The Role of ERF114 in Modulating Plant Immunity and Enhancing Disease Resistance
Abstract
ERF114, a member of the APETALA2/ethylene-responsive factor (AP2/ERF) family, plays a critical role in plant immunity, particularly in response to fungal pathogen effectors like PevD1 from Verticillium dahliae. This transcription factor modulates key defense pathways, such as the phenylpropanoid pathway, which leads to the production of lignin and salicylic acid (SA), both essential for enhancing plant resistance. ERF114 directly activates the PAL1 gene, increasing lignin and SA accumulation, which strengthens plant cell walls and amplifies systemic acquired resistance (SAR). Furthermore, ERF114 mediates effector-triggered immunity (ETI), enhancing the plant’s defense against a broad spectrum of pathogens. Overexpression of ERF114 enhances disease resistance, while its loss results in increased susceptibility, making ERF114 a promising target for genetic engineering to develop disease-resistant crops. This research highlights ERF114’s significant potential in agricultural applications for improved plant defense strategies.
Introduction to the Role of ERF114 in Plant Immunity
Plants have developed sophisticated response mechanisms under pathogen infection. Generally, there are two layers of innate immunity against invading pathogens in plants: pathogenassociated molecular pattern (PAMP)-triggered immunity (PTI) and effector-triggered immunity (ETI) ; . PAMPs are recognized by pattern recognition receptors (PRRs) located on the plant surface, resulting in the plant immune system PTI. ETI is elicited by recognition of pathogen-derived effectors via intra cellular nucleotide-binding domain leucine-rich repeat-containing receptors (NLRs). PTI and ETI are associated with various plant immunity responses, including the hypersensitive response (HR), reactive oxygen species (ROS) production, and the expression of various defence-related genes such as pathogenesis-related (PR) genes and transcription factors (TFs) . During the plant defence response, the phenylpropanoid pathway plays an important role in preventing pathogen infection. The phenylpropanoid metabolic pathway positively regulates plant basal immunity to viruses, bacteria, and fungi. Phenylalanine ammonialyase 1 (PAL1) is involved in the biosynthesis of multiple secondary metabolites, including lignin and salicylic acid (SA) in plants . Lignin as a defensive substance can limit the pathogen infection, therefore plant lignin accumulation can be used as a marker of the plant immune response. ERF114 is part of the large AP2/ERF family of transcription factors, which is well-known for its role in mediating plant responses to various biotic and abiotic stresses, including pathogen infection, drought, and extreme temperatures. The AP2/ERF transcription factors play a central role in regulating the expression of defense-related genes by binding to specific DNA sequences in their promoter regions, allowing them to modulate immune responses to a wide range of environmental stressors. Recent research has identified ERF114 as a critical modulator of plant immunity, particularly in the context of fungal infections. Studies have demonstrated that ERF114 plays a central role in mediating defense responses triggered by the fungal pathogen Verticillium dahliae and its effector PevD1. PevD1 is known to induce disease resistance in various plants by enhancing the plant’s immune system, including the production of reactive oxygen species (ROS) and the expression of pathogenesis-related (PR) genes such as PR1 and PR5. These immune responses are essential for limiting pathogen spread and damage to plant tissues. In Arabidopsis thaliana, ERF114 is strongly induced by PevD1, and its activation leads to enhanced disease resistance against bacterial pathogens like Pseudomonas syringae. When ERF114 is overexpressed, the plants show increased resistance to infection, while mutants lacking ERF114 exhibit reduced immunity. This suggests that ERF114 plays a crucial role in the defense signaling pathway, acting as a positive regulator of plant immune responses. One of the key pathways regulated by ERF114 is the phenylpropanoid pathway, which is essential for the production of secondary metabolites like lignin and salicylic acid (SA). These compounds play critical roles in strengthening plant cell walls and enhancing the plant’s defense mechanisms. Lignin accumulation, in particular, serves as a physical barrier that limits pathogen penetration and spread. ERF114 has been shown to bind directly to the promoter of the PAL1 gene, which encodes phenylalanine ammonia-lyase, a key enzyme in the phenylpropanoid pathway. This binding enhances the transcription of PAL1, leading to increased production of lignin and SA, both of which are vital for plant defense.
Overall, ERF114 is emerging as a critical transcription factor in the regulation of plant immunity. Its role in modulating the phenylpropanoid pathway and enhancing lignin and SA accumulation highlights its importance in the broader context of plant defense. Understanding the molecular mechanisms through which ERF114 operates could provide valuable insights into improving disease resistance in crops through genetic engineering or selective breeding, potentially offering a sustainable solution to agricultural challenges posed by plant pathogens.
