Search Results (127)

Cucumber (Cucumis sativus L.) is an economically important vegetable crop worldwide, but its yield and quality improvement are often constrained by drought stress. To investigate the physiological and molecular mechanisms by which exogenous allantoin enhances drought tolerance in cucumber, cucumber seedlings were sprayed with 6 mM allantoin solution once (A1), three times (A3), or five times (A5), while control plants were sprayed with distilled water (CK1, CK3, CK5). Each treatment consisted of three biological replicates. After treatment, drought stress was simulated by irrigating with 20% polyethylene glycol 6000 (PEG-6000) solution. The results showed that the protective effect of exogenous allantoin against drought stress was cumulative. After five applications (A5), the net photosynthetic rate (Pn) and water-use efficiency (WUE) of the plants were significantly higher than those of the corresponding control (CK5) (p < 0.01). The detached leaf water loss rate progressively decreased with an increasing number of allantoin applications, while the total leaf wax content increased approximately 2-fold (p < 0.01). Measurements of wax content in different plant tissues indicated that allantoin mainly induced wax accumulation in aboveground organs (leaf, stem, and fruit epidermis), and this effect was validated in three commercial varieties. Integrated transcriptomic and metabolomic analyses revealed that the cucumber CsCER1 gene (encoding a very-long-chain aldehyde decarbonylase) is a core allantoin-responsive gene. After silencing CsCER1 using virus-induced gene silencing (VIGS), the allantoin-induced wax accumulation and drought tolerance were almost completely lost: the wilting severity and detached leaf water loss rate of the silenced plants were comparable to those of the empty vector control, and no significant increase in wax content was observed. This study reveals a novel mechanism by which exogenous allantoin enhances drought tolerance in cucumber through activating CsCER1-mediated cuticular wax synthesis, providing a theoretical basis for the chemical regulation of drought tolerance in cucurbit crops. Full article

Tree peony (Paeonia suffruticosa Andr.) is a traditional ornamental plant of high economic and cultural value, but its flower longevity is often limited by petal water loss. Cuticular wax serves as an essential barrier against non-stomatal water loss, and the AP2/EREBP (APETALA2/Ethylene-Responsive Element Binding Protein) transcription factor family is known to regulate wax biosynthesis. However, little information is available on the roles of AP2/EREBP genes in petal cuticle formation in tree peony. In this study, we performed transcriptome sequencing on petals of the tree peony cultivar ‘Bai Wang Shi Zi’ at three developmental stages (early, middle, and late). Using the assembled transcriptomic data, we identified 29 high-confidence AP2/EREBP family members, which were phylogenetically classified into AP2, ERF, and DREB subfamilies. Expression profiling revealed that 18 of these genes exhibited stage-specific expression patterns during petal development. Among them, two homologs of Arabidopsis SHN1 (SHINE 1) and WRI3 (WRINKLED 3), designated PsSHN1 and PsWRI3, showed peak expression at the middle stage. By co-expression analysis and phylogenetic comparison, three downstream candidate genes were identified and named PsCER2, PsKAS1, and PsLTPG1, based on their homology with known wax-related genes. Dual-luciferase reporter assays indicated that PsSHN1 and PsWRI3 can activate the promoters of PsCER2, PsKAS1, and PsLTPG1, suggesting a possible cooperative regulation of cuticle formation. Collectively, our findings provide promising candidate genes for prolonging floral lifespan by improving petal cuticular wax accumulation, and lay a preliminary foundation for molecular breeding and quality improvement of tree peony and other ornamental flowers. Full article

Cuticular wax mixtures are the major components of the lipophilic cuticle coating of plant aerial organs during primary growth and they protect plants from environmental stresses. Decoding cuticular wax biosynthesis in bread wheat (Triticum aestivum L.) could contribute to the genetic improvement of this agriculturally important crop. Herein, we revealed that the wheat MYB46-like transcription factor TaMYB46 positively regulates cuticular wax by activating transcription of the long-chain acyl-CoA synthetase 1 (TaLACS1) gene. Knockdown of the wheat TaMYB46 gene resulted in significantly reduced cuticular wax loads and increased permeability of the wheat leaf cuticle. Furthermore, wheat long-chain acyl-CoA synthetase TaLACS1 was identified as a core component of the cuticular lipid biosynthetic machinery. Knockdown of the TaLACS1 gene led to reduced cuticular wax accumulation and increased leaf cuticle permeability. Moreover, the transcription factor TaMYB46 was found to enrich at the TaLACS1 promoter regions and activate TaLACS1 gene transcription. These findings collectively support the conclusion that the transcription factor TaMYB46 stimulates cuticular wax biosynthesis, likely by activating TaLACS1 transcription. Full article

