Jul 2026· Journal of plant physiology· Vol 325, pp.
154851
· 0 citations· 50 references
Medicine
TL;DR
Genotype- and tissue-specific flavonoid remodeling in C. rigescens under salt stress and overexpression of CrHPPD in Arabidopsis thaliana are revealed, suggesting two stress-responsive components of phenylalanine/tyrosine-derived metabolism, although their direct mechanistic connection requires further validation.
Abstract
Soil salinity severely limits plant growth and productivity. Carex rigescens, a low-maintenance turfgrass species native to China, exhibits remarkable tolerance to abiotic stresses. Previous studies have highlighted the importance of the phenylalanine metabolic pathway in salt stress defense in C. rigescens; however, the specific mechanisms remain poorly understood. To elucidate the downstream metabolic and molecular components of this pathway, we analyzed flavonoid metabolism in two contrasting C. rigescens varieties-salt-sensitive 'Lvping No. 1' and salt-tolerant 'Lvping No. 2'-and functionally characterized the 4-hydroxyphenylpyruvate dioxygenase (CrHPPD) gene. Salt stress altered the abundance of several flavonoid metabolites, including 2'-hydroxygenistein, genistin, kaempferol, taxifolin, myricetin, and eriodictyol, identifying them as candidate salt-responsive metabolites. Naringenin and apigenin showed genotype- and tissue-dependent abundance patterns between the two varieties. We cloned CrHPPD, characterized its encoded protein, and found that CrHPPD-GFP displayed a cell periphery-associated fluorescence pattern in transient expression assays, although precise localization requires marker-based validation. CrHPPD expression was induced by NaCl and ABA, whereas PEG treatment elicited a weaker and more transient response. Furthermore, overexpression of CrHPPD in Arabidopsis thaliana enhanced germination rate, root length, catalase activity, and chlorophyll retention under salt stress, with the chlorophyll effect being most evident in OE6. Collectively, these findings reveal genotype- and tissue-specific flavonoid remodeling in C. rigescens under salt stress and demonstrate that CrHPPD positively contributes to salt tolerance when overexpressed in Arabidopsis. These results suggest that flavonoid metabolism and the HPPD-associated homogentisate/tocopherol antioxidant branch may represent two stress-responsive components of phenylalanine/tyrosine-derived metabolism, although their direct mechanistic connection requires further validation.
Findings establish PbSTY46 as a key regulator that links JA signaling to antioxidant defense to confer salt tolerance in P. betulifolia and represents a promising candidate for marker‑assisted breeding of salt‑tolerant pear cultivars.
Ning Yan, Wei-Chi Wang, Aihao Zhao et al.· Plant Science· 0 citations
Drought and salinity are major abiotic stresses that severely constrain plant growth and agricultural productivity. Histidine kinases (HKs), as key components of the plant two-component system (TCS), play crucial roles in environmental signal perception and adaptive responses. In this study, we functionally characterized a sweet potato (Ipomoea batatas L.) HK gene, IbHK1a, and investigated its role in drought and salt stress tolerance. Expression analysis revealed that IbHK1a is predominantly expressed in root tissues, particularly in storage and fibrous roots, indicating its potential involvement in stress sensing and adaptation. Subcellular localization demonstrated that the IbHK1a protein is localized to the plasma membrane, suggesting a role in external signal perception. To elucidate its biological function, IbHK1a was heterologously overexpressed in Arabidopsis thaliana. Transgenic plants exhibited significantly enhanced tolerance to drought and salt stress, as evidenced by higher seed germination rates, improved primary root growth, reduced leaf wilting, and increased survival rates compared with wild-type (WT) plants. Physiological analyses showed that IbHK1a overexpression led to increased activities of antioxidant enzymes, including superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), accompanied by reduced accumulation of reactive oxygen species (ROS) such as hydrogen peroxide (H2O2) and malondialdehyde (MDA). Consistently, leaf histochemical staining confirmed lower ROS accumulation in transgenic plants under stress conditions. In sweet potato, overexpression of IbHK1a in transgenic hairy roots enhanced tolerance to drought and salinity, whereas RNA interference lines displayed increased sensitivity, further confirming its positive regulatory role. Additionally, protein interaction analysis indicated that IbHK1a interacts with Arabidopsis histidine phosphotransferase proteins (AHPs), suggesting its involvement in conserved TCS-mediated phosphorelay signaling pathways. Functional complementation analysis demonstrated that IbHK1a partially rescues the stress-sensitive phenotype of the AHK1 mutant, indicating functional conservation with Arabidopsis AHK1. Collectively, these findings demonstrate that IbHK1a positively regulates drought and salt stress tolerance by enhancing antioxidant defense and ROS homeostasis. Its interaction with AHPs and partial complementation of the ahk1 mutant further support its involvement in the conserved TCS phosphorelay pathway. These results establish IbHK1a as an important component of abiotic stress responses and a potential genetic target for improving drought and salinity tolerance in sweet potato.