The Mechanism of PevD1-Induced Disease Resistance
PevD1 is a fungal effector protein secreted by Verticillium dahliae, a plant pathogen known to cause wilt diseases in a wide range of crops. Effector proteins like PevD1 are critical components of the pathogen’s strategy to colonize host plants by manipulating their immune responses. However, PevD1 also triggers immune reactions that lead to enhanced disease resistance in plants. This dual role makes it a fascinating subject of study in plant-pathogen interactions. PevD1-induced disease resistance has been observed in various plants, including Arabidopsis thaliana, cotton, and tobacco. When PevD1 infiltrates plant tissues, it activates a series of defense responses that limit pathogen growth and enhance the plant's resistance to subsequent infections. One of the earliest responses to PevD1 is the production of reactive oxygen species (ROS), which act as signaling molecules in plant defense and contribute to localized cell death, a phenomenon known as the hypersensitive response (HR). HR serves to restrict the spread of the pathogen by killing infected cells. In addition to ROS production, PevD1 triggers the expression of defense-related genes such as PR1 and PR5, which are commonly associated with systemic acquired resistance (SAR). SAR is a plant-wide immune response that provides long-lasting protection against a broad spectrum of pathogens. Moreover, PevD1 promotes the activation of the phenylpropanoid pathway, which leads to the accumulation of lignin. Lignin is a structural compound that fortifies plant cell walls, making it more difficult for pathogens to penetrate. The ethylene-responsive factor ERF114 plays a pivotal role in mediating PevD1-induced resistance by directly binding to the promoters of genes involved in lignin biosynthesis, such as PAL1. This transcriptional regulation ensures a robust defense response, including the enhanced production of salicylic acid (SA), a key hormone in plant immunity. Through these mechanisms, PevD1 contributes to the strengthening of the plant’s immune defenses, providing protection against fungal and bacterial pathogens.Key Findings on ERF114's Role in Modulating Plant Defense
ERF114 is a member of the APETALA2/ethylene-responsive factor (AP2/ERF) family, which plays a critical role in regulating plant responses to various environmental stresses, including pathogen attacks. Recent studies have shed light on how ERF114 modulates plant defense, particularly in response to fungal pathogen effectors like PevD1, secreted by Verticillium dahliae. These findings have positioned ERF114 as a key transcription factor in enhancing plant immunity. One of the primary findings is that ERF114 positively regulates the plant defense response by modulating the phenylpropanoid pathway. This pathway is essential for the production of lignin and salicylic acid (SA), two critical components in plant immunity. Lignin fortifies the cell walls, making it harder for pathogens to invade, while SA acts as a signaling molecule that triggers systemic acquired resistance (SAR). ERF114 enhances the transcription of PAL1, a gene that encodes phenylalanine ammonia-lyase, a key enzyme in the phenylpropanoid pathway. By binding to the promoter region of PAL1, ERF114 directly increases the production of lignin and SA, which are pivotal in plant defense against pathogens. Another key finding is that the overexpression of ERF114 leads to enhanced disease resistance in Arabidopsis thaliana. Plants that overexpress ERF114 show increased resistance to bacterial pathogens such as Pseudomonas syringae, while loss-of-function mutants exhibit greater susceptibility. This demonstrates that ERF114 acts as a positive regulator of plant immune responses. Additionally, studies have revealed that ERF114 mediates PevD1-induced defense responses. When plants are exposed to PevD1, ERF114 is activated, leading to the upregulation of defense genes such as PR1 and PR5. These genes are associated with the hypersensitive response (HR) and ROS production, both of which are critical for limiting pathogen spread. In conclusion, ERF114 plays a pivotal role in modulating plant defense by regulating the phenylpropanoid pathway, enhancing lignin and SA production, and mediating responses to pathogen effectors. These findings highlight the potential of ERF114 in developing disease-resistant crops through genetic engineering.ERF114's Role in Regulating Plant Defense