Reducing herbicide input in paddy fields is essential for sustainable rice production and long-term soil health. Florpyrauxifen-benzyl effectively controls the dominant paddy weed barnyardgrass (Echinochloa crus-galli), yet excessive application poses environmental risks. Here, we investigated whether the compound adjuvant Sijiling, containing nonionic and anionic surfactants, could enable significant dose reduction in florpyrauxifen-benzyl while maintaining weed control efficacy and improving soil–plant system functions. Greenhouse dose–response assays and two-year field trials conducted in 2021 and 2022 demonstrated that the adjuvant permitted a 50% reduction in herbicide application without compromising control of barnyardgrass or other paddy weeds. Mechanistically, Sijiling disrupted the leaf cuticular wax barrier and amplified ethylene and ABA biosynthesis over two-fold. The reduced herbicide rate lowered residues in rice and soil, increased soil organic carbon and available potassium, and enhanced microbial diversity, particularly enriching beneficial Acidobacteria. Grain yield increased significantly under the reduced-input strategy, with Mantel analysis linking yield gains to improved soil available potassium and organic carbon. Our findings demonstrate that adjuvant-enabled herbicide dose reduction is an effective and sustainable weed management strategy for paddy rice, maintaining robust weed suppression while delivering measurable co-benefits for soil health and crop productivity, thereby supporting the sustainable intensification of rice-based cropping systems. Full article

The increased demand for higher-quality, longer-lasting blueberries has led to the development of preharvest strategies to improve their structural integrity sustainably. This study analysed the effects of the foliar application of two biostimulant–calcium (Ca) combinations, using Ecklonia maxima extract (EM + Ca) and glycine betaine (GB + Ca), on yield, biometric, mechanical, and histological properties, as well as cuticular wax composition of blueberries. Both biostimulants increased yield per plant and fruit weight and size in ‘Duke’, with superior results for GB + Ca. Fruit yield increased by 80% with GB + Ca and 40% with EM + Ca. Histological analysis showed increases in cuticle thickness, epidermal cell area and thickness, and hypodermal cell area and area/perimeter ratio. This thicker, denser tissue ultimately improved blueberries’ mechanical properties. Specifically, ‘Draper’ berries treated with GB + Ca had 36%, 15%, and 20% higher values for flesh firmness, stiffness, and deformation work, respectively, relative to the control. However, cuticular wax accumulation was more pronounced with EM + Ca for the ‘Duke’ cultivar, increasing by 12%. Overall, GB + Ca had the greatest impact on blueberry structural quality and may represent a promising strategy to improve postharvest quality and commercial production. Full article

Maize (Zea mays L.) is a vital global crop whose productivity is severely threatened by abiotic stresses. Epicuticular waxes provide a hydrophobic barrier that protects land plants from environmental stresses. However, the role of key wax biosynthetic enzymes, such as aldehyde decarbonylase CER1, in maize stress adaptation remains unclear. In this study, we performed a functional characterization of ZmCER1 in maize. Our results show that the overexpression of ZmCER1 in both Arabidopsis and maize substantially improved tolerance to these abiotic stresses. Under stress conditions, the transgenic plants displayed better growth performance, elevated activities of antioxidant enzymes, and reduced levels of oxidative damage markers. Additionally, the alkane content—especially that of C29 and C31—was significantly increased in the ZmCER1OE lines. Through a yeast two-hybrid screening (Y2H screening), we identified the peroxisomal membrane protein ZmPEX14 as an interacting partner of ZmCER1, and the interaction was further confirmed by luciferase complementation (LUC) and bimolecular fluorescence complementation (BiFC) assays. We propose a model wherein ZmCER1 enhances stress tolerance not only by reinforcing the cuticular wax barrier but also by potentially regulating reactive oxygen species (ROS) detoxification via association with ZmPEX14. Collectively, our findings establish ZmCER1 as a key regulator of abiotic stress tolerance in maize and a promising candidate for the molecular breeding of stress-resilient crops. Full article

