Search Results (9)

Plant cuticular wax serves as a critical component for defense against biotic and abiotic stresses, with its biosynthetic pathway regulated by the ECERIFERUM (CER) gene family. This study presents the first genome-wide identification of 79 CER genes (CalCERs) in pepper (Capsicum annuum L.), which are distributed across all 12 chromosomes. Phylogenetic analysis classified CalCERs into five clades, with clade-specific conservation of exon–intron architectures and protein motifs. Promoter cis-element analysis revealed enrichment of light-responsive elements, abscisic acid (ABA), jasmonic acid (JA), and stress-responsive regulatory motifs, indicating multi-pathway regulation. Transcriptomic data highlighted tissue-specific expression patterns, such as the root-predominant express gene CalCER1-2 and the flower-specific express gene CalCER3-1. Under abiotic stresses (drought, salt, heat, and cold), CalCER4-2 and CalCER6-6 responded rapidly, while most genes showed delayed differential expression. Under biotic stress, CalCER3-1 and CalCER5-3 were upregulated, whereas CalCER2-2 exhibited pathogen-specific suppression, suggesting roles in modulating wax-mediated pathogen resistance. Hormone treatments revealed dynamic responses: CalCER2-2 was persistently ABA-inducible, while CalCER3-1 specifically responded to JA. This study underscores evolutionary conservation and species-specific expansion of the pepper CER family, linking their expression to wax biosynthesis and stress adaptation. These insights provide a foundation for enhancing stress resilience in crops. Future work should employ gene editing and metabolomics to validate functional mechanisms and optimize breeding strategies. Full article

Salinity is a major environmental factor that adversely affects plant growth and production. Cuticular wax protects plants against external environmental stress. The relationship between cuticular wax biosynthesis and salt tolerance remains unclear in Salicornia europaea. This study examined the cuticle thickness, wax load, morphology, composition, and the expression of cuticular wax biosynthesis gene identification and expression. The results showed that 600 mM NaCl treatment enhanced the cuticle thickness and total wax load; crystal wax structures were also observed after NaCl treatment. The cuticular wax was mainly composed of fatty acids, alcohols, alkenes, and esters. The alcohol class accounted for the largest proportion, with docosanol (C₂₅H₅₄OSi) being the main specific alcohol compound, followed by fatty acids and alkanes. After a sequence database search, six fatty acyl-CoA reductases (FARs), sixteen wax synthase/diacylglycerol acyltransferases (WS/DGATs), three fatty alcohol oxidases (FAOs), five eceriferums (CERs), and eight mid-chain alkanes (MAHs) were identified as the putative wax biosynthesis enzymes. Their expression analysis revealed a differential response to 100 and 600 mM NaCl treatment and reached the highest level at 12 h or 48 h. The genes that were evidently upregulated with higher fold changes under salinity, such as SeFAR1, SeFAR2, and SeFAR3 are implied to synthesize primary alcohols, and SeWSs convert the primary alcohols to wax esters; SeCER1 and SeCER3 are also supposed to catalyze the conversion of aldehydes to alkanes while SeMAH7 catalyze alkanes to secondary alcohols in S. europaea in response to NaCl treatment. This study demonstrated that both the decarbonylation and acyl-reduction wax biosynthesis pathways may not be independent from each other. Full article

Cuticular wax mixtures cover the epidermis of land plants and shield plant tissues from abiotic and biotic stresses. Although cuticular wax-associated traits are employed to improve the production of bread wheat, regulatory mechanisms underlying wheat cuticular wax biosynthesis remain poorly understood. In this research, partially redundant transcription factors TaMYB60-1 and TaMYB60-2 were identified as positive regulators of wheat cuticular wax biosynthesis. Knock-down of wheat TaMYB60-1 and TaMYB60-2 genes by virus-induced gene silencing resulted in attenuated wax accumulation and enhanced cuticle permeability. The roles of wheat fatty acyl-ACP thioesterase genes TaFATB1 and TaFATB2 in cuticular wax biosynthesis were characterized. Silencing wheat TaFATB1 and TaFATB2 genes led to reduced wax accumulation and increased cuticle permeability, suggesting that TaFATB1 and TaFATB2 genes positively contribute to wheat cuticular wax biosynthesis. Importantly, transcription factors TaMYB60-1 and TaMYB60-2 exhibit transcriptional activation ability and could stimulate the expression of wax biosynthesis genes TaFATB1, TaFATB2, and ECERIFERUM 1 (TaCER1). These findings support that transcription factor TaMYB60 positively regulates wheat cuticular wax biosynthesis probably by activating transcription of TaFATB1, TaFATB2, and TaCER1 genes. Full article

