Horticulturae

18 pages, 7697 KB

Open AccessArticle

Regulation of Cell Metabolism and Changes in Berry Shape of Shine Muscat Grapevines Under the Influence of Different Treatments with the Plant Growth Regulators Gibberellin A3 and N-(2-Chloro-4-Pyridyl)-N′-Phenylurea

by Jiangbing Chen, Yanfei Guo, Haichao Hu, Congling Fang, Liru Wang, Lingling Hu, Zhihao Lin, Danyidie Zhang, Zhongyi Yang and Yueyan Wu

Horticulturae 2025, 11(10), 1160; https://doi.org/10.3390/horticulturae11101160 (registering DOI) - 28 Sep 2025

Abstract

Plant growth regulators Gibberellin A3 (GA₃) and N-(2-chloro-4-pyridyl)-N′-phenylurea (CPPU) are widely used in ‘Shine Muscat’ cultivation to regulate berry shape and size. However, the molecular mechanisms underlying their regulation of berry shape remain poorly understood. This study was designed to elucidate [...] Read more.

Plant growth regulators Gibberellin A3 (GA₃) and N-(2-chloro-4-pyridyl)-N′-phenylurea (CPPU) are widely used in ‘Shine Muscat’ cultivation to regulate berry shape and size. However, the molecular mechanisms underlying their regulation of berry shape remain poorly understood. This study was designed to elucidate the cytological processes and molecular basis through which GA₃ and CPPU modulate berry morphology in ‘Shine Muscat’. The results showed that spraying GA₃ or CPPU alone increases the hormone levels of endogenous auxin (IAA) and GA₃ and reduces the levels of endogenous 6-benzyladenine (6-BA). GA₃ treatment resulted in the number of cells per unit area being significantly reduced and the cell transverse and longitudinal diameters being significantly increased. CPPU treatment increases the number of cells per unit area, cell transverse and longitudinal diameters. In the results of CKvsG2 and CKvsC2 transcriptome sequencing, 2793 and 1082 differentially expressed genes (DEGs) were identified, respectively. These DEGs are significantly enriched in Gene Ontology (GO) terms related to plant hormones; the Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that the zeatin biosynthesis pathway (ko03030) is significantly enriched. The Arabidopsis response regulator (ARR) is down-regulated in response to GA₃ application and up-regulated in response to CPPU application. Transient overexpression of VvARR (OE-VvARR) in ‘Shine Muscat’ berry increased the number of berry cells and cell transverse and longitudinal diameters. Furthermore, virus-induced gene silencing of VvARR (VIGS-VvARR) reduced the number of berry cells but increased cell transverse and longitudinal diameters. The OE-VvARR grape hormone levels of endogenous GA₃, 6-BA, and IAA were significantly increased. In VIGS-VvARR grape, the levels of endogenous IAA and 6-BA are significantly increased, but there is no significant difference in endogenous GA₃. These findings offer novel insights into the molecular mechanisms by which GA₃ and CPPU govern berry development, corroborating the hypothesis that VvARR acts as a pivotal regulator mediating the effects of these plant growth regulators on berry cell morphology and, consequently, berry shape. Full article

(This article belongs to the Section Fruit Production Systems)

► Show Figures

Figure 1

19 pages, 355 KB

Open AccessFeature PaperArticle

Moderate Deficit Irrigation and Reduced Nitrogen Application Maintain Tuber Quality and Improve Nitrogen Use Efficiency of Potato (Solanum tuberosum L.)

by Abdulssamad M. H. Barka, Samuel Y. C. Essah and Jessica G. Davis

Horticulturae 2025, 11(10), 1159; https://doi.org/10.3390/horticulturae11101159 (registering DOI) - 28 Sep 2025

Abstract

Efficient water and nitrogen (N) management are essential for sustaining potato (Solanum tuberosum L.) production under limited resource conditions. This study investigated the effects of deficit irrigation and reduced N application on tuber quality parameters including specific gravity (SG), starch content (SC), [...] Read more.

