Differences in leaf cuticular wax induced by whole-genome duplication in autotetraploid sour jujube

Drought-resistant plants exhibit strong water retention capability.In this regard,the autotetraploid sour jujube leaves exhibit better water retention than diploid leaves.Morphological comparisons and physiological comparisons of diploid and autotetraploid leaves showed that the autotetraploid leaves had thicker leaf cuticles and more leaf wax accumulation than the diploid leaves,which could reduce cuticle permeability and improve the drought tolerance of leaves.In this study,the cuticular wax crystalloids on the adaxial and abaxial sides of young and mature jujube leaves were observed in the two ploidy types,and unique cuticular wax crystalloids covering a large area of the cuticle on autotetraploid sour jujube leaves may provide an advantage in reducing leaf non-stomata transpiration and improving plant drought tolerance.Based on the transcriptome,115 differentially expressed genes between diploids and autotetraploids were further analyzed and found to be involved in the accumulation of cuticular wax components,including terpenoids,fatty acids,and lipids,as well as ABC transporter and wax biosynthetic process.Finally,14 genes differentially expressed between glossy autotetraploid leaves and nonglossy diploid leaves,such as LOC107414787,LOC107411574 and LOC107413721,were screened as candidate genes by qRT-PCR analysis.This findings provided insights into how polyploidization improved drought tolerance.

Overexpression of ZxABCG11 from Zygophyllum xanthoxylum enhances tolerance to drought and heat in alfalfa by increasing cuticular wax deposition

Drought and heat stresses cause yield losses in alfalfa,a forage crop cultivated worldwide.Improving its drought and heat tolerance is desirable for maintaining alfalfa productivity in hot,arid regions.Cuticular wax forms a protective barrier on aerial surfaces of land plants against environmental stresses.ABCG11encodes an ATP binding cassette(ABC) transporter that functions in the cuticular wax transport pathway.In this study,Zx ABCG11 from the xerophyte Zygophyllum xanthoxylum was introduced into alfalfa by Agrobacterium tumefaciens-mediated transformation.Compared to the wild type(WT),transgenic alfalfa displayed faster growth,higher wax crystal density,and thicker cuticle on leaves under normal condition.Under either drought or heat treatment in greenhouse conditions,the plant height and shoot biomass of transgenic lines were significantly higher than those of the WT.Transgenic alfalfa showed excellent growth and 50% greater hay yield than WT under field conditions in a hot,arid region.Overexpression of Zx ABCG11 up-regulated wax-related genes and resulted in more cuticular wax deposition,which contributed to reduction of cuticle permeability and thus increased water retention and photosynthesis capacity of transgenic alfalfa.Thus,overexpression of Zx ABCG11 can simultaneously improve biomass yield,drought and heat tolerance in alfalfa by increasing cuticular wax deposition.Our study provides a promising avenue for developing novel forage cultivars suitable for planting in hot,arid,marginal lands.

Preharvest application of 1-methylcyclopropene and Ethephon altered cuticular wax biosynthesis and fruit quality of apples at harvest and during cold storage

To investigate the roles of Harvista(a sprayable 1-methylcyclopropene,1-MCP,available component is 150 g·hm^(-2))and Ethephon(1 mL·L^(-1))applied at preharvest in apple(Malus domestica Borkh.'Golden Delicious')fruit cuticular wax biosynthesis,the expression of genes related to fruit cuticular wax biosynthesis and ethylene biosynthesis and signaling,ethylene production rate,respiration rate,wax constituents and structure,and fruit quality were determined at harvest and during cold storage.The results showed that 1-MCP inhibited the expression levels of ethylene biosynthesis and signaling-related genes,decreased fruit ethylene production,and inhibited the expression of Md LACS1,Md CER6,Md CER4 and Md WSD1,which resulted in decreases in alcohols,acids,and esters content in fruit cuticular wax.1-MCP also reduced fruit dropping rate from 17.17%to 12%;maintained fruit firmness,soluble solids,titratable acidity during cold storage;showed about as one fifth in the total length and one third in the widest width of wax crack as that in control at harvest.In contrast,Ethephon produced the opposite effects.In conclusion,1-MCP inhibited fruit ethylene biosynthesis and signaling,and influenced fruit cuticular wax biosynthesis.Thus,the fruit cuticular wax constituents and structure was altered,and the fruit quality were maintained at harvest and during cold storage.The results provide a new technology for improving apple fruit harvest and postharvest quality by preharvest application of sprayable 1-MCP.

