RESUMEN

Brown planthopper (BPH) is the most destructive insect pest of rice. Drought is the most detrimental environmental stress. BPH infestation causes adaxial leaf-rolling and bulliform cells (BCs) shrinkage similar to drought. The BC-related abaxially curled leaf1 (ACL1) gene negatively regulates BPH resistance and drought tolerance, with decreased cuticular wax in the gain-of-function mutant ACL1-D. ACL1 shows an epidermis-specific expression. The TurboID system and multiple biochemical assays reveal that ACL1 interacts with the epidermal-characteristic rice outermost cell-specific (ROC) proteins. ROC4 and ROC5 positively regulate BPH resistance and drought tolerance through modulating cuticular wax and BCs, respectively. Overexpression of ROC4 and ROC5 both rescue ACL1-D mutant in various related phenotypes. ACL1 competes with ROC4/ROC5 in homo-dimer and hetero-dimer formation, and interacts with the repressive TOPLESS-related proteins. Altogether, we illustrate that ACL1-ROC4/5 complexes synergistically mediate drought tolerance and BPH resistance through regulating cuticular wax content and BC development in rice, a mechanism that might facilitate BPH-resistant breeding.

Asunto(s)

Sequías , Regulación de la Expresión Génica de las Plantas , Hemípteros , Oryza , Proteínas de Plantas , Hemípteros/fisiología , Oryza/parasitología , Oryza/genética , Oryza/metabolismo , Animales , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Enfermedades de las Plantas/parasitología , Enfermedades de las Plantas/inmunología , Enfermedades de las Plantas/genética , Hojas de la Planta/parasitología , Hojas de la Planta/metabolismo , Ceras/metabolismo , Estrés Fisiológico

RESUMEN

MAIN CONCLUSION: Microscopic analyses and chemical profiling demonstrate that the white rind phenotype in melon fruit is associated with the accumulation of n-alkanes, fatty alcohols, aldehydes and wax esters. Serving as an indicator of quality, the rind (or external) color of fruit directly affects consumer choice. A fruit's color is influenced by factors such as the levels of pigments and deposited epicuticular waxes. The latter produces a white-grayish coating often referred to as "wax bloom". Previous reports have suggested that some melon (Cucumis melo L.) accessions may produce wax blooms, where a dominant white rind color trait was genetically mapped to a major locus on chromosome 7 and suggested to be inherited as a single gene named Wi. We here provide the first direct evidence of the contribution of epicuticular waxes to the dominant white rind trait in melon fruit. Our light and electron microscopy and gas chromatography-mass spectrometry (GC-MS) comparative analysis of melon accessions with white or green rinds reveals that the rind of melon fruit is rich in epicuticular waxes. These waxes are composed of various biochemical classes, including fatty acids, fatty alcohols, aldehydes, fatty amides, n-alkanes, tocopherols, triterpenoids, and wax esters. We show that the dominant white rind phenotype in melon fruit is associated with increased accumulation of n-alkanes, fatty alcohols, aldehydes and wax esters, which are linked with the deposition of crystal-like wax platelets on their surfaces. Together, this study broadens the understanding of natural variation in an important quality trait of melon fruit and promotes the future identification of the causative gene for the dominant white rind trait.

Asunto(s)

Frutas , Ceras , Ceras/metabolismo , Ceras/química , Frutas/genética , Frutas/metabolismo , Fenotipo , Pigmentación/genética , Cucurbitaceae/genética , Cucurbitaceae/metabolismo , Cromatografía de Gases y Espectrometría de Masas , Cucumis melo/genética , Cucumis melo/metabolismo , Color , Blanco

RESUMEN

The bHLH (basic helix-loop-helix) transcription factor AtCFLAP2 regulates epidermal wax accumulation, but the underlying molecular mechanism remains unknown. We obtained BnUC1mut (BnaA05g18250D homologous to AtCFLAP2) from a Brassica napus mutant with up-curling leaves (Bnuc1) and epidermal wax deficiency via map-based cloning. BnUC1mut contains a point mutation (N200S) in the conserved dimerization domain. Overexpressing BnUC1mut in ZS11 (Zhongshuang11) significantly decreased the leaf epidermal wax content, resulting in up-curled and glossy leaves. In contrast, knocking out BnUC1mut in ZS11-NIL (Zhongshuang11-near-isogenic line) restored the normal leaf phenotype (i.e., flat) and significantly increased the leaf epidermal wax content. The point mutation weakens the ability of BnUC1mut to bind to the promoters of VLCFA (very-long-chain fatty acids) synthesis-related genes, including KCS (ß-ketoacyl coenzyme synthase) and LACS (long-chain acyl CoA synthetase), as well as lipid transport-related genes, including LTP (non-specific lipid transfer protein). The resulting sharp decrease in the transcription of genes affecting VLCFA biosynthesis and lipid transport disrupts the normal accumulation of leaf epidermal wax. Thus, BnUC1 influences epidermal wax formation by regulating the expression of LTP and genes associated with VLCFA biosynthesis. Our findings provide a foundation for future investigations on the mechanism mediating plant epidermal wax accumulation.