Efficient water and nitrogen (N) management are essential for sustaining potato (Solanum tuberosum L.) production under limited resource conditions. This study investigated the effects of deficit irrigation and reduced N application on tuber quality parameters including specific gravity (SG), starch content (SC), and tuber dry matter (TDM) as well as agronomic water use efficiency (WUE) and nitrogen use efficiency (NUE) in four commercial potato cultivars (Canela Russet, Mesa Russet, Russet Norkotah 3, and Yukon Gold) over two seasons (2016 and 2017) at Colorado State University’s San Luis Valley Research Center. Three irrigation levels (100%, ~80%, and ~70% evapotranspiration replacement) and two N application rates (165 and 131 kg N ha⁻¹) were evaluated using four replications. Moderate deficit irrigation (up to ~18% ET reduction) improved or maintained SG, SC, and TDM in all four cultivars, while severe deficit irrigation (~30–40% reduction) reduced tuber quality. Reduced N application improved NUE in all cultivars without compromising tuber quality or yield. While WUE responded variably to deficit irrigation, NUE was highest under moderate to full irrigation and low N rate. Although effects on WUE were variable, integrating moderate deficit irrigation (18%) with reduced N application (20%) enhanced NUE while maintaining tuber quality. Full article

(This article belongs to the Special Issue New Advances in Nutrient Management for Enhancing the Yield and Quality of Horticultural Crops)

► Show Figures

Figure 1

12 pages, 219 KB

Open AccessArticle

Metabolite Profiles of Thymus longedentatus from Natural and Cultivated Areas

by Milena Nikolova, Denitsa Kancheva, Rumen Denev, Malina Delcheva and Ina Aneva

Horticulturae 2025, 11(10), 1158; https://doi.org/10.3390/horticulturae11101158 (registering DOI) - 26 Sep 2025

Abstract

Thymus longedentatus (Degen & Urum.) Ronniger is a Balkan endemic species valued for its essential oils and phenolic compounds, yet little is known about its phytochemistry under cultivation. This study compared the metabolite profiles of wild populations from the Eastern Rhodopes (ER) and [...] Read more.

Thymus longedentatus (Degen & Urum.) Ronniger is a Balkan endemic species valued for its essential oils and phenolic compounds, yet little is known about its phytochemistry under cultivation. This study compared the metabolite profiles of wild populations from the Eastern Rhodopes (ER) and Thracian Lowland (TL) with a cultivated population near Sofia (CA). Hydrodistillation yielded 0.2% essential oil (EO) in wild plants and 0.3% in cultivated plants. GC–MS analysis revealed citral isomers (neral and geranial) as dominant constituents, exceeding 60% in cultivated samples. Methanolic extracts and acetone exudates contained rosmarinic acid and triterpene acids consistently across all populations. Quantitative differences were observed in stress-related metabolites: arbutin and hydroquinone were enriched in wild plants, while chlorogenic and geranic acids were higher in cultivated plants. These findings demonstrate that cultivation preserves the main phytochemical profile of T. longedentatus while modulating the abundance of specific compounds, offering potential for sustainable utilization and conservation. Full article

(This article belongs to the Special Issue Wild and Cultivated Culinary Plants)

20 pages, 3066 KB

Open AccessFeature PaperArticle

Enhancing Cherry Tomato Performance Under Water Deficit Through Microbial Inoculation with Bacillus subtilis and Burkholderia seminalis

by Henrique Fonseca Elias de Oliveira, Thiago Dias Silva, Jhon Lennon Bezerra da Silva, Priscila Jane Romano Gonçalves Selaria, Marcos Vinícius da Silva, Marcio Mesquita, Josef Augusto Oberdan Souza Silva and Rhuanito Soranz Ferrarezi

Horticulturae 2025, 11(10), 1157; https://doi.org/10.3390/horticulturae11101157 - 26 Sep 2025

Abstract

Crop productivity can be affected by biotic and abiotic stressors, and plant growth-promoting bacteria (PGPB) from the genera Bacillus and Burkholderia have the potential to maintain fruit yield and quality, as these bacteria can promote plant growth by solubilizing nutrients, fixing atmospheric nitrogen, [...] Read more.

