Aug 2026· Proceedings of the National Academy of Sciences of the United States of America· Vol 123 34, pp.
e2612340123
· 0 citations· 38 references
Medicine
TL;DR
It is demonstrated that the TaLYK5-TaDSK2a module functions as a molecular switch that dynamically regulates the trade-off between plant immunity and growth.
Abstract
Plants are constantly challenged by pathogenic microorganisms that threaten growth and survival. While the individual signaling pathways involved in these immune responses have been well characterized, how plants balance growth with rapid pathogen perception and immune signal transduction remains largely unclear. Here, we report that the receptor-like kinase TaLYK5 receptor of wheat (Triticum aestivum) recognizes chitin on the fungal pathogen Puccinia striiformis f. sp. tritici (Pst) and initiates a cascade of events that increase immune response while reducing growth. TaLYK5 acts as a positive regulator of defense by phosphorylating the ankyrin-repeat-containing protein TaAKR2A, which supports reactive oxygen species (ROS) production and defense responses. In parallel, activated TaLYK5 negatively regulates growth responses by phosphorylating serine residue S234 in the ubiquitin-binding protein TaDSK2a, blocking its ability to degrade TaLYK5. Without infection by Pst, TaAKR2A does not initiate ROS signaling and immune responses and TaDSK2a associates with polyubiquitin chains on TaLYK5 to mediate its degradation, suppress TaLYK5-mediated plant defense. Meanwhile, TaDSK2a regulates gibberellin (GA) accumulation to promote plant growth, possibly by accelerating the degradation of TaEUI, a GA-deactivating enzyme. These findings demonstrate that the TaLYK5-TaDSK2a module functions as a molecular switch that dynamically regulates the trade-off between plant immunity and growth.
Rice (Oryza sativa) is highly susceptible to a variety of devastating fungal diseases. However, whether these phylogenetically distinct fungal pathogens employ conserved effectors to disrupt common immune hubs remains unclear. Here, we identify a conserved virulence strategy in which multiple rice-infecting fungal pathogens employ a subtilisin-like protease effector, SBT1, to suppress host immunity. Upon secretion into plant cells, SBT1 directly targets the key immune signaling component OsMAPKKKα and mediates its degradation in a proteolytic activity-dependent manner. OsMAPKKKα acts in a linear signaling cascade: it is phosphorylated and stabilized by OsRLCK185 at Thr493, and subsequently phosphorylates OsMKK4 to activate downstream MAPK signaling. By degrading OsMAPKKKα, SBT1 disrupts the chitin-triggered immune signaling transduced through the OsCERK1–OsRLCK185–OsMAPKKKα–OsMKK4 module. Importantly, host-induced gene silencing (HIGS) targeting SBT1 confers broad-spectrum resistance against multiple fungal pathogens. Our study unveils a previously unexplored pathogen strategy wherein a secreted effector protease dismantles a central signaling node, and identifies OsMAPKKKα as a promising target for engineering disease-resistant crops.
Yuan Fang, Zhaoyun Wang, Wenjing Li et al.· Science Advances· 0 citations
In plants, numerous receptor-like kinases (RLKs) function as potential pattern recognition receptors (PRRs) involved in perceiving ligands to trigger pattern-triggered immunity (PTI); however, the roles of most RLKs remain uncharacterized. A previous study showed that the potato receptor-like kinase StLRPK1 interacts with the co-receptor SERK3A/BAK1 to positively regulate resistance against Phytophthora infestans, yet the underlying mechanism remains unknown. Here, we identified StLecRK. IX, a potato RLK that interacts with StLRPK1. The expression of StLecRK. IX was up-regulated in response to P. infestans inoculation. Transient overexpression of StLecRK. IX triggered strong cell death in Nicotiana benthamiana leaves. Moreover, stable overexpression of either StLecRK. IX or its N. benthamiana ortholog NbLecRK. IX significantly enhanced late blight resistance in both potato and N. benthamiana by activating a cascade of immune responses, including reactive oxygen species (ROS) burst, transcriptional upregulation of PTI marker genes, and callose deposition. StLecRK. IX contains two conserved functional motifs, HRD and DFG, within its kinase domain and exhibits strong kinase activity. Furthermore, we demonstrate that StLRPK1 and StLecRK. IX form a ternary protein complex with the co-receptor SERK3A/BAK1 to positively regulate late blight resistance. Together, these findings expand our understanding of plant RLK functions in late blight resistance and provide a strategic basis for utilizing StLecRK. IX and StLRPK1 to improve potato resistance, and highlight StLecRK. IX as a promising target for engineering disease resistance in crops.