Asunto(s)

Brassica napus , Regulación de la Expresión Génica de las Plantas , Epidermis de la Planta , Proteínas de Plantas , Ceras , Ceras/metabolismo , Brassica napus/metabolismo , Brassica napus/genética , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Epidermis de la Planta/metabolismo , Epidermis de la Planta/genética , Hojas de la Planta/metabolismo , Hojas de la Planta/genética , Metabolismo de los Lípidos/genética , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismo , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Transporte Biológico

RESUMEN

Microalgal oil production represents a promising renewable biofuel source. Metabolic engineering can enhance its utility, transforming it into an improved biofuel and expanding its applications as a feedstock for commodity chemicals, thereby increasing their value in biorefineries. This study focused on anaerobic wax ester production by the microalga Euglena gracilis, aiming to develop stable mutant strains with altered wax ester profiles through genome editing. Two enzymes in the fatty acid beta-oxidation pathway involved in wax ester production were targeted-3-ketoacyl-CoA thiolase and acyl-CoA dehydrogenase-using clustered regularly interspaced short palindromic repeats/Cas9. The results revealed one genetic mutation that lengthened and three that shortened the distribution of wax ester compositions compared to the wild-type (WT). The triple-knockout mutant, combining mutations that shorten wax ester chains, produced wax esters with acyl chains two carbons shorter than WT. This study established a methodology to stably modify wax ester composition in E. gracilis.

Asunto(s)

Ésteres , Euglena gracilis , Edición Génica , Mutagénesis , Ceras , Euglena gracilis/genética , Euglena gracilis/metabolismo , Ceras/metabolismo , Ésteres/metabolismo , Ésteres/química , Edición Génica/métodos , Anaerobiosis , Ácidos Grasos/metabolismo , Ingeniería Metabólica/métodos , Mutación/genética

RESUMEN

With glossy, wax-coated leaves, Rubus leucanthus is one of the few heat-tolerant wild raspberry trees. To ascertain the underlying mechanism of heat tolerance, we generated a high-quality genome assembly with a genome size of 230.9 Mb and 24,918 protein-coding genes. Significantly expanded gene families were enriched in the flavonoid biosynthesis pathway and the circadian rhythm-plant pathway, enabling survival in subtropical areas by accumulating protective flavonoids and modifying photoperiodic responses. In contrast, plant-pathogen interaction and MAPK signaling involved in response to pathogens were significantly contracted. The well-known heat response elements (HSP70, HSP90, and HSFs) were reduced in R. leucanthus compared to two other heat-intolerant species, R. chingii and R. occidentalis, with transcriptome profiles further demonstrating their dispensable roles in heat stress response. At the same time, three significantly positively selected genes in the pathway of cuticular wax biosynthesis were identified, and may contribute to the glossy, wax-coated leaves of R. leucanthus. The thick, leathery, waxy leaves protect R. leucanthus against pathogens and herbivores, supported by the reduced R gene repertoire in R. leucanthus (355) compared to R. chingii (376) and R. occidentalis (449). Our study provides some insights into adaptive divergence between R. leucanthus and other raspberry species on heat tolerance.

Asunto(s)

Genoma de Planta , Hojas de la Planta , Rubus , Ceras , Rubus/genética , Rubus/metabolismo , Hojas de la Planta/genética , Hojas de la Planta/metabolismo , Ceras/metabolismo , Regulación de la Expresión Génica de las Plantas , Termotolerancia/genética , Respuesta al Choque Térmico , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Transcriptoma

