Search Results (20)

Fruit rot caused by Lasiodiplodia pseudotheobromae poses a serious threat to longan (Dimocarpus longan Lour.) production. The present study evaluated antagonistic and phosphate-solubilizing bacteria for their potential use in environmentally responsible disease and soil management. Two complementary Bacillus isolates were selected. Bacillus amyloliquefaciens UPBA63 exhibited strong antagonistic activity against L. pseudotheobromae, whereas Bacillus subtilis SBP04 demonstrated superior phosphate-solubilizing and plant-growth-promoting traits. Their combined application provided complementary benefits for disease suppression and soil phosphorus availability. Biochemical assays and molecular identification using concatenated 16S rDNA and gyrB sequences assigned UPBA63 to Bacillus amyloliquefaciens and SBP04 to B. subtilis. Both isolates produced extracellular protease, cellulase, and amylase. UPBA63 significantly reduced fruit rot incidence in planta and during field trials, whereas SBP04 exhibited the greatest phosphate-solubilizing activity. Field application of UPBA63 and SBP04 combined with organic matter and a chemical fertilizer and fungicide at half the recommended doses reduced disease incidence to 15.40 ± 7.42% and improved yield relative to the untreated control. The integrated treatment combining Bacillus spp. with organic matter, half-rate chemical fertilizer, and half-rate fungicide resulted in a soil pH of 4.56, an organic matter content of 2.92%, and an available phosphorus of 149.25 mg kg⁻¹. Multifunctional Bacillus strains demonstrated dual capacity for pathogen suppression and nutrient mobilization, supporting their potential application in sustainable disease control and soil fertility management in longan orchards. Full article

Exogenous gibberellin (GA₃) significantly improves sugar accumulation in longan (Dimocarpus longan) fruit, yet its molecular mechanism remains unclear. This study demonstrates that 50 mg/L GA₃ optimally enhances sucrose, glucose, fructose, total sugar, and sweetness in longan. Transcriptomic analysis revealed 1345 differentially expressed genes (DEGs), including the sugar transporter gene DlSWEET3a, which was upregulated by GA₃. Subcellular localization confirmed DlSWEET3a resides on the plasma membrane. Functional assays in yeast demonstrated its ability to transport glucose, fructose, mannose, and galactose. Critically, transient overexpression of DlSWEET3a in longan fruit and stable overexpression in tobacco leaves significantly increased soluble sugar content. These results establish that GA₃ promotes sugar accumulation in longan fruit partly through the upregulation of the plasma membrane hexose transporter DlSWEET3a, providing a mechanistic insight into gibberellin-mediated fruit quality improvement. Full article

Corilagin is a hydrolyzable ellagitannin and naturally occurring polyphenolic compound widely distributed in medicinal plants. It is also present in longan (Dimocarpus longan), known as lumyai in Thailand, a subtropical fruit extensively cultivated across China and Southeast Asia. Corilagin has been reported to exhibit strong antioxidant, anti-inflammatory, hepatoprotective, and anticancer activities through modulation of multiple cellular signaling pathways. However, despite these well-established pharmacological properties, its potential role in regulating bone marrow mesenchymal stem cell (BM-MSC) differentiation has not been fully explored in biomedical applications. In this study, we investigated the effects of corilagin on BM-MSC viability, protein-binding interactions, and lineage-specific differentiation toward osteogenic and chondrogenic pathways. Cytotoxicity assessment using human synovial SW-982 cells demonstrated that corilagin maintained cell viability at concentrations ranging from 1.56 to 50 µg/mL within 48 h, whereas prolonged exposure resulted in a time-dependent reduction in viability. In BM-MSCs, corilagin significantly enhanced osteogenic and chondrogenic differentiation in a dose-dependent manner, as evidenced by increased mineral deposition and cartilage matrix formation, as revealed by Alizarin Red S, Toluidine Blue, and Alcian Blue staining. Quantitative analyses further showed the upregulation of key lineage-specific genes, including Runx2 and osteopontin (OPN) for osteogenesis and Sox9 and aggrecan for chondrogenesis. Protein-binding assays confirmed the molecular interaction capacity of corilagin, supporting its biological activity. Overall, these findings demonstrate that corilagin promotes MSC-mediated osteogenic and chondrogenic differentiation while maintaining acceptable cytocompatibility, highlighting its potential as a natural small-molecule candidate for bone and cartilage tissue engineering and other biomedical fields with regenerative medicine applications. Full article

