Plants

35 pages, 17263 KiB

Open AccessArticle

The Influence of Bacterial Inoculants and a Biofertilizer on Maize Cultivation and the Associated Shift in Bacteriobiota During the Growing Season

by Katarina Kruščić, Aleksandra Jelušić, Matjaž Hladnik, Tamara Janakiev, Jovana Anđelković, Dunja Bandelj and Ivica Dimkić

Plants 2025, 14(12), 1753; https://doi.org/10.3390/plants14121753 (registering DOI) - 7 Jun 2025

Abstract

Maize (Zea mays L.) relies heavily on nitrogen and phosphorus inputs, typically supplied through organic and inorganic fertilizers. However, excessive agrochemical use threatens soil fertility and environmental health. Sustainable alternatives, such as poultry manure (PM) and plant growth-promoting rhizobacteria (PGPR), offer promising [...] Read more.

Maize (Zea mays L.) relies heavily on nitrogen and phosphorus inputs, typically supplied through organic and inorganic fertilizers. However, excessive agrochemical use threatens soil fertility and environmental health. Sustainable alternatives, such as poultry manure (PM) and plant growth-promoting rhizobacteria (PGPR), offer promising solutions. This study examines the effects of a phytobiotic bacterial formulation (PHY), composed of Bacillus subtilis and Microbacterium sp., applied alone and in combination with PM, on maize’s rhizosphere bacteriobiome across key growth stages. Field trials included four treatments: a control, PHY-coated seeds, PM, and combined PHY_PM. The results show that early in development, the PM-treated rhizospheres increased the abundance of beneficial genera such as Sphingomonas, Microvirga, and Streptomyces, though levels declined in later stages. The PHY_PM-treated roots in the seedling phase showed a reduced abundance of taxa like Chryseobacterium, Pedobacter, Phyllobacterium, Sphingobacterium, and Stenotrophomonas, but this effect did not persist. In the PM-treated roots, Flavisolibacter was significantly enriched at harvesting. Overall, beneficial bacteria improved microbial evenness, and the PHY_PM treatment promoted bacterial diversity and maize growth. A genome analysis of the PHY strains revealed plant-beneficial traits, including nutrient mobilization, stress resilience, and biocontrol potential. This study highlights the complementarity of PM and PGPR, showing how their integration reshapes bacteriobiome and correlates with plant parameters in sustainable agriculture. Full article

(This article belongs to the Special Issue Advances in Microbial Solutions for Sustainable Agriculture)

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22 pages, 6281 KiB

Open AccessArticle

Selection and Validation of Reference Genes for RT-qPCR in Protonemal Tissue of the Desiccation-Tolerant Moss Pseudocrossidium replicatum Under Multiple Abiotic Stress Conditions

by Rosa María Nava-Nolazco, Selma Ríos-Melendez, Santiago Valentín Galván-Gordillo, Angélica C. Martínez-Navarro, Mishael Sánchez-Pérez, Rocio Alejandra Chavez-Santoscoy, Martha Bibbins-Martínez, Ignacio Eduardo Maldonado-Mendoza, Analilia Arroyo-Becerra and Miguel Angel Villalobos-López

Plants 2025, 14(12), 1752; https://doi.org/10.3390/plants14121752 (registering DOI) - 7 Jun 2025

Abstract

Plant abiotic stresses are the main cause of significant crop losses worldwide. The moss Pseudocrossidium replicatum is highly tolerant to different types of abiotic stress, such as desiccation. Our group is interested in identifying and characterising differentially expressed genes in response to abiotic [...] Read more.

Plant abiotic stresses are the main cause of significant crop losses worldwide. The moss Pseudocrossidium replicatum is highly tolerant to different types of abiotic stress, such as desiccation. Our group is interested in identifying and characterising differentially expressed genes in response to abiotic stress in this species. However, a collection of validated reference genes for RT-qPCR analysis is essential to normalise the expression of genes in response to the conditions of interest. Here, we assessed 13 candidate reference genes for P. replicatum based on their expression stability across transcriptomes from six abiotic stress-related conditions using the RefFinder, BestKeeper, geNorm, and NormFinder programs. The stability and reliability of the proposed reference genes were evaluated under six experimental conditions: control, dehydration, rehydration, abscisic acid (ABA), NaCl, and sorbitol. Interestingly, most proposed reference genes exhibited high stability (low M values) across all analysed abiotic stress conditions. A pairwise variation analysis indicated that only one pair is necessary to normalise RT-qPCR experiments. Each gene was confirmed to normalise the expression of both upregulated and downregulated genes. This represents the first report of validated reference genes for RT-qPCR gene expression studies under abiotic stress in the protonemal tissue of a fully desiccation-tolerant moss. Full article

(This article belongs to the Special Issue Plant Stress Physiology and Molecular Biology—2nd Edition)

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14 pages, 2479 KiB

Open AccessArticle

Bauhinia forficata Link Protects HaCaT Keratinocytes from H₂O₂-Induced Oxidative Stress and Inflammation via Nrf2/PINK1 and NF-κB Signaling Pathways

by Qiwen Zheng, Xiangji Jin, Trang Thi Minh Nguyen, Jae-Woo Kim, Yong-Min Kim and Tae-Hoo Yi

Plants 2025, 14(12), 1751; https://doi.org/10.3390/plants14121751 (registering DOI) - 7 Jun 2025

Abstract

Oxidative stress has been directly implicated in the pathogenesis of various skin disorders, making it a promising target for therapeutic intervention. Bauhinia forficata Link (BFL), commonly referred to as “plant insulin,” is well known for its antioxidant and antihyperglycemic properties; however, its potential [...] Read more.