Crop productivity can be affected by biotic and abiotic stressors, and plant growth-promoting bacteria (PGPB) from the genera Bacillus and Burkholderia have the potential to maintain fruit yield and quality, as these bacteria can promote plant growth by solubilizing nutrients, fixing atmospheric nitrogen, producing phytohormones, and exhibiting antagonistic activity against pathogens. This study aimed to evaluate the effects of inoculating plants with Bacillus subtilis and Burkholderia seminalis on their morphological characteristics, fruit technological attributes and yield of common cherry tomatoes (Solanum lycopersicum L.) subjected to induced water deficit. The study was arranged on a split-plot randomized block design, with four water replacement levels (40%, 60%, 80% and 100% of crop evapotranspiration, ETc) and three inoculation treatments (Bacillus subtilis ATCC 23858, Burkholderia seminalis TC3.4.2R3 and non-inoculation). Data were subjected to analysis of variance using the F-test and compared using Tukey’s test (p < 0.05) and multivariate statistics from principal component analysis. Inoculation with Burkholderia seminalis increased the plant fresh and dry shoot and root mass, as well as root volume. Inoculation with Bacillus subtilis increased carotenoid and chlorophyll b contents. Both inoculations enhanced leaf water content in plants experiencing severe water deficit (40% of ETc). The use of these strains as PGPB increased the fruit soluble solids content. Higher productivity in inoculated plants was achieved through a greater number of fruits per cluster, despite the individual fruits being lighter. Treatments with higher water replacement levels resulted in greater yield. Inoculations showed biotechnological potential in mitigating water deficit in cherry tomatoes. Full article

(This article belongs to the Special Issue Advancements in Horticultural Irrigation Water Management)

25 pages, 17130 KB

Open AccessArticle

Identification of Key Regulatory Genes Associated with Double-Petaled Phenotype in Lycoris longituba via Transcriptome Profiling

by Zhong Wang, Xiaoxiao Xu, Chuanqi Liu, Fengjiao Zhang, Xiaochun Shu and Ning Wang

Horticulturae 2025, 11(10), 1156; https://doi.org/10.3390/horticulturae11101156 - 26 Sep 2025

Abstract

Lycoris longituba produces a single flower bearing six tepals. The double-petaled phenotype of L. longituba has gained significant interest in China due to its ornamental and commercial value in tourism industries. This double-petal phenotype, characterized by stamen petalization, shows improved esthetic characteristics compared [...] Read more.

Lycoris longituba produces a single flower bearing six tepals. The double-petaled phenotype of L. longituba has gained significant interest in China due to its ornamental and commercial value in tourism industries. This double-petal phenotype, characterized by stamen petalization, shows improved esthetic characteristics compared with conventional single-petal form. However, the molecular mechanisms underlying this floral trait remain largely undefined. In this study, RNA-based comparative transcriptomic analysis was performed between single- and double-petaled flowers of L. longituba at the fully opened flower stage. Approximately 13,848 differentially expressed genes (DEGs) were identified (6528 upregulated and 7320 downregulated genes). Functional annotation through Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses revealed several DEGs potentially involved in double-petal development. Six candidate genes, including the hub genes LlbHLH49, LlNAC1, LlSEP, LlTIFY, and LlAGL11, were identified based on DEG functional annotation and weighted gene co-expression network analysis (WGCNA). Transcription factors responsive to phytohormonal signaling were found to play a pivotal role in modulating double-petal development. Specifically, 123 DEGs were involved in phytohormone biosynthesis and signal transduction pathways, including those associated with auxin, cytokinin, gibberellin, ethylene, brassinosteroid, and jasmonic acid. Moreover, 521 transcription factors (TFs) were identified, including members of the MYB, WRKY, AP2/ERF, and MADS-box families. These results improve the current understanding of the genetic regulation of the double tepal trait in L. longituba and offer a base for future molecular breeding strategies to enhance ornamental characteristics. Full article

