependent on ABA signaling along with enhanced antioxidant capacity.

Recent advances in functional assays of WRKY transcription factors in plant immunity against pathogens

WRKY transcription factors (TFs) are one of the largest transcription factor families in plants and play important roles in plant processes, most notably in responding to diverse biotic and abiotic stresses. This article reviews the recent research progresses on WRKY TFs in regulating plant immunity, which includes both positive and negative regulation. WRKY TFs were shown to regulate plant defense against pathogens including fungi, bacteria, oomycetes, and viruses by modulating downstream pathogen resistance genes or interacting with other regulators. Plant signaling pathways or components involved in the regulatory network of WRKY-mediated plant immunity mainly involve the action of phytohormones, MAPKs (Mitogen-activated protein kinases), and other transcription factors. The interaction of WRKY TFs with these factors during pathogen resistance was discussed in this article, which may contribute to understanding the mechanisms of WRKY transcription factors in plant immunity.

Genome-wide identification, characterization and expression analysis of WRKY transcription factors under abiotic stresses in Carthamus tinctorius L

BACKGROUND

WRKY transcription factors constitute one of the largest families of plant transcriptional regulators, playing pivotal roles in plant responses to biotic and abiotic stresses, as well as in hormonal signaling and secondary metabolism regulation. However, a comprehensive analysis of the WRKY family in Carthamus tinctorius (safflower) is lacking. This study aims to identify and characterize WRKY genes in safflower to enhance understanding of their roles in stress responses and metabolic regulation. Safflower, valued for its ornamental, medicinal, and culinary uses, exhibits significant resilience to salt, alkali, and drought. By elucidating the functions and expression patterns of WRKY genes, we aim to enhance breeding strategies for improved stress tolerance and metabolic traits in crops.

RESULTS

In this study, we identified 84 WRKY genes within the safflower genome, and classified them into three primary groups (Groups I, II, and III) based on molecular structure and phylogenetic relationships. Group II was further subdivided into five subgroups (II-a, II-b, II-c, II-d, and II-e). Gene structure, conserved domain, motif, cis-elements, and expression profiling were performed. Syntenic analysis revealed that there were 27 pairs of repetitive fragments. Expression profiles of CtWRKY genes were assessed across diverse tissues, colored cultivars, and abiotic stresses such as ABA, drought, and cold conditions. Several CtWRKY genes (e.g., CtWRKY44, CtWRKY63, CtWRKY65, CtWRKY70 and CtWRKY72) exhibited distinct expression patterns in response to cold stress and during different developmental stages. Additionally, CtWRKY13, CtWRKY69, CtWRKY29, CtWRKY56, and CtWRKY36 were upregulated across different flower colors. The expression patterns of CtWRKY48, CtWRKY58, and CtWRKY70 varied among safflower cultivars and flower colors. After exposure to drought stress, the expression levels of CtWRKY29 and CtWRKY58 were downregulated, while those of CtWRKY56 and CtWRKY62 were upregulated.

CONCLUSION

This study identified 84 WRKY genes in Carthamus tinctorius and classified them into three groups, with detailed analyses of their structure, conserved domains, motifs, and expression profiles under various stresses. Notably, several WRKY genes such as CtWRKY44, CtWRKY63, and CtWRKY72 displayed significant expression changes under cold stress, while CtWRKY56 and CtWRKY62 were responsive to drought stress. These findings highlight the critical roles of specific WRKY genes in abiotic stress tolerance and developmental regulation in safflower.

Comparative analysis of the WRKY gene family between Chimonanthus praecox and C. salicifolius

Gene duplications provide evolutionary potentials for generating novel functions. Chimonanthus praecox and C. salicifolius are closely related species from Calycantaceae, Magnoliids. In this study, we compared the WRKY gene family from C. praecox and C. salicifolius, and predicted the potential gene function through gene expression patterns to explore the evolution of orthologous and paralogous gene pairs. A total of 73 and 85 WRKY genes were identified and analyzed from the whole genome sequencing of C. praecox and C. salicifolius. Based on the phylogenetic analysis, CpWRKY and CsWRKY genes were clustered into three groups (Group I、II、III) and 5 subgroups (Group IIa、IIb、IIc、IId、IIe). In C. praecox and C. salicifolius, we identified thirty-six and fifty-four pairs of WRKY segmental duplicated genes, respectively, along with two and three pairs of tandem duplicates, indicating that segmental duplication plays a crucial role in the evolution of Chimonanthus WRKY gene family. Most WRKY duplication gene pairs originated from segmental duplications before the first whole genome duplication (WGD), highlighting this period as a significant source of genetic diversity and functionality for the WRKY family. The analysis of WRKY gene expression levels suggests that CsWRKY18 and CsWRKY68 may promote the growth of the roots in C. salicifolius. Comparisons of expression profiles between species revealed that five orthologous gene pairs presented identical expression trends, indicating functional conservation and absence of neo-functionalization or sub-functionalization. However, most orthologous gene pairs exhibit differences in expression patterns, suggesting that they have undergone functional divergence. This functional differentiation may be due to the different selective pressures faced by C. praecox and C. salicifolius during their speciation processes. This study provided detailed information on the WRKY gene family from C. praecox and C. salicifolius, and a new insight for studying gene duplication and function evolution.

Plant Coping with Cold Stress: Molecular and Physiological Adaptive Mechanisms with Future Perspectives

Cold stress strongly hinders plant growth and development. However, the molecular and physiological adaptive mechanisms of cold stress tolerance in plants are not well understood. Plants adopt several morpho-physiological changes to withstand cold stress. Plants have evolved various strategies to cope with cold stress. These strategies included changes in cellular membranes and chloroplast structure, regulating cold signals related to phytohormones and plant growth regulators (ABA, JA, GA, IAA, SA, BR, ET, CTK, and MET), reactive oxygen species (ROS), protein kinases, and inorganic ions. This review summarizes the mechanisms of how plants respond to cold stress, covering four main signal transduction pathways, including the abscisic acid (ABA) signal transduction pathway, Ca2+ signal transduction pathway, ROS signal transduction pathway, and mitogen-activated protein kinase (MAPK/MPK) cascade pathway. Some transcription factors, such as AP2/ERF, MYB, WRKY, NAC, and bZIP, not only act as calmodulin-binding proteins during cold perception but can also play important roles in the downstream chilling-signaling pathway. This review also highlights the analysis of those transcription factors such as bHLH, especially bHLH-type transcription factors ICE, and discusses their functions as phytohormone-responsive elements binding proteins in the promoter region under cold stress. In addition, a theoretical framework outlining plant responses to cold stress tolerance has been proposed. This theory aims to guide future research directions and inform agricultural production practices, ultimately enhancing crop resilience to cold stress.

Regulation of important natural products biosynthesis by WRKY transcription factors in plants

BACKGROUND

Plants produce abundant natural products, among which are species-specific and diversified secondary metabolites that are essential for growth and development, as well as adaptation to adversity and ecology. Moreover, these secondary metabolites are extensively utilized in pharmaceuticals, fragrances, industrial materials, and more. WRKY transcription factors (TFs), as a family of TFs unique to plants, have significant functions in many plant life activities. Especially in recent years, their role in the field of secondary metabolite biosynthesis regulation has received much attention. However, very little comprehensive summarization has been done to review their research progress.