Overexpression of BnKCS1-1,BnKCS1-2,and BnCER1-2 promotes cuticular wax production and increases drought tolerance in Brassica napus

Higher amounts of cuticular wax in plants have been associated with improved plant stress tolerance and increased potential for industrial use.In this study,orthologs of KCS1 and CER1 in Arabidopsis,designated BnKCS1-1,BnKCS1-2,and BnCER1-2,were isolated from Brassica napus.Transcription of BnKCS1-1 and BnKCS1-2 in B.napus were induced by abscisic acid(ABA)and drought treatment,while transcription of BnCER1-2 was induced only by drought treatment.All three gene transcripts decreased significantly when plants were treated with methyl jasmonate(MeJA)or subjected to cold stress.Overexpression of BnKCS1-1,BnKCS1-2,and BnCER1-2 under the control of the CaMV35S promoter led to a significant increase in cuticular wax on transgenic B.napus leaves.BnKCS1-1 and BnKCS1-2 overexpression led to similar differences from non-transformed plants,with significantly higher levels of aldehydes(C29 and C30),alkanes(C28,C29,and C31)and secondary alcohols(C28 and C29),and a significantly lower level of C29 ketone.Overexpression of BnCER1-2 led to an increase in alkanes(C27,C28,C29,and C31),a decrease in secondary alcohols(C28 and C29),and insignificant changes in other wax components.Scanning electron microscopy revealed that overexpression of BnKCS1-1,BnKCS1-2,and BnCER1-2 in B.napus resulted in a higher density of wax crystals on the leaf surface than observed in non-transformed plants.Transgenic plants showed a reduced rate of water loss and increased drought tolerance compared to non-transformed plants.These results suggest that BnKCS1-1,BnKCS1-2,and BnCER1-2 gene products can modify the cuticular wax of B.napus.Changing cuticular waxes using transgenic approaches is a new strategy for genetic improvement of plant drought tolerance and provides an opportunity for development of B.napus as a surface-wax crop.

QTL analysis reveals reduction of fruit water loss by NAC042 through regulation of cuticular wax synthesis in citrus fruit

Postharvest water loss is a critical factor that determines the quality and shelf life of fresh fruit.Cuticular wax constitutes a key barrier to reduce fruit water loss.Our previous study has shown that HJ(Citrus reticulata)has a significantly higher postharvest water loss rate than ZK(Poncirus trifoliata).Here,we investigated the fruit water loss rate of the HJ×ZK F1pseudo-testcross population in 2016 and 2019.QTL mapping for fruit water loss rate was performed by high-density genetic map and bulk segregant analysis,and QTL9 was identified to be associated with fruit water loss.The expression of NAC042 from QTL9 in ZK was 170-fold that in HJ.Heterologous expression in Arabidopsis showed that NAC042could reduce the water loss of leaves by increasing the cuticular wax content(especially alkanes).Further expression analysis revealed that NAC042 could enhance the expression of many wax-related genes in Arabidopsis leaves,including AtKCS1,AtKCS2,AtKCS9,AtKCS20,At CER1 and At CER3.Therefore,NAC042 might be involved in fruit cuticular wax synthesis to reduce fruit water loss.The findings provide new insights into the regulation of cuticular wax and fruit water loss as well as valuable information for breeding of citrus with better storability.