(This article belongs to the Topic Genetic Breeding and Biotechnology of Garden Plants)

► Show Figures

Figure 1

20 pages, 3592 KB

Open AccessArticle

Biocontrol Potential of Bacillus amyloliquefaciens PP19 in Alleviating Watermelon Continuous Cropping Obstacles

by Li Zheng, Jiehao Huang, Guansheng Li, Quan Chen, Tom Hsiang, Xiulong Chen and Shilian Huang

Horticulturae 2025, 11(10), 1155; https://doi.org/10.3390/horticulturae11101155 - 25 Sep 2025

Abstract

Continuous cropping obstacles (CCOs) lead to a decline in yield and quality under repeated cultivation in the same farmland. Notably, CCOs caused by fusarium wilt, autotoxicity, or imbalance in rhizosphere microbial communities reduce the productivity of watermelons (Citrullus lanatus). Considering the [...] Read more.

Continuous cropping obstacles (CCOs) lead to a decline in yield and quality under repeated cultivation in the same farmland. Notably, CCOs caused by fusarium wilt, autotoxicity, or imbalance in rhizosphere microbial communities reduce the productivity of watermelons (Citrullus lanatus). Considering the negative environmental impacts of conventional agrochemicals, it is necessary to evaluate the biocontrol efficiency of microorganisms. Therefore, this study aimed to investigate the biocontrol efficiency of Bacillus amyloliquefaciens strain PP19 against CCOs of watermelon so as to develop alternatives to agrochemicals. The inhibitory effect of PP19 on watermelon fusarium wilt was assessed through plate confrontation assays and field trials. The degradation and utilization of autotoxins by PP19 were examined via co-culture experiments. Additionally, 16S rRNA sequencing was employed to analyze the impact of PP19 on the rhizosphere soil microbial community of watermelon. Specifically, we analyzed the PP19 utilization of four phenolic autotoxins secreted by watermelon roots and assessed their effects on microbial diversity in the watermelon rhizosphere. Plant growth assays showed that PP19 improved the weight and quality of watermelon fruit. Although PP19 inhibited the growth of Fusarium oxysporum f. sp. niveum (Fon), the growth inhibitory effect was significantly enhanced by autotoxins produced by watermelon, including mixed phenolic, cinnamic, ferulic, and p-coumaric acids. Additionally, PP19 effectively degraded and utilized the autotoxins, and the autotoxins enhanced PP19’s swimming ability and biofilm formation. Moreover, PP19 treatment significantly enhanced the microbial diversity in watermelon rhizosphere, increased the number of beneficial bacterial genera, and decreased the number of pathogenic genera. Conclusively, these results suggest that B. amyloliquefaciens strain PP19 improves the resistance of watermelon to CCOs by effectively utilizing and degrading autotoxin, altering soil microbial community structure, and inhibiting Fon17 growth, resulting in improved fruit quality. Overall, PP19 possesses potential application as a biological control agent against CCOs in commercial watermelon cultivation. Full article

(This article belongs to the Special Issue Mitigating Soil-Borne Diseases in Horticultural Crops: Current Challenges and Management Strategies)

► Show Figures

Figure 1

12 pages, 425 KB

Open AccessFeature PaperArticle

Seed Germination Inhibitory Activity of Alkaloid Fractions from Narcissus pseudonarcissus cv. Carlton and Narcissus poeticus Leaves

by Milena Nikolova, Elina Yankova-Tsvetkova, Boriana Sijimova, Rumen Denev and Strahil Berkov

Horticulturae 2025, 11(10), 1154; https://doi.org/10.3390/horticulturae11101154 - 25 Sep 2025

Abstract

Narcissus species have been cultivated for centuries around the world and are mainly used as cut flowers. Although the bulbs of these species have been widely examined as sources of alkaloids and biological activity, the leaves have been understudied. In the present study [...] Read more.