MIXTA-like transcription factors AtMYB16 and AtMYB106 play important roles in the regulation of cuticular wax accumulation in dicot model plant Arabidopsis thaliana, but there are very few studies on the MIXTA-like transcription factors in monocot plants. Herein, wheat MIXTA-like transcription factors TaMIXTA1 and TaMIXTA2 were characterized as positive regulators of cuticular wax accumulation. The virus-induced gene silencing experiments showed that knock-down of wheat TaMIXTA1 and TaMIXTA2 expressions resulted in the decreased accumulation of leaf cuticular wax, increased leaf water loss rate, and potentiated chlorophyll leaching. Furthermore, three wheat orthologous genes of ECERIFERUM 5 (TaCER5-1A, 1B, and 1D) and their function in cuticular wax deposition were reported. The silencing of TaCER5 by BSMV-VIGS led to reduced loads of leaf cuticular wax and enhanced rates of leaf water loss and chlorophyll leaching, indicating the essential role of the TaCER5 gene in the deposition of wheat cuticular wax. In addition, we demonstrated that TaMIXTA1 and TaMIXTA2 function as transcriptional activators and could directly stimulate the transcription of wax biosynthesis gene TaKCS1 and wax deposition gene TaCER5. The above results strongly support that wheat MIXTA-Like transcriptional activators TaMIXTA1 and TaMIXTA2 positively regulate cuticular wax accumulation via activating TaKCS1 and TaCER5 gene transcription. Full article

Plant cuticular wax plays an important role in resistance to environmental stresses. Eceriferum (CER) genes are involved in wax synthesis. However, little information is available for tomato species. In this study, 26 SlCER genes were identified in tomato (S. lycopersicum), and they were classified into four clades. The physicochemical properties and conserved motifs of their proteins were predicted. These SlCERs were mainly expressed in leaves, flowers or fruits, and most SlCERs played roles in response to abiotic stresses, especially drought stress. Furthermore, the changes in haplotypes indicated that SlCERs might have been involved in adapting to the environments for wild species S. pimpinellifolium before domestication. These findings would lay a foundation for future functional studies of SlCERs and also provide insights for anti-stress improvement in tomato in the near future. Full article

Fruit glossiness is an important external fruit quality trait that greatly affects the marketability of fresh cucumber (Cucumis sativus) fruits. A few reports have suggested that the extent of cuticular wax loading influences the glossiness of the fruit surface. In the present study, we tested the wax contents of two inbred cucumber lines, comparing a line with waxy fruit (3401) and a line with glossy fruit (3413). Wax content analysis and dewaxing analysis demonstrate that fruit cuticular wax loads negatively correlate with fruit glossiness in cucumber. Identifying genes that were differentially expressed in fruit pericarps between 3401 and 3413 and genes induced by abscisic acid suggested that the wax biosynthesis gene CsCER6 (Cucumis sativus ECERIFERUM 6) and the regulatory gene CsCER7 may affect wax accumulation on cucumber fruit. Expression analysis via RT-qPCR, GUS-staining, and in situ hybridization revealed that CsCER6 and CsCER7 are abundantly expressed in the epidermis cells in cucumber fruits. Furthermore, the overexpression and RNAi lines of CsCER6 and CsCER7 showed dramatic effects on fruit cuticular wax contents, fruit glossiness, and cuticle permeability. Our results suggest that CsCER6 and CsCER7 positively regulate fruit cuticular wax accumulation and negatively influence fruit glossiness. Full article