Trade-offs between the accumulation of cuticular wax and jasmonic acid-mediated herbivory resistance in maize

Plants have evolved complex physical and chemical defense systems that allow them to withstand herbivory infestation.Composed of a complex mixture of very-long-chain fatty acids(VLCFAs)and their derivatives,cuticular wax constitutes the first physical line of defense against herbivores.Here,we report the function of Glossy 8(ZmGL8),which encodes a 3-ketoacyl reductase belonging to the fatty acid elongase complex,in orchestrating wax production and jasmonic acid(JA)-mediated defenses against herbivores in maize(Zea mays).The mutation of GL8 enhanced chemical defenses by activating the JA-dependent pathway.We observed a trade-off between wax accumulation and JA levels across maize glossy mutants and 24 globally collected maize inbred lines.In addition,we demonstrated that mutants defective in cuticular wax biosynthesis in Arabidopsis thaliana and maize exhibit enhanced chemical defenses.Comprehensive transcriptomic and lipidomic analyses indicated that the gl8 mutant confers chemical resistance to herbivores by remodeling VLCFA-related lipid metabolism and subsequent JA biosynthesis and signaling.These results suggest that VLCFA-related lipid metabolism has a critical role in regulating the trade-offs between cuticular wax and JA-mediated chemical defenses.

ZmCER1,a putative ECERIFERUM 1 protein in maize,functions in cuticular wax biosynthesis and bulliform cell development

The cuticular wax,acting as the ultimate defense barrier,is essential for the normal morphogenesis of plant organs.Despite this importance,the connection between wax composition and leaf development has not been thoroughly explored.In this study,we characterized a new maize mutant,ragged leaf4(rgd4),which exhibits crinkled and ragged leaves starting from the sixth leaf stage.The phenotype of rgd4 is conferred by ZmCER1,which encoding an aldehyde decarbonylase involved in wax biosynthesis.ZmCER1 function deficient mutant displayed reduced cuticular wax density and disordered bulliform cells(BCs),while ZmCER1 overexpressing plants exhibited the opposite effects,indicating that ZmCER1 regulates cuticular wax biosynthesis and BCs development.Additionally,as the density of cuticular wax increased,the water loss rate of detached leaf decreases,suggesting that ZmCER1 is positively correlated with plant drought tolerance.

Rice OsGL 1-1 Is Involved in Leaf Cuticular Wax and Cuticle Membrane

Cuticular wax forms a hydrophobic barrier on aerial plant organs; it plays an important role in protecting a plant from damage caused by many forms of environmental stress. In the present study, we characterized a rice leaf wax-deficient mutant osgll-1 derived from a spontaneous mutation, which exhibited a wax-deficient and highly hydro- philic leaf phenotype. We cloned the OsGLI-1 gene by the map-based cloning method and performed a complementation test to confirm the function of the candidate gene. Molecular studies revealed that OsGLI-1 was a member of the OsGL1 family, and contained regions that were homologous to some regions in sterol desaturases and short-chain dehydro- genases/reductases. Compared to the wild-type, the osgll-1 mutant showed decreased cuticular wax deposition, thinner cuticular membrane, decreased chlorophyll leaching, increased rate of water loss, and enhanced sensitivity to drought. OsGL 1-1 is expressed ubiquitously in rice. The transient expression of OsGLl-l-green fluorescent protein fusion protein indicated that OsGLI-1 is localized in the cytoplasm, plasma membrane, and nucleus.

Comparative Analysis of Leaf Trichomes, Epidermal Wax And Defense Enzymes Activities in Response to Puccinia horiana in Chrysanthemum and Ajania Species

White rust caused by Puccinia horiana is a destructive disease of chrysanthemum plants.To better understand the resistance mechanisms of composite species to this disease,the leaf cuticular traits,antioxidant and defensive enzymes activities of immune(Chrysanthemum makinoi var.wakasaense)and highly susceptible(Ajania shiwogiku var.kinokuniense)species were compared.Trichome density of two species was markedly different,negatively associated with plant resistance to P.horiana.Total wax load in C.makinoi var.wakasaense was two times more than that in A.shiwogiku var.kinokuniense.The wax composition in immune one was abundant in esters and primary alcohols.Superoxide dismutase(SOD,EC 1.15.1.1),peroxidase(POD,EC 1.11.1.7),polyphenoloxidase(PPO,EC 1.14.18.1 or EC 1.10.3.2)and phenylalanine ammonia lyase(PAL,EC 4.3.1.5)activitieswere investigated.In C.makinoi var.wakasaense,the activity of SOD and POD increased rapidly after inoculation,whichmight be non-host induced reactive oxygen species(ROS)activated antioxidant enzymes,however SOD and POD remained a low and steady level in the highly susceptible one after inoculation.Quick increase in PPO activities after inoculation was observed in both species,however it remained higher in C.makinoi var.wakasaense at the late period of inoculation.PAL in C.makinoi var.wakasaense was induced after pathogen inoculation,but not in A.shiwogiku var.kinokuniense,suggesting that these two enzymes might contribute to the resistance to P.horiana.