Narcissus species have been cultivated for centuries around the world and are mainly used as cut flowers. Although the bulbs of these species have been widely examined as sources of alkaloids and biological activity, the leaves have been understudied. In the present study alkaloid fractions of leaves from Narcissus pseudonarcissus cv. Carlton and N. poeticus L. were evaluated for inhibitory activity against seed germination of Lolium perenne L. and Trifolium pratense L. Separately, the metabolic profiles from seedlings of the target species were analyzed after treatment with a lycorine solution. The composition of methanolic extracts from seedlings and alkaloid fractions of Narcissus leaves were determined using GC/MS. The N. pseudonarcissus alkaloid fraction was more active than that of N. poeticus. Complete inhibitory activity of the alkaloid fraction was established at a concentration of 1 or 2 mg/mL, depending on the target species. Lycoramine and galanthine were identified as the main alkaloids of N. pseudonarcissus. 8-O-Demethylmaritidine, maritidine and homolycorine were found to be the predominant alkaloids of N. poeticus. Increased accumulation of some amino acids, saccharides and polyols, indicating protein synthesis inhibition, was the most common response of target species seedlings treated with 0.17 µM lycorine. The results showed the promising potential of alkaloid fractions from the leaves of Narcissus species as seed germination inhibitors. The study contributes to full utilization of the resources of these species and presents, to our knowledge, for the first time data on changes in the metabolic profiles of L. perenne and T. pratense seedlings after treatment with lycorine. Full article

(This article belongs to the Special Issue Research on Cultivation and Biological Activity of Medicinal Plants in Horticultural Production)

► Show Figures

Graphical abstract

18 pages, 1569 KB

Open AccessArticle

Data-Driven Optimization of Substrate Composition for Lettuce in Soilless Cultivation

by Ziran Ye, Lupin Deng, Mengdi Dai, Yu Luo, Dedong Kong and Xiangfeng Tan

Horticulturae 2025, 11(10), 1153; https://doi.org/10.3390/horticulturae11101153 - 25 Sep 2025

Abstract

Soilless cultivation has emerged as a sustainable solution for modern agriculture, yet substrate formulation is still often guided by empirical approaches, limiting efficiency and reproducibility. To address this gap, we established a data-driven framework for optimizing substrate composition in garden lettuce (Lactuca [...] Read more.

Soilless cultivation has emerged as a sustainable solution for modern agriculture, yet substrate formulation is still often guided by empirical approaches, limiting efficiency and reproducibility. To address this gap, we established a data-driven framework for optimizing substrate composition in garden lettuce (Lactuca sativa L.) cultivation. Using a randomized design, 200 substrate formulations were prepared from peat, vermiculite, and perlite, and their effects on plant growth were evaluated under controlled environmental conditions. Peat content reduced substrate porosity and water-holding capacity, whereas vermiculite increased both properties (linear regression, p < 0.05). Substrate formulations profoundly affected plant biomass, and the peat content was identified as a key predictor. Two rounds of substrate optimization resulted in a significant increase in shoot and root biomass and chlorophyll content, with increases of 57.5% (p = 9.2 × 10⁻⁸), 89.8% (p = 8.24 × 10⁻¹⁰), and 43.3% (p < 2 × 10⁻¹⁶), respectively, compared with the initial trial. Additionally, hyperspectral imaging (HSI) and RGB imaging were employed for growth monitoring. Random forest machine-learning method identified several red-edge indices (NDVI₇₀₅, mNDVI₇₀₅, mSR₇₀₅) as highly responsive predictors of substrate formulations, highlighting the potential of imaging traits as proxies for substrate optimization. This study provides a reproducible pathway for improving soilless substrate formulations, contributing to data-informed substrate design and advancing the practice of precision agriculture. Full article

(This article belongs to the Special Issue Advances in Soil and Plant Nutrient Management for Optimizing Horticultural Crop Yields and Soil Sustainability)

