Chitin is an abundant natural biopolymer that plays a crucial role in insect growth and development as a fundamental structural component of the exoskeleton.The membrane-integralβ-glycosyltransferase,chitin synthase,...Chitin is an abundant natural biopolymer that plays a crucial role in insect growth and development as a fundamental structural component of the exoskeleton.The membrane-integralβ-glycosyltransferase,chitin synthase,has been identified as the central component in chitin biosynthesis.However,the precise roles of other proteins in facilitating chitin synthase in chitin biosynthesis remain unclear.In this study,we employed split-ubiquitin membrane yeast two-hybrid(MYTH)and pull-down assays to demonstrate the physical interaction between Twinstar(Tsr),a small molecular protein in the actin-depolymerizing factor ADF/Cofilin protein family,and chitin synthase Krotzkopf verkehrt(Kkv)in Drosophila melanogaster in vitro.The RNA interference(RNAi)-mediated global knockdown of Tsr in D.melanogaster resulted in larval lethality.Furthermore,targeted suppression of Tsr in the tracheal and epidermal tissues also led to larval mortality,while knocking down Tsr in the wing tissues led to wrinkled wings.Additionally,silencing Tsr not only reduced the chitin content in the first longitudinal vein of the wings but also led to the absence of the chitin lamellar structure.To validate the functional conservation of Tsr in other insect orders,the two agricultural pests Ostrinia furnacalis and Tribolium castaneum,representing lepidoptera and coleoptera insects,respectively,were investigated.Knockdown experiments targeting the Drosophila Tsr orthologues OfTsr in O.furnacalis and TcTsr in T.castaneum produced abnormal larvae during molting or pupation in O.furnacalis and lethality in T.castaneum.Our findings not only improve ourknowledge of the chitin biosynthesis machinery in insect cuticles but also provide new potential targets for the control of major agricultural pests.展开更多
CRISPR/Cas9-based gene editing research has advanced greatly and shows broad potential for practical application in life sciences,but the Cas9 system is often constrained by the requirement of a protospacer adjacent m...CRISPR/Cas9-based gene editing research has advanced greatly and shows broad potential for practical application in life sciences,but the Cas9 system is often constrained by the requirement of a protospacer adjacent motif(PAM)at the target site.While xCas9,a variant derived from Streptococcus pyogenes Cas9(SpCas9),can recognize a broader range of PAMs,its application in non-model insects is lacking.In this study,we explored xCas9 activity in gene editing by selecting corazonin(Crz)and the target sites with various PAMs in Locusta migratoria,a destructive insect pest worldwide.We found that xCas9 could cleave the target site with AG PAM while SpCas9 could not,although xCas9 appeared to have lower activity than SpCas9 at the canonical NGG PAMs.The heritable homozygous Crz^(-/-)locust strain was generated by the application of xCas9.The Crz^(-/-)strain showed an albino body color,with significantly downregulated expression of several body color-related genes including Pale,Vermilion,Cinnabar,White andβ-carotene-binding protein.In addition,Crz^(-/-)mutants exhibited significantly reduced expression of Chitin synthase 1,along with a markedly lower chitin content as well as compact and rigid cuticles.Furthermore,Crz^(-/-)mutants displayed impaired performance under low-temperature stress,including prolonged lifespan,reduced body weight and smaller body size.Our results suggest that xCas9 is effective for insect genome editing,and Crz plays essential roles in insect body color,cuticle development and adaptation to low-temperature stress.The findings of this study extend the application of xCas9 in non-model insects and provide new insights into our understanding of the regulation of insect cuticle development and environmental adaptation.展开更多
Extreme environmental conditions such as temperature fluctuations,drought,and pathogen attacks can significantly impact plant growth,development,and productivity.Plants have evolved intricate enzymatic systems to miti...Extreme environmental conditions such as temperature fluctuations,drought,and pathogen attacks can significantly impact plant growth,development,and productivity.Plants have evolved intricate enzymatic systems to mitigate these stresses,among which GDSL esterase/lipase proteins (GELPs)-key members of the serine esterase/lipase superfamily-play important roles (Akoh et al.,2004).Characterized by a conserved GDSL motif and four essential amino acids (serine,glycine,asparagine,and histidine),GELPs exhibit versatile catalytic functions in lipid metabolism,cell wall modification,and stress responses (Ursache et al.,2021;Shen et al.,2022).展开更多
Although the research on Cordaites of the Cathaysian Flora in China started early in 1883, the study of the cordaitean cuticles began late in 1991. Up to now, four types of cordaitean cuticles in situ and three types ...Although the research on Cordaites of the Cathaysian Flora in China started early in 1883, the study of the cordaitean cuticles began late in 1991. Up to now, four types of cordaitean cuticles in situ and three types of dispersed ones have been reported from the Cathaysian Flora in China. However compared with the Euramerican Flora, the research work on cordaitean cuticles from the Cathaysian Flora in China is much more insufficient. In this paper, three kinds of dispersed cordaitean cuticles are described in detail from the Permian coal-bearing strata in China. Among these cuticles two kinds are collected from the roof shale of Coal Seam No. A(1) in Shanxi Formation (Lower Permian) in Xinzhuangzhi Coal Mine of Huainan, Anhui Province, southern border of North China Subprovince of the Cathaysian Flora in China. The third one was collected from Coal Seam No. 11 in the top of Longtan Formation (lower Upper Permian) in Dahebian Coal Mine of Shuicheng Mining District, Guizhou Province, South China Subprovince of the Cathaysian Flora in China. Comparison of these three kinds of cordaitean cuticles with the known ones from the Cathaysian Flora in China and from the Euramerican Flora is made. The authors consider that they are all new types of cordaitean cuticles. The significance they bear on palaeobotany is discussed.展开更多
The cuticle of dung beetle is a layered composite material in micro- or nano-scale. Dung beetle can fly, walk and dig. It can shovel and compact dung of mammals into balls. It use foreleg to walk, midleg and hindleg ...The cuticle of dung beetle is a layered composite material in micro- or nano-scale. Dung beetle can fly, walk and dig. It can shovel and compact dung of mammals into balls. It use foreleg to walk, midleg and hindleg to hold and impel dung ball. Its two foreleges as digging legs are developed. The factors impacting the nanoindentation testing results of the femur cuticle of forelegs of dung beetle Copris ochus Motschulsky were examined. The nanomechanical test instrument used for the tests was Hysitron nanomechanical system. The results shown that the holding time and loading time are important factors im- pacting the accuracy of such indentation properties as reduced modulus (Er) and the harness ( H ) of the femur cuticle of the forelegs of dung beetle Copris ochus Motschulsky in nanoscale. There exists a threshold holding time of 20 s for the reduced modulus of the femur cuticle. The tests of nanoindentation creep property and the regression analysis of relationship between the depth increment at the maximum load and the time further confirmed the correction of the above threshold holding time. There exist visco-elastic-plastic behaviour and creep phenomenon in the femur cuticle during indenting. Its creep property during the holding procedure at maximum load can be regressed by a general logarithmic equation. The equation fitted by the testing data is ? h = 54.83452 ln(0.00723t +1.00486), where, ? h is the depth increment at the maximum load and t is the time.展开更多