ERF114, a member of the APETALA2/ethylene-responsive factor (AP2/ERF) family, plays a significant role in regulating plant defense mechanisms, particularly in response to pathogen attacks. Recent studies have demonstrated that ERF114 is a key player in plant immunity by modulating the phenylpropanoid pathway, which is crucial for the production of lignin and salicylic acid (SA), both essential components in plant defense. Lignin is a critical structural polymer that fortifies the plant cell walls, creating a physical barrier against pathogen invasion. The phenylpropanoid pathway, regulated by ERF114, is responsible for the biosynthesis of lignin, making it harder for pathogens to penetrate plant tissues. Studies have shown that ERF114 directly binds to the promoter region of the PAL1 gene, which encodes phenylalanine ammonia-lyase, the enzyme responsible for initiating the phenylpropanoid pathway. This binding enhances the transcription of PAL1, leading to increased lignin accumulation, which is essential for plant resistance to pathogens. In addition to lignin production, ERF114 also regulates the synthesis of salicylic acid (SA), a phytohormone involved in systemic acquired resistance (SAR). SA acts as a signaling molecule, activating defense responses throughout the plant. ERF114’s role in SA accumulation further strengthens plant immunity by enhancing both local and systemic defenses against pathogen attacks. One of the most important findings regarding ERF114’s function is its involvement in effector-triggered immunity (ETI), particularly in response to the fungal pathogen Verticillium dahliae and its effector PevD1. PevD1 activates ERF114, leading to the upregulation of defense-related genes such as PR1 and PR5, which are associated with pathogen resistance. Overexpression of ERF114 enhances plant resistance to pathogens, while loss of function mutants exhibit increased susceptibility, demonstrating that ERF114 is a positive regulator of plant immune responses. In conclusion, ERF114 plays a central role in regulating plant defense by modulating the phenylpropanoid pathway, enhancing lignin and SA production, and activating defense-related genes in response to pathogen effectors. These findings make ERF114 a promising target for developing disease-resistant crops through genetic engineering.Conclusion
The role of ERF114 in plant defense represents a significant advancement in our understanding of plant immunity, particularly in response to fungal pathogens like Verticillium dahliae. ERF114, a member of the APETALA2/ethylene-responsive factor (AP2/ERF) family, has been shown to be a critical regulator of the phenylpropanoid pathway, which is essential for producing compounds such as lignin and salicylic acid (SA). Both lignin and SA play crucial roles in enhancing plant resistance to pathogens, with lignin reinforcing plant cell walls and SA acting as a key signaling molecule in systemic acquired resistance (SAR). Through its ability to bind to the promoter region of the PAL1 gene, ERF114 activates the transcription of phenylalanine ammonia-lyase (PAL), leading to the enhanced production of lignin and other phenylpropanoid compounds. This increase in lignin production provides a physical barrier to pathogen invasion, while the accumulation of SA amplifies the plant's immune response, further boosting both local and systemic defenses. Moreover, ERF114 is instrumental in mediating effector-triggered immunity (ETI), particularly in response to the fungal effector PevD1. This highlights its dual role in both local defense at the site of infection and in broader systemic immune responses. Plants that overexpress ERF114 exhibit enhanced resistance to bacterial and fungal pathogens, while ERF114 mutants display increased susceptibility, underscoring its importance in plant immunity. The discovery of ERF114’s role in regulating plant defense responses opens up new possibilities for agricultural applications. By targeting this transcription factor, it may be possible to develop crops with enhanced disease resistance through genetic engineering or selective breeding. This could lead to more resilient crop varieties, reducing the need for chemical pesticides and contributing to more sustainable farming practices. In conclusion, ERF114 is a crucial transcription factor in plant defense, regulating key pathways that enhance resistance to pathogens. Its role in modulating both local and systemic immune responses makes it a promising target for future research and agricultural innovation.References
- Bu, B., Qiu, D., Zeng, H., Guo, L., Yuan, J., & Yang, X. (2014). A fungal protein elicitor PevD1 induces Verticillium wilt resistance in cotton. Plant Cell Reports, 33(3), 461–470.
- Chen, Z., Zheng, Z., Huang, J., Lai, Z., & Fan, B. (2009). Biosynthesis of salicylic acid in plants. Plant Signaling & Behavior, 4(6), 493–496.
- Li, Z., Zhang, Y., Ren, J., Jia, F., Zeng, H., & Li, G. (2022). Ethylene-responsive factor ERF114 mediates fungal pathogen effector PevD1-induced disease resistance in Arabidopsis thaliana. Molecular Plant Pathology, 23(6), 819-831.
- Liu, Q., Luo, L., & Zheng, L. (2018). Lignins: Biosynthesis and biological functions in plants. International Journal of Molecular Sciences, 19(2), 335.
- Schwessinger, B., & Ronald, P. C. (2012). Plant innate immunity: Perception of conserved microbial signatures. Annual Review of Plant Biology, 63(1), 451–482.
- Yadav, V., Wang, Z., Wei, C., Amo, A., Ahmed, B., Yang, X., & Zhang, X. (2020). Phenylpropanoid pathway engineering: An emerging approach towards plant defense. Pathogens, 9(4), 312.
- Wang, B., Yang, X., Zeng, H., Liu, H., Zhou, T., & Tan, B. (2012). The purification and characterization of a novel hypersensitive-like response-inducing elicitor from Verticillium dahliae that induces resistance responses in tobacco. Applied Microbiology and Biotechnology, 93(1), 191-201.