► Show Figures

Figure 1

14 pages, 2112 KB

Open AccessArticle

Effect of Plastic MAH Storage, 1-MCP, and Coating on Fruit Storability of ‘Sweet Gold’ and ‘Goldone’ Kiwifruit

by Seok-Kyu Jung, Hye-Won Bang, Hyeon-Ji Hwang and Hyun-Sug Choi

Horticulturae 2025, 11(10), 1152; https://doi.org/10.3390/horticulturae11101152 - 25 Sep 2025

Abstract

We examined the modulation of ‘Sweet Gold’ and ‘Goldone’ kiwifruit (Actinidia spp.) ripening using modified atmosphere and humidity (MAH), 1-methylcyclopropene (1-MCP), and edible coating treatments up to 35 days after storage (DAS) at room temperature. The 1-MCP and coating treatments decreased [CO [...] Read more.

We examined the modulation of ‘Sweet Gold’ and ‘Goldone’ kiwifruit (Actinidia spp.) ripening using modified atmosphere and humidity (MAH), 1-methylcyclopropene (1-MCP), and edible coating treatments up to 35 days after storage (DAS) at room temperature. The 1-MCP and coating treatments decreased [CO₂] in both cultivars, whereas MAH treatment rapidly increased or decreased [CO₂]. Use of 1-MCP highly preserved firmness in both cultivars, followed by coating. MAH sharply reduced approximately 17% of ‘Goldone’ fruit firmness at 7 DAS compared to other treatments. MAH, 1-MCP, and coating reduced weight loss in ‘Sweet Gold’ kiwifruits from 14 to 35 DAS. Coating prevented approximately 14% of weight loss in ‘Goldone’ fruits during storage by strong adherence to the fruit surface. The flesh of control and MAH-treated fruits of both cultivars exhibited reduced acidity during storage, increasing the soluble solids content to acidity ratio. The use of 1-MCP delayed a reduction in L* values of the peel color of ‘Sweet Gold’ kiwifruits, while reduced L* values of flesh color were mostly observed with control and MAH treatment in both fruit cultivars. The use of 1-MCP, coating, and MAH maintained high total phenolics, ABTS, and vitamin C levels in both cultivars at 14 and 28 DAS. Fruit ripening was delayed by coating and promoted by MAH treatment, while maintaining the quality and functional substances of the fruit. Full article

(This article belongs to the Special Issue Postharvest Physiology and Quality Improvement of Fruit Crops)

► Show Figures

Figure 1

20 pages, 3564 KB

Open AccessArticle

Advancing Industrial Production of White Grifola frondosa: Liquid Inoculum Culture Parameter Optimization and Molecular Insights into Fruiting Body Development

by Hui-Hui Ren, Jia-Ye Zhang, Jia-Yuan Wang, Shang-Shang Xiao, Su-Ya Liu, Bao-Yue Sun, Shou-Mian Li, Ming Li, Zhi-Qiang Wen and Xiao Li

Horticulturae 2025, 11(10), 1151; https://doi.org/10.3390/horticulturae11101151 - 25 Sep 2025

Abstract

Grifola frondosa is a valuable medicinal and edible mushroom whose industrial cultivation and developmental mechanisms remain poorly understood. In this study, we systematically investigated the optimal cultivation parameters and molecular basis of fruiting body development using the white strain Gr0001+3 through integrated physiological [...] Read more.

Grifola frondosa is a valuable medicinal and edible mushroom whose industrial cultivation and developmental mechanisms remain poorly understood. In this study, we systematically investigated the optimal cultivation parameters and molecular basis of fruiting body development using the white strain Gr0001+3 through integrated physiological and transcriptomic approaches. The results showed that the optimal liquid medium composition was glucose (28.5 g/L), yeast extract (11.5 g/L), and MgSO₄ (2 g/L), with a C/N ratio of 10:1. This composition achieved a mycelial biomass of 2.333 g/L via an orthogonal design. Ideal culture conditions were 100 mL/250 mL liquid volume, 10% inoculum size, and pH 4.0 in single-factor experiments. The fruiting body developmental transcriptomes were analyzed in four stages: early primordia (EP), middle primordia (MP), late primordia (LP), and mature fruiting body (FB). Principal component analysis revealed distinct transcriptional profiles, with greater similarities among later developmental stages. Differential gene expression peaked during the LP vs. FB transition. Functional enrichment (GO/KEGG) showed conserved biological processes in the MP-LP-FB transitions. Heat shock proteins (hsp_78/hsp_82) and the cAMP signaling pathway component (PKAC) were involved in fruiting body development, based on RT-qPCR. This work establishes practical cultivation parameters and offers fundamental insights into the molecular regulation of G. frondosa development, providing a comprehensive foundation for advancing the industrial production of this mushroom. Full article