Coniopteris was a ubiquitous plant of the Jurassic and Cretaceous periods and played an important role in the flora of the time. However, its anatomical structure is relatively poorly known. The specimens of Coniopter...Coniopteris was a ubiquitous plant of the Jurassic and Cretaceous periods and played an important role in the flora of the time. However, its anatomical structure is relatively poorly known. The specimens of Coniopteris hymenophylloides(Brongniart) Seward described here were collected from the Yaojie Formation in Gansu Province, northwestern China. The sterile fronds are characterized as being at least bipinnate with alternate arranged linear pinnae covered by thin cuticles. Fertile fronds are linear-lanceolate, with single sorus at the margin of each fertile pinnule. In situ spores are typically trilete, triangle to subcircular in polar view, cap-shaped in equatorial view, and 37 μm in average diameter. The trilete marking is straight and narrow, generally extends to 4/5 of the spore radius. The spore surface is smooth, and parts of the exine are granulated. The epidermal cells of cuticles are irregular in shape, approximately 40-60μm long and 10-20 μm wide. The elliptical stomatal complexes are paracytic,approximately 30 μm long and 19 μm wide,and irregularly distributed. On the basis of its epidermal structures and comparisons with extant ferns, we consider that Coniopteris displays combined features of the related extant genera.展开更多
To better understand the interaction mechanisms of plant surfaces with polar organic compounds, sorption of 4-chlorophenol, 2,4- dichlorophenol, and 2,4,6-trichlorophenol by fruit cuticles （i.e., tomato, apple, and p...To better understand the interaction mechanisms of plant surfaces with polar organic compounds, sorption of 4-chlorophenol, 2,4- dichlorophenol, and 2,4,6-trichlorophenol by fruit cuticles （i.e., tomato, apple, and pepper）, and potato tuber periderm were investigated. The roles of cuticular components （waxes, cutin, cutan and sugar） on sorption of chlorophenols are quantitatively compared. Cutin and waxes govern the sorption capacity of bulk apple cuticle by hydrophobic interactions. Potato periderm with highest sugar content exhibits the lowest sorption capability for the chlorophenols. With the increase of hydrophobicity （i.e., Kow ） of sorbate, the relative contribution of lipophilic components （wax, cutin and cutan） on total sorption increases, however, the ratios of Koc to Kow decreases due to increasing ionization degree of sorbates.展开更多
Ulomoides dermestoides （Chevrolat） （Coleop- tera： Tenebrionidae） is one of the most notorious pests in northeastern China. We examined microtrichia on the thorax, elytra and abdomen of U. dermestoides using scann...Ulomoides dermestoides （Chevrolat） （Coleop- tera： Tenebrionidae） is one of the most notorious pests in northeastern China. We examined microtrichia on the thorax, elytra and abdomen of U. dermestoides using scanning electron microscopy and recorded their confor- mations （size, shape and insertion method） and distribu- tions （length, width and location）. Possible functions of the microtrichia were （1） stridulation： microtrichia on the inner surface of the elytra interacted with microtrichia on the dorsoventral axis of the thorax or on the costal vein of the hind wing; （2） to increase friction： at the major surface on the middle of the abdominal tergum, hind-wings, inner surface of the medial edge of the elytra and the posterior end of the elytra; （3） protection： the microtrichia covering the posterior face of the abdomen conserved water in the body and protected the body from damage; and （4） sensing organ： the special shape of the microtrichia on the nerva- tion near the vannal fold of the hind wing, the anterio- metapleuron on the metathorax, and the posterior field of the abdomen could perceive the environment. In conclusion, the size and shape of the microtrichia are tightly related to their functions, which may have evolved with the beetles＇ lifestyle.展开更多
Machilus maomingensis Jin et Tang,sp.nov.from the Eocene Youganwo Formation of the Maoming Basin,South China,is studied in detail from the perspective of the leaf architecture and the excellently preserved cuticle.The...Machilus maomingensis Jin et Tang,sp.nov.from the Eocene Youganwo Formation of the Maoming Basin,South China,is studied in detail from the perspective of the leaf architecture and the excellently preserved cuticle.The leaf margin is entire,the primary venation is pinnate;6 to 8secondary veins are present and the major secondary venation is eucamptodromous.Stomata are paracytic and occur on the lower epidermis.Trichome bases are unicellular.Oil cells are present in the upper epidermis.The new fossil species described has features of the Lauraceae,particularly of the extant genus Machilus Rumphius ex Nees,and it is most similar to Machilus chinensis（Bentham）Hemsley,an extant species distributed in southern China and Vietnam.Hence,Machilus maomingensis sp.nov.is inferred to live in a warm and humid climate.The discovery of the present fossil indicates that Machilus has existed in South China from at least the Eocene.展开更多
Plant cuticle,which covers the plant surface,consists of waxes and cutins,and is associated with plant drought,cold,and salt resistance.Hitherto,at least 47 genes participating in the formation of plant cuticle have b...Plant cuticle,which covers the plant surface,consists of waxes and cutins,and is associated with plant drought,cold,and salt resistance.Hitherto,at least 47 genes participating in the formation of plant cuticle have been cloned from Arabidopsis thaliana,Oryza sativa,Zea mays,Ricinus communis,Brassica napus,and Medicago truncatula;and about 85% of them encode proteins sharing above 50% identities with their rice homologous sequences.These cloned cuticle genes were mapped in silico on different chromosomes of rice and Arabidopsis,respectively.The mapping results revealed that plant cuticle genes were not evenly distributed in both genomes.About 40% of the mapped cuticle genes were located on chromosome 1 in Arabidopsis,while 20% of the mapped cuticle genes were located on chromosome 2 but none on chromosome 12 in rice.Some cloned plant cuticle genes have several rice homologous sequences,which might be produced by chromosomal segment duplication.The consensus map of cloned plant cuticle genes will provide important clues for the selection of candidate genes in a positional cloning of an unknown cuticle gene in plants.展开更多