AIM OF REVIEW

The purpose of this work is not only to provide valuable insights into the regulation of WRKY TFs over metabolic pathways through compiling the WRKY TFs involved in these processes, but also to offer research directions for WRKY TFs by summarizing the regulatory modes of WRKY TFs in the biosynthesis of secondary metabolites, thereby increasing the yield of valuable natural products in the future.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Secondary metabolites can be categorized into three major classes-terpenoids, phenolic compounds, and nitrogen-containing compounds-based on their structural characteristics and biosynthetic pathways, and further subdivided into numerous subclasses. We review in detail the research progressregardingthe regulatory roles of WRKY TFs in plant secondary metabolitebiosynthesis and summarize more than 40 major related species. Additionally, we have presented the concepts of action modes of WRKY TFs involved in metabolic pathways, including direct regulation, indirect regulation, co-regulation, and self-regulation. It is helpful for others to investigate the molecular mechanisms of TF-mediated regulation. Furthermore, regarding future research prospects, we believe that research in this area lays the foundation for increasing the yield of important plant-derived natural products by molecular breeding, generating significant economic and social benefits.

Genome-Wide Identification and Expression Analysis of NAC Gene Family Members in Seashore Paspalum Under Salt Stress

The NAC gene family plays a crucial role in plant growth, development, and responses to biotic and abiotic stresses. Paspalum Vaginatum, a warm-season turfgrass with exceptional salt tolerance, can be irrigated with seawater. However, the NAC gene family in seashore paspalum remains poorly understood. In this study, genome-wide screening and identification were conducted based on the NAC (NAM) domain hidden Markov model in seashore paspalum, resulting in the identification of 168 PvNAC genes. A phylogenetic tree was constructed, and the genes were classified into 18 groups according to their topological structure. The physicochemical properties of the PvNAC gene family proteins, their conserved motifs and structural domains, cis-acting elements, intraspecific collinearity analysis, GO annotation analysis, and protein-protein interaction networks were analyzed. The results indicated that the majority of PvNAC proteins are hydrophilic and predominantly localized in the nucleus. The promoter regions of PvNACs are primarily enriched with light-responsive elements, ABRE motifs, MYB motifs, and others. Intraspecific collinearity analysis suggests that PvNACs may have experienced a large-scale gene duplication event. GO annotation indicated that PvNAC genes were essential for transcriptional regulation, organ development, and responses to environmental stimuli. Furthermore, the protein interaction network predicted that PvNAC73 interacts with proteins such as BZIP8 and DREB2A to form a major regulatory hub. The transcriptomic analysis investigates the expression patterns of NAC genes in both leaves and roots under varying durations of salt stress. The expression levels of 8 PvNACs in roots and leaves under salt stress were examined and increased to varying degrees under salt stress. The qRT-PCR results demonstrated that the expression levels of the selected genes were consistent with the FPKM value trends observed in the RNA-seq data. This study established a theoretical basis for understanding the molecular functions and regulatory mechanisms of the NAC gene family in seashore paspalum under salt stress.

Carotenoid-carbohydrate crosstalk: evidence for genetic and physiological interactions in storage tissues across crop species

Carotenoids play essential roles in photosynthesis, photoprotection, and human health. Efforts to increase carotenoid content in several staple crops have been successful through both conventional selection and genetic engineering methods. Interestingly, in some cases, altering carotenoid content has had unexpected effects on other aspects of plant metabolism, impacting traits like sugar content, dry matter percentage, fatty acid content, stress tolerance, and phytohormone concentrations. Studies across several diverse crop species have identified negative correlations between carotenoid and starch contents, as well as positive correlations between carotenoids and soluble sugars. Collectively, these reports suggest a metabolic interaction between carotenoids and carbohydrates. We synthesize evidence pointing to four hypothesized mechanisms: (1) direct competition for precursors; (2) physical interactions in plastids; (3) influences of sugar or apocarotenoid signaling networks; and (4) nonmechanistic population or statistical sources of correlations. Though the carotenoid biosynthesis pathway is well understood, the regulation and interactions of carotenoids, especially in nonphotosynthetic tissues, remain unclear. This topic represents an underexplored interplay between primary and secondary metabolism where further research is needed.

Okra WRKY Transcription Factor AeWRKY32 and AeWRKY70 Are Involved in Salt Stress Response

Soil salinization is one of the abiotic stresses that inhibit plant growth and development, which seriously restricts global crop production. WRKY transcription factors play an important role in regulating plant responses to stress such as salt stress. In our previous study, two WRKY family genes from okra, AeWRKY32 and AeWRKY70, were significantly up-regulated and down-regulated, respectively, in response to salt stress. In this study, subcellular localization showed that they were localized to the nucleus. The down-regulation of AeWRKY32 and AeWRKY70 via whole plant virus-induced gene silencing (VIGS) increased and decreased plant sensitivity to salt stress, respectively. Ectopic expression of AeWRKY32 and AeWRKY70 led to promoted and reduced salt tolerance in transgenic Arabidopsis, respectively. There was no significant difference between transgenic plants and wild type (WT) without salt treatment. Salt stress significantly inhibited plant growth. The decrease of chlorophyll content and the increase of anthocyanin content in AeWRKY32-overexpressed transgenic plants were lower than those in the WT, while AeWRKY70-overexpressed plants had the opposite effect. Under salt stress, the AeWRKY70-overexpressed plants had the highest malondialdehyde (MDA) content, followed by the WT, and the lowest in AeWRKY32-overexpressed plants. The hydrogen peroxide (H2O2) content and superoxide anion (O2•-) generation rate were only slightly increased. Moreover, salt stress significantly increased plant proline content and antioxidant enzyme activities, which was highest in AeWRKY70-overexpressed plants except superoxide dismutase (SOD). Taken together, these results suggest that AeWRKY32 and AeWRKY70 play positive and negative roles in plant in response to salt stress, respectively.

Transcription factor gene TaWRKY76 confers plants improved drought and salt tolerance through modulating stress defensive-associated processes in Triticum aestivum L

WRKY transcription factor (TF) family acts as essential regulators in plant growth and abiotic stress responses. This study reported the function of TaWRKY76, a member of WRKY TF family in Triticum aestivum L., in regulating plant osmotic stress tolerance. TaWRKY76 transcripts were significantly upregulated upon drought and salt signaling, with dose extent- and stress temporal-dependent manners. Plant GUS activity assays suggested that stress responsive cis-acting elements, such as DRE and ABRE, exert essential roles in defining gene transcription under osmotic stress conditions. The TaWRKY76 protein targeted onto nucleus and possessed ability interacting with TaMYC2, a MYC TF member of wheat. TaWRKY76 and TaMYC2 positively regulated plant drought and salt adaptation by modulating osmotic stress-related physiological indices, including osmolyte contents, stomata movement, root morphology, and reactive oxygen species (ROS) homeostasis. Yeast one-hybrid assay indicated the binding ability of TaWRKY76 with promoters of TaDREB1;1, TaNCEB3, and TaCOR15;4. ChIP-PCR analysis confirmed that the osmotic stress genes are transcriptionally regulated by TaWRKY76. Moreover, the transgenic lines with knockdown of these stress-response genes displayed lowered plant biomass together with worsened root growth traits, decreased proline contents, and elevated ROS amounts. These results suggested that these stress defensive genes contributed to TaWRKY76-modulated osmotic stress tolerance. Highly positive correlations were observed between yield and the transcripts of TaWRKY76 in a wheat variety panel under field drought condition. A major haplotype TaWRKY76 Hap1 conferred improved drought tolerance. Our results suggested that TaWRKY76 is essential in plant drought and salt adaptation and a valuable target for molecular breeding stress-tolerant cultivars in Triticum aestivum L..