RESUMEN

Non-specific lipid-transfer proteins (nsLTPs) are a group of small, cysteine-rich proteins that are involved in the transport of cuticular wax and other lipid compounds. Accumulating evidence suggests that dynamic changes in cuticular waxes are strongly associated with fruit russeting, an undesirable visual quality that negatively affects consumer appeal in pears. Currently, the regulatory role of nsLTPs in cuticular wax deposition and pear fruit skin russeting remains unclear. Here, we characterized the variations of cuticular waxes in non-treated (russeted) and preharvest bagging treated (non-russeted) pear fruits throughout fruit development and confirmed that the contents of cuticular waxes were significantly negatively correlated with the occurrence of pear fruit russeting. Based on RNA-Sequencing (RNA-Seq) and quantitative real-time PCR (qRT-PCR) analyses, two nsLTP genes (PpyLTP36 and PpyLTP39) were identified, which exhibited high expression levels in non-russeted pear fruit skins and were significantly repressed during fruit skin russeting. Subcellular localization analysis demonstrated that PpyLTP36 and PpyLTP39 were localized to the plasma membrane (PM). Further, transient Virus-Induced Gene Silencing (VIGS) analyses of PpyLTP36 and PpyLTP39 in pear fruits significantly reduced cuticular wax deposition. In conclusion, PpyLTP36 and PpyLTP39 are involved in the transmembrane transport of cuticular wax and are associated with pear fruit skin russeting.

Asunto(s)

Frutas , Regulación de la Expresión Génica de las Plantas , Proteínas de Plantas , Pyrus , Ceras , Pyrus/metabolismo , Pyrus/química , Ceras/metabolismo , Ceras/química , Frutas/metabolismo , Frutas/química , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Proteínas Portadoras/metabolismo , Proteínas Portadoras/genética , Membrana Celular/metabolismo , Transporte Biológico , Epidermis de la Planta/metabolismo

RESUMEN

Long-chain acyl-CoA synthetases (LACSs), belonging to the acyl-activating enzyme superfamily, play crucial roles in lipid biosynthesis and fatty acid catabolism. Here, we identified 11 LACS genes in the tomato reference genome, and these genes were clustered into six subfamilies. Gene structure and conserved motif analyses indicated that LACSs from the same subfamily shared conserved gene and protein structures. Expression analysis revealed that SlLACS1 was highly expressed in the outer epidermis of tomato fruits and leaves. Subcellular localization assay results showed that SlLACS1 was located in the endoplasmic reticulum. Compared with wild-type plants, the wax content on leaves and fruits decreased by 22.5-34.2 % in SlLACS1 knockout lines, confirming that SlLACS1 was involved in wax biosynthesis in both leaves and fruits. Water loss, chlorophyll extraction, water-deficit, and toluidine blue assays suggested that cuticle permeability was elevated in SlLACS1 knockout lines, resulting in reduction in both drought stress resistance and fruit shelf-life. Overall, our analysis of the LACSs in tomato, coupled with investigations of SlLACS1 function, yielded a deeper understanding of the evolutionary patterns of LACS members and revealed the involvement of SlLACS1 in wax accumulation contribute to drought resistance and extended fruit shelf-life in tomato.

Asunto(s)

Coenzima A Ligasas , Regulación de la Expresión Génica de las Plantas , Solanum lycopersicum , Ceras , Coenzima A Ligasas/genética , Coenzima A Ligasas/metabolismo , Frutas/genética , Frutas/metabolismo , Familia de Multigenes , Filogenia , Epidermis de la Planta/metabolismo , Epidermis de la Planta/genética , Hojas de la Planta/genética , Hojas de la Planta/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Proteínas de Plantas/química , Solanum lycopersicum/genética , Solanum lycopersicum/metabolismo , Solanum lycopersicum/enzimología , Ceras/metabolismo

RESUMEN

Plants have, throughout evolution, developed a hydrophobic cuticle to protect them from various stresses in the terrestrial environment. The cuticle layer is mainly composed of cutin and cuticular wax, a mixture of very-long-chain fatty acids and their derivatives. With the progress of transcriptome sequencing and other research methods, the key enzymes, transporters and regulatory factors in wax synthesis and metabolism have been gradually identified, especially the study on the regulation of wax metabolism by transcription factors and others in response to plant stress has become a hot topic. Drought is a major abiotic stress that limits plant growth and crop productivity. Plant epidermal wax prevents non-stomatal water loss and improves water use efficiency to adapt to arid environments. In this study, the ways of wax synthesis, transport, metabolism and regulation at different levels are reviewed. At the same time, the regulation of wax by different transcription factors and plant hormones in response to drought is elaborated, and key research questions and important directions for future solutions are proposed to enhance the potential application of epidermal wax in agriculture and the environment.