Trichomes are specialized epidermal structures that play pivotal roles in plant defense against biotic and abiotic stresses. Inositol polyphosphate kinase 2 (IPK2) is a key enzyme in inositol phosphate metabolism with diverse functions in eukaryotic cellular processes. However, its involvement in trichome development remains uncharacterized. Here, we systematically analyzed the function of a rice inositol polyphosphate kinase gene (OsIPK2) in trichome development using transgenic rice lines and heterologously expressing Arabidopsis lines. Scanning electron microscopy (SEM) analysis revealed that OsIPK2 acts as an organ-specific modulator of trichome development in rice. Its overexpression repressed macrohair initiation and microhair elongation in leaves, while promoting trichome development on the glumes. Metabolomic profiling revealed that OsIPK2 overexpression reprogrammed cuticular wax metabolism in transgenic rice leaves, shifting fatty acid flux toward long-chain wax precursors and increasing soluble carbohydrate levels. Transcriptomic and qPCR analysis confirmed that OsIPK2 modulated the expression of genes involved in cuticular wax biosynthesis, auxin homeostasis, and the core trichome regulatory cascade in rice. Conversely, heterologous overexpression of OsIPK2 in Arabidopsis strongly suppressed trichome initiation and branching, resulting in drastically reduced trichome density and fewer trichome branches. These phenotypes were associated with the downregulation of the MYB-bHLH-WD40 (MBW) transcriptional complex and its downstream target genes. Collectively, our findings suggest that OsIPK2 modulated trichome development through organ- and species-specific mechanisms. In rice, it coordinated wax metabolism and the OsSPL10-OsSCR1/2-OsWOX3B-OsHL6 cascade to affect organ-specific trichome formation. In Arabidopsis, it inhibited trichome development by repressing the MBW complex. These results uncover a novel role of OsIPK2 in plant epidermal cell fate specification and advance our understanding of the molecular mechanisms underlying organ- and species-specific regulation of trichome development. Full article

Bacterial stem and root rot (BSRR), caused by Dickeya dadantii, poses a severe threat to global sweetpotato production, yet the genetic architecture underlying resistance remains elusive. To dissect these mechanisms, we conducted a high-resolution genome-wide association study (GWAS) on 135 diverse accessions, integrating two-year field phenotyping with best linear unbiased prediction (BLUP) and 6.8 million single-nucleotide polymorphism (SNP) markers. This approach mapped nine quantitative trait loci (QTLs) exhibiting significant allelic dosage-dependent effects, with the major locus, qBSRR.6.1 was the primary discriminator between resistant and susceptible genotypes. Crucially, transcriptomic profiling within these loci revealed distinct expression patterns: IbTCP5 and IbERF003 (located in qBSRR.5.1 and qBSRR.6.2) were highly expressed in the susceptible cultivar ‘Xinxiang’ but suppressed in the resistant ‘Guangshu87’. Furthermore, BSRR challenge identified IbPUB4, IbKCS5, and IbLig1 as priority candidate genes involved in defense, with expression patterns suggesting roles in ubiquitin-mediated protein turnover, cuticular wax biosynthesis, and DNA repair, respectively. In stark contrast, IbPUB25 was constitutively upregulated in ‘Xinxiang’, potentially acting as a negative regulator of immunity via degradation of target proteins. These findings elucidate the polygenic, dosage-sensitive nature of BSRR resistance and prioritize specific targets for future functional characterization. Pyramiding favorable alleles of positive candidates while silencing potential negative regulators like IbPUB25 offers a promising avenue for developing durable, high-resistance sweetpotato varieties. Full article

Phytopathogenic Ascomycetes Blumeria graminis f. sp. tritici (Bgt) causes wheat powdery mildew disease and impacts global wheat production. Decoding the molecular wheat-Bgt interaction could facilitate the wheat disease resistance breeding. In this study, we elucidated that wheat histone deacetylase 19 (TaHDA19) regulates susceptibility to Bgt pathogen by suppressing biosynthesis of cuticular wax and salicylic acid (SA). Knockdown of wheat TaHDA19 gene expression led to in enhanced cuticular wax and SA accumulation, potentiated Bgt conidia germination and appressoria formation, attenuated formation of Bgt haustoria and microcolonies. Histone deacetylase TaHDA19 is enriched at the TaECR and TaSARD1 promoter regions to facilitate histone deacetylation, and thus suppressing TaECR and TaSARD1 transcription. In addition, we identified cuticular wax and SA regulated by TaHDA19 as chemical cues determining wheat pre- and postsusceptibility to Bgt pathogen. These findings collectively support that the wheat histone deacetylase TaHDA19 epigenetically suppresses cuticular wax and SA biosynthesis, thereby dampening chemical cues essential for the wheat powdery mildew susceptibility. Full article

