The plant hormone, abscisic acid (ABA), is not only important for promoting abiotic stress responses but also plays a versatile and crucial role in plant immunity. The pathogen infection-induced dynamic accumulation of ABA mediates the degradation of non-expresser of PR genes 1 (NPR1) through the CUL3 proteasome pathway. However, the functional significance of NPR1 degradation by other E3 ligases in response to ABA remains unclear. Here, we report that NPR1 is induced transcriptionally by ABA and that mutation results in ABA insensitivity during seed germination and seedling growth. Mutants lacking downregulate the expression of ABA-responsive transcription factors ABA INSENSITIVE4 (ABI4) and ABA INSENSITIVE5 (ABI5), and that of their downstream targets , , , and . The mutation also affects the transcriptional activity of WRKY18, which activates in the presence of ABA. Furthermore, NPR1 directly interacts with and is degraded by HOS15, a substrate receptor for the DDB1-CUL4 ubiquitin E3 ligase complex. Collectively, our findings demonstrate that NPR1 acts as a positive regulator of ABA-responsive genes, whereas HOS15 promotes NPR1 degradation in a proteasome-dependent manner.
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http://dx.doi.org/10.3390/plants11060815 | DOI Listing |
Hortic Res
January 2025
Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Sciences, China Agricultural University, Beijing 100193, China.
Drought stress and lateral branches are both important factors affecting crop yield. Cucumber is a widely planted vegetable crop that requires a large amount of water during its production and varieties with few lateral branches are preferred. However, the mechanisms regulating cucumber drought tolerance and lateral branch development remain largely unclear.
View Article and Find Full Text PDFPLoS One
January 2025
Wuzhou University, College of Food and Pharmaceutical Engineering, Guangxi, P. R. China.
Ginsenosides are the most important secondary metabolites of ginseng. Ginseng has developed certain insect resistance properties during the course of evolutionary environmental adaptation. However, the mechanism underlying the insect resistance of ginseng is poorly understood.
View Article and Find Full Text PDFPlant Cell Environ
January 2025
College of Bioengineering and Biotechnology, Tianshui Normal University, Tianshui, China.
A key feature of stress responses [closely relative to the phytohormone abscisic acid (ABA)] and associated acclimation in plants is the dynamic adjustments and related optimisation of carbohydrate content between sink and source organs. The production of stomata, which consist of a pore between two adjacent guard cells, are central to plant adaptation to changing environment conditions. In this context, ABA is a core modulator of environmentally determined stomatal development.
View Article and Find Full Text PDFNew Phytol
January 2025
State Key Laboratory of Plant Environmental Resilience, Zhejiang University, Hangzhou, 310058, China.
The apoplastic pH (pH) in plants is susceptible to environmental stimuli. However, the biological implications of pH variation have remained largely unknown. The universal stress phytohormone abscisic acid (ABA) as well as the major environmental stimuli drought and salinity were selected as representative cases to investigate how changes in pH relate to plant behaviors in Arabidopsis.
View Article and Find Full Text PDFPlant Physiol Biochem
January 2025
Department of Biology, Faculty of Science, Ege University, Izmir, Türkiye. Electronic address:
Salinization is a significant global issue causes irreversible damage to plants by reducing osmotic potential, inhibiting seed germination, and impeding water uptake. Seed germination, a crucial step towards the seedling stage is regulated by several hormones and genes, with the balance between abscisic acid and gibberellin being the key mechanism that either promotes or inhibits this process. Additionally, mucilage, a gelatinous substance, is known to provide protection against drought, herbivory, soil adhesion, and seed sinking.
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