不同油梨品种果面蜡质超微结构和组分分析

【目的】明确不同油梨品种果面蜡质的微观结构和化学组成,为深入研究蜡质功能提供基础数据。【方法】以5个不同油梨品种(Peterson、RKYYL6-2、Pollock、Walter Hole和RKYYL8-13)为研究材料,利用阿拉伯树胶分离果实外蜡,通过三氯甲烷提取果实内蜡,利用扫描电镜、GC-MS和GC-FID对油梨果面蜡质的超微结构、化学成分及含量进行研究。【结果】油梨蜡质的晶体结构主要为相互堆叠的片状和颗粒状。油梨外蜡的化学成分由六大类物质组成,分别为烷烃、醛类、酸类、醇类、甾醇和单酰甘油;除以上物质外,油梨内蜡的化学成分还包括生育酚。5个油梨品种的外蜡含量为0.17~0.87μg·cm-2,内蜡含量为2.00~8.22μg·cm-2;其中,RKYYL6-2的外蜡、内蜡含量最低,而Walter Hole的外蜡、内蜡含量最高。进一步对外蜡、内蜡各组分含量在不同品种间进行统计分析,结果表明,Walter Hole外蜡、内蜡中的烷烃(C27除外)、醛类、酸类和醇类含量高于其他品种,且Walter Hole内蜡中的生育酚含量在5个品种中最高;Peterson外蜡、内蜡中的甾醇含量在所有品种中最高;Peterson外蜡中的单酰甘油含量显著高于其他品种,而Walter Hole内蜡中的单酰甘油含量在5个品种中最高。【结论】油梨蜡质的晶体结构通常为片状和颗粒状,不同油梨品种的果实在外蜡、内蜡的含量和化学组成上差异明显。研究结果为进一步明确油梨蜡质的生物学功能奠定了基础。

Fine mapping of a novel wax crystal-sparse leaf3 gene in rice

Cuticular wax plays an important role in protecting plants against water loss and pathogen infection and in the adaptations to environmental stresses. The genetic mechanism of the biosynthesis and accumulation of epicuticular wax in rice remains largely unknown. Here, we show a spontaneous mutant displaying wax crystal-sparse leaves and decreased content of epicuticular wax that was derived from the cytoplasmic male sterility （CMS） restorer line Zhenhui 714. Compared with the wild type Zhenhui 714, the mutant exhibited hydrophilic features on leaf surface and more sensitivity to drought stress. The mutation also caused lower grain number per panicle and thousand grain weight, leading to the decline of yield. Genetic analysis indicates that the mutation is controlled by a single recessive gene, named wax crystal-sparse leaf3 （wsl3）. Using segregation populations derived from crosses of mutant/Zhendao 88 and mutant/Wuyujing 3, respectively, the wsl3 gene was fine-mapped to a 110-kb region between markers c3-16 and c3-22 on chromosome 3. According to the rice reference genome and gene analysis, we conclude that a novel gene/mechanism involved in regulation of rice cuticular wax formation.