Methyl jasmonic acid (MeJA) is a vital phytohormone that plays a key role in plant growth and adaptation to various environmental stresses. In the present study, on the basis of the longan genome, we identified a total of seven versatile putative abscisic acid-insensitive genes, which are the key players in plant growth and stress response. On the basis of bioinformatics analysis, transcriptome data, exogenous treatment experiments, and RT-qPCR findings, a comprehensive evolutionary pattern of ABI genes in different plant species and the effect of different MeJA treatments during early somatic embryogenesis in D. longan was carried out. The phylogeny results revealed that the seven DlABI genes evolved independently in monocots and dicots, having high protein sequence similarity, especially with Arabidopsis ABI genes. The comparative findings of gene structure, motif prediction, and synteny analysis suggest that DlABI genes disperse mainly through duplication events rather than localized tandem repeats. Furthermore, the correlations among the expressions of DlABI genes propose that the organization of the cis-regulatory elements in the promoter regions may regulate the temporal and spatial transcription activation of these genes. The qRT-PCR results revealed that the 50 µM MeJA treatment significantly upregulated the expression of DlABI3, followed by DlABI1, DlABI2, DlABI5, DlABI4, and DlABI8, respectively. The ROS findings clearly revealed that MeJA distinctly elevated the SOD, POD, and H₂O₂ activities while reducing catalase and MDA contents. The subcellular localization of DlABI3 further confirmed its presence in the nucleus, suggesting its predicated transcriptional regulatory role in MeJA-mediated early SE in longan. Our findings reveal that the ABI genes are integral to the mechanism of MeJA-induced early somatic embryogenesis in longan by maintaining the ROS activity. Full article

Dimocarpus longan Lour. is an evergreen tree of the genus Longan in the Sapindaceae family, native to tropical and subtropical regions. Longan embryonic development is closely related to fruit set and fruit quality. An in-depth study of the mechanism of longan embryonic development could therefore contribute to the development of the longan industry. DIMBOA is the principal compound representing benzoxazinoids (BXs), and is closely linked to auxin biosynthesis and signal transduction. Auxin is one of the crucial hormones for inducing somatic embryogenesis (SE) in plants. Previous research has shown that DIMBOA promotes morphogenesis in the early somatic embryogenesis of longan, but the specific regulatory mechanism has not yet been clarified. To elucidate the molecular mechanism by which DIMBOA affects early somatic embryogenesis in longan, we chose longan embryogenic cultures grown under 0 mg/L DIMBOA as the control group (the check, CK), and longan embryogenic cultures grown under 0.1 mg/L DIMBOA as the treatment group (D) to be analyzed by transcriptomic sequencing. A total of 478 differentially expressed genes (DEGs) are detected in check vs. D, of which 193 are upregulated and 285 are downregulated. These DEGs are significantly enriched in the biosynthetic and metabolic functions of various substances such as vitamin B₆ (VB₆) biosynthesis, phenylpropanoid pathways, and carbohydrate metabolism. DIMBOA affects SE processes in longan via TFs, including MYB, ZF, bHLH, LBD, NAC, WRKY, etc. After DIMBOA treatment, the expression of most of the key genes for IAA synthesis was significantly downregulated, VB₆ content was significantly reduced, and H₂O₂ content was significantly increased. Therefore, it is suggested that DIMBOA directly or indirectly affects the H₂O₂ content through the VB₆ metabolic pathway, thereby regulating the endogenous IAA level to modulate the early SE morphogenesis of longan. Full article

Benzoxazinoids (BXs) are tryptophan-derived indole metabolites and play a role in various physiological processes, such as auxin metabolism. Auxin is essential in the process of somatic embryogenesis (SE) in plants. In this study, we used bioinformatics, transcriptome data, exogenous treatment experiments, and qPCR analysis to study the evolutionary pattern of Bx genes in green plants, the regulatory mechanism of DlBx genes during early SE, and the effect of 2,4-dihydroxy-7-methoxy-1,4-benzoxazine-3-one (DIMBOA) on the early SE in Dimocarpus longan Lour. The results showed that 27 putative DlBxs were identified in the longan genome; the Bx genes evolved independently in monocots and dicots, and the main way of gene duplication for the DlBx was tandem duplication (TD) and the DlBx were strongly constrained by purification selection during evolution. The transcriptome data indicated varying expression levels of DlBx during longan early SE, and most DlBxs responded to light, temperature, drought stress, and 2,4-dichlorophenoxyacetic acid (2,4-D) treatment; qRT-PCR results showed DlBx1, DlBx6g and DlBx6h were responsive to auxin, and treatment with 0.1mg/L DIMBOA for 9 days significantly upregulated the expression levels of DlBx1, DlBx3g, DlBx6c, DlBx6f, DlB6h, DlBx7d, DlBx8, and DlBx9b. The correlation analysis showed a significantly negative correlation between the expression level of DlBx1 and the endogenous IAA contents; DIMBOA significantly promoted the early SE and significantly changed the endogenous IAA content, and the IAA content increased significantly at the 9th day and decreased significantly at the 13th day. Therefore, the results suggested that DIMBOA indirectly promote the early SE by changing the endogenous IAA content via affecting the expression level of DlBx1 and hydrogen peroxide (H₂O₂) content in longan. Full article