Oxidative stress has been directly implicated in the pathogenesis of various skin disorders, making it a promising target for therapeutic intervention. Bauhinia forficata Link (BFL), commonly referred to as “plant insulin,” is well known for its antioxidant and antihyperglycemic properties; however, its potential role in skin protection remains unexplored. In this study, we investigated the protective effects of BFL against H₂O₂-induced oxidative stress and inflammation in HaCaT keratinocytes. The major phytochemical constituents of BFL were identified by high-performance liquid chromatography (HPLC). Its antioxidant capacity was evaluated using 2,2′-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 2,2-Diphenyl-1-picrylhydrazyl (DPPH), oxygen radical absorbance capacity (ORAC), and superoxide dismutase (SOD). In an H₂O₂-induced oxidative stress model, we assessed intracellular reactive oxygen species (ROS) levels and apoptosis using flow cytometry. Cellular respiration was analyzed using a Seahorse XFp analyzer, while molecular mechanisms were examined by reverse transcription polymerase chain reaction (RT-PCR) and western blotting. Our results demonstrated that BFL significantly reduced intracellular ROS levels and apoptosis, primarily by activating the nuclear factor erythroid 2–related factor 2 (Nrf2)/PINK1 pathway, which promoted mitochondrial quality control and redox homeostasis. Additionally, BFL suppressed inflammatory responses by downregulating the nuclear factor-κB (NF-κB) signaling pathway and reducing the secretion of pro-inflammatory cytokines interleukin (IL)-6, IL-1β, and tumor necrosis factor-alpha (TNF-α). These findings suggest that BFL is a potent antioxidant and anti-inflammatory agent, with potential as an adjunctive therapy for oxidative stress-related skin conditions. Full article

(This article belongs to the Special Issue Antioxidant and Anti-Inflammatory Activities of Plant Extracts and Phytochemicals)

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14 pages, 1316 KiB

Open AccessArticle

The Enhancement of a Saccharum spontaneum Population and a Genetic Impact Analysis of the Agronomic and Yield Traits of Its Progeny

by Jiayong Liu, Maoyong Ran, Liping Zhao, Lianan Tao, Fenggang Zan, Li Yao, Xin Hu, Shenglin Ren, Yong Zhao, Hongming Xia, Jing Zhang, Xinyuan Pu, Zhongfu Zhang and Zuhu Deng

Plants 2025, 14(12), 1750; https://doi.org/10.3390/plants14121750 (registering DOI) - 7 Jun 2025

Abstract

Saccharum spontaneum serves as an essential genetic resource for sugarcane improvement. Traditional breeding methods, characterized by slow selection and limited germplasm exploitation, often lead to suboptimal progeny performance. In this study, we revised the utilization strategy by initially hybridizing several S. spontaneum clones, [...] Read more.

Saccharum spontaneum serves as an essential genetic resource for sugarcane improvement. Traditional breeding methods, characterized by slow selection and limited germplasm exploitation, often lead to suboptimal progeny performance. In this study, we revised the utilization strategy by initially hybridizing several S. spontaneum clones, followed by intercrossing their F1 progeny to establish a heterogeneous ‘polymeric’ population, which was then subjected to ‘nobilization’. A natural Saccharum spontaneum (S0) plant was used as the parent to create a hybrid (S1) containing two S. spontaneum bloodlines. The agronomic traits of S1 were compared, leading to the identification of three superior hybrids. These hybrids were then crossed in a complete diallel design, resulting in six crosses. Significant genetic variation was observed for the agronomic traits. Compared with S0, the plant height in S1 increased by 31.5%, and by 32.22% in S2. The stem diameter in S1 increased by 38.71%, and by 51.61% in S2. The single stem weight increased by 125% in S1 and 150% in S2. Other yield traits also showed varying degrees of improvement. A correlation analysis indicated that the plant height, stalk diameter, single stalk weight, and leaf width were significantly positively correlated with yield, and the leaf width with brix. There was no significant correlation between the millable stalks and yield. This study successfully developed a novel S. spontaneum hybrid with significantly improved agronomic traits, enhancing the genetic foundation of S. spontaneum germplasm for nobilization breeding programs. These findings provide a valuable germplasm base for developing high-performance sugarcane varieties, improving the utilization of S. spontaneum. Full article

(This article belongs to the Section Plant Genetics, Genomics and Biotechnology)

14 pages, 1233 KiB

Open AccessArticle

Exploring the Potential of Plant Cytokinins Against Common Human Pathogens: In Vitro Assessment and In Silico Insights

by Jelena Lazarević, Aleksandar Veselinović, Marija Stojiljković, Miloš Petrović, Pierangela Ciuffreda and Enzo Santaniello

Plants 2025, 14(12), 1749; https://doi.org/10.3390/plants14121749 (registering DOI) - 7 Jun 2025

Abstract

Cytokinins, plant hormones derived from adenine, are best known for regulating growth and stress responses in plants. Recent findings suggest they may also influence microbial viability, yet their direct antimicrobial potential remains underexplored. This study evaluates the antimicrobial activities of four natural cytokinins [...] Read more.