Identification of a 301 bp promoter core region of the SrUGT91D2 gene from Stevia rebaudiana that contributes to hormone and abiotic stress inducibility

BACKGROUND

The UDP-glucuronosyltransferase 91D2 (SrUGT91D2) gene is a crucial element in the biosynthetic pathway of steviol glycosides (SGs) and is responsible for creating 1,2-β-D glucosidic bonds at the C19 and C13 positions. This process plays a vital role in the synthesis of rebaudioside M (RM) and rebaudioside D (RD). The promoter, which regulates gene expression, requires functional analysis to understand gene expression regulation. However, investigations into the function of the promoter of SrUGT91D2 (pSrUGT91D2) have not been reported.

RESULTS

The pSrUGT91D2 was isolated from six S. rebaudiana lines, and subsequent multiple sequence comparisons revealed the presence of a 26 bp inDel fragment (pSrUGT91D2-B1188 type) in lines GP, GX, 110, 1114, and B1188 but not in the pSrUGT91D2 of line 023 (pSrUGT91D2-023 type). Bioinformatics analysis revealed a prevalence of significant cis-regulatory elements (CREs) within the promoter sequences, including those responsive to abscisic acid, light, anaerobic conditions, auxin, drought, low temperature, and MeJA. To verify the activity of pSrUGT91D2, the full-length promoter and a series of 5' deletion fragments (P1-P7) and a 3' deletion fragment (P8) from various lines were fused with the reporter β-glucuronidase (GUS) gene to construct the plant expression vector, pCAMBIA1300-pro∷GUS. The transcriptional activity of these genes was examined in tobacco leaves through transient transformation. GUS tissue staining analysis and enzyme activity assays demonstrated that both the full-length promoter and truncated pSrUGT91D2 were capable of initiating GUS expression in tobacco leaves. Interestingly, P8-pSrUGT91D2-B1188 (containing the inDel segment, 301 bp) exhibited enhanced activity in driving GUS gene expression. Transient expression studies of P8-pSrUGT91D2-B1188 and P8-pSrUGT91D2-023 in response to exogenous hormones (abscisic acid and indole-3-acetic acid) and light indicated the necessity of the inDel region for P8 to exhibit transcriptional activity, as it displayed strong responsiveness to abscisic acid (ABA), indole-3-acetic acid (IAA), and light induction.

CONCLUSIONS

These findings contribute to a deeper understanding of the regulatory mechanism of the upstream region of the SrUGT91D2 gene and provide a theoretical basis for future studies on the interaction between CREs of pSrUGT91D2 and related transcription factors.

Genome-Wide Identification and Analysis of the WRKY Transcription Factor Family Associated with Leaf Senescence in Alfalfa

Leaves are the most significant parts of forage crops such as alfalfa. Senescence is the terminal stage of leaf development and is controlled by an integrated myriad of endogenous signals and environmental stimuli. WRKY transcription factors (TFs) play essential roles in regulating leaf senescence; however, only a few studies on the analysis and identification of the WRKY TF family in Medicago Sativa have been reported. In this study, we identified 198 WRKY family members from the alfalfa (M. sativa L.) cultivar 'XinjiangDaye' using phylogenetic analysis and categorized them into three subfamilies, Groups I, II, and III, based on their structural characteristics. Group II members were further divided into five subclasses. In addition, several hormone- and stress-related cis-acting elements were identified in the promoter regions of MsWRKYs. Furthermore, 14 aging-related MsWRKYs genes from a previous transcriptome in our laboratory were selected for RT-qPCR validation of their expression patterns, and subsequently cloned for overexpression examination. Finally, MsWRKY5, MsWRKY66, MsWRKY92, and MsWRKY141 were confirmed to cause leaf yellowing in Nicotiana benthaminana using a transient expression system. Our findings lay a groundwork for further studies on the mechanism of M. sativa leaf aging and for the creation of new germplasm resources.

Identification and Analysis of WRKY Transcription Factors in Response to Cowpea Fusarium Wilt in Cowpea

In plants, WRKY transcription factors play a crucial role in plant growth, development, and response to abiotic and biotic stress. Cowpea (Vigna unguiculata) is an important legume crop. However, cowpea Fusarium wilt (CFW), caused by Fusarium oxysporum f. sp. tracheiphilum (Fot), poses a serious threat to its production. In this study, we systematically identified members of the cowpea WRKY (VuWRKY) gene family and analyzed their expression patterns under CFW stress. A total of 91 WRKY transcription factors were identified in the cowpea genome. Phylogenetic and synteny analyses indicated that the expansion of VuWRKY genes in cowpea is primarily due to recent duplication events. Transcriptome analysis of cowpea inoculated with Fo revealed 31 differentially expressed VuWRKY genes, underscoring their role in the response to CFW infection. Four differentially expressed WRKY genes were selected for validation. Subcellular localization and Western blot assays showed their nuclear localization and normal expression in N. benthamiana. Additionally, yeast one-hybrid assays demonstrated that VuWRKY2 can bind to the promoter region of the Catalase (CAT) gene, indicating its potential role in transcriptional regulation. This study establishes a foundation for further exploration of the role and regulatory mechanisms of VuWRKY genes in response to CFW stress.

PoWRKY69-PoVQ11 module positively regulates drought tolerance by accumulating fructose in Paeonia ostii

Drought is a detrimental environmental factor that restricts plant growth and threatens food security throughout the world. WRKY transcription factors play vital roles in abiotic stress response. However, the roles of IIe subgroup members from WRKY transcription factor family in soluble sugar mediated drought response are largely elusive. In this study, we identified a drought-responsive IIe subgroup WRKY transcription factor, PoWRKY69, from Paeonia ostii. PoWRKY69 functioned as a positive regulator in response to drought stress with nucleus expression and transcriptional activation activity. Silencing of PoWRKY69 increased plants sensitivity to drought stress, whereas conversely, overexpression of PoWRKY69 enhanced drought tolerance in plants. As revealed by yeast one-hybrid, electrophoretic mobility shift assay, and luciferase reporter assays, PoWRKY69 could directly bind to the W-box element of fructose-1,6-bisphosphate aldolase 5 (PoFBA5) promoter, contributing to a cascade regulatory network to activate PoFBA5 expression. Furthermore, virus-induced gene silencing and overexpression assays demonstrated that PoFBA5 functioned positively in response to drought stress by accumulating fructose to alleviate membrane lipid peroxidation and activate antioxidant defense system, these changes resulted in reactive oxygen species scavenging. According to yeast two-hybrid, bimolecular fluorescence complementation, and firefly luciferase complementation imaging assays, valine-glutamine 11 (PoVQ11) physically interacted with PoWRKY69 and led to an enhanced activation of PoWRKY69 on PoFBA5 promoter activity. This study broadens our understanding of WRKY69-VQ11 module regulated fructose accumulation in response to drought stress and provides feasible molecular measures to create novel drought-tolerant germplasm of P. ostii.

