Search Results (136)

Powdery mildew (PM) is a major disease affecting bitter gourd cultivation, and resolving the molecular regulatory mechanisms underlying PM resistance is important for bitter gourd molecular breeding for resistance. In this study, morphological and molecular methods were used to identify the PM pathogen in bitter gourd, and comparative transcriptome analysis was performed on leaves of the resistant cultivar R and the susceptible cultivar S after PM infection. The morphological and molecular identification results showed that the PM pathogen in bitter gourd was Podosphaera xanthii. Scanning electron microscopy results revealed that the P. xanthii exhibited distinct growth patterns in the R and S after P. xanthii infection. Compared to the S, the R exhibited 3966, 2729, 5891, and 3878 differentially expressed genes (DEGs) at 0, 2, 3, and 4 days after P. xanthii infection, respectively. KEGG enrichment analysis showed that DEGs were primarily enriched in plant–pathogen interactions, MAPK signaling pathway plants, and plant hormone signal transduction pathways. Transcription factor (TF) analysis of differentially expressed genes revealed that MYB, bHLH, and ERF family members could be involved in the defense process against the P. xanthii infection. Moreover, the analysis of the MLO genes revealed that Moc10g30350.1 could be involved in regulating PM resistance. These findings could enrich the molecular theoretical basis for resistance to PM, and provide new insights for the molecular breeding process of bitter gourd resistance to PM. Full article

Tea plants (Camellia sinensis) uniquely hyperaccumulate fluoride (F) and concurrently exhibit a preference for ammonium nitrogen (NH₄⁺-N) over nitrate nitrogen (NO₃⁻-N). However, the mechanistic basis for co-existence of NH₄⁺-N preference and F hyperaccumulation in C. sinensis remains unexplored. Here, we investigated F accumulation and translocation with varying N supplies (0 mM and 2.854 mM N with NH₄⁺-N:NO₃⁻-N ratios of 3:1, 4:0 and 0:4) and F concentrations (0, 8 and 16 mg·L⁻¹ NaF) to reveal the mechanism driving NH₄⁺-N preference and F hyperaccumulation in C. sinensis. Results show that NH₄⁺-N supply enhanced H⁺ efflux, mobilizing aluminum (Al) to form mobile Al-F complexes for translocation to shoots, thereby alleviating F toxicity in roots. This process was facilitated by transporters including CsCLCd, CsCLCe, CsCLCf2 and CsFEX. In contrast, NO₃⁻-N promoted root sequestration of F as immobile calcium (Ca)-F complexes, exacerbating damage. Under NO₃⁻-N supply, CsCLCb primarily mediated NO₃⁻ transport, while CsCLCc, CsCLCe, CsCLCf1, CsCLCf2 and CsFEX were involved in F transport. In leaves, CsCLCd, CsCLCe, CsCLCf1, CsCLCf2, CsCLCg and CsFEX mediated vacuolar sequestration under both N conditions. These findings elucidate that NH₄⁺-N preference is mechanistically linked to F hyperaccumulation through an Al-assisted translocation pathway, which confers tolerance by exporting F from roots. Full article

Heat threatens male fertility in crops, yet the regulatory basis of anther dehiscence under high temperatures remains unclear. We compared a heat-sensitive pepper cultivar (DL) with a heat-tolerant landrace (B021) across two anther stages using integrated transcriptome, small-RNA, degradome, co-expression, and enzymatic assays. DL showed a collapse of anther dehiscence above 34–38 °C, whereas B021 retained normal dehiscence at 39 °C, and histology revealed tapetal enlargement, premature degeneration, and locule contraction only in DL. RNA-seq indicated genotype- and stage-dependent reprogramming, with DL suppressing phenylpropanoid/cell-wall, transport, and proteostasis pathways, while B021 maintained reproductive and stress-integration programs. Small-RNA profiling and degradome sequencing identified conserved miRNA families with in vivo target cleavage, and notably, miR397 targeting a laccase gene showed stronger evidence in B021, which is consistent with controlled lignification. Functional organization of differentially expressed miRNA targets highlighted modules in respiration/redox, hormone and terpenoid metabolism, vascular–cell-wall programs, and proteostasis/osmotic buffering. WGCNA modules correlated with heat-tolerance traits converged on the same processes. Enzyme assays corroborated multi-omics predictions, with SOD, CAT, and POD activities consistently induced in B021 and limited MDA accumulation. Together, the data supports a model in which tolerant anthers sustain dehiscence under heat by coordinating secondary-wall formation, auxin/jasmonate/gibberellin crosstalk, respiratory and reactive oxygen species buffering, and protein/membrane quality control, providing tractable targets for breeding heat-resilient peppers. Full article