Cytokinins, plant hormones derived from adenine, are best known for regulating growth and stress responses in plants. Recent findings suggest they may also influence microbial viability, yet their direct antimicrobial potential remains underexplored. This study evaluates the antimicrobial activities of four natural cytokinins (iPA, B, K, and p-T) and their N⁹-ribosides (iPAR, BR, KR, and p-TR) against selected human pathogens. Using the broth microdilution method, we assessed their effects on Gram-positive and Gram-negative bacteria, as well as fungal strains. While Gram-negative species showed no susceptibility, all tested compounds exhibited bacteriostatic activity against Bacillus subtilis and Enterococcus faecalis. Most notably, kinetin (K) and kinetin riboside (KR) displayed strong antifungal activity against Candida albicans, with MIC values comparable to the reference drug nystatin. Molecular docking studies supported these findings by showing that K and KR form favorable interactions with two validated antifungal targets in Candida albicans: secreted aspartic proteinase 3 (SAP3) and dihydrofolate reductase (DHFR). This is, to our knowledge, the first report linking natural cytokinins to direct antifungal action against C. albicans supported by in silico evidence. These findings highlight the potential of K and KR as promising leads for the development of cytokinin-based antifungal agents. Full article

(This article belongs to the Special Issue Plant-Derived Natural Products: Development and Utilization)

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15 pages, 7351 KiB

Open AccessArticle

Characterization and Expression Analysis of the SABATH Gene Family Under Abiotic Stresses in Cucumber (Cucumis sativus L.)

by Xinjie Zhang, Shanyu Li, Yang Zhou, Mengxin Chen, Lisi Jiang and Wei Fu

Plants 2025, 14(12), 1748; https://doi.org/10.3390/plants14121748 (registering DOI) - 7 Jun 2025

Abstract

SABATH methyltransferase can methylate small-molecule metabolites of plants to generate different products, and it plays a crucial role in plant growth and development as well as stress response. In this study, 13 SABATH genes distributed on five chromosomes of cucumbers were identified, and [...] Read more.

SABATH methyltransferase can methylate small-molecule metabolites of plants to generate different products, and it plays a crucial role in plant growth and development as well as stress response. In this study, 13 SABATH genes distributed on five chromosomes of cucumbers were identified, and the synergistic effects among their domains, gene structures, conserved motifs, phylogenetic relationships, collinearity analysis, cis-acting elements, expression patterns, and plant growth-promoting rhizosphere bacteria (PGPR) were analyzed. The gene structure and conserved motifs of the same group of CsSABATH have similar intron numbers and conserved motifs. We detected 10 cis-elements in the promoter of the CsSABATH gene, indicating that they may be involved in different signaling pathways. qRT-PCR revealed the tissue-specific, drought and salt stress-responsive expression of the SABATH gene in cucumbers. Furthermore, we also verified that the expression level of CsaV3_6G046510 after inoculation with PGPR-GD17 bacteria under drought and salt stress was significantly lower than normal drought and salt dress, indicating that this gene may respond to PGPR and in abiotic stress play an important role. This study provides valuable insights into the molecular characteristics and evolutionary history of the SABATH gene family in cucumbers, laying a foundation for further analysis of the function of the CsSABATH gene in cucumbers. Full article

(This article belongs to the Special Issue Reproductive and Developmental Mechanisms of Vegetable Crops)

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19 pages, 2223 KiB

Open AccessArticle

The Effect of Salinity on Heavy Metal Tolerance in Two Energy Willow Varieties

by Kinga Drzewiecka, Zuzanna Kaźmierczak, Magdalena Woźniak and Michał Rybak

Plants 2025, 14(12), 1747; https://doi.org/10.3390/plants14121747 (registering DOI) - 7 Jun 2025

Abstract

This study evaluated the response of two willow varieties, Salix × smithiana Willd. and Salix viminalis L. var. Gigantea, to selected heavy metals and elevated soil salinity, simulating complex environmental conditions during phytoremediation. Plants propagated from stem cuttings were cultivated in pots under [...] Read more.

This study evaluated the response of two willow varieties, Salix × smithiana Willd. and Salix viminalis L. var. Gigantea, to selected heavy metals and elevated soil salinity, simulating complex environmental conditions during phytoremediation. Plants propagated from stem cuttings were cultivated in pots under field conditions in soil artificially contaminated with a mixture of Cd, Ni, Cu, Zn, and Pb salts at two concentration levels representing lower and higher guideline thresholds. Sodium chloride was added to induce salinity stress. S. × smithiana exhibited enhanced growth under combined metal and salinity stress, suggesting efficient tolerance mechanisms. This was reflected in elevated relative water content (RWC) and increased accumulation of Zn and Cd in shoots. In contrast, Gigantea showed growth inhibition and primarily sequestered metals in roots, indicating a stress-avoidance strategy and reduced metal translocation. While salinity alone negatively affected both varieties, its combination with metals mitigated growth reduction in S. × smithiana, possibly due to improved ion homeostasis or cross-tolerance. Zn and Cd displayed the highest bioconcentration and mobility. Based on bioconcentration factor (BCF) and translocation factor (TF), S. × smithiana appears suitable for phytoextraction, whereas S. viminalis var. Gigantea appears suitable for phytostabilization. These results support species-specific approaches to phytoremediation in multi-contaminant environments. Full article

(This article belongs to the Special Issue Plant Functioning Under Abiotic Stress)

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21 pages, 1099 KiB

Open AccessReview

A Review of the Ethnomedicine, Phytochemistry, Pharmacology and Toxicological Studies on Ptaeroxylon obliquum (Thunb.) Radlk. (Rutaceae)

by Ntanganedzeni Makumbane, Sanah Malomile Nkadimeng, Edward Thato Khunoana and Thanyani Emelton Ramadwa

Plants 2025, 14(12), 1746; https://doi.org/10.3390/plants14121746 - 6 Jun 2025

Abstract

Ptaeroxylon obliquum (Thunb.) Radlk. (Rutaceae) is traditionally used for a range of purposes, including ethnoveterinary medicine and to treat various human ailments such as tuberculosis, inflammatory diseases, and bacterial and fungal infections. This review aims to comprehensively summarize the traditional uses, phytochemistry, toxicology, [...] Read more.