The yellow granules in the gastral cuticle of the Oriental hornet Vespa oriental＆ （Hymenoptera, Vespinae） are located in yellow stripes. In the present study, we focus on the micromorphology and formation of the ye...The yellow granules in the gastral cuticle of the Oriental hornet Vespa oriental＆ （Hymenoptera, Vespinae） are located in yellow stripes. In the present study, we focus on the micromorphology and formation of the yellow granules from their inception to their spread in the regions which are destined to acquire a yellow color, The cuticle was observed with several methods of electron microscopy. The results showed that the yellow granules comprise a layer which is 20-25 μm thick, within the total cuticular thickness of 40-45 μm. In the mentioned regions one can see, from above, many apertures of about 0.5μm in diameter which extends into a peripheral photoreceptor cell. In each yellow granule, one discerns a myoid envelope inside which there are 9 fibrils arranged in a circle. Yellow granules maturation process involves infiltration of canals that give rise to the incipient ball-shaped primary granules which increase in number （as a result of continues budding off the walls of a canal） as the cuticle matures and transform into secondary barrel shaped granules, becoming elongated and then splitting into shorter barrels that fill up the entire area. Preliminary examinations have suggested liver-like function activity within the layer of yellow granules.展开更多
During postmortem storage,fluoride in Antarctic krill can be enriched in the muscle.Trypsin,as the most important digestive enzyme in Antarctic krill with a high activity in low temperature,plays a potential role in t...During postmortem storage,fluoride in Antarctic krill can be enriched in the muscle.Trypsin,as the most important digestive enzyme in Antarctic krill with a high activity in low temperature,plays a potential role in this process.In this study,endogenous trypsin was purified and its properties were investigated.The involvement of trypsin in the generation of free fluoride from Antarctic krill cuticle was explored.Cuticle microstructure before and after hydrolysis was compared with scanning electron microscopy,and the ash samples of the hydrolyzed Antarctic krill cuticle were analyzed with X-ray diffraction,Fourier transform infrared spectroscopy,and electron dispersive spectroscopy,respectively.Mass spectrometry analysis and inhibition tests confirmed that the purified enzyme was endogenous trypsin.Results of the present study indicated that trypsin digestion caused the increases of the concentrations of both fluoride ions and free amino N simultaneously,while the protein coated on the cuticle surface was dissolved too.However,no compositional change was detected in the cuticle inorganic salts.These findings suggest that trypsin triggered free fluoride release from Antarctic krill cuticle.In addition,the kinetics of free fluoride release could be described by the equation C_(W)=(1-0.97^(-0.006t)-0.03e^(0.0558t))×337.53+10.50.The present study improved the understanding of the role of trypsin in free fluoride release from Antarctic krill cuticle,facilitating future studies aimed at reducing the fluoride content in krill protein during Antarctic krill processing.展开更多
Chitin is the most widespread amino polysaccharide in nature. Chitin synthase （CHS） plays an important role in chitin formation in the cuticle and the peritrophic membrane （PM） lining the midgut. Total RNA was iso...Chitin is the most widespread amino polysaccharide in nature. Chitin synthase （CHS） plays an important role in chitin formation in the cuticle and the peritrophic membrane （PM） lining the midgut. Total RNA was isolated from the cuticle of Mamestra brassicae （L.） fourth instar larva, cDNA sequence was cloned by RT-PCR and Rapid Amplification of cDNA Ends （RACE）. cDNA 5 220 bp in length, contained an open reading frame of 4 704 bp coding for a polypeptide of 1 567 amino acid residues with a predicted molecular weight of 178.3 ku and its pI was 6.42. The deduced amino acid sequence from Mi brassicae （L.） shared the high level of identity with chitin synthase sequences from other insects, especially lepidopteran insects, cDNA sequence has been deposited with GenBank under accession No. GQ281761展开更多
Barley(Hordeum vulgare L.)is one of the earliest domesticated crop species and ranked as the fourth largest cereal production worldwide.Forward genetic studies in barley have greatly advanced plant genetics during the...Barley(Hordeum vulgare L.)is one of the earliest domesticated crop species and ranked as the fourth largest cereal production worldwide.Forward genetic studies in barley have greatly advanced plant genetics during the last century;however,most genes are identified by the conventional mapping method.Array genotyping and exome-capture sequencing have also been successfully used to target the causal mutation in barley populations,but these techniques are not widely adopted because of associated costs and partly due to the huge genome size of barley.This review summarizes three mapping cases of barley cuticle mutants in our laboratory with the help of RNA-sequencing.The causal mutations have been successfully identified for two of them and the target genes are located in the pericentromeric regions.Detailed information on the mapping-by-sequencing,mapping-and-sequencing,and RNA-sequencing assisted linkage mapping are presented and some limitations and challenges on the mapping assisted by RNA sequencing are also discussed.The alternative and elegant methods presented in this review may greatly accelerate forward genetics of barley mapping,especially for laboratories without large funding.展开更多
Microscopic analysis of the skin and cuticle of wool fibers in Dubska pramenka show different qualitative parameters. The research study included different parts of the body and the samples of the wool fibers from dif...Microscopic analysis of the skin and cuticle of wool fibers in Dubska pramenka show different qualitative parameters. The research study included different parts of the body and the samples of the wool fibers from different regions of the body. Histological description shows difference in the basic structurers of the skin in Dubska pramenka. A very pronounced thin epidermis, while dermis and hypodermis are more developed on the samples from the shoulder. Cornified flakes-cuticle of the root of the tail was of a fine structure, and comified flakes from the rump showed the features of the rough wool fibers. ＂Transitional form of cuticle＂ was dominant on the shoulder. The qualitative parameters have a significant influence on the overall quality of wool in general, and the research contributes to a greater usability value of the wool and development of livestock farming in areas in a broader sense.展开更多
We have developed a method where, after glutaraldehyde fixation, human hair shafts and insect cuticles are treated with ammonium thioglycolate (ATG) to improve ultrastructural staining. Conventional transmission elect...We have developed a method where, after glutaraldehyde fixation, human hair shafts and insect cuticles are treated with ammonium thioglycolate (ATG) to improve ultrastructural staining. Conventional transmission electron microscopic (TEM) preparations do not distinguish the A-layer and the exocuticles of hair shafts. However, after ATG treatment, the A-layer appears in higher contrast. ATG treatment has also been used to observe the fibrillar structure in the cortex. In the cuticle of beetles, the epicuticle is stained by ATG. Although the human hair shaft (keratin) and insect cuticle (chitin) are composed of different materials, both can be reduced by the ATG solution. The ammonium in the ATG solution reacts with hair shafts and insect cuticles, causing a reduction of swelled cuticles. Therefore, ATG not only stains, but also reduces human hair shafts and the cuticles of beetles.展开更多