高粱表皮蜡质缺失突变体sb1抗旱生理生化分析

植物抗旱性与体表蜡质积累有关,高粱是抗旱性极强的作物,茎秆和叶片表面覆盖一层厚厚的蜡质,开展高粱体表蜡质层对高粱抗旱能力的研究,为高粱抗旱品种选育和抗旱分子机制提供理论依据。以高粱品种BTx623和表皮蜡质缺失突变体sb1为试验材料,统计农艺性状以及扫描电镜观察叶片表面蜡质形态结构;分析表皮蜡质的有无对离体叶片失水速率和叶绿素浸提率的影响;检测在干旱胁迫处理下植株的表型变化以及超氧化物歧化酶(SOD)、过氧化物酶(POD)的活性变化。结果表明,与对照BTx623相比,表皮蜡质缺失突变体sb1株高明显降低、抽穗开花期延后1周、叶片远轴面片状蜡质缺失,其他农艺性状变化不明显。突变体sb1离体叶片失水速率和叶绿素浸提率显著高于对照。在干旱胁迫处理条件下,随着干旱胁迫时间的增长,对照BTx623和突变体sb1的SOD和POD活性均增强,但对照SOD和POD活性均显著高于突变体sb1,且干旱处理96 h和复水后突变体sb1都造成叶片大面积干枯。突变体sb1表皮蜡质缺失后叶片渗透性增强,清除活性氧的能力减弱,抗旱性降低。

采后果实表皮蜡质结构、功能及其调控——综述与展望

表皮蜡质在植物果实生长和贮藏中发挥着重要作用。蜡质是覆盖在果实表皮细胞最外层不溶于水的物质,主要包括超长链脂肪酸(VLCFA)及其衍生物(酯、初级醇、次级醇、醛、酮等)和三萜。这种复杂的脂类化合物在大多数植物表皮细胞中合成并转运至细胞表面。蜡质不仅有利于果实免受微生物侵染,还能减少果实的机械损伤,从而保持果实的商品价值。迄今为止,关于果实蜡质的研究多集中于采前果实蜡质的变化、功能和调控,而忽略了果实采后贮藏过程中蜡质变化及生物学功能。本文对果实表皮蜡质组成、结构及其代谢调控进行综述。重点阐述影响蜡质组成的采后因素,如贮藏温度、相对湿度(RH)、气体环境、外源激素等,以及蜡质对果实采后品质的影响,包括水分散失、果实软化、生理失调、抗病性等。这些总结可能有助于更好地了解采后果实表皮蜡质变化及其在果实品质保持中的作用。

木纳格葡萄表皮蜡质提取工艺优化及其成分分析

表皮蜡质是影响果蔬耐贮性的重要因素之一,故本研究以木纳格葡萄为材料,采用响应面法对有机溶剂浸泡提取葡萄表皮蜡质的工艺进行优化分析,同时利用气相色谱-质谱联用技术(gas chromatography-mass spectrometry,GC-MS)对葡萄表皮蜡质成分及其含量进行鉴定分析。结果表明:在单因素基础上,响应面法优化蜡质提取最佳条件为二氯甲烷与正己烷混合比3:1 mL/mL,液料比2:1 mL/g,提取时间7.5 min,在该提取条件下,蜡质提取量为43.60±1.04 mg/100 g,这与响应面预测值相差0.98%。表皮蜡质经GC-MS检测,共鉴定出61种蜡质化合物,包括脂肪酸、烃类各13种,醇类10种,酯类9种,醛类5种,萜类4种,未分类化合物7种,其中脂肪酸的相对含量最高,占总蜡质含量的58.06%。这为深入研究葡萄表皮蜡质化学成分与果实采后品质之间的关系提供理论参考。

大麦表皮蜡质组分及晶体结构的差异性分析

为了解不同大麦品种(系)表皮蜡质组分及结构的差异,以7个大麦品种(系)开花期的倒二叶、穗下节及穗为材料,利用GC-MS和S-4800场发射扫描电子显微镜测定不同器官表皮蜡质组分,观察其晶体结构。结果表明,大麦不同器官表皮蜡质均是由烷烃、初级醇、醛、脂肪酸、二酮等20种物质组成,不同品种及不同器官表皮蜡质组分种类无明显差异,但组分含量差异显著;同一品种(系),表面有白霜覆盖器官蜡质总量明显高于无白霜覆盖器官。穗下节表皮蜡质及穗部白霜型品种(系)表皮蜡质的二酮含量最高,穗部无白霜品种(系)(QS、FR、SYR01)表皮蜡质以烷烃和初级醇为主,二酮含量显著低于白霜型品种;叶片表皮蜡质则以初级醇为主,含量明显高于其他组分,且品种(系)间差异显著。电镜观察结果表明,参试品种(系)倒二叶近轴面和远轴面表皮蜡质晶体均呈片状结构;穗下节表皮蜡质晶体结构均呈棒状,SYR01穗下节蜡质晶体附着密度远小于其余6个穗下节有白霜覆盖品种(系)。白霜型大麦品种(系)穗部表皮蜡质完全为棒状,非白霜型品种(系)穗部表面仅有少量片状蜡质晶体或无蜡质晶体附着。