Ptaeroxylon obliquum (Thunb.) Radlk. (Rutaceae) is traditionally used for a range of purposes, including ethnoveterinary medicine and to treat various human ailments such as tuberculosis, inflammatory diseases, and bacterial and fungal infections. This review aims to comprehensively summarize the traditional uses, phytochemistry, toxicology, in silico, and pharmacological activities of P. obliquum and discuss the advances made to date. The phytochemistry of P. obliquum revealed the abundance of secondary metabolites such as coumarins and chromones, essential oils, and several other classes of bioactive compounds. A total of 80 secondary metabolites have been reported from this plant species. In vitro studies on P. obliquum explored its therapeutic potential and reported pharmacological properties such as antifungal, antibacterial, antiparasitic, antimycobacterial, anti-inflammatory, and antiproliferative activities. This review highlights the diversity of the medicinal use of P. obliquum and encourages its preservation. Future research should focus on the efficacy of P. obliquum's most promising bioactive compounds, and the ADME (absorption, distribution, metabolism, and excretion) pharmacological activities may help determine therapeutic potential in in vivo animal models and validate the wide range of traditional uses of P. obliquum. Full article

(This article belongs to the Special Issue Phytochemistry, Pharmacology, and Toxicity of Medicinal Plants)

17 pages, 5777 KiB

Open AccessArticle

Coordinated cpSRP43 and cpSRP54 Abundance Is Essential for Tetrapyrrole Biosynthesis While cpSRP43 Is Independent of Retrograde Signaling

by Shuiling Ji, Huijiao Yao and Bernhard Grimm

Plants 2025, 14(12), 1745; https://doi.org/10.3390/plants14121745 - 6 Jun 2025

Abstract

The chloroplast signal recognition particle (cpSRP) components cpSRP43 and cpSRP54 not only form a complex with light-harvesting chlorophyll (Chl)-binding proteins to direct them to the thylakoid membrane, but also serve other functions. cpSRP43 independently acts as a chaperone for some tetrapyrrole biosynthesis (TBS) [...] Read more.

The chloroplast signal recognition particle (cpSRP) components cpSRP43 and cpSRP54 not only form a complex with light-harvesting chlorophyll (Chl)-binding proteins to direct them to the thylakoid membrane, but also serve other functions. cpSRP43 independently acts as a chaperone for some tetrapyrrole biosynthesis (TBS) enzymes, while cpSRP54 participates in the co-translational targeting of plastid-encoded proteins. However, it remains unclear to what extent the two cpSRP components are coregulated—despite their distinct functions—and whether both participate in genomes-uncoupled (GUN)-mediated retrograde signaling. Here, we demonstrate that cpSRP43 and cpSRP54 accumulation is strongly interdependently controlled: overexpression of one protein increases the level of the other, while a deficiency in one of the two proteins leads to a simultaneous decrease in the other component. Disruption of this balance, e.g., by combining the overexpression of one component with a knockout of the other, results in severe chlorosis, stunted growth, and reduced levels of Chl and tetrapyrrole intermediates. Moreover, cpSRP43 deficiency exacerbates the pale-green phenotype of gun4 and gun5 mutants, highlighting a synergistic impact on TBS; however, cpSRP43 overexpression fails to rescue these defects. Remarkably, loss of cpSRP43 does not affect the expression of nuclear-encoded photosynthetic genes under intrinsic plastid stress, clearly demonstrating that cpSRP43 is not involved in plastid-to-nucleus retrograde signaling. Overall, our findings underscore that the fine-tuned expression of cpSRP43 and cpSRP54 is crucial for proper chloroplast function and pigment biosynthesis, while cpSRP43 alone does not participate in the retrograde signaling pathway. Full article

(This article belongs to the Special Issue Advances in Plant Photobiology)

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17 pages, 3018 KiB

Open AccessArticle

Modeling the Combined Effects of Straw Returning, Urease Inhibitors, and Nitrogen Split Application on Rice Yield and Ammonia Volatilization in Purple Soil Area

by Tianxiang Xu, Hong Wang, Huirong Hao, Chaowen Lin and Kelin Hu

Plants 2025, 14(12), 1744; https://doi.org/10.3390/plants14121744 - 6 Jun 2025

Abstract

The application of urease inhibitors (UIs) and optimizing nitrogen (N) split application ratio (NSR) can both minimize ammonia (NH₃) volatilization and increase rice yield. However, few studies have analyzed the combined effects of these two practices with straw returning on rice [...] Read more.