MbWRKY53, a M. baccata WRKY Transcription Factor, Contributes to Cold and Drought Stress Tolerance in Transgenic Arabidopsis thaliana

Apple is an important horticultural crop, but various adverse environmental factors can threaten the quality and yield of its fruits. The ability of apples to resist stress mainly depends on the rootstock. Malus baccata (L.) Borkh. is a commonly used rootstock in Northeast China. In this study, it was used as the experimental material, and the target gene MbWRKY53 was screened through transcriptome analysis and Real-Time Quantitative Reverse Transcription Polymerase Chain Reaction (RT-qPCR) after cold and drought treatment. Bioinformatics analysis revealed that this transcription factor (TF) belonged to the WRKY TF family, and its encoded protein was localized in the nucleus. RT-qPCR showed that the gene was more easily expressed in roots and young leaves and is more responsive to cold and drought stimuli. Functional validation in Arabidopsis thaliana confirmed that MbWRKY53 can enhance plant tolerance to cold and drought stress. Furthermore, by analyzing the expression levels of genes related to cold and drought stress in transgenic Arabidopsis lines, it was inferred that this gene can regulate the expression of stress-related genes through multiple pathways such as the CBF pathway, SOS pathway, Pro synthesis pathway, and ABA-dependent pathways, enhancing the adaptability of transgenic Arabidopsis to cold and drought environments.

Genome-Wide Identification of WRKY Transcription Factor Family in Chinese Rose and Response to Drought, Heat, and Salt Stress

The WRKY gene family is a key transcription factor family for plant development and the stress response. However, few studies have investigated the WRKY gene family in Chinese rose (Rosa chinensis). In this study, 68 RcWRKY genes were identified from the Chinese rose genome and classified into three primary groups and five subgroups based on the structural and phylogenetic characteristics. The analysis of the conserved domains, motifs, and gene structure revealed that the RcWRKY genes within the same group had the same exon-intron organization and composition. Chromosome mapping and gene duplication revealed that the RcWRKY genes were randomly dispersed across seven chromosomes. Fragment duplication and refined selection may have influenced the evolution of the WRKY gene family in Chinese rose. The cis-acting elements in the WRKY promoter region revealed that the RcWRKY genes contained numerous abiotic stress response elements. The results of qRT-PCR revealed that the expression of RcWRKY was tissue-specific, with high expression being observed under drought, heat, and salt stress. Notably, RcWRKY49's expression increased more than fivefold following salt stress, indicating that it is a crucial gene mediating the salt stress response of Chinese rose. These findings shed light on the regulatory role of RcWRKY in the growth and development of Chinese rose, and they serve as a foundation for future molecular breeding programs and gene discovery.

The WRKY gene family in the halophyte Limonium bicolor: identification, expression analysis, and regulation of salt stress tolerance

KEY MESSAGE

63 L. bicolor WRKY genes were identified and their informatics was analyzed. The results suggested that the LbWRKY genes involved in the development and salt secretion of salt glands in L. bicolor. Salt stress, as a universal abiotic stress, severely inhibits the growth and development of plants. WRKY transcription factors play a vital role in plant growth and development, as well as in response to various stresses. Nevertheless, little is known of systematic genome-wide analysis of the WRKY genes in Limonium bicolor, a model recretohalophyte. In this study, 63 L. bicolor WRKY genes were identified (LbWRKY1-63), which were unevenly distributed across seven chromosomes and one scaffold. Based on the structural and phylogenetic characteristics, 63 LbWRKYs are divided into three main groups. Cis-elements in the LbWRKY promoters were related to growth and development, phytohormone responses, and stress responses. Colinearity analysis showed strong colinearity between LbWRKYs and GmWRKYs from soybean (Glycine max). Therefore, LbWRKY genes maybe have similar functions to GmWRKY genes. Expression analysis showed that 28 LbWRKY genes are highly expressed in roots, 9 in stems, 26 in leaves, and 12 in flowers and most LbWRKY genes responded to NaCl, ABA, and PEG6000. Silencing LbWRKY10 reduced salt gland density and salt secretion ability of leaves, and the salt tolerance of the species. Consistent with this, genes associated with salt gland development were markedly down-regulated in the LbWRKY10-silenced lines. Our findings suggested that the LbWRKY genes involved in the development and salt secretion of salt glands in L. bicolor. Our research provides new insights into the functions of the WRKY family in halophytes.

Genome-wide profiling of WRKY genes involved in flavonoid biosynthesis in Erigeron breviscapus

The transcription factors of WRKY genes play essential roles in plant growth, stress responses, and metabolite biosynthesis. Erigeron breviscapus, a traditional Chinese herb, is abundant in flavonoids and has been used for centuries to treat cardiovascular and cerebrovascular diseases. However, the WRKY transcription factors that regulate flavonoid biosynthesis in E. breviscapus remain unknown. In this study, a total of 75 EbWRKY transcription factors were predicted through comprehensive genome-wide characterization of E. breviscapus and the chromosomal localization of each EbWRKY gene was investigated. RNA sequencing revealed transient responses of 74 predicted EbWRKY genes to exogenous abscisic acid (ABA), salicylic acid (SA), and gibberellin 3 (GA3) after 4 h of treatment. In contrast, the expression of key structural genes involved in flavonoid biosynthesis increased after 4 h in GA3 treatment. However, the content of flavonoid metabolites in leaves significantly increased at 12 h. The qRT-PCR results showed that the expression patterns of EbWRKY11, EbWRKY30, EbWRKY31, EbWRKY36, and EbWRKY44 transcription factors exhibited a high degree of similarity to the 11 structural genes involved in flavonoid biosynthesis. Protein-DNA interactions were performed between the key genes involved in scutellarin biosynthesis and candidate WRKYs. The result showed that F7GAT interacts with EbWRKY11, EbWRKY36, and EbWRKY44, while EbF6H has a self-activation function. This study provides comprehensive information on the regulatory control network of flavonoid accumulation mechanisms, offering valuable insights for breeding E. breviscapus varieties with enhanced scutellarin content.

Transcriptional Control of Seed Life: New Insights into the Role of the NAC Family

Transcription factors (TFs) regulate gene expression by binding to specific sequences on DNA through their DNA-binding domain (DBD), a universal process. This update conveys information about the diverse roles of TFs, focusing on the NACs (NAM-ATAF-CUC), in regulating target-gene expression and influencing various aspects of plant biology. NAC TFs appeared before the emergence of land plants. The NAC family constitutes a diverse group of plant-specific TFs found in mosses, conifers, monocots, and eudicots. This update discusses the evolutionary origins of plant NAC genes/proteins from green algae to their crucial roles in plant development and stress response across various plant species. From mosses and lycophytes to various angiosperms, the number of NAC proteins increases significantly, suggesting a gradual evolution from basal streptophytic green algae. NAC TFs play a critical role in enhancing abiotic stress tolerance, with their function conserved in angiosperms. Furthermore, the modular organization of NACs, their dimeric function, and their localization within cellular compartments contribute to their functional versatility and complexity. While most NAC TFs are nuclear-localized and active, a subset is found in other cellular compartments, indicating inactive forms until specific cues trigger their translocation to the nucleus. Additionally, it highlights their involvement in endoplasmic reticulum (ER) stress-induced programmed cell death (PCD) by activating the vacuolar processing enzyme (VPE) gene. Moreover, this update provides a comprehensive overview of the diverse roles of NAC TFs in plants, including their participation in ER stress responses, leaf senescence (LS), and growth and development. Notably, NACs exhibit correlations with various phytohormones (i.e., ABA, GAs, CK, IAA, JA, and SA), and several NAC genes are inducible by them, influencing a broad spectrum of biological processes. The study of the spatiotemporal expression patterns provides insights into when and where specific NAC genes are active, shedding light on their metabolic contributions. Likewise, this review emphasizes the significance of NAC TFs in transcriptional modules, seed reserve accumulation, and regulation of seed dormancy and germination. Overall, it effectively communicates the intricate and essential functions of NAC TFs in plant biology. Finally, from an evolutionary standpoint, a phylogenetic analysis suggests that it is highly probable that the WRKY family is evolutionarily older than the NAC family.