Cuticular waxes form a crucial hydrophobic barrier on the surface of aboveground organs in terrestrial plants. It strongly influences crop stress tolerance and yield stability, making them important target traits in modern crop breeding. This review systematically summarizes recent advances in how cuticular waxes contribute to crop stress tolerance and yield formation. It covers the chemical composition of cuticular waxes, key pathways and regulatory networks, and the physiological and biochemical mechanisms. In addition, this review highlights the role of cuticle waxes in maintaining crop yield and quality by regulating essential physiological processes, including photosynthetic metabolism and water-use efficiency. Current research indicates that cuticular wax accumulation shows strong crop-specific patterns and is dynamically regulated by environmental factors. Breakthrough studies in major crops have clarified the regulatory mechanisms of several core genes and demonstrated that cuticular waxes enhance stress resistance by strengthening physical barriers, improving water-use efficiency, and protecting photosynthetic structures. A deeper understanding of cuticular wax regulatory mechanisms will help reveal the molecular basis of crop stress resistance and provide both theoretical support and practical guidance for breeding crop varieties with enhanced stress tolerance and stable yields. Full article

Cutin matrices and wax mixtures are major components of lipophilic cuticles, shielding plant tissues from stressful environments. Identifying the key regulators governing biosynthesis of cutin and cuticular wax in bread wheat (Triticum aestivum L.) could contribute to wheat breeding for stress resistance. In this study, we reported that the wheat class I TCP transcription factor TaTCP15 positively regulates cutin and cuticular wax biosynthesis. The CYP86A family cytochrome P450 enzymes, TaCYP86A2 and TaCYP86A4, were characterized as essential components of wheat cutin biosynthetic machinery. Wheat transcription factor TaSHN1 targets TaCYP86A2, TaCYP86A4, and wax biosynthesis gene TaECR and recruits the mediator subunit TaCDK8 to activate these genes’ transcription. Furthermore, we demonstrated that TaSHN1 gene transcription is directly activated by the transcription factor TaTCP15. Expression of TaSHN1, TaCYP86A2, TaCYP86A4, and TaECR genes, as well as cutin and wax accumulation, was attenuated by silencing of the TaTCP15 gene. Collectively, these findings suggest that wheat class I TCP transcription factor TaTCP15 positively regulates cutin and cuticular wax biosynthesis, probably via directly targeting the TaSHN1 gene and upregulating TaCYP86A2, TaCYP86A4, and TaECR expression, providing valuable information for developing wheat plants with improved cuticle-associated traits. Full article

Grapevine downy mildew is a major disease in vineyards all around the world, caused by the oomycete Plasmopara viticola (Berk. & M. A. Curtis) Berl. & De Toni. Normally, its control depends almost exclusively on chemical and copper-based fungicides, especially in high-incidence areas with high relative humidity and mild temperatures. However, the European Union is determined to reduce the application of these phytochemicals by at least 50% by 2030, forcing winegrowers to seek alternative low-input strategies for proper sanitary maintenance. Basic substances (BSs), described in European Regulation (EC) 1107/2009, stand out as promising alternatives, but their molecular mechanism of action remains mostly unknown. In this context, this study analyzed the genetic effect in grapevine plants of several commercial products composed of BSs (chitosan, soy lecithin, Equisetum arvense and Salix cortex). All products exhibited promising results, triggering the induction of similar defence mechanisms, which included pathogenesis-related proteins (PRs), involved in direct pathogen repression; stilbenes, capable of producing antimicrobial compounds such as resveratrol and pterostilbene; several hormones, including oxylipins, ethylene, salicylic acid and terpenes, mediating immune signalling; and genes related to structural features of the plant, such as lignin, callose, cellulose and cuticular wax, constituting a first physiological barrier against P. viticola. Disease severity reduction differed among treatments, with Salix cortex showing the highest efficacy (58%), followed by BABA (38%) and LESOY (35%), while LECI and CHIT had minor effects (<9%). Gene expression analyses revealed that Salix cortex modulated the highest percentage of genes (41%), followed by natural infection without treatment (32%), LESOY (27%), BABA (26%), LECI (23%) and CHIT (23%). In terms of defence mechanisms, Salix cortex promoted the most pathways, LESOY induced eight, BABA and LECI seven and CHIT five. Overall, these results indicate that BSs can modulate several defence pathways in grapevine, supporting their potential use as sustainable alternatives for controlling downy mildew. Full article

