Добірка наукової літератури з теми "Cutin monomers"

The fungal pathogen Diplocarpon rosae causes rose blackspot disease, a serious problem for roses (Rosa) in the managed landscape. To prevent this disease, homeowners and professional growers often apply chemical fungicide. However, increased use of fungicides poses an environmental hazard and an economic burden to the user. New landscape rose cultivars like ‘Knockout’ possess increased disease resistance, but the biological basis for this resistance is still unknown. To investigate the potential role of leaf cuticle in blackspot resistance in rose, five rose cultivars known to vary greatly in blackspot resistance were examined for variation in the major lipids of the leaf cuticle, specifically the monomers of the cutin polyester and the free cuticular waxes. This is the first report of cutin monomers in the Rosa genera. The rose cultivars selected for this study were ‘Knockout’, ‘Mister Lincoln’, ‘Garden Party’, ‘Purple Passion’, and ‘Bicolor’. ‘Knockout’ and ‘Garden Party’ had significantly lower total cutin monomer amount per leaf area than the other cultivars, whereas the most cutin monomers were observed on ‘Purple Passion’, ‘Bicolor’, and ‘Mister Lincoln’. Five major cutin monomers (mostly hydroxylated 16 carbon fatty acids) dominated the cutin profiles of both adaxial and adaxial surfaces of all cultivars, with the 10,16-dihydroxy hexadecanoic acids being most abundant. The proportion of 10,16-dihydroxy hexadecanoic acids was slightly higher in the adaxial than abaxial leaf cuticles of all cultivars. Correspondingly, other cutin monomers were relatively lower in the adaxial cuticle, except 16-hydroxy hexadecanoic acid that differed little. Uniquely, this is the first report of cutin monomer composition of isolated abaxial and adaxial leaf cuticles of any plant. Total leaf cuticular wax amounts were lowest on ‘Purple Passion’ and ‘Knockout’, intermediate in ‘Mister Lincoln’ and ‘Garden Party’, and highest on ‘Bicolor’, with alkanes as the most abundant wax class. Consistent with previously published disease susceptibility ratings, our visual scores showed that ‘Knockout’ was most resistant to blackspot pathogen infection with a visual disease rating score of 1.0, followed by ‘Mister Lincoln’ at 1.8, ‘Garden Party’ at 5.4, ‘Bicolor’ at 7.5, and ‘Purple Passion’ with the most visible disease damage at 8.8. Regression analysis revealed that the alkane and ester proportions were most closely associated with blackspot disease susceptibility ratings, being inversely (R2 = 0.63, P = 0.05) and directly (R2 = 0.81, P = 0.05) correlated, respectively. More studies on the role of cuticle in rose susceptibility to blackspot are now clearly warranted.

Abstract Background and Aims The cuticle of a limited number of plant species contains cutan, a chemically highly resistant biopolymer. As yet, the biosynthesis of cutan is not fully understood. Attempting to further unravel the origin of cutan, we analysed the chemical composition of enzymatically isolated cuticular membranes of Agave americana leaves. Methods Cuticular waxes were extracted with organic solvents. Subsequently, the dewaxed cuticular membrane was depolymerized by acid-catalysed transesterification yielding cutin monomers and cutan, a non-hydrolysable, cuticular membrane residue. The cutan matrix was analysed by thermal extraction, flash pyrolysis and thermally assisted hydrolysis and methylation to elucidate the monomeric composition and deduce a putative biosynthetic origin. Key Results According to gas chromatography–mass spectrometry analyses, the cuticular waxes of A. americana contained primarily very-long-chain alkanoic acids and primary alkanols dominated by C32, whereas the cutin biopolyester of A. americana mainly consisted of 9,10-epoxy ω-hydroxy and 9,10,ω-trihydroxy C18 alkanoic acids. The main aliphatic cutan monomers were alkanoic acids, primary alkanols, ω-hydroxy alkanoic acids and alkane-α,ω-diols ranging predominantly from C28 to C34 and maximizing at C32. Minor contributions of benzene-1,3,5-triol and derivatives suggested that these aromatic moieties form the polymeric core of cutan, to which the aliphatic moieties are linked via ester and possibly ether bonds. Conclusions High similarity of aliphatic moieties in the cutan and the cuticular wax component indicated a common biosynthetic origin. In order to exclude species-specific peculiarities of A. americana and to place our results in a broader context, cuticular waxes, cutin and cutan of Clivia miniata, Ficus elastica and Prunus laurocerasus leaves were also investigated. A detailed comparison showed compositional and structural differences, indicated that cutan was only found in leaves of perennial evergreen A. americana and C. miniata, and made clear that the phenomenon of cutan is possibly less present in plant species than suggested in the literature.