Identification of WRKY gene family in Dioscorea opposita Thunb. reveals that DoWRKY71 enhanced the tolerance to cold and ABA stress

WRKY transcription factors constitute one of the largest plant-specific gene families, regulating various aspects of plant growth, development, physiological processes, and responses to abiotic stresses. This study aimed to comprehensively analyze the WRKY gene family of yam (Dioscorea opposita Thunb.), to understand their expression patterns during the growth and development process and their response to different treatments of yam and analyze the function of DoWRKY71 in detail. A total of 25 DoWRKY genes were identified from the transcriptome of yam, which were divided into six clades (I, IIa, IIc, IId, IIe, III) based on phylogenetic analysis. The analysis of conserved motifs revealed 10 motifs, varying in length from 16 to 50 amino acids. Based on real-time quantitative PCR (qRT-PCR) analysis, DoWRKY genes were expressed at different stages of growth and development and responded differentially to various abiotic stresses. The expression level of DoWRKY71 genes was up-regulated in the early stage and then down-regulated in tuber enlargement. This gene showed responsiveness to cold and abiotic stresses, such as abscisic acid (ABA) and methyl jasmonate (MeJA). Therefore, further study was conducted on this gene. Subcellular localization analysis revealed that the DoWRKY71 protein was localized in the nucleus. Moreover, the overexpression of DoWRKY71 enhanced the cold tolerance of transgenic tobacco and promoted ABA mediated stomatal closure. This study presents the first systematic analysis of the WRKY gene family in yam, offering new insights for studying WRKY transcription factors in yam. The functional study of DoWRKY71 lays theoretical foundation for further exploring the regulatory function of the DoWRKY71 gene in the growth and development related signaling pathway of yam.

Genome-wide identification of WRKY transcription factor family members in Miscanthus sinensis (Miscanthus sinensis Anderss)

Miscanthus is an emerging sustainable bioenergy crop whose growing environment is subject to many abiotic and biological stresses. WRKY transcription factors play an important role in stress response and growth of biotic and abiotic. To clarify the distribution and expression of the WRKY genes in Miscanthus, it is necessary to classify and phylogenetically analyze the WRKY genes in Miscanthus. The v7.1 genome assembly of Miscanthus was analyzed by constructing an evolutionary tree. In Miscanthus, there are 179 WRKY genes were identified. The 179 MsWRKYs were classified into three groups with conserved gene structure and motif composition. The tissue expression profile of the WRKY genes showed that MsWRKY genes played an essential role in all growth stages of plants. At the early stage of plant development, the MsWRKY gene is mainly expressed in the rhizome of plants. In the middle stage, it is mainly expressed in the leaf. At the end stage, mainly in the stem. According to the results, it showed significant differences in the expression of the MsWRKY in different stages of Miscanthus sinensis. The results of the study contribute to a better understanding of the role of the MsWRKY gene in the growth and development of Miscanthus.

Genome and Transcriptome Analysis of the Torreya grandis WRKY Gene Family during Seed Development

Torreya grandis, an economically significant evergreen tree species exclusive to subtropical China, is highly valued for its seeds. However, the seed development process of T. grandis remains relatively unexplored. Given the pivotal role WRKY transcription factors (TFs) play in coordinating diverse cellular and biological activities, as well as crucial signaling pathways essential for plant growth and development, and the lack of comprehensive investigation into their specific functions in T. grandis, our study investigated its genome and successfully isolated 78 WRKY genes and categorized them into three distinct clades. A conserved motif analysis unveiled the presence of the characteristic WRKY domain in each identified TgWRKY protein. The examination of gene structures revealed variable numbers of introns (ranging from zero to eight) and exons (ranging from one to nine) among TgWRKY genes. A chromosomal distribution analysis demonstrated the presence of TgWRKY across eight chromosomes in T. grandis. Tissue-specific expression profiling unveiled distinctive patterns of these 78 TgWRKY genes across various tissues. Remarkably, a co-expression analysis integrating RNA-seq data and morphological assessments pinpointed the pronounced expression of TgWRKY25 during the developmental stages of T. grandis seeds. Moreover, a KEGG enrichment analysis, focusing on genes correlated with TgWRKY25 expression, suggested its potential involvement in processes such as protein processing in the endoplasmic reticulum, starch, and sucrose metabolism, thereby modulating seed development in T. grandis. These findings not only underscore the pivotal role of WRKY genes in T. grandis seed development but also pave the way for innovative breeding strategies.

Review: Structural-functional relationship of WRKY transcription factors: Unfolding the role of WRKY in plants

WRKY as the name suggests, are the transcription factors (TFs) that contain the signature WRKY domains, hence named after it. Since their discovery in 1994, they have been well studied in plants with exploration of approximately 74 WRKY genes in the model plant, Arabidopsis alone. However, the study of these transcription factors (TFs) is not just limited to model plant now. They have been studied widely in crop plants as well, because of their tremendous contribution in stress as well as in growth and development. Here, in this review, we describe the story of WRKY TFs from their identification to their origin, the binding mechanisms, structure and their contribution in regulating plant development and stress physiology. High throughput transcriptomics-based data also opened a doorway to understand the comprehensive and detailed functioning of WRKY TFs in plants. Indeed, the detailed functional role of each and every WRKY member in regulating the gene expression is required to pave the path to develop holistic understanding of their role in stress physiology and developmental processes in plants.

Transcriptional regulation of tomato fruit ripening

An intrinsic and genetically determined ripening program of tomato fruits often depends upon the appropriate activation of tissue- and stage-specific transcription factors in space and time. The past two decades have yielded considerable progress in detailing these complex transcriptional as well as hormonal regulatory circuits paramount to fleshy fruit ripening. This non-linear ripening process is strongly controlled by the MADS-box and NOR family of proteins, triggering a transcriptional response associated with the progression of fruit ripening. Deepening insights into the connection between MADS-RIN and plant hormones related transcription factors, such as ERFs and ARFs, further conjugates the idea that several signaling units work in parallel to define an output fruit ripening transcriptome. Besides these TFs, the role of other families of transcription factors such as MYB, GLK, WRKY, GRAS and bHLH have also emerged as important ripening regulators. Other regulators such as EIN and EIL proteins also determine the transcriptional landscape of ripening fruits. Despite the abundant knowledge of the complex spectrum of ripening networks in the scientific domain, identifying more ripening effectors would pave the way for a better understanding of fleshy fruit ripening at the molecular level. This review provides an update on the transcriptional regulators of tomato fruit ripening.

