With the intensification of global climate change, abiotic stresses such as drought, high temperatures, and salinization occur frequently, posing a serious threat to crop production. When plants confront environmental stresses, they often need to suppress growth to activate defense mechanisms. However, this “growth-stress tolerance” trade-off significantly reduces crop yields. Research has shown that the transcription factor JUNGBRUNNEN1 (JUB1) plays a crucial role in regulating this balance. It can simultaneously delay leaf senescence and enhance resistance to various stresses. Nevertheless, how JUB1 integrates different hormone signaling pathways, such as gibberellin, brassinosteroid, and abscisic acid, to coordinate growth and defense responses, as well as its conserved functions in major crops, remain unclear. In-depth analysis of the molecular regulatory network of JUB1 will provide important theoretical basis for breeding stress-tolerant and high-yield crops. Recently, Plant, Cell & Environment published a review paper titled “JUNGBRUNNEN1, a Central Regulator of Plant Growth and Stress Response”, which systematically analyzed for the first time how the transcription factor JUNGBRUNNEN1 (JUB1) integrates the signaling pathways of gibberellin, brassinosteroid, and abscisic acid to balance plant growth and environmental stress tolerance.
As a member of the NAC transcription factor family, the function of JUB1 depends on the conserved N-terminal DNA-binding domain (containing subdomains A-E) and the variable C-terminal transcriptional activation domain. Studies have found that JUB1 inhibits cell elongation and leads to plant dwarfing by suppressing the key enzyme genes involved in gibberellin and brassinosteroid synthesis (such as GA3ox1 and DWF4) and activating DELLA proteins (such as GAI). In addition, JUB1 delays leaf senescence by regulating the reactive oxygen species (ROS) scavenging system (such as APX2) and heat shock proteins (HSPs). The recently identified splicing variant JUB1iso, which lacks the N-terminal dimerization domain, may regulate target genes in an atypical manner, although its functional mechanism still requires further verification. JUB1 also integrates light signals (such as PIF4) with hormone pathways (such as cytokinin, ABA), forming a complex regulatory network to balance the resource allocation between plant growth and stress responses.
JUB1 serves as a key regulatory hub for plants to cope with multiple stresses. In the face of abiotic stresses, JUB1 enhances heat, drought, and salt tolerance by inducing heat shock memory genes (such as HSFA2, HSA32) and osmotic regulators (such as proline). In the case of biotic stresses, it resists pathogen invasion by coordinating the salicylic acid and jasmonic acid pathways. Research indicates that overexpression of JUB1 homologous genes in tomato (SlJUB1) and rice (OsNAC5) can significantly improve stress tolerance without significantly inhibiting yield. Future research needs to optimize the inducible expression system of JUB1 to avoid growth inhibition caused by constitutive expression and explore its associations with root development and mycorrhizal symbiosis. These findings provide a theoretical basis for designing climate-smart crops.