All land plants seal their above ground body parts with a lipid-rich hydrophobic barrier called the cuticle to protect themselves from dehydration and other terrestrial threats. Mutational studies in several model species have identified multiple loci regulating cuticular metabolism and development. Of particular importance are the eceriferum (cer) mutants characterized by a loss of cuticular wax. Some barley cer mutants, including cer-x, show defects in the distinctive β-diketone-enriched wax bloom on reproductive stage leaf sheaths, stems, and spikes. We exploited extensive allelic populations, near-isogenic lines, and powerful genotyping platforms to identify variation in the HvWAX INDUCER1 (HvWIN1) gene, encoding a SHINE transcription factor, as underlying cer-x. Comparing the cer-x allelic glossy sheath4.l Bowman Near Isogenic Line BW407 to cv. Bowman revealed an increased cuticular permeability in tissues showing reduced accumulation of β-diketones and altered cuticular metabolic gene expression in BW407. Analyses across the barley pangenome and hundreds of exome-capture datasets revealed high sequence conservation of HvWIN1 and two non-synonymous variants exclusive to the cultivated germplasm. Taken together, we suggest that variation in HvWIN1 controls multiple cuticular features in barley. Full article

Zanthoxylum bungeanum is one of the most important medicinal and edible homologous plants because of its potential health benefits and unique flavors. The chemical components in compositions and contents vary with plant genotype variations and various environmental stress conditions. Fatty acids participate in various important metabolic pathways in organisms to resist biotic and abiotic stresses. To determine the variations in metabolic profiling and genotypes, the fatty acid profiling and key differential genes under low temperature stress in two Z. bungeanum varieties, cold-tolerant (FG) and sensitive (FX), were investigated. Twelve main fatty acids were found in two Z. bungeanum varieties under cold stress. Results showed that the contents of total fatty acids and unsaturated fatty acids in FG were higher than those in FX, which made FG more resistant to low temperature. Based on the result of orthogonal partial least squares discriminant analysis, palmitic acid, isostearic acid, linolenic acid and eicosenoic acid were the important differential fatty acids in FG under cold stress, while isomyristic acid, palmitic acid, isostearic acid, stearic acid, oleic acid, linolenic acid and eicosenoic acid were the important differential fatty acids in FX. Furthermore, fatty acid synthesis pathway genes fatty acyl-ACP thioesterase A (FATA), Delta (8)-fatty-acid desaturase 2 (SLD2), protein ECERIFERUM 3 (CER3), fatty acid desaturase 3 (FAD3) and fatty acid desaturase 5 (FAD5) played key roles in FG, and SLD2, FAD5, 3-oxoacyl-[acyl-carrier-protein] synthase I (KAS I), fatty acyl-ACP thioesterase B (FATB) and acetyl-CoA carboxylase (ACC) were the key genes responding to low temperature in FX. The variation and strategies of fatty acids in two varieties of Z. bungeanum were revealed at the metabolic and molecular level. This work provides a reference for the study of chemical components in plant stress resistance. Full article

The elongation of very-long-chain fatty acids is a conserved process used for the production of many metabolites, including plant cuticular waxes. The elongation of precursors of the most abundant cuticular wax components of some plants, however, is unique in requiring ECERIFERUM2-LIKE (CER2-LIKE) proteins. CER2-LIKEs are a clade within the BAHD superfamily of acyltransferases. They are known to be required for cuticular wax production in both Arabidopsis and maize based on mutant studies. Heterologous expression of Arabidopsis and rice CER2-LIKEs in Saccharomyces cerevisiae has demonstrated that they modify the chain-length specificity of elongation when paired with particular condensing enzymes. Despite sequence homology, CER2-LIKEs are distinct from the BAHD superfamily in that they do not appear to use acyl transfer activity to fulfill their biological function. Here, we review the discovery and characterization of CER2-LIKEs, propose several models to explain their function, and explore the importance of CER2-LIKE proteins for the evolution of plant cuticles. Full article