Genomic characterization of WRKY transcription factors related to secoiridoid biosynthesis in Gentiana macrophylla

Gentiana macrophylla is one of Chinese herbal medicines in which 4 kinds of iridoids or secoiridoids, such as loganic acid, sweroside, swertiamarin, and gentiopicroside, are identified as the dominant medicinal secondary metabolites. WRKY, as a large family of transcription factors (TFs), plays an important role in the synthesis of secondary metabolites in plants. Therefore, WRKY genes involved in the biosynthesis of secoiridoids in G. macrophylla were systematically studied. First, a comprehensive genome-wide analysis was performed, and 42 GmWRKY genes were identified, which were unevenly distributed in 12 chromosomes. Accordingly, gene structure, collinearity, sequence alignment, phylogenetic, conserved motif and promoter analyses were performed, and the GmWRKY proteins were divided into three subfamilies based on phylogenetic and multiple sequence alignment analyses. Moreover, the enzyme-encoding genes of the secoiridoid biosynthesis pathway and their promoters were then analysed, and the contents of the four secoiridoids were determined in different tissues. Accordingly, correlation analysis was performed using Pearson's correlation coefficient to construct WRKY gene-enzyme-encoding genes and WRKY gene-metabolite networks. Meanwhile, G. macrophylla seedlings were treated with methyl jasmonate (MeJA) to detect the dynamic change trend of GmWRKYs, biosynthetic genes, and medicinal ingredient accumulation. Thus, a total of 12 GmWRKYs were identified to be involved in the biosynthesis of secoiridoids, of which 8 (GmWRKY1, 6, 12, 17, 33, 34, 38 and 39) were found to regulate the synthesis of gentiopicroside, and 4 (GmWRKY7, 14, 26 and 41) were found to regulate the synthesis of loganic acid. Taken together, this study systematically identified WRKY transcription factors related to the biosynthesis of secoiridoids in G. macrophylla, which could be used as a cue for further investigation of WRKY gene functions in secondary metabolite accumulation.

MdVQ12 confers resistance to Valsa mali by regulating MdHDA19 expression in apple

Valine-glutamine (VQ) motif-containing proteins play a crucial role in plant biotic stress responses. Apple Valsa canker, caused by the ascomycete Valsa mali, stands as one of the most severe diseases affecting apple trees. Nonetheless, the underlying resistance mechanism of VQ proteins against this disease has remained largely unexplored. This study reports MdVQ12, a VQ motif-containing protein, as a positive regulator of apple Valsa canker resistance. Genetic transformation experiments demonstrated that MdVQ12 overexpression increased resistance to V. mali, while gene silencing lines exhibited significantly reduced resistance. MdVQ12 interacted with the transcription factor MdWRKY23, which bound to the promoter of the histone deacetylase gene MdHDA19, activating its expression. MdHDA19 enhanced apple resistance to V. mali by participating in the jasmonic acid (JA) and ethylene (ET) signalling pathways. Additionally, MdVQ12 promoted the transcriptional activity of MdWRKY23 towards MdHDA19. Our findings reveal that MdVQ12 enhances apple resistance to V. mali by regulating MdHDA19 expression and thereby regulating the JA and ET signalling pathways, offering potential candidate gene resources for breeding apple Valsa canker-resistant germplasm.

Multifaceted roles of WRKY transcription factors in abiotic stress and flavonoid biosynthesis

Increasing biotic and abiotic stresses are seriously impeding the growth and yield of staple crops and threatening global food security. As one of the largest classes of regulators in vascular plants, WRKY transcription factors play critical roles governing flavonoid biosynthesis during stress responses. By binding major W-box cis-elements (TGACCA/T) in target promoters, WRKYs modulate diverse signaling pathways. In this review, we optimized existing WRKY phylogenetic trees by incorporating additional plant species with WRKY proteins implicated in stress tolerance and flavonoid regulation. Based on the improved frameworks and documented results, we aim to deduce unifying themes of distinct WRKY subfamilies governing specific stress responses and flavonoid metabolism. These analyses will generate experimentally testable hypotheses regarding the putative functions of uncharacterized WRKY homologs in tuning flavonoid accumulation to enhance stress resilience.

Genome-wide identification and expression analysis of WRKY gene family members in red clover (Trifolium pratense L.)

Trifolium pratense is an important legume forage grass and a key component of sustainable livestock development. Serving as an essential component, the WRKY gene family, a crucial group of regulatory transcription factors in plants, holds significant importance in their response to abiotic stresses. However, there has been no systematic analysis conducted on the WRKY gene family in Trifolium pratense. This study conducted a comprehensive genomic characterization of the WRKY gene family in Trifolium pratense, utilizing the latest genomic data, resulting in the identification of 59 TpWRKY genes. Based on their structural features, phylogenetic characteristics, and conserved motif composition, the WRKY proteins were classified into three groups, with group II further subdivided into five subgroups (II-a, II-b, II-c, II-d, and II-e). The majority of the TpWRKYs in a group share a similar structure and motif composition. Intra-group syntenic analysis revealed eight pairs of duplicate segments. The expression patterns of 59 TpWRKY genes in roots, stems, leaves, and flowers were examined by analyzing RNA-seq data. The expression of 12 TpWRKY genes under drought, low-temperature (4°C), methyl jasmonate (MeJA) and abscisic acid (ABA) stresses was analyzed by RT-qPCR. The findings indicated that TpWRKY46 was highly induced by drought stress, and TpWRKY26 and TpWRKY41 were significantly induced by low temperature stress. In addition, TpWRKY29 and TpWRKY36 were greatly induced by MeJA stress treatment, and TpWRKY17 was significantly upregulated by ABA stress treatment. In this research, we identified and comprehensively analyzed the structural features of the WRKY gene family in T.pratense, along with determined the possible roles of WRKY candidate genes in abiotic stress. These discoveries deepen our understandings of how WRKY transcription factors contribute to species evolution and functional divergence, laying a solid molecular foundation for future exploration and study of stress resistance mechanisms in T.pratense.

Review: Defense responses in sweetpotato (Ipomoea batatas L.) against biotic stress

Sweetpotato (Ipomoea batatas L.) is regarded as amongst the world's most important crops for food, vegetable, forage, and raw material for starch and alcohol production. Since pest attack and disease infection are the main limiting aspects frequently causing the yield loss and quality degradation of sweetpotato, it is a great demand to develop the effective defense strategies for maintaining productivity. In the past decade, many studies have focused on dynamic analysis at the physiological, biochemical, and molecular responses of sweetpotatoes to environmental challenges. This review offers an overview of the defense mechanisms against biotic stresses in sweetpotato observed so far, particularly insect herbivory and pathogen infections. The defenses of sweetpotato include the regulation of the toxic and anti-digestive proteins, plant-derived compounds, physical barrier formation, and sugar distribution. Ipomoelin and sporamin have been extensively researched for the defense against herbivore wounding. Herbivory-induced plant volatiles, chlorogenic acid, and latex phytochemicals play important roles in defenses for insect herbivory. Induction of IbSWEET10 reduces sugar content to mediate F. oxysporum resistance. Therefore, these researches provide the genetic strategies for improving resistance bioengineering and breeding of sweetpotato crops and future prospects for research in this field.