Asunto(s)

Sequías , Regulación de la Expresión Génica de las Plantas , Reguladores del Crecimiento de las Plantas , Estrés Fisiológico , Factores de Transcripción , Ceras , Ceras/metabolismo , Reguladores del Crecimiento de las Plantas/metabolismo , Factores de Transcripción/metabolismo , Factores de Transcripción/genética , Epidermis de la Planta/metabolismo , Epidermis de la Planta/fisiología , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética

RESUMEN

MAIN CONCLUSION: We identified tomato leaf cuticle and root suberin monomers that play a role in the response to nitrogen deficiency and salinity stress and discuss their potential agronomic value for breeding. The plant cuticle plays a key role in plant-water relations, and cuticle's agronomic value in plant breeding programs is currently under investigation. In this study, the tomato cutin mutant cd1, with altered fruit cuticle, was physiologically characterized under two nitrogen treatments and three salinity levels. We evaluated leaf wax and cutin load and composition, root suberin, stomatal conductance, photosynthetic rate, partial factor productivity from applied N, flower and fruit number, fruit size and cuticular transpiration, and shoot and root biomass. Both nitrogen and salinity treatments altered leaf cuticle and root suberin composition, regardless of genotype (cd1 or M82). Compared with M82, the cd1 mutant showed lower shoot biomass and reduced partial factor productivity from applied N under all treatments. Under N depletion, cd1 showed altered leaf wax composition, but was comparable to the WT under sufficient N. Under salt treatment, cd1 showed an increase in leaf wax and cutin monomers. Root suberin content of cd1 was lower than M82 under control conditions but comparable under higher salinity levels. The tomato mutant cd1 had a higher fruit cuticular transpiration rate, and lower fruit surface area compared to M82. These results show that the cd1 mutation has complex effects on plant physiology, and growth and development beyond cutin deficiency, and offer new insights on the potential agronomic value of leaf cuticle and root suberin for tomato breeding.

Asunto(s)

Lípidos de la Membrana , Mutación , Nitrógeno , Hojas de la Planta , Raíces de Plantas , Salinidad , Solanum lycopersicum , Solanum lycopersicum/genética , Solanum lycopersicum/fisiología , Solanum lycopersicum/metabolismo , Nitrógeno/metabolismo , Lípidos de la Membrana/metabolismo , Hojas de la Planta/genética , Hojas de la Planta/fisiología , Hojas de la Planta/efectos de los fármacos , Hojas de la Planta/metabolismo , Raíces de Plantas/genética , Raíces de Plantas/fisiología , Raíces de Plantas/crecimiento & desarrollo , Raíces de Plantas/efectos de los fármacos , Raíces de Plantas/metabolismo , Lípidos , Frutas/genética , Frutas/crecimiento & desarrollo , Frutas/efectos de los fármacos , Frutas/fisiología , Fotosíntesis , Transpiración de Plantas , Estrés Salino/genética , Ceras/metabolismo , Biomasa , Flores/genética , Flores/fisiología , Flores/crecimiento & desarrollo , Flores/efectos de los fármacos

RESUMEN

BACKGROUND: Ideally, the barrier properties of a fruit's cuticle persist throughout its development. This presents a challenge for strawberry fruit, with their rapid development and thin cuticles. The objective was to establish the developmental time course of cuticle deposition in strawberry fruit. RESULTS: Fruit mass and surface area increase rapidly, with peak growth rate coinciding with the onset of ripening. On a whole-fruit basis, the masses of cutin and wax increase but on a unit surface-area basis, they decrease. The decrease is associated with marked increases in elastic strain. The expressions of cuticle-associated genes involved in transcriptional regulation (FaSHN1, FaSHN2, FaSHN3), synthesis of cutin (FaLACS2, FaGPAT3) and wax (FaCER1, FaKCS10, FaKCR1), and those involved in transport of cutin monomers and wax constituents (FaABCG11, FaABCG32) decreased until maturity. The only exceptions were FaLACS6 and FaGPAT6 that are presumably involved in cutin synthesis, and FaCER1 involved in wax synthesis. This result was consistent across five strawberry cultivars. Strawberry cutin consists mainly of C16 and C18 monomers, plus minor amounts of C19, C20, C22 and C24 monomers, ω-hydroxy acids, dihydroxy acids, epoxy acids, primary alcohols, carboxylic acids and dicarboxylic acids. The most abundant monomer is 10,16-dihydroxyhexadecanoic acid. Waxes comprise mainly long-chain fatty acids C29 to C46, with smaller amounts of C16 to C28. Wax constituents are carboxylic acids, primary alcohols, alkanes, aldehydes, sterols and esters. CONCLUSION: The downregulation of cuticle deposition during development accounts for the marked cuticular strain, for the associated microcracking, and for their high susceptibility to the disorders of water soaking and cracking.