The application of urease inhibitors (UIs) and optimizing nitrogen (N) split application ratio (NSR) can both minimize ammonia (NH₃) volatilization and increase rice yield. However, few studies have analyzed the combined effects of these two practices with straw returning on rice yield and NH₃ volatilization. In this study, based on a field experiment involving rice yield, aboveground dry matter (ADM), crop N uptake (N_upt), and NH₃ volatilization from 2018 to 2019 in Sichuan Basin, China, the WHCNS (soil water heat carbon nitrogen simulator) model was used to simulate the effects of straw returning, UI, and NSR on rice growth and NH₃ volatilization. The results showed that the WHCNS model performed well in simulating rice growth and NH₃ volatilization. With straw return amount exceeding 4 t ha⁻¹, rice yield increased slowly or stabilized, while N_upt and NH₃ volatilization continued to increase. Increasing the panicle fertilizer (PF) proportion enhanced N_upt during the PF stage, thereby promoting yield improvement. The NSR₃ (a 1:1:3 ratio of base fertilizer, tiller fertilizer, and PF) achieved the highest yield, exceeding that of 2:1:2 by 0.29, 0.23, and 0.08 t ha⁻¹ at straw return amounts of 2, 3, and 4 t ha⁻¹, respectively. However, the effects of UI on N_upt and yield enhancement were limited. Furthermore, optimized NSR and the application of UI reduced NH₃ volatilization during the basal or tiller fertilizer stages, leading to an average decrease of 5.5% and 8.5% in total NH₃ volatilization, respectively. Meanwhile, the increase in straw return amount reduced the NH₃ volatilization reduction effects of both practices. Overall, the combination of NSR₃ and UI with the straw return amount of 3 t ha⁻¹ was the optimal practice for balancing food security and environmental benefits in purple soil area. Full article

(This article belongs to the Special Issue Water and Nitrogen Management in the Soil–Crop System (3rd Edition))

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15 pages, 974 KiB

Open AccessArticle

Plant Growth, Yield, and Quality of Bush Tea (Athrixia phylicoides) as Affected by Deficit Hidrico and Mulching

by Vhuhwavho Tshilidzi Ndou, Tafadzwanashe Mabhaudhi, Mangaliso Goge, Tshephiso Papo, Mzamo Shozi, Maanea Lonia Ramphinwa and Fhatuwani Nixwell Mudau

Plants 2025, 14(12), 1743; https://doi.org/10.3390/plants14121743 - 6 Jun 2025

Abstract

Native to South Africa, Bush tea is a plant that thrives in various climates. Cultural practices such as mineral nutrition, fertigation, pruning, and harvesting have been shown to influence bush tea’s quality, growth, and yield. This study set out to determine the effects [...] Read more.

Native to South Africa, Bush tea is a plant that thrives in various climates. Cultural practices such as mineral nutrition, fertigation, pruning, and harvesting have been shown to influence bush tea’s quality, growth, and yield. This study set out to determine the effects of mulching and deficit irrigation on the growth, yield, and quality of bush tea. Three deficit irrigation treatments (0%, 30%, and 100% Crop evapotranspiration (ETc) on field capacity) and three mulch treatments (sawdust, black plastic mulch, and no mulch) were included in a two-factor experiment, which was set up in a randomized complete block design (RCBD) with three replications. Physiological and growth parameters were taken every two weeks. The number of branches was counted, and measurements of chlorophyll content and the proportion of radiation intercepted by the canopy were recorded. Yield and secondary metabolites such as sugar residuals, fatty acids, and phenols of bush tea were determined after harvest. Growing bush tea under various water regimes showed that a 30% water regime significantly enhanced plant growth characteristics, including the proportion of intercepted radiation, plant height, and both fresh and dry weight. Furthermore, under different water regimes, sawdust improved plant growth in bush tea grown in the field. Black plastic mulch and a 0% water regime produced more compounds beneficial to health than tea treated with half or full irrigation. The extraction of data for Proton Nuclear Magnetic Resonance (NMR) and Mass Spectrometry analyses was conducted for quality components. Our study did not show any distinct structural differences in the tea under different water regimes or mulching. Flavones, phenols, diterpenes, and gardoside were some of the most abundant compounds found in bush tea using mass spectrometry. Principal Component Analysis was performed on the NMR spectral data across 27 samples of bush tea. Full article

(This article belongs to the Special Issue Integrated Soil–Plant Management for Resilient and Sustainable Agroecosystems)

12 pages, 1058 KiB

Open AccessArticle

Indole Alkaloids and Phenolic Amides from the Rhizomes of Cimicifuga heracleifolia and Their In Vitro Soluble Epoxide Hydrolase (sEH) Inhibitory Activity

by Yanwen Sun, Chunyu Fan, Liyi Chen, Xueting Cui, Kouharu Otsuki, Mi Zhang, Feng Qiu, Liqin Ding and Wei Li

Plants 2025, 14(12), 1742; https://doi.org/10.3390/plants14121742 - 6 Jun 2025

Abstract

Cimicifuga heracleifolia is a perennial herb that belongs to the Ranunculaceae family. Its dried rhizomes are a source of Cimicifugae Rhizoma, a traditional Chinese medicine used for detoxification, the treatment of febrile diseases, and the prevention of pathogenic invasion. In the present study, [...] Read more.