Wheat WRKY transcription factor TaWRKY24 confers drought and salt tolerance in transgenic plants

Drought and salt stress are major environmental conditions that severely limit plant growth and productivity. WRKY transcription factors play a vital role in the responses against biotic or abiotic stress. In this study, TaWRKY24, a gene of the IIe WRKY family identified in wheat, was cloned and characterized. TaWRKY24 was mainly expressed in wheat leaf and stem and induced by treatment with PEG6000, salt, H2O2, ABA, MeJA, and ethrel. TaWRKY24 transient expression in onion epidermal cells suggested its nuclear localization and its transcriptional activation capability characteristics. Overexpression of TaWRKY24 in tobacco improved the seed germination rate and root growth of seedlings in transgenic lines when subjected to higher mannitol and NaCl concentrations. Further research showed that transgenic lines had higher proline and soluble sugars and lower levels of reactive oxygen species (ROS) and malondialdehyde (MDA). Moreover, compared to normal and negative control plants, TaWRKY24 silenced wheat seedlings had reduced growth under salt and drought stress. This study shows that wheat TaWRKY24 is crucial to plant stress, providing an excellent candidate gene for wheat resistance breeding.

Lupenone, a wonder chemical obtained from Euphorbia segetalis to boost affinity for the transcriptional factor escalating drought-tolerance in Solanum Lycopersicum: A cutting-edge computational biology approach

Drought is the single greatest abiotic factor influencing crop yield worldwide. Plants remain in one area for extended periods, making them vulnerable to natural and man-made influences. Understanding plant drought responses will help us develop strategies for breeding drought-resistant crops. Large proteome analysis revealed that leaf and root tissue proteins respond to drought differently depending on the plant's genotype. Commonly known as tomatoes, Solanum Lycopersicum is a globally important vegetable crop. However, drought stress is one of the most significant obstacles to tomato production, making the development of cultivars adapted to dry conditions an essential goal of agricultural biotechnology. Breeders have put quite a lot of time and effort into the tomato to increase its productivity, adaptability, and resistance to biotic and abiotic challenges. However, conventional tomato breeding has only improved drought resistance due to the complexity of drought traits. The resilience of tomatoes under drought stress has been the subject of extensive study. Using contemporary sequencing approaches like genomics, transcriptomics, proteomics, and metabolomics has dramatically aided in discovering drought-responsive genes. One of the most prominent families of plant transcription factors, WRKY genes, plays a crucial role in plant growth and development in response to natural and abiotic stimuli. To develop plants that can withstand both biotic and abiotic stress, understanding the relationships between WRKY-proteins (transcription factors) and other proteins and ligands in plant cells is essential. This is despite the fact that tomatoes have a long history of domestication. This research aims to utilize Lupenone, a hormone produced in plant roots in response to stress, to increase drought resistance in plants. Lupenone exhibits a strong affinity for the WRKY protein at -9.64 kcal/mol. Molecular docking and modeling studies show that these polyphenols have a significant role in making Solanum Lycopersicum drought-resistant and improving the quality of its fruit. As a result of climate change, droughts are occurring more frequently and persisting for more extended periods, making it necessary to breed crops resistant to drought. While considerable variability for tolerance exists in wild cousins, little is known about the processes and essential genes influencing drought tolerance in cultivated tomato species.

Full-Length Transcriptome Sequencing Analysis and Characterization of WRKY Transcription Factors Responsive to Cadmium Stress in Arabis paniculata

Arabis paniculata is a newly discovered hyperaccumulator known for its ability to accumulate multiple metals. WRKY proteins play a significant role in plant responses to various stresses, including cadmium (Cd) stress. However, there is limited research on the molecular biology of Arabis paniculata, especially regarding the WRKY family. In this study, we conducted third-generation sequencing for functional annotation and structural analysis of Arabis paniculata. We obtained 41,196 high-quality isoforms from the full-length transcriptome, with an average length of 1043 bp. A total of 26,670 genes were predicted against NR, Swissprot, KOG, and KEGG databases. Functional comparison using the KOG database revealed excellent annotation in 25 functional categories, with general function prediction (1822 items) being the most predominant. MISA analysis identified 12,593 SSR loci, with single nucleotide repeats being the largest category (44.83% of the total). Moreover, our predictions provide insights into 20,022 coding sequences (CDS), 811 transcription factors, and 17,963 LncRNAs. In total, 34 WRKY gene sequences were identified in Arabis paniculata. Bioinformatics analysis revealed diverse numbers of amino acids in these WRKYs (113 to 545 aa), and a conserved WRKYGQK sequence within the N-terminus of the WRKY protein. Furthermore, all WRKYs were found to be localized in the nucleus. Phylogenetic analysis classified the WRKY genes into three categories: I (14 members), II (17 members), and III (3 members). Category II was subsequently divided into four sub-categories: II-a (8 members), II-b (1 member), II-c (1 member), and II-d (7 members). Our quantitative real-time polymerase chain reaction (qRT-PCR) experiments revealed that ApWRKY23 and ApWRKY34 exhibited the highest expression levels at the 24-h time point, suggesting their potential role as the candidate genes for Cd stress response. These findings contribute to our understanding of the genomic information of Arabis paniculata and provide a basis for the analysis of its genetic diversity. Additionally, this study paves the way for a comprehensive exploration of the molecular mechanisms underlying the WRKY genes in Arabis paniculata under Cd stress conditions.

AnWRKY29 from the desert xerophytic evergreen Ammopiptanthus nanus improves drought tolerance through osmoregulation in transgenic plants

As a significant transcription factor family in plants, WRKYs have a crucial role in responding to different adverse environments. They have been repeatedly demonstrated to contribute to drought resistance. However, no systematic exploration of the WRKY family has been reported in the evergreen shrub Ammopiptanthus nanus under drought conditions. Here, we showed that AnWRKY29 expression is strongly induced under drought stress. AnWRKY29 belongs to the group IIe of WRKY gene family. To characterize the function of AnWRKY29, we generated transgenic plants overexpressing this gene in Arabidopsis thaliana. We determined that AnWRKY29 overexpression of mainly improves the drought resistance of transgenic plants to water stress by reducing water loss, preventing electrolyte leakage, and increasing the absorption of inorganic ions. In addition, the AnWRKY29 transgenic plants synthesized more trehalose under water stress. The overexpression of AnWRKY29 also enhanced the antioxidant and osmoregulation capacity of transgenic plants by increasing the activities of catalase, peroxidase and superoxide dismutase, thus increasing the scavenging of reactive oxygen species and propylene glycol synthesis aldehyde oxidase. In summary, our study shows that AnWRKY29 plays an important role in the drought tolerance pathway in plants.

Genome-Wide Identification and Characterization of WRKY Transcription Factors in Betula platyphylla Suk. and Their Responses to Abiotic Stresses

The WRKY transcription factor (TF) family is one the largest plant-specific transcription factor families. It has been proven to play significant roles in multiple plant biological processes, especially stress response. Although many WRKY TFs have been identified in various plant species, WRKYs in white birch (Betula platyphylla Suk.) remain to be studied. Here, we identified a total of 68 BpWRKYs, which could be classified into four main groups. The basic physiochemical properties of these TFs were analyzed using bioinformatics tools, including molecular weight, isoelectric point, chromosome location, and predicted subcellular localization. Most BpWRKYs were predicted to be located in the nucleus. Synteny analysis found 17 syntenic gene pairs among BpWRKYs and 52 syntenic gene pairs between BpWRKYs and AtWRKYs. The cis-acting elements in the promoters of BpWRKYs could be enriched in multiple plant biological processes, including stress response, hormone response, growth and development, and binding sites. Tissue-specific expression analysis using qRT-PCR showed that most BpWRKYs exhibited highest expression levels in the root. After ABA, salt (NaCl), or cold treatment, different BpWRKYs showed different expression patterns at different treatment times. Furthermore, the results of the Y2H assay proved the interaction between BpWRKY17 and a cold-responsive TF, BpCBF7. By transient expression assay, BpWRKY17 and BpWRKY67 were localized in the nucleus, consistent with the previous prediction. Our study hopes to shed light for research on WRKY TFs and plant stress response.