Fungal spores that land on aerial surfaces of plants first come into contact with plant cuticle. The cuticle is composed of an insoluble polyester called cutin, which is composed of hydroxy and hydroxyepoxy fatty acids and associated soluble waxes. The wax components can trigger differentiation of germinating fungal spores into infection structures. The penetration of the fungus into the plant requires enzymatic degradation of the polyester and the underlying carbohydrate barriers. The polyesterase, called cutinase, is induced by the contact with the plant surface. The small amount of cutinase carried by the spore generates a small amount of cutin monomers upon contact with the host, and the unique monomers trigger expression of the cutinase gene. This transcriptional level control can be demonstrated with isolated nuclei. Upon incubation of nuclei with cutin monomer and a soluble protein factor from the fungus, cutinase transcription is selectively activated. Structure activity relationships showed that the cutinase transcription activation required all of the structural elements of the cutin monomer. The cutinase transcript generated by the isolated nuclei was identical in size to the cutinase mRNA induced in the fungal cultures, which indicated usual initiation and termination. Fungal infection triggers defense reaction in plants. Plant peroxidases were implicated in the defense response of plants to fungal attack and stress. A highly anionic peroxidase involved in suberization of cell walls in tomato plants in response to fungal attack was cloned and sequenced. It was observed that in resistant lines of tomato the expression of this anionic peroxidase was induced 1 day earlier than in susceptible lines.Key words: cutinase, cutin monomers, pectate lyase, Fusarium solani pisi, anionic peroxidase.

Leaf cuticular membranes (CMs) of Sonneratia alba are considered to play an important role in environmental tolerance, and chemical and mechanical properties of their CMs are crucial factors which provide protective barrier and mechanical supports. Leaf CMs were enzymatically isolated from both adaxial and abaxial sides of young matured leaves (L3), and their chemical and mechanical properties were compared. Chemical compositions of both CMs were similar reflecting their morphological similarity. The adaxial CM was consisted of 23.4% wax, 64.2% cutin, 7.4% cutan and 6.1% polysaccharides with thickness of 9 µm, and the abaxial CM had the values of 23.9%, 63.2%, 9.4%, 4.2% and 8 µm, respectively. Major monomers in both cutins were 9,10-epoxy-18-hydroxyoctadecanoic acid and 9(10),16-dihydroxyhexadecanoic acid. Mechanical properties of both CMs were also similar reflecting their morphological and chemical compositional similarities.

Plant cuticles have attracted attention because they can be used to produce hydrophobic films as models for novel biopolymers. Usually, cuticles are obtained from agroresidual waste. To find new renewable natural sources to design green and commercially available bioplastics, fruits of S. aculeatissimum and S. myriacanthum were analyzed. These fruits are not used for human or animal consumption, mainly because the fruit is composed of seeds. Fruit peels were object of enzymatic and chemical methods to get thick cutins in good yields (approximately 77% from dry weight), and they were studied by solid-state resonance techniques (CPMAS 13C NMR), attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), atomic force microscopy (AFM) and direct injection electrospray ionization mass spectrometry (DIESI-MS) analytical methods. The main component of S. aculeatissimum cutin is 10,16-dihydroxypalmitic acid (10,16-DHPA, 69.84%), while S. myriacanthum cutin besides of 10,16-DHPA (44.02%); another two C18 monomers: 9,10,18-trihydroxy-octadecanoic acid (24.03%) and 18-hydroxy-9S,10R-epoxy-octadecanoic acid (9.36%) are present. The hydrolyzed cutins were used to produce films demonstrating that both cutins could be a potential raw material for different biopolymers.