甘蓝型油菜长链烷烃合成相关基因的克隆及其与BnCER1-2的互作

长链烷烃是甘蓝型油菜角质层蜡质的优势组分,在阻止植株的非气孔性水分散失中起主要作用。BnCER1-2催化甘蓝型油菜长链烷烃的生物合成,但BnCER1-2是否通过与其他蛋白互作调控长链烷烃合成还不清楚。前期通过甘蓝型油菜蜡质差异材料转录组筛选获得4个长链烷烃合成相关基因BnCER3.a10、BnCER3.c02、BnCYTB5B.c09、BnCER1-L2.a05。本研究克隆了这4个基因的编码序列,序列分析表明BnCER3.a10/c02和BnCER1-L2.a05前体蛋白具有典型的脂肪酸羟化酶与WAX2C末端结构域,而BnCYTB5B.c09具有Cyt_B5蛋白家族保守结构域。亚细胞定位结果表明,BnCER3.a10/c02、BnCYTB5B.c09和BnCER1-L2.a05均定位于细胞内质网,与BnCER1-2共定位。双分子荧光互补(bimolecular fluorescent complementation,BiFC)与萤火素酶互补试验(luciferase complementation assay,LCA)检测结果表明,BnCER3.a10、BnCYTB5B.c09、BnCER1-L2.a05与BnCER1-2蛋白存在相互作用,而BnCER3.c02与BnCER1-2蛋白不互作。实时荧光定量PCR结果显示,与BnCER1-2的表达模式一致,BnCER3.a10和BnCYTB5B.c09主要在甘蓝型油菜茎/叶中表达,并受干旱胁迫诱导显著上调。BnCER3.a10在NaCl与低温胁迫下表达量显著减少,其中BnCER3.a10受MeJA、ACC诱导显著下调,BnCYTB5B.c09表达受ABA诱导上调。BnCER1-L2.a05在花中的表达量最高,在茎和叶片中的表达量最低,在干旱、低温及NaCl胁迫下转录水平均显著下降,其中SA诱导BnCER1-L2.a05表达上调,而MeJA诱导其表达下调。蜡质差异材料荧光定量PCR结果证实,BnCER3.a10与BnCYTB5B.c09在高蜡(烷)油菜中的表达量显著高于低蜡(烷)油菜,而BnCER1-L2.a05则呈相反变化。综合分析认为,BnCER3.a10和BnCYTB5B.c09可能通过与BnCER1-2互作而促进甘蓝型油菜长链烷烃的生物合成,BnCER1-L2.a05可能通过与BnCER1-2互作负调控长链烷烃的合成。