Naked cuticle homolog 2(NKD2)has been recognized as an antagonist of Wnt/β-catenin signaling and a tumor suppressor.The role of NKD2 in osteoblast and osteoclast differentiation and the mechanism are not fully unders...Naked cuticle homolog 2(NKD2)has been recognized as an antagonist of Wnt/β-catenin signaling and a tumor suppressor.The role of NKD2 in osteoblast and osteoclast differentiation and the mechanism are not fully understood.In this study,we identified the up-regulation of NKD2 during osteoblast and adipocyte differentiation.Functional experiments revealed that NKD2 stimulated osteoblast differentiation and suppressed adipocyte formation.Furthermore,NKD2 down-regulated the expression of receptor activator of nuclear factor-κB ligand in bone marrow mesenchymal stem cells and inhibited osteoclast formation from osteoclast precursor cells.Mechanistic investigations revealed that the regulation of osteoblast and adipocyte differentiation by NKD2 involved Wnt/β-catenin and tuberous sclerosis complex subunit 1(TSC1)/mechanistic target of rapamycin complex 1(mTORC1)signaling pathways.Unlike in undifferentiated mesenchymal cells where NKD2 promoted Dishevelled-1 degradation,in the cells differentiating toward osteoblasts or adipocytes NKD2 down-regulated secreted frizzled related protein 1/4 expression and failed to destabilize Dishevelled-1,thereby activating Wnt/β-catenin signaling.Moreover,NKD2 bound to TSC1 and inhibited mTORC1 signaling.Further investigation uncovered an interplay between TSC1/mTORC1 and Wnt/β-catenin signaling pathways.Finally,transplantation of NKD2-overexpressing bone marrow mesenchymal stem cells into the marrow of mice increased osteoblasts,reduced osteoclasts and marrow fat,and partially prevented bone loss in ovariectomized mice.This study provides evidence that NKD2 in mesenchymal stem/progenitor cells reciprocally regulates the differentiation of osteoblasts and adipocytes by modulating Wnt/β-catenin and mTORC1 pathways and inhibits osteoclast formation by down-regulating receptor activator of nuclear factor-κB ligand.It suggests that NKD2 up-regulation may ameliorate postmenopausal bone loss.展开更多
Many holo-and hemimetabolous insects enhance their eggshells during embryogenesis by forming a serosal cuticle(SC).To date,scholarly understanding of the SC composition and SC-related gene functions has been limited,e...Many holo-and hemimetabolous insects enhance their eggshells during embryogenesis by forming a serosal cuticle(SC).To date,scholarly understanding of the SC composition and SC-related gene functions has been limited,especially for hemimetabolous insects.In this study,we initially performed transmission electron microscopic(TEM)observation and chitin staining of the SC in Nilaparvata lugens,a hemimetabolous rice pest known as the brown planthopper(BPH).We confirmed that the SC was a chitin-rich lamellar structure deposited gradually during the early embryogenesis.Parental RNA interference(RNAi)against Nilaparvata lugens chitin synthase 1(NlCHS1)in newly emerged and matured females resulted in decreases of egg hatchability by 100%and 76%,respectively.Ultrastructural analyses revealed loss of the lamellar structure of the SC in dsNlCHS1-treated eggs.According to temporal expression profiles,five cuticle protein coding genes,NlugCpr1/2/3/8/90,were specifically or highly expressed during the SC formation period,and NlugCpr1/2/3/90 were further detected in 72 h eggshells extract by ultra-performance liquid chromatography-tandem mass spectrometry/mass spectrometry.NlugCpr2/3/90 were likely three SC-specific cuticle proteins.TEM observations of the SC following parental RNAi against NlugCpr1/2/3/8/90 demonstrated that NlugCpr3/8/90 were essential for SC formation.The study provided an understanding of the SC formation process and SC-related cuticle proteins in BPHs,which offer potential targets for pest control in the egg stage as well.展开更多
Leaf cuticle analysis has long been a powerful tool for fossil plant identification,systematics,and palaeoclimatological recon-struction.In recent decades the application of stomatal frequency data that are relied on ...Leaf cuticle analysis has long been a powerful tool for fossil plant identification,systematics,and palaeoclimatological recon-struction.In recent decades the application of stomatal frequency data that are relied on precise calculation of stomata on plant fossil cuticles to reconstruct ancient atmospheric CO_(2)concentration made the preparation of cuticular membrane with sufficient size a critical technique in palaeoclimatological research.However,for plants with originally thin and fragile cuticles,e.g.,most deciduous plants,conventional techniques sometimes fail to obtain cuticular membranes with sufficient size,or sometimes unable to recover any.This has largely hampered the usage of fossil cuticle analysis in palaeobotanical and palaeo-climatological research.Here,we describe a new method using clear nail polish as a medium to"strengthen"the originally thin and fragile cuticles prior to maceration procedures.We demonstrate the method by using middle Eocene Metasequoia fossils that were notorious for the difficulty of recovering large-sized clean cuticular membranes due to their thin and fragile nature.Metasequoia,with well-documented and widely-distributed fossil records since the Late Cretaceous and with a living repre-sentative,114.glyptostroboides,as a comparative reference,bas been widely used as a model genus for the study of evolution of plants,palaeoclimatological reconstruction,and plant adaptation to climate changes.But its deciduous habit produces thin cuticles and makes the preparation of clean cuticular membranes a tedious process.The new method successfully allows us to recover its delicate cuticular membranes with sufficient sizes for SEM observation and stomatal frequency analysis.展开更多
Anther cuticle and pollen exine act as protective envelopes for the male gametophyte or pollen grain, but the mechanism underlying the synthesis of these lipidic polymers remains unclear. Previously, a tapetum‐expres...Anther cuticle and pollen exine act as protective envelopes for the male gametophyte or pollen grain, but the mechanism underlying the synthesis of these lipidic polymers remains unclear. Previously, a tapetum‐expressed CYP703A3, a putative cytochrome P450 fatty acid hydroxylase, was shown to be essential for male fertility in rice（Oryza sativa L.）. However,the biochemical and biological roles of CYP703A3 has not been characterized. Here, we observed that cyp703a3‐2 caused by one base insertion in CYP703A3 displays defective pollen exine and anther epicuticular layer, which differs from Arabidopsis cyp703a2 in which only defective pollen exine occurs. Consistently, chemical composition assay showed that levels of cutin monomers and wax components were dramatically reduced in cyp703a3‐2 anthers. Unlike the wide range of substrates of Arabidopsis CYP703A2, CYP703A3 functions as an in‐chain hydroxylase only for a specific substrate, lauric acid, preferably generating 7‐hydroxylated lauric acid. Moreover, chromatin immunoprecipitation and expression analyses revealed that the expression of CYP703A3 is directly regulated by Tapetum Degeneration Retardation, a known regulator of tapetum PCD and pollen exine formation. Collectively, our results suggest that CYP703A3 represents a conserved and diversified biochemical pathway for in‐chain hydroxylation of lauric acid required for the development of male organ in higher plants.展开更多
基金supported by the National Natural Science Foundation of China(32161133010)the National Key Research and Development Program of China(2022YFD1700200)+2 种基金the Innovation Program of Chinese Academy of Agricultural Sciences(CAAS-CSCB-202302)the Shenzhen Science and Technology Program,China(KQTD20180411143628272)the Special Funds for Science Technology Innovation and Industrial Development of Shenzhen Dapeng New District,China(PT202101-02).