GATA transcription factors, which are DNA-binding proteins with type IV zinc finger binding domains, have a role in transcriptional regulation in biological organisms. They have an indispensable role in the growth and development of plants, as well as in improvements in their ability to face various environmental stresses. To date, GATAs have been identified in many gene families, but the GATA gene in longan (Dimocarpus longan Lour) has not been studied in previous explorations. Various aspects of genes in the longan GATA family, including their identification and classification, the distribution of their positions on chromosomes, their exon/intron structures, a synteny analysis, their expression at different temperatures, concentration of PEG, early developmental stages of somatic embryos and their expression levels in different tissues, and concentrations of exogenous hormones, were investigated in this study. This study showed that the 22 DlGATAs could be divided into four subfamilies. There were 10 pairs of homologous GATA genes in the synteny analysis of DlGATA and AtGATA. Four segmental replication motifs and one pair of tandem duplication events were present among the DlGATA family members. The cis-acting elements located in promoter regions were also found to be enriched with light-responsive elements, which contained related hormone-responsive elements. In somatic embryos, DlGATA4 is upregulated for expression at the globular embryo (GE) stage. We also found that DlGATA expression was strongly up-regulated in roots and stems. The study demonstrated the expression of DlGATA under hormone (ABA and IAA) treatments in embryogenic callus of longan. Under ABA treatment, DlGATA4 was up-regulated and the other DlGATA genes did not respond significantly. Moreover, as demonstrated with qRT-PCR, the expression of DlGATA genes showed strong up-regulated expression levels under 100 $\mathsf{\mu }\mathrm{m}\mathrm{o}\mathrm{l}·{\mathrm{L}}^{-1}$ concentration IAA treatment. This experiment further studied these and simulated their possible connections with a drought response mechanism, while correlating them with their expression under PEG treatment. Overall, this experiment explored the GATA genes and dug into their evolution, structure, function, and expression profile, thus providing more information for a more in-depth study of the characteristics of the GATA family of genes. Full article

We aimed to analyze the increase in the sleep-promoting effects based on the mixed ratio of botanical extracts, Ziziphus jujuba seeds, Dimocarpus longan fruits, and Lactuca sativa leaves, using animal models. Behavioral analyses, including an analysis of the total sleep time of Drosophila melanogaster, were conducted to select the optimal mixed ratio of the three botanical extracts. The effects were verified in a caffeine-induced sleepless model, specific neurotransmitter receptor antagonists, and ICR mice. In D. melanogaster exposed to 2.0% of each extract, group behavior was significantly reduced, and the mixed extracts of Z. jujuba, D. longan, and L. sativa (4:1:1 and 1:4:1) significantly increased the total sleep time with individual fruit flies. In the caffeine-induced insomnia model, mixed extracts (4:1:1 and 1:4:1) led to the highest increase in total sleep time. An analysis of locomotor ability revealed a significant reduction in the mobility percentage in the mixed extract groups (0:0:1, 1:0:1, 1:1:1, 4:1:1, and 1:4:1). The administration of Z. jujuba extract and mixed extracts (4:1:1) significantly increased the expression of GABA_A-R, whereas the administration of the mixed extracts (4:1:1) and (1:4:1) significantly increased the expression of GABAB-_R1 and GABAB-_R2, respectively. D. longan extract and the mixed ratio (1:4:1) reduced the subjective nighttime movement and increased the total sleep time in the presence of flumazenil. An analysis of ICR mice indicated that the administration of mixed extracts (4:1:1) significantly increased sleep duration in a dose-dependent manner. These results indicated that the mixed ratio of Z. jujuba, D. longan, and L. sativa extracts, particularly the mixed ratio of 4:1:1, may have sleep-enhancing effects in fruit flies and mice. The study also identified changes in gene expression related to GABA receptors, indicating the potential mechanism for the observed sleep-promoting effects. Full article