Ru-Xue Huo, Imran Khan, Jia Shi et al.· Plants· 0 citations
Flavonoids play critical roles in plant adaptation to abiotic stress; however, how salt stress modulates metabolic flux distribution within flavonoid branches remains poorly understood, particularly in non-model medicinal plants. Here, we integrated targeted metabolomics, transcriptomics, and proteomics to examine flavonoid regulation in Anoectochilus roxburghii under 0, 50, 100, and 200 mmol·L− 1 NaCl. Metabolite profiling showed that salinity reshaped flavonoid composition rather than uniformly increasing flavonoid abundance. A metabolite-derived branch bias index (MI), representing the balance between reductive branch metabolites and flavonol products, increased under salt treatment, peaked at 100 mmol·L− 1 NaCl, and declined at 200 mmol·L− 1, indicating maximal branch bias under moderate stress followed by partial rebalancing under severe stress. Transcriptomic analysis showed induction of upstream phenylpropanoid and flavonoid entry genes, including PAL, 4CL, and CHS, whereas F3H was suppressed and FLS showed no induction. Furthermore, several short-chain dehydrogenase/reductase homologs (IFR-like SDR homologs) were upregulated, and the transcript-derived reductive branch index (EI) increased progressively across the salt gradient. EI was positively associated with MI, although the relationship was not strictly proportional under severe stress (200 mmol·L− 1 NaCl). Proteomic profiling further provided supportive evidence for sustained activation of upstream flavonoid biosynthesis, such as salt-induced accumulation of chalcone synthase (CHS) protein, complementing the transcriptomic and metabolomic datasets. Together, these results indicate that salt stress reorganizes flavonoid metabolism in A. roxburghii through persistent upstream activation and branch-specific regulation, favoring the reductive branch under moderate salinity. Salt stress reprograms flavonoid branch reprogramming in Anoectochilus roxburghii, coupling sustained upstream activation with repression of the flavonol node and preferential engagement of the reductive branch.
Hui-Ming Huang, Wen-Qing Bao, Jiang-Bo Lin et al.· BMC Plant Biology· 0 citations
It is demonstrated that PlPAT1 functions as a positive regulator of salt stress tolerance, likely through modulating osmotic balance and enhancing reactive oxygen species scavenging capacity.
Jian Cai, Xuemei Zhang, Cong Yan et al.· BMC Genomics· 0 citations
This study provides a root-focused transcriptomic resource and identifies candidate regulatory genes potentially linking ABA-related responses with lignin/lignan-associated metabolism in H. pedunculosum under salt stress.
Yang Tao, Xiao Huang, Enhao Zhang et al.· Plant physiology and biochem...· 2 citations
The physiological and metabolic mechanisms by which plants manage severe chemical stress during critical reproductive stages remain poorly understood. Here, we investigated the system-level phytotoxic responses and metabolic reprogramming of a tolerant species (Oryza sativa L.) and a susceptible species (Echinochloa crus-galli) exposed to the chemical stressor propanil using GC-MS/MS and LC-MS/MS. Under severe chemical stress, O. sativa maintained relatively stable antioxidant-related metabolism in grains, with α-tocopherol and phylloquinone showing only modest decreases of 0.86- and 0.90-fold, respectively. β-Sitosterol oryzanol was also preserved or increased in rice tissues, showing 1.05-fold in grain and 1.48-fold in husk, whereas it was not detected in E. crus-galli. In contrast, E. crus-galli exhibited stronger antioxidant perturbation, with α-tocopherol decreasing to 0.57-fold in grain and 0.72-fold in husk and (all-E)-zeaxanthin accumulating markedly in grain by 5.30-fold. Furthermore, the non-detection of oryzanol esters in E. crus-galli highlights a fundamental biochemical limitation in its oxidative stress defense. Ultimately, these findings suggest that resilience to chemical stressors may not rely solely on enzymatic detoxification, but may also involve coordinated, organ-specific metabolic buffering and targeted antioxidant reallocation.
Ji-Woo Yu, Min-Ho Song, Jung-Hoon Lee et al.· Ecotoxicology and Environmen...· 0 citations
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