Asunto(s)

Fragaria , Frutas , Lípidos de la Membrana , Ceras , Fragaria/crecimiento & desarrollo , Fragaria/genética , Fragaria/metabolismo , Fragaria/enzimología , Frutas/crecimiento & desarrollo , Frutas/genética , Frutas/metabolismo , Ceras/metabolismo , Lípidos de la Membrana/metabolismo , Regulación de la Expresión Génica de las Plantas , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética

RESUMEN

Alka(e)nes are produced by many living organisms and exhibit diverse physiological roles, reflecting a high functional versatility. Alka(e)nes serve as waterproof wax in plants, communicating pheromones for insects, and microbial signaling molecules in some bacteria. Although alka(e)nes have been found in cyanobacteria and algal chloroplasts, their importance for photosynthetic membranes has remained elusive. In this study, we investigated the consequences of the absence of alka(e)nes on membrane lipid composition and photosynthesis using the cyanobacterium Synechocystis PCC6803 as a model organism. By following the dynamics of membrane lipids and the photosynthetic performance in strains defected and altered in alka(e)ne biosynthesis, we show that drastic changes in the glycerolipid contents occur in the absence of alka(e)nes, including a decrease in the membrane carotenoid content, a decrease in some digalactosyldiacylglycerol (DGDG) species and a parallel increase in monogalactosyldiacylglycerol (MGDG) species. These changes are associated with a higher susceptibility of photosynthesis and growth to high light in alka(e)ne-deficient strains. All these phenotypes are reversed by expressing an algal photoenzyme producing alka(e)nes from fatty acids. Therefore, alkenes, despite their low abundance, are an essential component of the lipid composition of membranes. The profound remodeling of lipid composition that results from their absence suggests that they play an important role in one or more membrane properties in cyanobacteria. Moreover, the lipid compensatory mechanism observed is not sufficient to restore normal functioning of the photosynthetic membranes, particularly under high-light intensity. We conclude that alka(e)nes play a crucial role in maintaining the lipid homeostasis of thylakoid membranes, thereby contributing to the proper functioning of photosynthesis, particularly under elevated light intensities.

Asunto(s)

Carotenoides , Glucolípidos , Lípidos de la Membrana , Fotosíntesis , Synechocystis , Synechocystis/metabolismo , Synechocystis/crecimiento & desarrollo , Carotenoides/metabolismo , Glucolípidos/metabolismo , Lípidos de la Membrana/metabolismo , Membrana Celular/metabolismo , Galactolípidos/metabolismo , Ceras/metabolismo

RESUMEN

Metabolic engineering enables oilseed crops to be more competitive by having more attractive properties for oleochemical industrial applications. The aim of this study was to increase the erucic acid level and to produce wax ester (WE) in seed oil by genetic transformation to enhance the industrial applications of B. carinata. Six transgenic lines for high erucic acid and fifteen transgenic lines for wax esters were obtained. The integration of the target genes for high erucic acid (BnFAE1 and LdPLAAT) and for WEs (ScWS and ScFAR) in the genome of B. carinata cv. 'Derash' was confirmed by PCR analysis. The qRT-PCR results showed overexpression of BnFAE1 and LdPLAAT and downregulation of RNAi-BcFAD2 in the seeds of the transgenic lines. The fatty acid profile and WE content and profile in the seed oil of the transgenic lines and wild type grown in biotron were analyzed using gas chromatography and nanoelectrospray coupled with tandem mass spectrometry. A significant increase in erucic acid was observed in some transgenic lines ranging from 19% to 29% in relation to the wild type, with a level of erucic acid reaching up to 52.7%. Likewise, the transgenic lines harboring ScFAR and ScWS genes produced up to 25% WE content, and the most abundant WE species were 22:1/20:1 and 22:1/22:1. This study demonstrated that metabolic engineering is an effective biotechnological approach for developing B. carinata into an industrial crop.

Asunto(s)

Brassica , Ácidos Erucicos , Ésteres , Ingeniería Metabólica , Plantas Modificadas Genéticamente , Semillas , Ceras , Ácidos Erucicos/metabolismo , Ingeniería Metabólica/métodos , Plantas Modificadas Genéticamente/genética , Plantas Modificadas Genéticamente/metabolismo , Ceras/metabolismo , Ésteres/metabolismo , Semillas/genética , Semillas/metabolismo , Brassica/genética , Brassica/metabolismo , Ácidos Grasos/metabolismo , Aceites de Plantas/metabolismo , Regulación de la Expresión Génica de las Plantas , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo

RESUMEN

Cuticular waxes are essential for protecting plants from various environmental stresses. Allium fistulosum serves as an excellent model for investigating the regulatory mechanisms underlying cuticular wax synthesis with notable epidermal wax characteristics. A combination of gas chromatography-mass spectrometry (GC-MS) metabolite analysis and transcriptomics was used to investigate variations in metabolites and gene expression patterns between the wild type (WT) and glossy mutant type (gl2) of A. fistulosum. The WT surface had a large number of acicular and lamellar waxy crystals, whereas the leaf surface of gl2 was essentially devoid of waxy crystals. And the results revealed a significant decrease in the content of 16-hentriacontanone, the principal component of cuticular wax, in the gl2 mutant. Transcriptomic analysis revealed 3084 differentially expressed genes (DEGs) between WT and gl2. Moreover, we identified 12 genes related to fatty acid or wax synthesis. Among these, 10 DEGs were associated with positive regulation of wax synthesis, whereas 2 genes exhibited negative regulatory functions. Furthermore, two of these genes were identified as key regulators through weighted gene co-expression network analysis. Notably, the promoter region of AfisC5G01838 (AfCER1-LIKE1) exhibited a 258-bp insertion upstream of the coding region in gl2 and decreased the transcription of the AfCER1-LIKE1 gene. This study provided insights into the molecular mechanisms governing cuticular wax synthesis in A. fistulosum, laying the foundation for future breeding strategies.

Asunto(s)

Allium , Cromatografía de Gases y Espectrometría de Masas , Perfilación de la Expresión Génica , Regulación de la Expresión Génica de las Plantas , Transcriptoma , Ceras , Ceras/metabolismo , Cromatografía de Gases y Espectrometría de Masas/métodos , Perfilación de la Expresión Génica/métodos , Allium/genética , Allium/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo

RESUMEN

BACKGROUND AND AIMS: The benefits and costs of amphistomy (AS) vs. hypostomy (HS) are not fully understood. Here, we quantify benefits of access of CO2 through stomata on the upper (adaxial) leaf surface, using 13C abundance in the adaxial and abaxial epicuticular wax. Additionally, a relationship between the distribution of stomata and epicuticular wax on the opposite leaf sides is studied. METHODS: We suggest that the 13C content of long-chain aliphatic compounds of cuticular wax records the leaf internal CO2 concentration in chloroplasts adjacent to the adaxial and abaxial epidermes. This unique property stems from: (1) wax synthesis being located exclusively in epidermal cells; and (2) ongoing wax renewal over the whole leaf lifespan. Compound-specific and bulk wax 13C abundance (δ) was related to amphistomy level (ASL; as a fraction of adaxial in all stomata) of four AS and five HS species grown under various levels of irradiance. The isotopic polarity of epicuticular wax, i.e. the difference in abaxial and adaxial δ (δab - δad), was used to calculate the leaf dorsiventral CO2 gradient. Leaf-side-specific epicuticular wax deposition (amphiwaxy level) was estimated and related to ASL. KEY RESULTS: In HS species, the CO2 concentration in the adaxial epidermis was lower than in the abaxial one, independently of light conditions. In AS leaves grown in high-light and low-light conditions, the isotopic polarity and CO2 gradient varied in parallel with ASL. The AS leaves grown in high-light conditions increased ASL compared with low light, and δab - δad approached near-zero values. Changes in ASL occurred concomitantly with changes in amphiwaxy level. CONCLUSIONS: Leaf wax isotopic polarity is a newly identified leaf trait, distinguishing between hypo- and amphistomatous species and indicating that increased ASL in sun-exposed AS leaves reduces the CO2 gradient across the leaf mesophyll. Stomata and epicuticular wax deposition follow similar leaf-side patterning.

Asunto(s)

Dióxido de Carbono , Isótopos de Carbono , Epidermis de la Planta , Hojas de la Planta , Estomas de Plantas , Ceras , Ceras/metabolismo , Ceras/química , Isótopos de Carbono/análisis , Dióxido de Carbono/metabolismo , Estomas de Plantas/fisiología , Epidermis de la Planta/metabolismo , Hojas de la Planta/metabolismo , Fotosíntesis

RESUMEN

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.

Asunto(s)

Regulación de la Expresión Génica de las Plantas , Proteínas de Plantas , Factores de Transcripción , Triticum , Ceras , Ceras/metabolismo , Triticum/metabolismo , Triticum/genética , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Factores de Transcripción/metabolismo , Factores de Transcripción/genética , Hojas de la Planta/metabolismo , Hojas de la Planta/genética , Clorofila/metabolismo , Transactivadores/metabolismo , Transactivadores/genética , Epidermis de la Planta/metabolismo