From the 1950s to the 1970s, approximately 80,000 kg of tea seeds were introduced from mainland China to the Xizang Autonomous Region for experimental cultivation. To assess the genetic diversity patterns of these tea accessions following more than half a century of acclimatization to plateau environments, we analyzed genetic variation, population structure, and genetic distinctiveness among fifty tea germplasm using nine phenotypic traits and 30 SSR markers. Phenotypic analysis revealed a moderately high level of genetic diversity, as indicated by the mean Shannon diversity index (H′ = 1.29). Principal component analysis (PCA) indicated that phenotypic variation was not geographically structured across the collection sites. The SSR markers exhibited a high degree of polymorphism, with an average polymorphic information content (PIC) of 0.610 and a genetic diversity index (I) of 1.437, indicating substantial genetic variation. Analysis of molecular variance (AMOVA) revealed that genetic differentiation occurred predominantly within populations, accounting for 91.49% of the total genetic variation. Similarly, 97.86% of the variation was attributed to differences within elevational gradients. Discriminant analysis of principal components (DAPC) and Bayesian population structure modeling (STRUCTURE) both identified two genetic clusters among the studied genotypes. Our results have practical implications for tea breeding programs by providing guidance for parental selection, informing germplasm collection management, and supporting the conservation of genetic resources. Full article

Background: Chionanthus retusus Lindl. et Paxt., a deciduous tree of the genus Chionanthus (Oleaceae), represents a significant native species and a widely cultivated ornamental. Its tender leaves can be processed into tea, traditionally consumed in southern China under the common name “Nuomi Cha”. Methods: Our team quantified the tea polyphenol content across 150 individual trees of C. retusus and selected three low-polyphenol (ZB_D_14, AQ_2, AQ_1) and three high-polyphenol (SX_3, SXG_D_8, TS_D_13) lines for transcriptome sequencing of their young leaves. The resulting data were analyzed to screen for candidate genes. Subsequently, transgenic plants were constructed, and their tea polyphenol content was determined. Results: A significant difference in tea polyphenol content was confirmed between the high- and low-polyphenol lines. Weighted Gene Co-expression Network Analysis (WGCNA) pinpointed a key module strongly associated with tea polyphenol synthesis, encompassing 432 DEGs, which were predominantly enriched in pathways like phenylpropanoid biosynthesis. A comparative transcriptomic analysis further yielded 84 DEGs (40 up- and 44 down-regulated). Enrichment analysis showed these were primarily involved in flavonoid and phenylpropanoid biosynthesis pathways. Expression profiling of genes in the tea polyphenol biosynthetic pathway indicated that several key genes (e.g., 4CL, CHS, DFR) were highly expressed in the high-content lines. A gene interaction network related to this synthesis identified 20 hub genes (e.g., CrHSP70-14, CrMYB44, CrbHLH92). Functional validation of four hubs (CrMYB44, CrHSP70-14, CrCDC6B, CrRAE1) via tobacco transient transformation assays demonstrated that all four significantly elevated tea polyphenol levels, with CrHSP70-14 overexpression yielding the highest content. Furthermore, stable CrHSP70-14 overexpression transgenic tobacco lines were generated, exhibiting significantly higher leaf tea polyphenol content versus controls. Conclusions: This study identifies multiple regulatory genes involved in C. retusus tea polyphenol biosynthesis, provides initial mechanistic insights, and establishes a molecular foundation for breeding specialized tea cultivars of this species. Full article

Cadmium (Cd), a toxic and mobile heavy metal, poses significant risks to agricultural systems due to industrial pollution. Tea plants (Camellia sinensis L.) efficiently absorb and accumulate Cd from soil, leading to contamination in leaves. Chronic consumption of Cd-laden tea can cause severe health issues, including neurological, reproductive, and immunological disorders, as well as increased cancer risk. Despite growing concerns, the molecular mechanisms of Cd stress response in tea plants remain poorly understood. Current research highlights key physiological adaptations, including activation of antioxidant defenses and modulation of secondary metabolite pathways, which influence tea quality. Cd disrupts photosynthesis, induces oxidative stress, and alters the biosynthesis of flavor-related compounds. Several critical genes involved in Cd transport (e.g., CsNRAMP5, CsHMA3, CsZIP1), sequestration (CsPCS1), and stress regulation (CsMYB73, CsWRKY53, CsbHLH001) have been identified, offering insights into molecular responses. This review systematically examines Cd dynamics in the soil-tea plant system, its effects on growth, photosynthesis, and quality, and the physiological and biochemical mechanisms underlying Cd tolerance. By consolidating recent findings on Cd-responsive genes and regulatory pathways, this study provides a theoretical foundation for breeding Cd-resistant tea varieties and ensuring production safety. Furthermore, it identifies future research directions, emphasizing the need for deeper mechanistic insights and practical mitigation strategies. These advancements will contribute to safer tea consumption and sustainable cultivation practices in Cd-contaminated regions. Full article