Alkane is a predominant wax component, whose production requires the aids of CER1 and CER3. In rice, OsCER1 and OsCER3 are present in multiple copies. Until now, the roles of these genes have been studied individually; however, a systematic comparison of their relative contributions to cuticular wax biosynthesis has not yet been carried out. Phylogenetic tree analysis revealed that CER1s and CER3s from different plants are classified into two subgroups. RT-qPCR analysis showed that these genes display distinct expression patterns, revealing their specific roles in wax production. Promoter prediction analysis showed that cis-elements responding to light, phytohormones and stress are enriched in the promoter region of OsCER1s and OsCER3s. These proteins are all localized in the endoplasmic reticulum. Further study showed that OsCER1s and OsCER3s are inclined to form a complex during the wax synthesis. Finally, the wax analysis of single mutants showed that among the examined genes, OsCER3a mutation greatly reduced the total wax amounts to 19.6% of wild-type plant with a decrease in most of wax components, whereas mutation of other genes including OsCER3b, OsCER3c, OsCER1a and OsCER1c slightly or barely affect wax production, suggesting that OsCER3a plays major roles in rice wax production whereas other proteins redundantly participate in the wax synthesis. Additionally, the wax increasing rates of Arabidopsis expressing OSCER1 are lower than those of overexpressing AtCER1. Taken together, our study identified the predominant genes involved in wax production, which will be useful for genetically engineering rice with enhanced stress tolerance. Full article

Glossy appearance is a critical trait that affects the appearance quality and marketability of leafy vegetables, including Chinese cabbage. The glossy trait is primarily associated with cuticular wax. Although several genes involved in cuticular wax biosynthesis have been characterized in Chinese cabbage, the regulatory relationships among them remain unclear. In this study, we identified a glossy mutant, glossy leaf4 (gl4), and cuticular wax crystals in the gl4 mutant were obviously reduced. Genetic analysis indicated that the glossy phenotype in the gl4 mutant appears to be controlled by a single recessive gene. Using a bulked segregant analysis coupled with next-generation sequencing (BSA-seq) and map-based cloning methods, the AtCER2 homologous gene BrCER2 was identified as the candidate gene. BrCER2 was expressed in various tissues, and BrCER2-GFP was localized in the endoplasmic reticulum (ER). Furthermore, BrCER2 could interact with BrKCS6 in the ER, and the expression levels of some wax biosynthesis-related genes were decreased in the gl4 mutant. Our overall results provide insights about the role of BrCER2 in wax biosynthesis through ER localization and interaction with BrKCS6 in Chinese cabbage. Full article

Cuticular wax plays an important role in the quality of kumquat (Fortunella crassifolia Swingle) fruit. In this study, the wax morphology, compositional profile of epi- and intracuticular wax, and crucial gene expression in ‘Rongan’ kumquat (RAK) and ‘Huapi’ kumquat (HPK) were analyzed during fruit development. The results showed that the surfaces of two kumquat fruits were covered with an amorphous wax layer containing a small number of platelets. Compared to RAK, HPK contained more abundant and larger wax crystals during fruit development. In two kumquat fruits, the epicuticular wax and its major compositions consistently displayed significantly higher levels than the intracuticular wax. Additionally, their main wax composition shifted from alkanes in the early developmental stages to triterpenoids at harvest in both layers, while aldehydes were specifically enriched in the epicuticular wax. During the fruit development from 90 to 180 DAF, HPK fruit exhibited significantly higher levels of epicuticular wax and its majority fractions than RAK fruit. Meanwhile, the intracuticular wax contents of HPK from 90 DAF to 150 DAF were significantly higher than those in RAK, with triterpenoids accounting for the largest proportion of this increase. qRT-PCR results indicated that the up-regulation of wax-related genes in HPK was linked to its increased epicuticular wax deposition during the development. Overall, this study provided a comprehensive overview of the morphology, composition, and biosynthesis of cuticular wax in kumquat fruit during development. Full article