Agriculture, entwined with climatic conditions, plays a pivotal role in Thailand’s sustenance and economy. This study aimed to examine the trends of climate variability and its correlation with crop yields and social and farm factors affecting farm net income in Chiang Mai province, Thailand. Time series climate data (2002–2020) on temperature and rainfall and yields were analyzed using the Mann–Kendall trend test and Sen’s slope estimation to investigate the trends and their changes. The Pearson correlation was used to assess the association between climate variability and cultivated crop yields, and multiple linear regression was used to detect the factors influencing the farm net income. The findings show that the total annual rainfall showed an unchanged trend, but the annual temperature increased over time. Higher temperature negatively impacted longan yield but positively affected maize, with no significant impact on rice yield. The rainfall trend had no effect on crop yields. Despite declining trends in some cultivated crops’ yield, farm net income was unaffected by individual crop types. Farm income relied on cumulative output and geographic location. This research emphasizes the need for integrating climate data and forecasting models considering agronomic and socio-economic factors and crop suitability assessments for specific regions into adaptation policies and practice. Full article

The selenylated polysaccharides chemically belong to the organic Se-conjugated macromolecules and have recently been attracting more and more attention due to their potential to promote body health or prevent cancers. Longan (Dimocarpus longan L.), as a subtropical fruit, contains soluble and non-digestible polysaccharides that are regarded with health care functions in the body. In this study, the longan polysaccharides (LP) were obtained via enzyme-assisted water extraction, and then chemically selenylated using a reaction system composed of HNO₃–Na₂SeO₃ to yield two selenylated products, namely, SeLP1 and SeLP2, with Se contents of 1.46 and 4.79 g/kg, respectively. The anti-cancer effects of the three polysaccharide samples (LP, SeLP1, and SeLP2) were thus investigated using the human colon cancer HT-29 cells as the cell model. The results showed that SeLP1 and SeLP2 were more able than LP to inhibit cell growth, alter cell morphology, cause mitochondrial membrane potential loss, increase intracellular reactive oxygen and [Ca²⁺]_i levels, and induce apoptosis via regulating the eight apoptosis-related genes and proteins including Bax, caspases-3/-8/-9, CHOP, cytochrome c, DR5, and Bcl-2. It was thereby proven that the selenylated polysaccharides could induce cell apoptosis via activating the death receptor, mitochondrial-dependent, and ER stress pathways. Collectively, both SeLP1 and SeLP2 showed higher activities than LP in HT-29 cells, while SeLP2 was consistently more active than SeLP1 in exerting these assessed anti-cancer effects on the cells. In conclusion, this chemical selenylation covalently introduced Se into the polysaccharide molecules and caused an enhancement in their anti-cancer functions in the cells, while higher selenylation extent was beneficial to the activity enhancement of the selenylated products. Full article

ε-poly-l-lysine (ε-PL) holds a strong antibacterial property and is widely used for food preservation. However, the application of ε-PL to enhance fruit disease resistance in postharvest longans (Dimocarpus longan Lour.) has not been explored. The objective of this study was to explore the impact of ε-PL treatment on disease occurrence and energy metabolism of longans infected with Phomopsis longanae Chi (P. longanae). It was found that, in comparison with P. longanae-inoculated longans, ε-PL could decrease the fruit disease index and adenosine monophosphate (AMP) content, increase the amounts of adenosine triphosphate (ATP), adenosine diphosphate (ADP), and energy charge, and enhance the activities of adenosine triphosphatase (ATPase) (such as H⁺-, Mg²⁺-, and Ca²⁺-ATPase) in the mitochondria, protoplasm, and vacuole. The results suggest that the higher levels of ATPase activity and energy status played essential roles in disease resistance of postharvest longan fruit. Therefore, the ε-PL treatment can be used as a safe and efficient postharvest method to inhibit the disease occurrence of longan fruit during storage at room temperature. Full article

Polyamines (PAs) play an important regulatory role in many basic cellular processes and physiological and biochemical processes. However, there are few studies on the identification of PA biosynthesis and metabolism family members and the role of PAs in the transition of plant embryogenic calli (EC) into globular embryos (GE), especially in perennial woody plants. We identified 20 genes involved in PA biosynthesis and metabolism from the third-generation genome of longan (Dimocarpus longan Lour.). There were no significant differences between longan and other species regarding the number of members, and they had high similarity with Citrus sinensis. Light, plant hormones and a variety of stress cis-acting elements were found in these family members. The biosynthesis and metabolism of PAs in longan were mainly completed by DlADC2, DlSAMDC2, DlSAMDC3, DlSPDS1A, DlSPMS, DlCuAOB, DlCuAO3A, DlPAO2 and DlPAO4B. In addition, 0.01 mmol∙L⁻¹ 1-aminocyclopropane-1-carboxylic acid (ACC), putrescine (Put) and spermine (Spm), could promote the transformation of EC into GE, and Spm treatment had the best effect, while 0.01 mmol∙L⁻¹ D-arginine (D-arg) treatment inhibited the process. The period between the 9th and 11th days was key for the transformation of EC into GE in longan. There were higher levels of gibberellin (GA), salicylic acid (SA) and abscisic acid (ABA) and lower levels of indole-3-acetic acid (IAA), ethylene and hydrogen peroxide (H₂O₂) in this key period. The expression levels in this period of DlADC2, DlODC, DlSPDS1A, DlCuAOB and DlPAO4B were upregulated, while those of DlSAMDC2 and DlSPMS were downregulated. These results showed that the exogenous ACC, D-arg and PAs could regulate the transformation of EC into GE in longan by changing the content of endogenous hormones and the expression levels of PA biosynthesis and metabolism genes. This study provided a foundation for further determining the physicochemical properties and molecular evolution characteristics of the PA biosynthesis and metabolism gene families, and explored the mechanism of PAs and ethylene for regulating the transformation of plant EC into GE. Full article