Cimicifuga heracleifolia is a perennial herb that belongs to the Ranunculaceae family. Its dried rhizomes are a source of Cimicifugae Rhizoma, a traditional Chinese medicine used for detoxification, the treatment of febrile diseases, and the prevention of pathogenic invasion. In the present study, a phytochemical investigation of the rhizomes of C. heracleifolia resulted in the isolation of three indole alkaloids (1–3) and seven phenolic amides (4–10), including three new compounds, 6-methoxy-3-(3-methyl-1-oxo-2-butenyl) 1H indole (1), (3R)-1-(β-d-glucopyranosyl)-3-hydroxy-3-(3-methylbutyl)-2-oxindole (3), and N-acetyldopamine-3-O-β-d-allopyranoside (4). Their structures were elucidated using extensive physicochemical and spectroscopic analyses. All the isolated compounds were evaluated for their inhibitory activity against soluble epoxide hydrolase (sEH). The results showed that cimicifugamide A (6) exhibited the most potent inhibitory activity, with an IC₅₀ value of 8.74 μM, followed by cimicifugamide (7), demethoxycimicifugamide (8), and N-trans-feruloyl tyramine (10), with IC₅₀ values ranging from 15.63 to 20.58 μM. Kinetic analysis revealed that compound 6 inhibited sEH through a non-competitive mechanism. Full article

(This article belongs to the Section Phytochemistry)

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14 pages, 1992 KiB

Open AccessArticle

Peanut 9-Cis-Epoxycarotenoid Dioxygenase Enhances Salt and Drought Stress Tolerance by Regulating ROS Homeostasis

by Wenlin Wang, Mo Zhou, Shaohui Xu, Zhong Huang, Xiaobei Li, Cai Zhou, Siming Wang, Kaiyuan Zhang, Lixian Qiao and Yanyan Tang

Plants 2025, 14(12), 1741; https://doi.org/10.3390/plants14121741 - 6 Jun 2025

Abstract

Peanut (Arachis hypogaea L.), a vital oilseed and cash crop, faces yield limitations due to abiotic stresses. The 9-cis-epoxycarotenoid dioxygenase (NCED) enzyme, a key enzyme in abscisic acid (ABA) biosynthesis regulating plant development and stress responses, remains mechanistically uncharacterized in [...] Read more.

Peanut (Arachis hypogaea L.), a vital oilseed and cash crop, faces yield limitations due to abiotic stresses. The 9-cis-epoxycarotenoid dioxygenase (NCED) enzyme, a key enzyme in abscisic acid (ABA) biosynthesis regulating plant development and stress responses, remains mechanistically uncharacterized in peanut abiotic stress tolerance. In this study, we isolated a novel gene, AhNCED4, from the salt-tolerant mutant M24. The expression of AhNCED4 was strongly induced by NaCl, PEG6000, and ABA in peanut huayu20. Overexpression of AhNCED4 enhanced salt and drought tolerance in Arabidopsis. Transgenic overexpression of AhNCED4 improved salt and stress resistance through upregulated ROS-scavenging genes superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) with elevated enzymatic activities while reducing malondialdehyde (MDA), superoxide anion (O²⁻), and hydrogen peroxide (H₂O₂) accumulation compared to wild-type plants. Further research showed that the chlorophyll fluorescence parameters of transgenic lines were significantly increased, while light damage was significantly reduced. These findings establish AhNCED4 as a critical regulator of stress adaptation and an excellent candidate gene for resistance breeding in peanut. Full article

(This article belongs to the Section Plant Physiology and Metabolism)

19 pages, 4335 KiB

Open AccessArticle

Functional Characterization of Squalene Epoxidases from Siraitia grosvenorii

by Huan Zhao, Ze Song, Xuan Liu, Shukun Gong, Qi Tang, Changli Liu, Yifeng Zhang, Xianan Zhang, Haiyun Gao, Wei Gao, Yating Hu and Luqi Huang

Plants 2025, 14(12), 1740; https://doi.org/10.3390/plants14121740 - 6 Jun 2025

Abstract

The medicinal plant Siraitia grosvenorii produces sweet-tasting cucurbitane-type mogrosides from the atypical triterpenoid precursor 2,3,22,23-dioxidosqualene (SDO), rather than the conventional 2,3-oxidosqualene (SQO). However, SDO formation in mogroside biosynthesis remains unclear. Here, we systematically characterized two squalene epoxidases (SgSQE1/2) through phylogenetic analysis, heterologous expression, [...] Read more.

The medicinal plant Siraitia grosvenorii produces sweet-tasting cucurbitane-type mogrosides from the atypical triterpenoid precursor 2,3,22,23-dioxidosqualene (SDO), rather than the conventional 2,3-oxidosqualene (SQO). However, SDO formation in mogroside biosynthesis remains unclear. Here, we systematically characterized two squalene epoxidases (SgSQE1/2) through phylogenetic analysis, heterologous expression, subcellular localization, qRT-PCR, and alanine scanning studies. Both SgSQE1 and SgSQE2 exhibited squalene epoxidase activity, with SgSQE2 catalyzing SDO formation in yeast. We identified two critical catalytic residues governing epoxidation efficiency through mutagenesis. Both SgSQEs were localized in the ER, while expression profiling revealed a similar trend between SgSQE2 expression and mogroside accumulation in fruits. In our study, we developed a genomically engineered strategy for heterologous SQE characterization. These results lay the foundation for the SQE catalytic reaction involved in mogroside biosynthesis, and provide gene resources and a feasible approach for triterpene metabolic engineering. Full article

(This article belongs to the Special Issue Biosynthetic Pathways and Molecular Regulatory Mechanisms of Active Ingredients in Medicinal Plants)

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14 pages, 4930 KiB

Open AccessArticle

The Fiber Cell-Specific Overexpression of COMT2 Modulates Secondary Cell Wall Biosynthesis in Poplar

by Hanyu Chen, Hong Wang, Zhengjie Zhao, Jiarui Pan, Yao Yao, Yihan Wang, Keming Luo and Qin Song

Plants 2025, 14(12), 1739; https://doi.org/10.3390/plants14121739 - 6 Jun 2025

Abstract

Wood, as a natural and renewable resource, plays a crucial role in industrial production and daily life. Lignin, as one of the three major components of the plant cell secondary wall, plays a key role in conferring mechanical strength and enhancing stress resistance. [...] Read more.