Zhu Yang, Lang Liu, Chunju Yin et al.· Plant Science· 0 citations
Fine-tuning immune receptor stability is essential for maintaining the balance between defense and growth in crops. Here, we identify an AAA+ ATPase–F-box regulatory module that negatively regulates potato immunity by promoting the degradation of the immune co-receptor StSOBIR1. The AAA+ ATPase StGCN4 functions as a negative regulator of potato immunity. Silencing of StGCN4 markedly enhanced resistance to Phytophthora infestans without affecting plant growth, while overexpression increased susceptibility. StGCN4 interacts with the PP2-type F-box protein StPFB1 and stabilizes it at the plasma membrane, which also negatively regulate immunity and together they facilitate proteasomal degradation of StSOBIR1, thereby dampening receptor-mediated defense signaling. Suppression of StGCN4 or StPFB1 enhances reactive oxygen species (ROS) production, salicylic acid accumulation, and expression of defense-related genes, resulting in strong resistance to P. infestans without growth penalty. These findings reveal a previously unrecognized AAA+ ATPase–F-box module that controls receptor homeostasis and identify StGCN4 as a promising molecular target for breeding high-yielding and late blight resistant potato cultivars.
Plasmodesmata (PD) play vital roles in plant growth and defense through controlling symplastic transport of important molecules. Here we report that a conserved COBRA-like protein, COBL3, is required for PD-mediated antiviral defense (PMAD) against divergent plant RNA viruses in wheat (Triticum aestivum) and tobacco (Nicotiana benthamiana) via positively regulating callose accumulation. The wheat COBL3 protein, TaCOBL3, interacts with the 17K movement protein (MP) of barley yellow dwarf virus-GAV (BYDV-GAV). TaCOBL3 is associated with the plasma membrane and co-locates with 17K MP at PD. Genetic analysis with overexpression and knockout lines reveals that TaCOBL3 positively regulates wheat defense against BYDV-GAV through modulating callose accumulation at PD. Interestingly, TaCOBL3 interacts with the wheat homolog of PDLP5, a conserved key PD permeability regulator in higher plants. Silencing TaPDLP5 diminishes the elevated BYDV-GAV defense conferred by TaCOBL3 overexpression in wheat. Furthermore, transient expression of TaCOBL3 promotes callose accumulation and lowers PD permeability in tobacco cells, which is, however, largely compromised when tobacco PDLP5 is silenced. Notably, BYDV 17K MP weakens the interaction between TaCOBL3 and TaPDLP5 and inhibits their callose binding activities. Finally, silencing tobacco NbCOBL3 gene decreases callose content and attenuated host defense against two tobraviruses, one potexvirus, and one hordeivirus. Overall, our study reveals a previously unknown role of COBRA-like proteins in PMAD and provides insight into how a plant viral MP sabotages PMAD through perturbing COBL3-PDLP5 interaction to facilitate virus spread through PD. The conserved COBL3 gene may represent a valuable target for engineering broad-spectrum antiviral resistance in crop plants.
Jin Yang, Kai Gao, Xiaohuan Jin et al.· Plant Communications· 0 citations
Plant immune activation often reduces growth, which is defined as “growth-defense trade-off” (GDT). Uncoupling GDT is promising for breeding of elite cultivars with strong growth and immunity. We previously identified that AP2 transcription factor TARGET OF EARLY3 (TOE3) promotes both growth and antiviral defense. However, the mechanism underlying this GDT uncoupling remains unknown. Here, we find that the amino-terminal domain of TOE3 (T3N) inhibits abscisic acid (ABA) signaling. Mechanistically, T3N binds to an ABA receptor PYL4 to interfere with PYL4-PP2C4 interaction. The PYL4-PP2C4 module regulates tobacco growth and antiviral immunity. Thus, under normal conditions, T3N enhances tobacco growth via down-regulating ABA response. Upon TMV infection, the phosphorylation of T3N is induced. Phosphorylated T3N exhibits stronger binding affinity to PYL4 to further amplify its disruptive effect on PYL4-PP2C4 module and strongly block ABA response, thereby boosting antiviral immunity. These findings reveal how TOE3 uncouples GDT to provide strategies for breeding crops with strong growth and antiviral immunity.
Bolei Jiao, Baijun Wu, H. Fang et al.· Science Advances· 0 citations
It is proposed that ILKs contribute to pathways connecting elicitor-triggered immune signaling with cell-wall-associated stress responses and that ILK-related defense functions may extend to the cotton root-nematode interaction, while the mechanism remains to be elucidated.
Gizem Dimlioglu, N. Nejat, Emily G Cooley et al.· Plant Science· 0 citations