RESUMEN

Cucumber (Cucumis sativus L.) is an important horticultural crop in China. Consumer requirements for aesthetically pleasing appearances of horticultural crops are gradually increasing, and cucumbers having a good visual appearance, as well as flavor, are important for breeding and industry development. The gloss of cucumber fruit epidermis is an important component of its appeal, and the wax layer on the fruit surface plays important roles in plant growth and forms a powerful barrier against external biotic and abiotic stresses. The wax of the cucumber epidermis is mainly composed of alkanes, and the luster of cucumber fruit is mainly determined by the alkane and silicon contents of the epidermis. Several genes, transcription factors, and transporters affect the synthesis of ultra-long-chain fatty acids and change the silicon content, further altering the gloss of the epidermis. However, the specific regulatory mechanisms are not clear. Here, progress in research on the luster of cucumber fruit epidermis from physiological, biochemical, and molecular regulatory perspectives are reviewed. Additionally, future research avenues in the field are discussed.

Asunto(s)

Cucumis sativus , Frutas , Regulación de la Expresión Génica de las Plantas , Cucumis sativus/genética , Cucumis sativus/metabolismo , Cucumis sativus/crecimiento & desarrollo , Frutas/genética , Frutas/metabolismo , Epidermis de la Planta/metabolismo , Epidermis de la Planta/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Ceras/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo

RESUMEN

The cuticle is a hydrophobic coating of most aerial plant surfaces crucial for limiting non-stomatal water loss. Plant cuticles consist of the lipid polyester cutin and associated waxes with compositions varying widely between plant species and organs. Here, we aimed to provide a comparative analysis of the dark-glossy adaxial and pale-glaucous abaxial sides of Drimys winteri (Winteraceae) leaves. Scanning electron microscopy showed nanotubular wax crystals lining the entire abaxial side of the leaf (including stomatal pores), while the adaxial side had patches of mixed platelet/tubule crystals and smooth areas between them. Consecutive treatments for wax removal and cutin depolymerization revealed that the waxes were deposited on a cutin network with micron-scale cavities across the entire abaxial surface including the stomata pores, and on a microscopically smooth cutin surface on the adaxial side of the leaf. Gas chromatography coupled to mass spectrometry and flame ionization detection showed that the wax mixtures on both sides of the leaf were complex mixtures of very-long-chain compounds dominated by the secondary alcohol nonacosan-10-ol and alkanediols with one hydroxyl on C-10. It is therefore very likely that the characteristic tubular wax crystals of both leaf sides are formed by these alcohols and diols. Further secondary alcohols and alkanediols, as well as ketols and alkanetriols with one functional group on C-10, were identified based on mass spectral fragmentation patterns. The similarities between all these mid-chain-functionalized compounds suggest that they are derived from nonacosan-10-ol via regio-specific hydroxylation reactions, likely catalyzed by three P450-dependent monooxygenases with different regio-specificities.

Asunto(s)

Alcoholes , Hojas de la Planta , Ceras , Ceras/metabolismo , Ceras/química , Hojas de la Planta/metabolismo , Alcoholes/metabolismo , Alcoholes/química , Microscopía Electrónica de Rastreo , Cromatografía de Gases y Espectrometría de Masas , Epidermis de la Planta/ultraestructura , Epidermis de la Planta/metabolismo , Epidermis de la Planta/química , Lípidos de la Membrana/metabolismo

RESUMEN

Wax biosynthesis is closely controlled by many regulators under different environmental conditions. We have previously shown that the module miR156-SQUAMOSA PROMOTER BINDING PROTEIN-LIKE9 (SPL9)-DEWAX is involved in the diurnal regulation of wax production; however, it was not determined whether other SPLs are also involved in wax synthesis. Here, we report that SPL13 also regulates drought-induced wax production, by directly and indirectly affecting the expression of the two wax biosynthesis genes ECERIFERUM1 (CER1) and CER4, respectively. In addition, we show that SPL13 together with SPL9 redundantly regulates wax accumulation under both normal and drought stress conditions, and that simultaneous mutation of both genes additively increases cuticle permeability and decreases drought tolerance. However, in contrast to SPL9, SPL13 does not seem to participate in the DEWAX-mediated diurnal regulation of wax production.