Wood, as a natural and renewable resource, plays a crucial role in industrial production and daily life. Lignin, as one of the three major components of the plant cell secondary wall, plays a key role in conferring mechanical strength and enhancing stress resistance. The caffeic acid-O-methyltransferase (COMT) family of oxygen-methyltransferases is a core regulatory node in the downstream pathway of lignin biosynthesis. Here, our report shows that caffeic acid-O-methyltransferase 2 (COMT2) exhibits high conservation across several species. Tissue expression analysis reveals that COMT2 is specifically highly expressed in the secondary xylem of Populus tomentosa stems. We demonstrated that the specific overexpression of COMT2 in fiber cells of Populus tomentosa led to a significant increase in plant height, stem diameter, internode number, and stem dry weight. Furthermore, we found that the specific overexpression of COMT2 in fiber cells promotes xylem differentiation, lignin accumulation, and the thickening of the secondary cell wall (SCW) in fiber cells. Our results indicate that key downstream lignin biosynthesis enzyme genes are upregulated in transgenic plants. Additionally, mechanical properties of stem bending resistance, puncture resistance, and compressive strength in the transgenic lines are significantly improved. Moreover, we further created the DUFpro:COMT2 transgenic lines of Populus deltoides × Populus. euramericana cv ‘Nanlin895’ to verify the functional conservation of COMT2 in closely related poplar species. The DUFpro:COMT2 Populus deltoides × Populus. euramericana cv ‘Nanlin895’ transgenic lines exhibited phenotypes similar to those observed in the P. tomentosa transgenic plants, which showed enhanced growth, increased lignin accumulation, and greater wood strength. Overall, the specific overexpression of the caffeic acid O-methyltransferase gene COMT2 in poplar stem fiber cells has enhanced the wood biomass, wood properties, and mechanical strength of poplar stems. Full article

(This article belongs to the Special Issue Recent Progress in Exploring Plant Metabolic Pathways: Unraveling the Complexity of Plant Biochemistry)

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17 pages, 1217 KiB

Open AccessReview

Role of Serotonin in Cadmium Mitigation in Plants

by Hesham F. Oraby, Nehal Z. Elnaggar, Ahmad A. Omar and Azza H. Mohamed

Plants 2025, 14(12), 1738; https://doi.org/10.3390/plants14121738 - 6 Jun 2025

Abstract

Contamination of the soil with cadmium (Cd) presents serious hazards to plant growth, ecosystem harmony, and human health. Plants have evolved various mechanisms to address Cd toxicity, such as sequestration, chelation, and antioxidant defense systems. Knowledge of these mechanisms is an important requisite [...] Read more.

Contamination of the soil with cadmium (Cd) presents serious hazards to plant growth, ecosystem harmony, and human health. Plants have evolved various mechanisms to address Cd toxicity, such as sequestration, chelation, and antioxidant defense systems. Knowledge of these mechanisms is an important requisite for the development of strategies to relieve Cd stress in plants. More recent studies also implicate the role of the neurotransmitter 5-hydroxytryptamine (serotonin) in enabling Cd mitigation behavior in plants. Beyond its well-known role in animals, serotonin has emerged as a vital signaling molecule in plants, contributing to stress responses and regulatory pathways. This review focuses on the different Cd tolerance mechanisms in plants and describes the role of serotonin in protection against Cd toxicity. Moreover, it investigates how serotonin interacts with other signaling molecules to coordinate Cd stress responses. Understanding the intricate network of Cd tolerance mechanisms and the involvement of serotonin is essential for developing effective strategies to combat Cd stress in plants and improve environmental quality. Full article

(This article belongs to the Section Plant Molecular Biology)

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14 pages, 2086 KiB

Open AccessArticle

Genetic Mapping of QTL Associated with 100-Kernel Weight Using a DH Population in Maize

by Huawei Li, Hao Li, Jian Chen, Xiangbo Zhang, Baobao Wang, Shujun Zhi, Haiying Guan, Weibin Song, Jinsheng Lai, Haiming Zhao and Rixin Gao

Plants 2025, 14(12), 1737; https://doi.org/10.3390/plants14121737 - 6 Jun 2025

Abstract

Grain yield establishment is a complex progress and the genetic basis of one of the most important yield components, 100-kernel weight, remains largely unknown. Here, we employed a double haploid (DH) population containing 477 lines which was developed from a cross of two [...] Read more.