(This article belongs to the Section Medicinals, Herbs, and Specialty Crops)

► Show Figures

Figure 1

21 pages, 8141 KB

Open AccessArticle

Comprehensive Histological, Endogenous Hormone, and Transcriptome Analysis to Reveal the Mechanism of Hormone Regulation Mediating Pepper (Capsicum annum L.) Fruit Size

by Sijie Tang, Zekui Ou, Xiaowen Fan, Qijian Ning, Wei Liu, Xin Liu, Xingtian Long, Jiahao Zhou and Yuhua Liu

Horticulturae 2025, 11(10), 1150; https://doi.org/10.3390/horticulturae11101150 - 25 Sep 2025

Abstract

As the only harvest organ of pepper, fruit size is an important yield determinant. To elucidate the molecular mechanisms underlying pepper fruit size, we performed histological, physiological, and transcriptomic analyses on the pepper varieties QB6 (large fruit) and CXJ82 (small fruit). High contents [...] Read more.

As the only harvest organ of pepper, fruit size is an important yield determinant. To elucidate the molecular mechanisms underlying pepper fruit size, we performed histological, physiological, and transcriptomic analyses on the pepper varieties QB6 (large fruit) and CXJ82 (small fruit). High contents of auxin and cytokinin in the early stage of fruit development promoted the rapid division of fruit cells in both varieties, which provided sufficient cells for subsequent fruit enlargement. High gibberellin accumulation induced the elongation and expansion of QB6 pericarp cells. Transcriptome analysis showed that genes related to cell division, cell wall polysaccharide degradation, and photosynthesis were highly expressed in QB6 fruit, likely contributing to its larger size. In the hormone–signal transduction factor–gene interaction network, GID6, GID1, IAA12, MYC30, and SAUR36 exhibited high correlations with numerous genes related to cell division, the cell wall, and photosynthesis, emerging as key signal transduction factors for the hormone-mediated regulation of pepper fruit size. Weighted gene co-expression network analysis identified the transcription factors OFP20, HD-ZIP6, and HD-ZIP13 as fundamental for pepper fruit size regulation. Our results expand the understanding of hormone regulation of pepper fruit size, providing a foundation for the breeding and improvement of excellent pepper varieties. Full article

(This article belongs to the Special Issue Genomics and Genetic Diversity in Vegetable Crops)

► Show Figures

Figure 1

15 pages, 1964 KB

Open AccessArticle

Expression Regulatory Mechanisms of the Key Structural Genes in the Carotenoid Biosynthesis Pathway Under Salt Stress of Lycium barbarum

by Zhi-Hang Hu, Li-Xiang Wang, Nan Zhang, Chen Chen, Jing Zhuang, Yue Yin and Ai-Sheng Xiong

Horticulturae 2025, 11(10), 1149; https://doi.org/10.3390/horticulturae11101149 - 24 Sep 2025

Viewed by 116

Abstract

Salt stress is a major abiotic factor limiting wolfberry (Lycium barbarum) growth. As a high-value medicinal and edible crop, wolfberry relies on its carotenoid content, a critical determinant of fruit quality and nutritional value. To elucidate the expression regulatory mechanisms of [...] Read more.