This study comprehensively analysed the chemical composition of the cuticle in pitaya fruits. The total coverage amount of the waxes versus cutin monomers accumulated at a ratio of 0.6, corresponding to masses per unit of 30.3 μg·cm−2 and 50.8 μg·cm−2, respectively. The predominant wax mixtures were n-alkanes in homologous series of C20–C35, dominated by C31 and C33; as well as triterpenoids with an abundant amount of uvaol, lupenon, β-amyrinon, and β-amyrin. The most prominent cutin compounds were C16- and C18-type monomers, in which 9(10),16-diOH-hexadecanoic acid and 9,10-epoxy-ω-OH-octadecanoic acid predominated, respectively. The average chain length (ACL) of aliphates in pitaya fruit cuticle (30.5) was similar to that estimated in leaf waxes, and higher than that in most of the fruit and petal waxes that have been reported. We propose that the relatively high ACL and wax/cutin ratio might enhance the cuticular barrier properties in pitaya fruit cuticle to withstand drought.

The use of agro-industrial wastes to obtain compounds with a high added-value is increasing in the last few years in accordance with the circular economy concept. In this work, a cascade extraction approach was developed based on ultrasound-assisted extraction (UAE) for tomato, watermelon, and apple peel wastes. The protein and antioxidant compounds were obtained during the first extraction step (NaOH 3 wt.%, 98.6 W, 100% amplitude, 6.48 W/cm2, 6 min). The watermelon peels (WP) showed higher proteins and total phenolic contents (857 ± 1 mg BSA/g extract and 107.2 ± 0.2 mg GAE/100 g dm, respectively), whereas the highest antioxidant activity was obtained for apple peels (1559 ± 20 µmol TE/100 g dm, 1767 ± 5 µmol TE/100 g dm, and 902 ± 16 µmol TE/100 g dm for ABTS, FRAP and DPPH assays, respectively). The remaining residue obtained from the first extraction was subsequently extracted to obtain cutin (ethanol 40 wt.%, 58 W, 100% amplitude, 2 W/cm2, 17 min, 1/80 g/mL, pH 2.5). The morphological studies confirmed the great efficiency of UAE in damaging the vegetal cell walls. WP showed a higher non-hydrolysable cutin content (55 wt.% of the initial cutin). A different monomers’ profile was obtained for the cutin composition by GC-MS, with the cutin from tomato and apple peels being rich in polyhydroxy fatty acids whereas the cutin extracted from WP was mainly based on unsaturated fatty acids. All of the cutin samples showed an initial degradation temperature higher than 200 °C, presenting an excellent thermal stability. The strategy followed in this work has proved to be an effective valorization methodology with a high scaling-up potential for applications in the food, pharmaceutical, nutraceutical, cosmetics and biopolymer sectors.