Background: Heterosis (hybrid vigor) is a fundamental phenomenon in plant breeding, but its molecular basis remains poorly understood in perennial crops such as tea (Camellia sinensis). This study aimed to elucidate the molecular mechanisms underlying heterosis in tea and its hybrids by performing integrated transcriptomic and metabolomic analyses of F₁ hybrids derived from two elite cultivars, Fuding Dabaicha (FD) and Baojing Huangjincha 1 (HJC). Methods: Comprehensive RNA sequencing and widely targeted metabolomic profiling were conducted on the parental lines and F₁ hybrids at the one-bud-one-leaf stage. Primary metabolites (including amino acids, nucleotides, saccharides, and fatty acids) were quantified, and gene expression profiles were obtained. Transcriptomic and metabolomic datasets were integrated using KEGG pathway enrichment and co-expression network analysis to identify coordinated molecular changes underlying heterosis. Results: Metabolomic profiling detected 977 primary metabolites, many of which displayed non-additive accumulation patterns. Notably, linoleic acid derivatives (9(S)-HODE, 13(S)-HODE) and nucleotides (guanosine, uridine) exhibited significant positive mid-parent heterosis. Transcriptomic analysis revealed extensive non-additive gene expression in F₁ hybrids, and upregulated genes were enriched in fatty acid metabolism, nucleotide biosynthesis, and stress signaling pathways. Integrated analysis demonstrated strong coordination between differential gene expression and metabolite accumulation, especially in linoleic acid metabolism, cutin/suberine biosynthesis, and pyrimidine metabolism. Positive correlations between elevated fatty acid levels and transcript abundance of lipid metabolism genes suggest that the transcriptional remodeling of lipid pathways contributes to heterosis. Conclusions: These findings provide novel insights into tea plant heterosis and identify potential molecular targets for breeding high-quality cultivars. Full article

Gardenia tea is esteemed for its delicate and fragrant aroma. Background: However, there is a scarcity of studies focused on the aromatic properties of gardenia-scented white tea, particularly regarding how these aroma profiles evolve over different storage durations. Methods: This research sought to analyze the volatile compounds present in gardenia white tea through headspace solid-phase microextraction gas chromatography–mass spectrometry (HS-SPME-GC-MS) alongside multivariate analysis techniques. Results: Findings indicated that the main chemical categories found in newly white tea (NWT), aged white tea (AWT), gardenia newly white tea (GNWT), and gardenia aged white tea (GAWT) included esters, terpenoids and ketones. The multivariate analysis pinpointed 11 significant volatile compounds (such as linalool, [(Z)-non-6-enyl] acetate, and (E)-non-4-enal) and an 10 additional key volatile compounds (including linalool, [(Z)-non-6-enyl] acetate, and 1-isothiocyanato-3-(methylthio)-2-Propane) that had variable importance in projection (VIP) values exceeding 2 and odor activity values (OAVs) greater than 1. These compounds effectively distinguished the aroma profiles of GNWT from NWT and GAWT from AWT. Notably, the levels of these compounds were significantly elevated in GNWT and GAWT compared to their NWT and AWT counterparts. Additionally, three volatile compounds in GNWT and six in GAWT showed a decline in concentration relative to NWT and AWT. Conclusions: These compositional differences are suggested to clarify the aromatic distinctions between gardenia-scented white tea and its white tea base. The outcomes of this study will contribute to a deeper chemical understanding of the unique aroma of gardenia white tea, providing a theoretical basis for assessing quality and developing products based on different storage periods. Full article