文摘Chitin is an abundant natural biopolymer that plays a crucial role in insect growth and development as a fundamental structural component of the exoskeleton.The membrane-integralβ-glycosyltransferase,chitin synthase,has been identified as the central component in chitin biosynthesis.However,the precise roles of other proteins in facilitating chitin synthase in chitin biosynthesis remain unclear.In this study,we employed split-ubiquitin membrane yeast two-hybrid(MYTH)and pull-down assays to demonstrate the physical interaction between Twinstar(Tsr),a small molecular protein in the actin-depolymerizing factor ADF/Cofilin protein family,and chitin synthase Krotzkopf verkehrt(Kkv)in Drosophila melanogaster in vitro.The RNA interference(RNAi)-mediated global knockdown of Tsr in D.melanogaster resulted in larval lethality.Furthermore,targeted suppression of Tsr in the tracheal and epidermal tissues also led to larval mortality,while knocking down Tsr in the wing tissues led to wrinkled wings.Additionally,silencing Tsr not only reduced the chitin content in the first longitudinal vein of the wings but also led to the absence of the chitin lamellar structure.To validate the functional conservation of Tsr in other insect orders,the two agricultural pests Ostrinia furnacalis and Tribolium castaneum,representing lepidoptera and coleoptera insects,respectively,were investigated.Knockdown experiments targeting the Drosophila Tsr orthologues OfTsr in O.furnacalis and TcTsr in T.castaneum produced abnormal larvae during molting or pupation in O.furnacalis and lethality in T.castaneum.Our findings not only improve ourknowledge of the chitin biosynthesis machinery in insect cuticles but also provide new potential targets for the control of major agricultural pests.
基金supported by the Key Research and Development Project of Henan Province,China(221111112200)the National Natural Science Foundation of China(32070502 and 32072419)+1 种基金the Fundamental Research Program of Shanxi Province,China(202303021224005)the Natural Science Foundation of Henan Province,China(232300420185).
文摘CRISPR/Cas9-based gene editing research has advanced greatly and shows broad potential for practical application in life sciences,but the Cas9 system is often constrained by the requirement of a protospacer adjacent motif(PAM)at the target site.While xCas9,a variant derived from Streptococcus pyogenes Cas9(SpCas9),can recognize a broader range of PAMs,its application in non-model insects is lacking.In this study,we explored xCas9 activity in gene editing by selecting corazonin(Crz)and the target sites with various PAMs in Locusta migratoria,a destructive insect pest worldwide.We found that xCas9 could cleave the target site with AG PAM while SpCas9 could not,although xCas9 appeared to have lower activity than SpCas9 at the canonical NGG PAMs.The heritable homozygous Crz^(-/-)locust strain was generated by the application of xCas9.The Crz^(-/-)strain showed an albino body color,with significantly downregulated expression of several body color-related genes including Pale,Vermilion,Cinnabar,White andβ-carotene-binding protein.In addition,Crz^(-/-)mutants exhibited significantly reduced expression of Chitin synthase 1,along with a markedly lower chitin content as well as compact and rigid cuticles.Furthermore,Crz^(-/-)mutants displayed impaired performance under low-temperature stress,including prolonged lifespan,reduced body weight and smaller body size.Our results suggest that xCas9 is effective for insect genome editing,and Crz plays essential roles in insect body color,cuticle development and adaptation to low-temperature stress.The findings of this study extend the application of xCas9 in non-model insects and provide new insights into our understanding of the regulation of insect cuticle development and environmental adaptation.
基金supported by the National Natural Science Foundation of China(Grant No.32402580)the Science and Technology Program of Guangdong Province(Grant No.2023A0505090005)Modern Seed Industry Innovation Capability Enhancement Project of Guangdong Academy of Agricultural Sciences.
文摘Extreme environmental conditions such as temperature fluctuations,drought,and pathogen attacks can significantly impact plant growth,development,and productivity.Plants have evolved intricate enzymatic systems to mitigate these stresses,among which GDSL esterase/lipase proteins (GELPs)-key members of the serine esterase/lipase superfamily-play important roles (Akoh et al.,2004).Characterized by a conserved GDSL motif and four essential amino acids (serine,glycine,asparagine,and histidine),GELPs exhibit versatile catalytic functions in lipid metabolism,cell wall modification,and stress responses (Ursache et al.,2021;Shen et al.,2022).
文摘Although the research on Cordaites of the Cathaysian Flora in China started early in 1883, the study of the cordaitean cuticles began late in 1991. Up to now, four types of cordaitean cuticles in situ and three types of dispersed ones have been reported from the Cathaysian Flora in China. However compared with the Euramerican Flora, the research work on cordaitean cuticles from the Cathaysian Flora in China is much more insufficient. In this paper, three kinds of dispersed cordaitean cuticles are described in detail from the Permian coal-bearing strata in China. Among these cuticles two kinds are collected from the roof shale of Coal Seam No. A(1) in Shanxi Formation (Lower Permian) in Xinzhuangzhi Coal Mine of Huainan, Anhui Province, southern border of North China Subprovince of the Cathaysian Flora in China. The third one was collected from Coal Seam No. 11 in the top of Longtan Formation (lower Upper Permian) in Dahebian Coal Mine of Shuicheng Mining District, Guizhou Province, South China Subprovince of the Cathaysian Flora in China. Comparison of these three kinds of cordaitean cuticles with the known ones from the Cathaysian Flora in China and from the Euramerican Flora is made. The authors consider that they are all new types of cordaitean cuticles. The significance they bear on palaeobotany is discussed.
文摘The cuticle of dung beetle is a layered composite material in micro- or nano-scale. Dung beetle can fly, walk and dig. It can shovel and compact dung of mammals into balls. It use foreleg to walk, midleg and hindleg to hold and impel dung ball. Its two foreleges as digging legs are developed. The factors impacting the nanoindentation testing results of the femur cuticle of forelegs of dung beetle Copris ochus Motschulsky were examined. The nanomechanical test instrument used for the tests was Hysitron nanomechanical system. The results shown that the holding time and loading time are important factors im- pacting the accuracy of such indentation properties as reduced modulus (Er) and the harness ( H ) of the femur cuticle of the forelegs of dung beetle Copris ochus Motschulsky in nanoscale. There exists a threshold holding time of 20 s for the reduced modulus of the femur cuticle. The tests of nanoindentation creep property and the regression analysis of relationship between the depth increment at the maximum load and the time further confirmed the correction of the above threshold holding time. There exist visco-elastic-plastic behaviour and creep phenomenon in the femur cuticle during indenting. Its creep property during the holding procedure at maximum load can be regressed by a general logarithmic equation. The equation fitted by the testing data is ? h = 54.83452 ln(0.00723t +1.00486), where, ? h is the depth increment at the maximum load and t is the time.