Salt stress is a major abiotic factor limiting wolfberry (Lycium barbarum) growth. As a high-value medicinal and edible crop, wolfberry relies on its carotenoid content, a critical determinant of fruit quality and nutritional value. To elucidate the expression regulatory mechanisms of key genes in the carotenoid biosynthesis pathway under salt stress, this study systematically identified 17 structural genes within the L. barbarum carotenoid pathway using genomic and transcriptomic approaches. Comprehensive analyses were conducted on gene structure, chromosomal distribution, conserved domains, and cis-acting elements. The results revealed that these genes were clustered on chromosomes Chr08 and Chr10 and exhibit strong collinearity with tomato (18 syntenic pairs). Their promoters were enriched with light-responsive (G-box) and stress-responsive (ABRE, DRE) elements. Tissue-specific expression analysis demonstrated high expression in mid-to-late fruit developmental stages (LbaPSY1, LbaPDS) and in photoprotective genes (LbaZEP, LbaVDE) in leaves. Under 300 mM NaCl stress treatment, the genes exhibited a staged response: Early stage (1–3 h): upstream MEP pathway genes (LbaDXS, LbaGGPS) were rapidly induced to supply precursors. Mid-stage (6–12 h): midstream genes (LbaPSY, LbaPDS, LbaZDS) were continuously upregulated, promoting lycopene synthesis and preferentially activating the β-branch (LbaLCYB). Late stage (12–24 h): downstream xanthophyll cycle genes (LbaBCH, LbaZEP, LbaVDE) were significantly enhanced, facilitating the accumulation of antioxidant compounds like violaxanthin and neoxanthin. This coordinated regulation formed a synergistic “precursor supply–antioxidant product” network. This study revealed the phased and coordinated regulatory network of carotenoid biosynthesis genes under salt stress in L. barbarum. It also provided potential target genes for the new cultivar selection with enhanced salt tolerance and nutritional quality. Full article

(This article belongs to the Special Issue New Insights into Protected Horticulture Stress)

► Show Figures

Figure 1

21 pages, 5551 KB

Open AccessArticle

The SlJMJ15, a Putative Histone Demethylase Gene, Acts as a Negative Regulator of Drought Tolerance in Tomato

by Lang Wu, Hanling Zhao, Jiajia Xu, Fasen Lin, Qingxia Yan, Yan Liang, Danyang Xu, Yu Pan, Xingguo Zhang and Jinhua Li

Horticulturae 2025, 11(10), 1148; https://doi.org/10.3390/horticulturae11101148 - 23 Sep 2025

Viewed by 219

Abstract

JmjC domain proteins play crucial roles in plant growth and development, regulation of epigenetic processes, flowering control, and stress defence. However, these proteins have not been systematically identified or characterised in tomato. Here, we performed a genome-wide identification of JmjC domain-containing genes ( [...] Read more.

JmjC domain proteins play crucial roles in plant growth and development, regulation of epigenetic processes, flowering control, and stress defence. However, these proteins have not been systematically identified or characterised in tomato. Here, we performed a genome-wide identification of JmjC domain-containing genes (JMJ family) in tomato and identified 23 SlJMJ genes within the tomato genome. Expression analysis indicated that SlJMJ15 was responsive to drought stress, prompting us to investigate its functional role in tomato plants. We found that SlJMJ15-RNAi lines displayed a severe dwarf phenotype, whereas SlJMJ15-overexpression lines exhibited increased drought sensitivity compared to wild-type plants, indicating that SlJMJ15 negatively regulates drought tolerance in tomatoes. Further investigation suggests that SlJMJ15 may reduce drought tolerance in tomatoes by modulating the expression of key genes involved in abscisic acid signalling pathways through its demethylation activity. This study deepens our understanding of the roles of SlJMJ family genes in tomato growth and abiotic stress responses, laying the foundation for developing strategies to improve drought stress tolerance in tomatoes. Full article

(This article belongs to the Special Issue Breeding by Design: Advances in Vegetables)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Horticulturae, Volume 11, Issue 10 (October 2025) – 13 articles

Further Information

Guidelines

MDPI Initiatives

Follow MDPI