Gardenia black tea (GBT) is a prized Chinese scented tea, renowned for its pleasant aroma. However, the influence of repeated scenting rounds on its volatile profile remains poorly characterized. This study investigated the aroma profiles of GBT produced with zero, two, and three scenting rounds (T0, T1, T2) using sensory evaluation and Headspace Solid-Phase Microextraction–Gas Chromatography–Mass Spectrometry (HS-SPME-GC-MS). Sensory analysis revealed that GBTs (T1, T2) scored significantly higher in aroma and taste than the black tea base (T0). GC-MS analysis identified numerous volatile compounds, with esters, terpenoids, and ketones being predominant. Multivariate analysis identified 52 key volatiles (VIP > 2.0) that differentiated the tea samples. Among these, 28 compounds had odor activity values (OAVs) > 1, indicating significant sensory contributions. Ultimately, 11 volatiles, including (Z)-hex-3-enyl acetate, linalool, and (E)-hex-2-enal, were identified as the crucial basis for the characteristic fresh and floral scent of GBTs. The specific abundance levels of these compounds are hypothesized to underlie the superior, fresh, and elegant aroma of T1, compared to the slightly ripe and stuffy floral notes of T2. Therefore, it is advisable to prioritize two rounds of scenting during the production of gardenia black tea. These findings provide a theoretical foundation for optimizing the scenting process and enhancing the quality of GBT. Full article

The absence of a high-efficiency and stable genetic transformation system has been a critical bottleneck, impeding both functional gene characterization and precision breeding efforts in Camellia sinensis (tea), and browning is the first problem encountered in tissue culture of tea. In this paper, to identify optimal spectral conditions for minimizing browning in tissue culture, we subjected three tea plant cultivars to distinct light quality treatments and conducted comprehensive metabolomic profiling of their phytochemical contents. This study demonstrates that wavelength-specific light treatments can induce reversible modifications in the physicochemical characteristics of tea leaves, effectively reducing the accumulation of flavonoid compounds, including polyphenols, in plant tissues. Notably, tissues subjected to optimized wavelength conditions exhibit superior performance as explant sources for in vitro culture systems, demonstrating significantly lower browning rates. Comparative analysis of 460 nm, 660 nm, and 730 nm irradiation treatments revealed consistent suppression of polyphenol biosynthesis across all examined cultivars. However, the wavelength eliciting maximal reduction showed significant cultivar-dependent variation, indicating genotype-specific photoresponsive regulation of secondary metabolism. Full article

Tea (Camellia sinensis (L). Kuntze) cultivation by smallholder out-growers has grown significantly. Recent government initiatives have expanded production from traditional tea growing regions. This study investigated how smallholder farmers perceive and prefer different commercial tea clones. It also looked at the factors that influence their choices across major tea-growing regions of Uganda. A structured questionnaire was administered to 324 randomly selected tea out-growers from Central, Western, Kigezi, and West Nile regions. Data was analyzed using descriptive statistics, a Tea Preference Index (rating clone attributes on a 1–5 scale), and a multivariate Probit (MVP) model to evaluate farmers’ choices and preferences. Clone 303/577 is the most cultivated, accounting for 59%. Adoption rates were high in West Nile (98%), Kigezi (77%), and Central (67%) regions. Clone 6/8 ranked second at 47%, while clone 100/5 had the lowest cultivation rate at 10%. The ranking of clones by preference was 303/577, 6/8, 108/82, 31/8, and 100/5. Key attributes influencing preferences included, yield potential, canopy width, post-plucking/pruning recovery rate, shoot tenderness and cup quality. Results showed that a farmers’ choice of clone 303/577 was significantly influenced by shoot density, gender and tea farming experience. For clone 108/82, the most important factors were quick recovery after plucking/pruning, education level and household size. This information is vital for agricultural policy, extension services, tea breeding and genetic improvement programs in the tea sector. Full article

In this study, twenty-seven novel SSR markers derived from tetranucleotide or pentanucleotide repeat sequences were developed for tea plants (Camellia sinensis). These markers, along with three previously reported pentanucleotide SSR markers, were assessed for their polymorphisms and capabilities for parental analysis. Analysis of 48 tea cultivars revealed 142 alleles with an average polymorphic information content (PIC) of 0.44, confirming the high polymorphism of these markers. Meanwhile, the capability of these markers for paternal identification in tea plants was also validated. Theoretical calculations yielded a cumulative exclusion probability (CPE) over 99.9999%. In the analyses of real samples using the exclusion method, among eight samples with confirmed parent–offspring relationships, both pair- and trio-mismatch counts were ≤1, whereas non-paternal samples exhibited average pair- and trio-mismatches of 5.13 and 7.96, respectively. When assessed by the combined parentage index (CPI), all trio-CPI values for confirmed parents–offspring exceeded 10⁴ (average: 1.18 × 10⁷), while the average trio-CPI for combinations with correct maternal but incorrect paternal parents remained below 10⁻². Finally, using this set of markers, we successfully identified 41 offspring derived from reciprocal crosses with open pollination between ‘Fuding Dabaicha’ and ‘Chuancha Erhao’. Their trio-mismatches with the parent pair were ≤1, while trio-CPI exceeded 10⁴, meeting the established criteria for parentage relationships. Full article