Grain yield establishment is a complex progress and the genetic basis of one of the most important yield components, 100-kernel weight, remains largely unknown. Here, we employed a double haploid (DH) population containing 477 lines which was developed from a cross of two maize elite inbred lines, PHBA6 and Chang7-2, to identify quantitative trait loci (QTL) that related to 100-kernel weight. The phenotypes of the DH population were acquired over three years in two different locations, while the DH lines were genotyped by next-generation sequencing technology of massively parallel 3ʹ end RNA sequencing (MP3RNA-seq). Eventually, 28,874 SNPs from 436 DH lines were preserved after SNP calling and filtering and a genetic map with a length of 837 cM was constructed. Then, single environment QTL analysis was performed using the R/qtl program, and it was found that a total of 17 QTLs related to 100-kernel weight were identified and distributed across the whole genome except chromosomes 5 and 6. The total phenotypic variation explained by QTLs detected in three different environments (BJ2016, BJ2107, and HN2018) was 22.2%, 32.9%, and 51.38%, respectively. Among these QTLs, three of them were identified across different environments as environmentally stable QTLs and explained more than 10% of the phenotypic variance each. Together, the results provided in this study preliminarily revealed the genetic basis of 100-kernel weight and will enhance molecular breeding for key agronomic kernel-related traits in maize. Full article

(This article belongs to the Section Plant Genetics, Genomics and Biotechnology)

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28 pages, 7191 KiB

Open AccessArticle

Selenium Alleviates Cadmium Toxicity by Regulating Carbon Metabolism, AsA-GSH Cycle, and Cadmium Transport in Glycyrrhiza uralensis Fisch. Seedlings

by Xuerong Zheng, Jiafen Luo, Xin Li, Chaoyue Zhang, Guigui Wan, Caixia Xia and Jiahui Lu

Plants 2025, 14(12), 1736; https://doi.org/10.3390/plants14121736 - 6 Jun 2025

Abstract

Cadmium (Cd) accumulation in plants hinders their growth and development while posing significant risks to human health through food chain transmission. Glycyrrhiza uralensis Fisch. (G. uralensis) is a medicinal plant valued for its roots and plays a crucial role in harmonizing [...] Read more.

Cadmium (Cd) accumulation in plants hinders their growth and development while posing significant risks to human health through food chain transmission. Glycyrrhiza uralensis Fisch. (G. uralensis) is a medicinal plant valued for its roots and plays a crucial role in harmonizing various herbs in traditional Chinese medicine prescriptions. However, widespread Cd contamination in soil limits safe cultivation and application. Selenium (Se), a beneficial element in plants, can regulate plant growth by enhancing carbon metabolism and reducing heavy metal uptake. This study aimed to elucidate the protective mechanisms of Se application in licorice plants exposed to 20 μM Cd. Experiments with 1 and 5 μM of Se revealed that 1 μM of Se provided the best protective effects. This concentration reduced the Cd²⁺ content in the roots of G. uralensis, while significantly increasing plant biomass, root length, SPAD value, and contents of K⁺, Ca²⁺, and S²⁻. Additionally, the treatment reduced the malondialdehyde (MDA) content by 30.71% and 58.91% at 12 h and 30 d, respectively. The transcriptome analysis results suggest that Se mitigated Cd toxicity by enhancing carbon metabolism, regulating the AsA-GSH cycle, reducing Cd absorption, promoting Cd transport and compartmentalization, and modulating Cd resistance-associated transcription factors. These findings clarify the mechanisms by which Se alleviates Cd toxicity in G. uralensis and offer a promising strategy for the safe cultivation and quality control of medicinal herbs in Cd-contaminated soils. Full article

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16 pages, 1894 KiB

Open AccessArticle

Genome-Wide Identification and Analysis of DNA Methyltransferase and Demethylase Gene Families in Sweet Potato and Its Diploid Relative

by Songtao Yang, Shuai Qiao, Yan Yang, Fang Wang, Wei Song, Wenfang Tan, Yongping Li and Youlin Zhu

Plants 2025, 14(11), 1735; https://doi.org/10.3390/plants14111735 - 5 Jun 2025

Abstract

DNA methylation is a conserved and vital epigenetic modification that plays essential roles in plant growth, development, and responses to environmental stress. Cytosine-5 DNA methyltransferases (C5-MTases) and DNA demethylases (dMTases) are key regulators of DNA methylation dynamics. However, a comprehensive characterization of these [...] Read more.

DNA methylation is a conserved and vital epigenetic modification that plays essential roles in plant growth, development, and responses to environmental stress. Cytosine-5 DNA methyltransferases (C5-MTases) and DNA demethylases (dMTases) are key regulators of DNA methylation dynamics. However, a comprehensive characterization of these gene families in sweet potato has remained elusive. In this study, we systematically identified and analyzed eight C5-MTase and five dMTase genes in the genomes of diploid (Ipomoea trifida, 2n = 2x = 30) and autohexaploid (Ipomoea batatas, 2n = 6x = 90) sweet potato. Phylogenetic, structural, and synteny analyses revealed a high degree of conservation among these genes, suggesting their essential roles during evolution. Promoter analysis uncovered multiple cis-acting elements, particularly those responsive to light and hormones. In addition, we examined the expression profiling of IbC5-MTases and IbdMTases genes during storage root development, revealing that several were highly expressed during the early and rapid expansion stages. These findings suggest that C5-MTases and dMTases may contribute to the regulation of storage root formation in sweet potato through epigenetic mechanisms, offering valuable insights for future functional studies and epigenetic breeding efforts. Full article

(This article belongs to the Section Plant Genetics, Genomics and Biotechnology)

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