基金project received financial support from the National Natural Science Foundation of China (No. 41262001)the Science and Technology Support Fund of Gansu Province (No. 1104FKCA116)
文摘Coniopteris was a ubiquitous plant of the Jurassic and Cretaceous periods and played an important role in the flora of the time. However, its anatomical structure is relatively poorly known. The specimens of Coniopteris hymenophylloides(Brongniart) Seward described here were collected from the Yaojie Formation in Gansu Province, northwestern China. The sterile fronds are characterized as being at least bipinnate with alternate arranged linear pinnae covered by thin cuticles. Fertile fronds are linear-lanceolate, with single sorus at the margin of each fertile pinnule. In situ spores are typically trilete, triangle to subcircular in polar view, cap-shaped in equatorial view, and 37 μm in average diameter. The trilete marking is straight and narrow, generally extends to 4/5 of the spore radius. The spore surface is smooth, and parts of the exine are granulated. The epidermal cells of cuticles are irregular in shape, approximately 40-60μm long and 10-20 μm wide. The elliptical stomatal complexes are paracytic,approximately 30 μm long and 19 μm wide,and irregularly distributed. On the basis of its epidermal structures and comparisons with extant ferns, we consider that Coniopteris displays combined features of the related extant genera.
基金supported by the National Natural Science Foundation of China (No. 20977081)the Foundation forthe Author of National Excellent Doctoral Dissertation of China (No. 200765)+1 种基金the Zhejiang Provincial Natural Science Foundation of China (No. R5100105)the Doctoral Fund of Ministry of Education of China (No.J20091588)
文摘To better understand the interaction mechanisms of plant surfaces with polar organic compounds, sorption of 4-chlorophenol, 2,4- dichlorophenol, and 2,4,6-trichlorophenol by fruit cuticles （i.e., tomato, apple, and pepper）, and potato tuber periderm were investigated. The roles of cuticular components （waxes, cutin, cutan and sugar） on sorption of chlorophenols are quantitatively compared. Cutin and waxes govern the sorption capacity of bulk apple cuticle by hydrophobic interactions. Potato periderm with highest sugar content exhibits the lowest sorption capability for the chlorophenols. With the increase of hydrophobicity （i.e., Kow ） of sorbate, the relative contribution of lipophilic components （wax, cutin and cutan） on total sorption increases, however, the ratios of Koc to Kow decreases due to increasing ionization degree of sorbates.
基金supported by the National Natural Science Foundation of China(NSFC Grant No.31370649)
文摘Ulomoides dermestoides （Chevrolat） （Coleop- tera： Tenebrionidae） is one of the most notorious pests in northeastern China. We examined microtrichia on the thorax, elytra and abdomen of U. dermestoides using scanning electron microscopy and recorded their confor- mations （size, shape and insertion method） and distribu- tions （length, width and location）. Possible functions of the microtrichia were （1） stridulation： microtrichia on the inner surface of the elytra interacted with microtrichia on the dorsoventral axis of the thorax or on the costal vein of the hind wing; （2） to increase friction： at the major surface on the middle of the abdominal tergum, hind-wings, inner surface of the medial edge of the elytra and the posterior end of the elytra; （3） protection： the microtrichia covering the posterior face of the abdomen conserved water in the body and protected the body from damage; and （4） sensing organ： the special shape of the microtrichia on the nerva- tion near the vannal fold of the hind wing, the anterio- metapleuron on the metathorax, and the posterior field of the abdomen could perceive the environment. In conclusion, the size and shape of the microtrichia are tightly related to their functions, which may have evolved with the beetles＇ lifestyle.
基金supported by the National Natural Science Foundation of China(Grant No.41210001)State Key Laboratory of Palaeobiology and Stratigraphy (Nanjing Institute of Geology and Palaeontology,CAS) (Grant No.123110)+1 种基金the Fundamental Research Funds for the Central Universities(Grant No.161gjc28)the Scientific Research Fund,Hongda Zhang,Sun Yat-sen University
文摘Machilus maomingensis Jin et Tang,sp.nov.from the Eocene Youganwo Formation of the Maoming Basin,South China,is studied in detail from the perspective of the leaf architecture and the excellently preserved cuticle.The leaf margin is entire,the primary venation is pinnate;6 to 8secondary veins are present and the major secondary venation is eucamptodromous.Stomata are paracytic and occur on the lower epidermis.Trichome bases are unicellular.Oil cells are present in the upper epidermis.The new fossil species described has features of the Lauraceae,particularly of the extant genus Machilus Rumphius ex Nees,and it is most similar to Machilus chinensis（Bentham）Hemsley,an extant species distributed in southern China and Vietnam.Hence,Machilus maomingensis sp.nov.is inferred to live in a warm and humid climate.The discovery of the present fossil indicates that Machilus has existed in South China from at least the Eocene.
基金supported by the One Hundred Talents Project of the Chinese Academy of Sciences (O827751001)the National Natural Science Foundation of China(30970449)
文摘Plant cuticle,which covers the plant surface,consists of waxes and cutins,and is associated with plant drought,cold,and salt resistance.Hitherto,at least 47 genes participating in the formation of plant cuticle have been cloned from Arabidopsis thaliana,Oryza sativa,Zea mays,Ricinus communis,Brassica napus,and Medicago truncatula;and about 85% of them encode proteins sharing above 50% identities with their rice homologous sequences.These cloned cuticle genes were mapped in silico on different chromosomes of rice and Arabidopsis,respectively.The mapping results revealed that plant cuticle genes were not evenly distributed in both genomes.About 40% of the mapped cuticle genes were located on chromosome 1 in Arabidopsis,while 20% of the mapped cuticle genes were located on chromosome 2 but none on chromosome 12 in rice.Some cloned plant cuticle genes have several rice homologous sequences,which might be produced by chromosomal segment duplication.The consensus map of cloned plant cuticle genes will provide important clues for the selection of candidate genes in a positional cloning of an unknown cuticle gene in plants.