Dodder (Cuscuta spp.) is a parasitic weed damaging many plants and agricultural production. The native obligate parasite Cuscuta japonica Choisy (Japanese dodder) parasitizes Dimocarpus longans Lour., Ficus septica Burm. F., Ficus microcarpa L.f., Mikania micrantha H.B.K. and Melia azedarach Linn, respectively. Five Japanese dodders growing on different plants exhibit slightly different metabolites and amounts which present different pharmacological effects. Among these plants, a significant antiviral activity against influenza A virus (IAV) was found in Japanese dodder parasitizing on D. longans Lour. (CL). To further explore methanol extract components in Japanese dodder (CL), four undescribed aromatic glycosides, cuscutasides A–D (compounds 1–4) were isolated, together with twenty-six known compounds 5–30. The chemical structures of 1–4 were elucidated using a combination of spectroscopic techniques. The eighteen isolated compounds were evaluated for antiviral activity against IAV activity. Among them, 1-monopalmitin (29) displayed potent activity against influenza A virus (A/WSN/1933(H1N1)) with EC₅₀ 2.28 ± 0.04 μM and without noteworthy cytotoxicity in MDCK cells. The interrupt step of 29 on the IAV life cycle was determined. These data provide invaluable information for new applications for this otherwise harmful weed. Full article

Dimocarpus longan, Litchi chinensis, and Nephelium lappaceum are commercially valuable subtropical and tropical fruits of the Sapindaceae family. Arillus and seeds of the three species have very similar morphologies; however, the arillus of D. longan is used as the herbal medicine Longan Arillus and seeds of L. chinensis are used as Litchi Semen in Korean and Chinese pharmacopoeias. The adulteration of herbal medicines with inauthentic species, including the use of Aril and seed fractions acquired from a single species for two herbal medicines (e.g., Longan Arillus and Litchi Semen), is often driven by economic motives. DNA markers are a tool for the detection of adulterants in commercial products. To establish rapid and reliable assays for the genetic identification of authentic Longan Arillus and Litchi Semen, we developed DNA markers with high specificity and sensitivity based on internal transcribed spacer (ITS) sequences. The newly developed DNA markers and multiplex PCR assay may contribute to efforts to protect against adulteration, quality control, and the standardization of herbal medicines. Full article

In the Northwest Vietnam, traditional maize (Zea mays) cultivation practices of farmers mainly based on sole cropping, intensive tillage combined with burning crop residues on steep slopes. These cultivation practices resulted in severe erosion, soil degradation, reducing crop production and un-sustainable production systems. It requires assessing of the impact of agroforestry practice on the soil conservation in the context of the upland areas in Northwest Vietnam. This study has been carried out since 2017 to present the actual impact of agroforestry practice including longan (Dimocarpus longan)+mango (Mangifera indica L.)+maize+forage grass strips (Guinea-Panicum maximum) on soil conservation. The assessment based on quantifying soil loss by soil traps and evaluating terrace’s formation by erosion pins placing above forage grass strips. The sole maize system had been using for the comparison. The initial results showed that the evaluated agroforestry practice reduced soil loss from 18.3 to 37.4% in compared with the sole maize system in 2017 and 2018, respectively. In the second year (2018), the deposition of sediment on the front and rear pins at the above grass trips was 0.81 and 0.41 cm, respectively. It indicated the increment in soil surface at the above grass strips. In contrast, the negative value of the deposition of sediment was recorded in the sole maize system. We are continuing to monitor the impact of agroforestry practices on reducing soil loss and terrace formation, and evaluate the function of the system on soil fertility improvement, nutrient use efficiency and economic profitability. Full article