La colonisation réussie et durable des terres par les plantes a nécessité l'apparition de certains traits afin de survivre aux nouvelles contraintes telles que l'accès limité aux nutriments et à l'eau, la gravité, l'environnement oxydatif et les radiations UV. Chez les plantes terrestres existantes, les polymères hydrophobes déposés à la surface de différents tissus, tels que la sporopollénine, la cuticule, la subérine et la lignine, sont connus pour contribuer à la limitation de la perte d'eau et à la résistance à d'autres stress abiotiques, ce qui en fait des "innovations de terrestrialisation" potentielles. Comment et quand ces traits ont évolué chez les plantes restent insaisissables. Les données fossiles et l'analyse phylogénétique des gènes impliqués dans la biosynthèse de ces polymères chez les plantes ont proposé la cutine, la partie hydrophobe et polymérisée de la cuticule, comme le meilleur candidat pour la terrestrialisation des plantes. Cette thèse décrit des recherches menées pour déterminer la distribution de la cutine dans les plantes, l'évolution des gènes nécessaires à sa biosynthèse et la fonction de deux d'entre eux chez la Bryophyte modèle, Marchantia polymorpha. La présence de la cutine dans les espèces de Zygnematophyceae, qui sont les algues les plus proches des plantes terrestres, et dans diverses plantes terrestres a été surveillée par des observations microscopiques et des analyses biochimiques. La cutine n'a été détectée que dans les plantes terrestres, de même qu'une enzyme terminale de la biosynthèse des monomères de cutine, les glycérol-phosphates acyle transférases (GPATs). Pour confirmer l'origine de la cutine chez les Embryophytes, nous avons étudié les GPATs chez M. polymorpha. Tout d'abord, le pattern d'expression des GPATs de M. polymorpha a été étudié en utilisant la fusion promoteur:GUS. Les activités de ces promoteurs ont été principalement détectées là où la cutine est formée. Ensuite, une lignée mutante GPAT de M. polymorpha a été isolée. Des analyses macroscopiques de ce mutant ont montré que, comme chez les autres Embryophytes, les gènes liés à la cutine de Marchantia sont impliqués dans le développement des organes aériens. L'analyse biochimique, la génétique inverse et la phylogénétique ont été combinées pour parvenir à la conclusion selon laquelle la cutine a évolué dans les premières plantes terrestres avec une classe d'enzymes de biosynthèse de la cutine, les GPATs, et joue probablement une fonction dans le développement chez les Bryophytes
The successful and long-lasting colonization of lands by plants required the evolution of innovations in order to survive to the novel constraints such as limited nutrient and water access, gravity, oxidative environment and UV radiations. In extant land plants, hydrophobic polymers deposited on the surface of different tissues, such as sporopollenin, cuticle, suberin and lignin, are known to contribute to the limitation of water loss, and resistance to other abiotic stresses, making them potential "terrestrialization innovations". How and when these traits evolved in plants remains elusive. Fossils data and phylogenetical analysis of genes involved in cutin biosynthesis in plants proposed cutin as the best candidate for plant terrestrialization. However, works testing this hypothesis are actually scares and the evidence limited. This thesis describes conducted investigations to determine the distribution of cutin in plants, the evolution of the genes required for its biosynthesis and the function of two of them in the model bryophyte, Marchantia polymorpha. The presence of cutin in species from the zygnematophyceae, which are the closest algal relatives to land plants, and in diverse land plants was monitored through microscopic observations and biochemical analyses. Cutin was only detected in land plants, as was one terminal enzyme in the biosynthesis of the cutin monomer, the Glycerol-Phosphate Acyl Transferases (GPATs). To confirm the origin of cutin in Embryophytes we have studied GPAT in the Bryophyte M. polymorpha. First, the expression pattern of M. polymorpha GPAT were studied using promoter:GUS fusion. The M. polymorpha GPATs promoter activities were mainly detected where cutin is formed. Then a mutant line of M. polymorpha GPAT was isolated. Macroscopic analysis of this mutant have shown that such as in Embryophytes, Marchantia cutin-related genes are involved in development of aerial organs. Biochemical analysis, reverse-genetics and phylogenetics were combined to reach the conclusion that cutin evolved in the first land plants together with one class of cutin-biosynthesis enzymes, the GPATs, and likely play a function in development in Bryophytes. This works indicates that cutin evolution in Embryophytes played a role in the terrestrialization event

La cuticule, une matrice lipidique extracellulaire constituée de cires et d'un squelette de cutine, est la barrière de défense la plus externe des plantes face à leur environnement. Elle intervient dans de nombreuses propriétés agronomiques comme la conservation post récolte, les propriétés mécaniques ou bien l'aspect du fruit, dont la brillance. Afin d'isoler des mutants de cuticule, le criblage d'une collection de mutants EMS de tomate a été entrepris, en se basant sur la brillance des fruits, conduisant à la sélection de 24 mutants. Chez ceux-ci, des analyses biochimiques ont montré de fortes variations de charge et de composition de la cuticule, notamment chez les mutants de cutine. La caractérisation de 4 mutants remarquables a été entreprise afin d'identifier les mutations responsables des phénotypes de brillance. Le mutant le plus affecté, présentant une charge en cutine réduite de 85% par rapport au type sauvage, a révélé une mutation du gène SlGDSL2 codant pour une acylhydrolase à motif GDSL, responsable de la polymérisation de la cutine. Afin d'étudier la formation et la régulation de la cutine, la suite du travail a consisté à obtenir et à caractériser des simples et des doubles mutants affectés dans la synthèse des monomères de cutine, le transport apoplastique et la polymérisation de la cutine.