文摘The yellow granules in the gastral cuticle of the Oriental hornet Vespa oriental＆ （Hymenoptera, Vespinae） are located in yellow stripes. In the present study, we focus on the micromorphology and formation of the yellow granules from their inception to their spread in the regions which are destined to acquire a yellow color, The cuticle was observed with several methods of electron microscopy. The results showed that the yellow granules comprise a layer which is 20-25 μm thick, within the total cuticular thickness of 40-45 μm. In the mentioned regions one can see, from above, many apertures of about 0.5μm in diameter which extends into a peripheral photoreceptor cell. In each yellow granule, one discerns a myoid envelope inside which there are 9 fibrils arranged in a circle. Yellow granules maturation process involves infiltration of canals that give rise to the incipient ball-shaped primary granules which increase in number （as a result of continues budding off the walls of a canal） as the cuticle matures and transform into secondary barrel shaped granules, becoming elongated and then splitting into shorter barrels that fill up the entire area. Preliminary examinations have suggested liver-like function activity within the layer of yellow granules.
基金supported by the Guangdong Provincial Key Laboratory of Aquatic Product Processing and Safety(No.GDPKLAPPS2005)the School Level Talent Project of Lingnan Normal University(No.ZL2021009)+2 种基金the Science and Technology Planning Project of Zhanjiang(No.2020A01040)the Study on the Preparation of Active Polypeptide from the Processing Waste of White Shrimp and its Fatigue Resistance(No.2021E05022)the Scientific Research Capacity Improvement Project of the Key Construction Discipline of Guangdong Province(No.2022ZD JS079).
文摘During postmortem storage,fluoride in Antarctic krill can be enriched in the muscle.Trypsin,as the most important digestive enzyme in Antarctic krill with a high activity in low temperature,plays a potential role in this process.In this study,endogenous trypsin was purified and its properties were investigated.The involvement of trypsin in the generation of free fluoride from Antarctic krill cuticle was explored.Cuticle microstructure before and after hydrolysis was compared with scanning electron microscopy,and the ash samples of the hydrolyzed Antarctic krill cuticle were analyzed with X-ray diffraction,Fourier transform infrared spectroscopy,and electron dispersive spectroscopy,respectively.Mass spectrometry analysis and inhibition tests confirmed that the purified enzyme was endogenous trypsin.Results of the present study indicated that trypsin digestion caused the increases of the concentrations of both fluoride ions and free amino N simultaneously,while the protein coated on the cuticle surface was dissolved too.However,no compositional change was detected in the cuticle inorganic salts.These findings suggest that trypsin triggered free fluoride release from Antarctic krill cuticle.In addition,the kinetics of free fluoride release could be described by the equation C_(W)=(1-0.97^(-0.006t)-0.03e^(0.0558t))×337.53+10.50.The present study improved the understanding of the role of trypsin in free fluoride release from Antarctic krill cuticle,facilitating future studies aimed at reducing the fluoride content in krill protein during Antarctic krill processing.
基金Supported by Natural Science Foundation of Heilongjiang Province (C2007-7)Scientific and Technical Innovation Fund of Harbin (RC2006QN002027)Northeast Agricultural University Research Fund (2005)
文摘Chitin is the most widespread amino polysaccharide in nature. Chitin synthase （CHS） plays an important role in chitin formation in the cuticle and the peritrophic membrane （PM） lining the midgut. Total RNA was isolated from the cuticle of Mamestra brassicae （L.） fourth instar larva, cDNA sequence was cloned by RT-PCR and Rapid Amplification of cDNA Ends （RACE）. cDNA 5 220 bp in length, contained an open reading frame of 4 704 bp coding for a polypeptide of 1 567 amino acid residues with a predicted molecular weight of 178.3 ku and its pI was 6.42. The deduced amino acid sequence from Mi brassicae （L.） shared the high level of identity with chitin synthase sequences from other insects, especially lepidopteran insects, cDNA sequence has been deposited with GenBank under accession No. GQ281761
基金grants from the National Natural Science Foundation of China(No.41621001,No.31870381,and No.31970352)by the Youth Innovation Promotion Association,CAS(2018463).
文摘Barley(Hordeum vulgare L.)is one of the earliest domesticated crop species and ranked as the fourth largest cereal production worldwide.Forward genetic studies in barley have greatly advanced plant genetics during the last century;however,most genes are identified by the conventional mapping method.Array genotyping and exome-capture sequencing have also been successfully used to target the causal mutation in barley populations,but these techniques are not widely adopted because of associated costs and partly due to the huge genome size of barley.This review summarizes three mapping cases of barley cuticle mutants in our laboratory with the help of RNA-sequencing.The causal mutations have been successfully identified for two of them and the target genes are located in the pericentromeric regions.Detailed information on the mapping-by-sequencing,mapping-and-sequencing,and RNA-sequencing assisted linkage mapping are presented and some limitations and challenges on the mapping assisted by RNA sequencing are also discussed.The alternative and elegant methods presented in this review may greatly accelerate forward genetics of barley mapping,especially for laboratories without large funding.
文摘Microscopic analysis of the skin and cuticle of wool fibers in Dubska pramenka show different qualitative parameters. The research study included different parts of the body and the samples of the wool fibers from different regions of the body. Histological description shows difference in the basic structurers of the skin in Dubska pramenka. A very pronounced thin epidermis, while dermis and hypodermis are more developed on the samples from the shoulder. Cornified flakes-cuticle of the root of the tail was of a fine structure, and comified flakes from the rump showed the features of the rough wool fibers. ＂Transitional form of cuticle＂ was dominant on the shoulder. The qualitative parameters have a significant influence on the overall quality of wool in general, and the research contributes to a greater usability value of the wool and development of livestock farming in areas in a broader sense.
文摘We have developed a method where, after glutaraldehyde fixation, human hair shafts and insect cuticles are treated with ammonium thioglycolate (ATG) to improve ultrastructural staining. Conventional transmission electron microscopic (TEM) preparations do not distinguish the A-layer and the exocuticles of hair shafts. However, after ATG treatment, the A-layer appears in higher contrast. ATG treatment has also been used to observe the fibrillar structure in the cortex. In the cuticle of beetles, the epicuticle is stained by ATG. Although the human hair shaft (keratin) and insect cuticle (chitin) are composed of different materials, both can be reduced by the ATG solution. The ammonium in the ATG solution reacts with hair shafts and insect cuticles, causing a reduction of swelled cuticles. Therefore, ATG not only stains, but also reduces human hair shafts and the cuticles of beetles.
基金funded by the National Natural Science Foundation of China(No.82072389,82272444,81972033).