Genome-wide identification and comprehensive analysis of WRKY transcription factor family in safflower during drought stress

The WRKY family is an important family of transcription factors in plant development and stress response. Currently, there are few reports on the WRKY gene family in safflower (Carthamus tinctorius L.). In this study, a total of 82 CtWRKY genes were identified from the safflower genome and could be classified into 3 major groups and 5 subgroups based on their structural and phylogenetic characteristics. The results of gene structure, conserved domain and motif analyses indicated that CtWRKYs within the same subfamily maintained a consistent exon/intron organization and composition. Chromosomal localization and gene duplication analysis results showed that CtWRKYs were randomly localized on 12 chromosomes and that fragment duplication and purification selection may have played an important role in the evolution of the WRKY gene family in safflower. Promoter cis-acting element analysis revealed that the CtWRKYs contain many abiotic stress response elements and hormone response elements. Transcriptome data and qRT-PCR analyses revealed that the expression of CtWRKYs showed tissue specificity and a strong response to drought stress. Notably, the expression level of the CtWRKY55 gene rapidly increased more than eightfold under drought treatment and rehydration, indicating that it may be a key gene in response to drought stress. These results provide useful insights for investigating the regulatory function of the CtWRKY gene in safflower growth and development, as well as identifying key genes for future molecular breeding programmes.

Genome-Wide Identification and Analysis of WRKY Gene Family in Melastoma dodecandrum

WRKY is one of the largest transcription factor families in plants and plays an important role in plant growth and development as well as in abiotic and biological stresses. However, there is little information about the WRKY family in Melastoma dodecandrum. In this study, 126 WRKY members were identified in M. dodecandrum. According to phylogenetic analysis, they were divided into three major groups, and group II was further divided into five subgroups. MedWRKY genes were unevenly distributed on 12 chromosomes. Additionally, the gene structure and sequence composition were similar within the same group and differed between groups, suggesting their functional diversity. The promoter sequence analysis identified a number of cis-acting elements related to plant growth and development, stress response, and secondary metabolite synthesis in the WRKY gene family. The collinearity analysis showed that gene replication events were the main driving force of MedWRKY gene evolution. The transcriptome data and RT-qPCR analysis suggested that MedWRKY genes had higher expression in the roots and ripe fruit of M. dodecandrum. In short, this paper lays a foundation for further study of the functions and molecular mechanism of M. dodecandrum WRKY gene family.

Plant salinity stress, sensing, and its mitigation through WRKY

Salinity or salt stress has deleterious effects on plant growth and development. It imposes osmotic, ionic, and secondary stresses, including oxidative stress on the plants and is responsible for the reduction of overall crop productivity and therefore challenges global food security. Plants respond to salinity, by triggering homoeostatic mechanisms that counter salt-triggered disturbances in the physiology and biochemistry of plants. This involves the activation of many signaling components such as SOS pathway, ABA pathway, and ROS and osmotic stress signaling. These biochemical responses are accompanied by transcriptional modulation of stress-responsive genes, which is mostly mediated by salt-induced transcription factor (TF) activity. Among the TFs, the multifaceted significance of WRKY proteins has been realized in many diverse avenues of plants' life including regulation of plant stress response. Therefore, in this review, we aimed to highlight the significance of salinity in a global perspective, the mechanism of salt sensing in plants, and the contribution of WRKYs in the modulation of plants' response to salinity stress. This review will be a substantial tool to investigate this problem in different perspectives, targeting WRKY and offering directions to better manage salinity stress in the field to ensure food security.

Gene Expression and Interaction Analysis of FsWRKY4 and FsMAPK3 in Forsythia suspensa

Forsythia suspensa is a deciduous shrub that belongs to the family Myrtaceae, and its dried fruits are used as medicine. F. suspensa contains several secondary metabolites, which exert pharmacological effects. One of the main active components is forsythin, which exhibits free radical scavenging, antioxidant, anti-inflammatory, and anti-cancer effects. Mitogen-activated protein kinase (MAPKs) can increase the activity of WRKY family transcription factors in a phosphorylated manner, thereby increasing the content of secondary metabolites. However, the mechanism of interaction between MAPKs and WRKYs in F. suspensa remains unclear. In this study, we cloned the genes of FsWRKY4 and FsMAPK3, and performed a bioinformatics analysis. The expression patterns of FsWRKY4 and FsMAPK3 were analyzed in the different developmental stages of leaf and fruit from F. suspensa using real-time fluorescence quantitative PCR (qRT-PCR). Subcellular localization analysis of FsWRKY4 and FsMAPK3 proteins was performed using a laser scanning confocal microscope. The existence of interactions between FsWRKY4 and FsMPAK3 in vitro was verified by yeast two-hybridization. Results showed that the cDNA of FsWRKY4 (GenBank number: OR566682) and FsMAPK3 (GenBank number: OR566683) were 1587 and 522 bp, respectively. The expression of FsWRKY4 was higher in the leaves than in fruits, and the expression of FsMAPK3 was higher in fruits but lower in leaves. The subcellular localization results indicated that FsWRKY4 was localized in the nucleus and FsMAPK3 in the cytoplasm and nucleus. The prey vector pGADT7-FsWRKY4 and bait vector pGBKT7-FsMAPK3 were constructed and co-transferred into Y2H Glod yeast receptor cells. The results indicated that FsWRKY4 and FsMAPK3 proteins interact with each other in vitro. The preliminary study may provide a basis for more precise elucidation of the synthesis of secondary metabolites in F. suspensa.

Binding of stress-responsive OsWRKY proteins through WRKYGQK heptapeptide residue with the promoter region of two rice blast disease resistance genes Pi2 and Pi54 is important for development of blast resistance

Molecular docking was done to investigate the interactions between five differentially expressed rice WRKY proteins when challenged with the rice blast disease caused by Magnaporthe oryzae and drought stresses applied either individually or overlapped, with the promoter region of two blast resistance genes (Pi2 and Pi54). Molecular docking was performed using the HDOCK server. Initially, the homology models for each of the five rice WRKY proteins were prepared using I-TASSER server, and then the secondary structure as well as the DNA-binding pockets were predicted using PSIPRED and BindUP servers, respectively. The molecular docking study revealed a differential binding pattern of the rice WRKYs with the two blast resistance genes. The WRKY proteins (OsWRKY88 and OsWRKY102), whose transcript levels decrease when drought and blast stresses are overlapped, interact with the two resistance genes mostly involving the residues of the zinc finger structure. On the other hand, the WRKY proteins (OsWRKY53-1 and OsWRKY113), whose transcript levels did not reduce significantly when challenged by drought and blast overlapped condition compared to individual treatment of blast, interact mostly involving the residues of the conserved WRKYGQK heptapeptide sequence. Interestingly, the protein OsWRKY74 whose transcript levels are unaffected in both individual and overlapped stresses, interacts with both the blast resistance genes involving few residues of both WRKYGQK heptapeptide and the zinc finger structure. The findings thus indicate that the interaction of OsWRKY proteins involving the conserved WRKYGQK heptapeptide sequence with the blast resistance genes Pi2 and Pi54 is important to mitigate the blast challenge in rice even during overlapping challenges of drought.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-023-03711-y.