La matière organique des sols (MOS) représente un réservoir majeur de carbone. Certaines pratiques agricoles ont pour effet de minéraliser la MOS. Dans un système où les résidus de cultures sont retournés au sol, la biomasse racinaire contribue plus à la MOS que les parties aériennes, alors que la proportion de MO contenue dans les racines est plus faible. Afin de mieux comprendre les processus de dégradation et/ou de stabilisation de la MOS, nous avons choisi d'étudier dans une chronoséquence blé/maïs, la dynamique des marqueurs de deux biopolyesters, les cutines et les subérines, spécifiques des parties aériennes et souterraines des plantes. Le blé est une plante en C3 (13C ≈ -28‰) alors que le maïs est une plante en C4 (13C ≈ -12‰). Ce dispositif permet de suivre in situ, l'incorporation des marqueurs provenant du maïs à la MOS, par mesure de leur 13C dans le sol. Les marqueurs des cutines du maïs ne sont pas ou peu incorporés à la MOS, alors que ceux des subérines du maïs le sont, lors des six premières années de culture de maïs. Les marqueurs des cutines sont stabilisés dans le sol, soit parce qu'ils appartiennent à un compartiment chimiquement réfractaire, soit parce qu'ils sont protégés par la matrice du sol (protection physique, adsorption sur les minéraux). Les marqueurs des subérines, présentent deux compartiments cinétiques, un rapidement renouvelable, l'autre plus stable suivant les mécanismes de protections semblables à ceux des cutines. En profondeur, la concentration des marqueurs des subérines des racines de maïs augmente alors que celle des cutines diminue, indiquant que le changement de culture de blé à maïs influence la dynamique de la MOS.

The fruit of pepper (Capsicum annuum) commonly wilts (or shrivels) during postharvest storage due to rapid water loss, a condition that greatly reduces its shelf life and market value. The fact that pepper fruit are hollow, and thus have limited water content, only exacerbates this problem in pepper. The collaborators on this project completed research whose findings provided new insight into the genetic, physiological, and biochemical basis for water loss from the fruits of pepper (Capsicum annuum and related Capsicum species). Well-defined genetic populations of pepper were used in this study, the first being a series of backcross F₁ and segregating F₂, F₃, and F₄ populations derived from two original parents selected for having dramatic differences in fruit water loss rate (very high and very low water loss). The secondly population utilized in these studies was a collection of 50 accessions representing world diversity in both species and cultivar types. We found that an unexpectedly large amount of variation was present in both fruit wax and cutin composition in these collections. In addition, our studies revealed significant correlations between the chemical composition of both the fruit cuticular waxes and cutin monomers with fruit water loss rate. Among the most significant were that high alkane content in fruit waxes conferred low fruit water loss rates and low permeability in fruit cuticles. In contrast, high amounts of terpenoids (plus steroidal compounds) were associated with very high fruit water loss and cuticle permeability. These results are consistent with our models that the simple straight chain alkanes pack closely together in the cuticle membrane and obstruct water diffusion, whereas lipids with more complex 3-dimensional structure (such as terpenoids) do not pack so closely, and thus increase the diffusion pathways. The backcross segregating populations were used to map quantitative trait loci (QTLs) associated with water loss (using DART markers, Diversity Arrays Technology LTD). These studies resulted in identification of two linked QTLs on pepper’s chromosome 10. Although the exact genetic or physiological basis for these QTLs function in water loss is unknown, the genotypic contribution in studies of near-isogenic lines selected from these backcross populations reveals a strong association between certain wax compounds, the free fatty acids and iso-alkanes. There was also a lesser association between the water loss QTLs with both fruit firmness and total soluble sugars. Results of these analyses have revealed especially strong genetic linkages between fruit water loss, cuticle composition, and two QTLs on chromosome 10. These findings lead us to further speculate that genes located at or near these QTLs have a strong influence on cuticle lipids that impact water loss rate (and possibly, whether directly or indirectly, other traits like fruit firmness and sugar content). The QTL markers identified in these studies will be valuable in the breeding programs of scientists seeking to select for low water loss, long lasting fruits, of pepper, and likely the fruits of related commodities. Further work with these newly developed genetic resources should ultimately lead to the discovery of the genes controlling these fruit characteristics, allowing for the use of transgenic breeding approaches toward the improvement of fruit postharvest shelf life.