文摘Naked cuticle homolog 2(NKD2)has been recognized as an antagonist of Wnt/β-catenin signaling and a tumor suppressor.The role of NKD2 in osteoblast and osteoclast differentiation and the mechanism are not fully understood.In this study,we identified the up-regulation of NKD2 during osteoblast and adipocyte differentiation.Functional experiments revealed that NKD2 stimulated osteoblast differentiation and suppressed adipocyte formation.Furthermore,NKD2 down-regulated the expression of receptor activator of nuclear factor-κB ligand in bone marrow mesenchymal stem cells and inhibited osteoclast formation from osteoclast precursor cells.Mechanistic investigations revealed that the regulation of osteoblast and adipocyte differentiation by NKD2 involved Wnt/β-catenin and tuberous sclerosis complex subunit 1(TSC1)/mechanistic target of rapamycin complex 1(mTORC1)signaling pathways.Unlike in undifferentiated mesenchymal cells where NKD2 promoted Dishevelled-1 degradation,in the cells differentiating toward osteoblasts or adipocytes NKD2 down-regulated secreted frizzled related protein 1/4 expression and failed to destabilize Dishevelled-1,thereby activating Wnt/β-catenin signaling.Moreover,NKD2 bound to TSC1 and inhibited mTORC1 signaling.Further investigation uncovered an interplay between TSC1/mTORC1 and Wnt/β-catenin signaling pathways.Finally,transplantation of NKD2-overexpressing bone marrow mesenchymal stem cells into the marrow of mice increased osteoblasts,reduced osteoclasts and marrow fat,and partially prevented bone loss in ovariectomized mice.This study provides evidence that NKD2 in mesenchymal stem/progenitor cells reciprocally regulates the differentiation of osteoblasts and adipocytes by modulating Wnt/β-catenin and mTORC1 pathways and inhibits osteoclast formation by down-regulating receptor activator of nuclear factor-κB ligand.It suggests that NKD2 up-regulation may ameliorate postmenopausal bone loss.
基金supported by the National Natural Science Foundation of China(31630057 and 31871954).
文摘Many holo-and hemimetabolous insects enhance their eggshells during embryogenesis by forming a serosal cuticle(SC).To date,scholarly understanding of the SC composition and SC-related gene functions has been limited,especially for hemimetabolous insects.In this study,we initially performed transmission electron microscopic(TEM)observation and chitin staining of the SC in Nilaparvata lugens,a hemimetabolous rice pest known as the brown planthopper(BPH).We confirmed that the SC was a chitin-rich lamellar structure deposited gradually during the early embryogenesis.Parental RNA interference(RNAi)against Nilaparvata lugens chitin synthase 1(NlCHS1)in newly emerged and matured females resulted in decreases of egg hatchability by 100%and 76%,respectively.Ultrastructural analyses revealed loss of the lamellar structure of the SC in dsNlCHS1-treated eggs.According to temporal expression profiles,five cuticle protein coding genes,NlugCpr1/2/3/8/90,were specifically or highly expressed during the SC formation period,and NlugCpr1/2/3/90 were further detected in 72 h eggshells extract by ultra-performance liquid chromatography-tandem mass spectrometry/mass spectrometry.NlugCpr2/3/90 were likely three SC-specific cuticle proteins.TEM observations of the SC following parental RNAi against NlugCpr1/2/3/8/90 demonstrated that NlugCpr3/8/90 were essential for SC formation.The study provided an understanding of the SC formation process and SC-related cuticle proteins in BPHs,which offer potential targets for pest control in the egg stage as well.
基金supported by CAS/SAFEA International Partnership Program for Creative Research Teams,the Pilot Project of Knowledge Innovation of CAS(Grant No.KZCX2-YW-105)National Basic Research Program of China(Grant No.2006CB806400)National Natural Science Foundation of China(Grant Nos.40402002,40872011)
文摘Leaf cuticle analysis has long been a powerful tool for fossil plant identification,systematics,and palaeoclimatological recon-struction.In recent decades the application of stomatal frequency data that are relied on precise calculation of stomata on plant fossil cuticles to reconstruct ancient atmospheric CO_(2)concentration made the preparation of cuticular membrane with sufficient size a critical technique in palaeoclimatological research.However,for plants with originally thin and fragile cuticles,e.g.,most deciduous plants,conventional techniques sometimes fail to obtain cuticular membranes with sufficient size,or sometimes unable to recover any.This has largely hampered the usage of fossil cuticle analysis in palaeobotanical and palaeo-climatological research.Here,we describe a new method using clear nail polish as a medium to"strengthen"the originally thin and fragile cuticles prior to maceration procedures.We demonstrate the method by using middle Eocene Metasequoia fossils that were notorious for the difficulty of recovering large-sized clean cuticular membranes due to their thin and fragile nature.Metasequoia,with well-documented and widely-distributed fossil records since the Late Cretaceous and with a living repre-sentative,114.glyptostroboides,as a comparative reference,bas been widely used as a model genus for the study of evolution of plants,palaeoclimatological reconstruction,and plant adaptation to climate changes.But its deciduous habit produces thin cuticles and makes the preparation of clean cuticular membranes a tedious process.The new method successfully allows us to recover its delicate cuticular membranes with sufficient sizes for SEM observation and stomatal frequency analysis.
基金supported by funds from National Natural Science Foundation of China (31230051, 30971739, 31270222, and 31110103915)National Key Basic Research Developments Program, Ministry of Science and Technology, China (2013CB126902 and 2011CB100101)+2 种基金China Innovative Research Team, Ministry of Education111 Project (B14016)the 863 High‐Tech Project, Ministry of Science and Technology, China (2011AA10A101 and 2012AA10A302)
文摘Anther cuticle and pollen exine act as protective envelopes for the male gametophyte or pollen grain, but the mechanism underlying the synthesis of these lipidic polymers remains unclear. Previously, a tapetum‐expressed CYP703A3, a putative cytochrome P450 fatty acid hydroxylase, was shown to be essential for male fertility in rice（Oryza sativa L.）. However,the biochemical and biological roles of CYP703A3 has not been characterized. Here, we observed that cyp703a3‐2 caused by one base insertion in CYP703A3 displays defective pollen exine and anther epicuticular layer, which differs from Arabidopsis cyp703a2 in which only defective pollen exine occurs. Consistently, chemical composition assay showed that levels of cutin monomers and wax components were dramatically reduced in cyp703a3‐2 anthers. Unlike the wide range of substrates of Arabidopsis CYP703A2, CYP703A3 functions as an in‐chain hydroxylase only for a specific substrate, lauric acid, preferably generating 7‐hydroxylated lauric acid. Moreover, chromatin immunoprecipitation and expression analyses revealed that the expression of CYP703A3 is directly regulated by Tapetum Degeneration Retardation, a known regulator of tapetum PCD and pollen exine formation. Collectively, our results suggest that CYP703A3 represents a conserved and diversified biochemical pathway for in‐chain hydroxylation of lauric acid required for the development of male organ in higher plants.