Asunto(s)

Proteínas de Arabidopsis , Arabidopsis , Sequías , Regulación de la Expresión Génica de las Plantas , Ceras , Arabidopsis/genética , Arabidopsis/metabolismo , Arabidopsis/fisiología , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Estrés Fisiológico , Factores de Transcripción/metabolismo , Factores de Transcripción/genética , Ceras/metabolismo

RESUMEN

The main challenge in the development of agrochemicals is the lack of new leads and/or targets. It is critical to discover new molecular targets and their corresponding ligands. YZK-C22, which contains a 1,2,3-thiadiazol-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazole skeleton, is a fungicide lead compound with broad-spectrum fungicidal activity. Previous studies suggested that the [1,2,4]triazolo[3,4-b][1,3,4]thiadiazole scaffold exhibited good antifungal activity. Inspired by this, a series of pyrrolo[2,3-d]thiazole derivatives were designed and synthesized through a bioisosteric strategy. Compounds C1, C9, and C20 were found to be more active against Rhizoctonia solani than the positive control YZK-C22. More than half of the target compounds provided favorable activity against Botrytis cinerea, where the EC50 values of compounds C4, C6, C8, C10, and C20 varied from 1.17 to 1.77 µg/mL. Surface plasmon resonance and molecular docking suggested that in vitro potent compounds C9 and C20 have a new mode of action instead of acting as pyruvate kinase inhibitors. Transcriptome analysis revealed that compound C20 can impact the tryptophan metabolic pathway, cutin, suberin, and wax biosynthesis of B. cinerea. Overall, pyrrolo[2,3-d]thiazole is discovered as a new fungicidal lead structure with a potential new mode of action for further exploration.

Asunto(s)

Botrytis , Fungicidas Industriales , Rhizoctonia , Tiazoles , Triptófano , Ceras , Fungicidas Industriales/farmacología , Fungicidas Industriales/química , Fungicidas Industriales/síntesis química , Rhizoctonia/efectos de los fármacos , Botrytis/efectos de los fármacos , Tiazoles/farmacología , Tiazoles/química , Tiazoles/metabolismo , Triptófano/metabolismo , Triptófano/química , Ceras/química , Ceras/metabolismo , Relación Estructura-Actividad , Redes y Vías Metabólicas/efectos de los fármacos , Simulación del Acoplamiento Molecular , Pirroles/farmacología , Pirroles/química , Pirroles/metabolismo , Enfermedades de las Plantas/microbiología , Estructura Molecular

RESUMEN

BACKGROUND: The cuticular wax serves as a primary barrier that protects plants from environmental stresses. The Eceriferum (CER) gene family is associated with wax production and stress resistance. RESULTS: In a genome-wide identification study, a total of 52 members of the CER family were discovered in four Gossypium species: G. arboreum, G. barbadense, G. raimondii, and G. hirsutum. There were variations in the physicochemical characteristics of the Gossypium CER (GCER) proteins. Evolutionary analysis classified the identified GCERs into five groups, with purifying selection emerging as the primary evolutionary force. Gene structure analysis revealed that the number of conserved motifs ranged from 1 to 15, and the number of exons varied from 3 to 13. Closely related GCERs exhibited similar conserved motifs and gene structures. Analyses of chromosomal positions, selection pressure, and collinearity revealed numerous fragment duplications in the GCER genes. Additionally, nine putative ghr-miRNAs targeting seven G. hirsutum CER (GhCER) genes were identified. Among them, three miRNAs, including ghr-miR394, ghr-miR414d, and ghr-miR414f, targeted GhCER09A, representing the most targeted gene. The prediction of transcription factors (TFs) and the visualization of the regulatory TF network revealed interactions with GhCER genes involving ERF, MYB, Dof, bHLH, and bZIP. Analysis of cis-regulatory elements suggests potential associations between the CER gene family of cotton and responses to abiotic stress, light, and other biological processes. Enrichment analysis demonstrated a robust correlation between GhCER genes and pathways associated with cutin biosynthesis, fatty acid biosynthesis, wax production, and stress response. Localization analysis showed that most GCER proteins are localized in the plasma membrane. Transcriptome and quantitative reverse transcription-polymerase chain reaction (qRT-PCR) expression assessments demonstrated that several GhCER genes, including GhCER15D, GhCER04A, GhCER06A, and GhCER12D, exhibited elevated expression levels in response to water deficiency stress compared to control conditions. The functional identification through virus-induced gene silencing (VIGS) highlighted the pivotal role of the GhCER04A gene in enhancing drought resistance by promoting increased tissue water retention. CONCLUSIONS: This investigation not only provides valuable evidence but also offers novel insights that contribute to a deeper understanding of the roles of GhCER genes in cotton, their role in adaptation to drought and other abiotic stress and their potential applications for cotton improvement.

Asunto(s)

Sequías , Gossypium , Familia de Multigenes , Proteínas de Plantas , Gossypium/genética , Gossypium/fisiología , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Regulación de la Expresión Génica de las Plantas , Estrés Fisiológico/genética , Genes de Plantas , Filogenia , Adaptación Fisiológica/genética , Ceras/metabolismo , MicroARNs/genética