Low-temperature stress severely restricts the growth, development, and yield of bitter gourd (Momordica charantia L.), a warm-loving crop with inherent low cold tolerance. NAC transcription factors (TFs) serve as crucial regulators in plant responses to abiotic stresses like cold, while their roles in coping with cold stress in bitter gourd remain unclear. This study identified cold-responsive genes in bitter gourd and characterized the candidate NAC TF McNAC087 through transcriptome analysis. Transcriptome sequencing of cold-tolerant (R) and cold-sensitive (S) bitter gourd inbred lines under 5 °C stress (0 h, 6 h, 12 h, 24 h) revealed 1157 co-expressed differentially expressed genes (DEGs), enriched via Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis in cold tolerance-related pathways (signal transduction, carbohydrate/amino acid metabolism). RT-qPCR showed higher McNAC087 expression in R than S under cold stress, and subcellular localization confirmed it as a nucleus-localized protein. McNAC087 overexpression in Arabidopsis enhanced cold tolerance after sequential stress (−14 °C for 1.5 h, 4 °C for 16 h, and 22 °C recovery for 2 days), with less damage compared to wildtype (WT). Physiologically, overexpressing lines had higher proline, elevated superoxide dismutase/peroxidase/catalase (SOD/POD/CAT) activities, lower malondialdehyde/hydrogen peroxide/superoxide anion (MDA/H₂O₂/O₂⁻) accumulation under cold stress, and upregulated ICE-CBF-COR pathway marker genes (CBF1, DREB2A, RD29A, COR47). In conclusion, McNAC087 enhances Arabidopsis cold tolerance by regulating physiology and activating cold-responsive genes, providing insights for bitter gourd cold tolerance mechanisms and crop breeding. Full article

Watermelon silver mottle virus (WSMoV) is a thrips-transmitted Orthotospovirus that severely impacts cucurbits production across Asia. Although previous diversity studies focused on the nucleocapsid (N) gene, genome-level evolutionary analyses are lacking. In 2023 and 2024, symptomatic watermelon in Jiangxi Province, China, was analyzed by RT-PCR and high-throughput sequencing, yielding complete genomes of two WSMoV isolates, FZNC and THBC. Multiple-sequence alignment and phylogenetic analysis of the complete sequences of L, M, and S RNAs defined two phylogenetic clades (O and N). However, the Jiangxi isolates clustered in different clades for the L segment versus the M and S segments, suggesting a potential reassortment event. This conclusion was confirmed by RDP4 and RT-PCR analysis, which identified a significant reassortment event involving an L RNA segment derived from a Guangdong isolate (Clade N) and the M and S segments from a Taiwan isolate (Clade O). This study provides the first evidence of natural reassortment in WSMoV, underscoring its potential for rapid evolution. It also constitutes the first report of WSMoV in Jiangxi Province, in East China, marking a concerning expansion of its geographic range into inland China and raising the risk of cucurbit production. Full article

Oviposition attractants can enhance both the surveillance and control of container-breeding Aedes mosquitoes. Although green tea has been reported to attract Ae. aegypti, the specific bioactive botanical compounds responsible remain unidentified. We evaluated teas across fermentation stages (non-fermented, fully fermented, and post-fermented) at 5 g/L for gravid Ae. albopictus using dual-choice assays. The most attractive tea (Liu-pao) was further tested across concentrations (0.5–5 g/L) and infusion ages (1–28 days). Autoclaved vs. non-autoclaved infusions assessed microbial contributions, while headspace volatiles were analyzed via HS-SPME-GC-MS. Individual compounds (cedrol and linalool oxide) were bioassayed. Only Liu-pao tea consistently attracted Ae. albopictus (OAI ≥ 0.3), peaking at 5 g/L after 7–14 days (OAIs 0.73/0.67). A 0.5 g/L infusion aged 21–28 days also attracted Ae. aegypti (OAIs 0.89/0.63). Autoclaving did not reduce attraction, confirming volatile compounds, not live microbe-mediated effects. Cedrol (1 mg/L) elicited moderate attraction (OAI 0.29) in Ae. albopictus, while linalool oxide was inactive. Post-fermented Liu-pao tea acts as a potent botanical attractant for Aedes mosquitoes. Cedrol contributes partially, but whole tea infusions outperform single compounds. These findings support developing multi-volatile “attract-and-kill” strategies targeting gravid mosquitoes. Full article