不同有机溶剂提取翠冠梨果皮蜡质效果比较研究

【目的】通过对不同有机溶剂提取梨果皮蜡质的安全性和有效性进行比较和鉴定,以筛选出低毒、高效的果皮蜡质提取溶剂,替代传统毒性较高的提取溶剂——三氯甲烷,为梨果皮蜡质相关研究工作奠定基础。【方法】以翠冠梨成熟果实为试材,用三氯甲烷(对照)和7种毒性相对较低的有机溶剂(碳酸二甲酯、乙醚、乙酸丁酯、丙酮、乙酸乙酯、甲醇、正己烷)分别提取果皮蜡质,并通过气相色谱-质谱联用仪进行蜡质组分检测,比较不同有机溶剂的毒性与蜡质提取效果。【结果】通过比较分析发现,甲醇和乙醚的蜡质提取效果整体较差;乙酸丁酯提取效果好于三氯甲烷,且毒性为三氯甲烷的1/14,但其挥发性差;正己烷虽然毒性最低,对烷烃提取效果较好,但其对萜类物质的提取效果较差,且属易燃易爆危化品。因此,这4种有机溶剂均不宜作为改良溶剂。丙酮提取萜类化合物含量为三氯甲烷的3倍,因此可以用作果皮萜类化合物提取的改良溶剂;乙酸乙酯的半数致死量(median lethal dose,LD_(50))为5620 mg·kg^(-1),毒性为三氯甲烷的1/6,且蜡质提取效果优于三氯甲烷,可作为替代溶剂;而碳酸二甲酯的LD_(50)为13000 mg·kg^(-1),毒性仅为三氯甲烷的1/14,提取效果与三氯甲烷相当,可作为替代溶剂。【结论】丙酮是提取萜类的优势型溶剂,可作为改良溶剂。乙酸乙酯蜡质提取效果优于三氯甲烷和碳酸二甲酯,且毒性较低,可作为蜡质提取最优溶剂。筛选出来的溶剂将有助于植物表皮蜡质提取及相关组分研究工作。

黄瓜β-酮脂酰辅酶A合成酶基因CsKCS11的功能初步分析

为了鉴定和挖掘黄瓜β-酮脂酰辅酶A合成酶(β-KetoacylCoAsynthetase,KCS)编码基因,以设施黄瓜为材料,通过转录组测序鉴定、基因克隆与表达载体的构建、干旱胁迫下的表达分析和转化拟南芥等方法,研究了CsKCS11的生物学功能。结果表明,黄瓜CsKCS11基因(NCBI登录号OL660537)的开放阅读框为1542 bp,编码513个氨基酸;序列分析表明,CsKCS11蛋白亲疏水性平均值(Gravy)为-0.083,为亲水性蛋白,二级结构中α螺旋、无规则卷曲、延伸链和β转角所占比例分别为44.64%、35.48%、15.20%和4.68%;系统进化分析表明,CsKCS11与冬瓜KCS11蛋白亲缘关系最近;同时将CsKCS11转化拟南芥,转基因拟南芥后代植株具有抵御干旱胁迫的能力;干旱胁迫下的表达分析表明,黄瓜CsKCS11能够被干旱胁迫诱导表达,且随着干旱胁迫时间的延长,其表达量呈现出先升高后降低的趋势,并且在干旱胁迫12h时达到最高。研究结果为进一步阐明黄瓜CsKCS11参与蜡质合成的机制奠定了基础。

ZxNHX1-VP1-1和ZxABCG11转基因紫花苜蓿在田间条件下的生长发育及饲用品质分析

为探究霸王(Zygophyllum xanthoxylum)液泡膜Na^(+)区域化功能基因ZxNHX1和H^(+)-焦磷酸酶(H^(+)-pyrophosphatase)编码基因ZxVP1-1及角质层蜡质转运基因ZxABCG11对“新疆大叶”紫花苜蓿(Medicago sativa)生长发育及饲用品质的影响,测定野生型及ZxNHX1-VP1-1和ZxABCG11转基因紫花苜蓿在田间条件下的生长发育和饲用品质相关指标.结果表明,ZxNHX1-VP1-1转基因苜蓿的叶面积和干草产量分别比野生型高56.4%和74.5%,净光合速率和水分利用率均显著高于野生型(P<0.05),花期比野生型延长19d;ZxABCG11转基因苜蓿的叶面积和茎粗均显著大于野生型(P<0.05),净光合速率和水分利用率分别比野生型高81.7%和80.5%,花期比野生型延长38d;ZxNHX1-VP1-1转基因苜蓿的中性洗涤纤维、酸性洗涤纤维和酸性洗涤木质素含量显著低于野生型(P<0.05),相对饲用价值比野生型提高了35.4%.霸王ZxNHX1和ZxVP1-1的超表达提高了紫花苜蓿的生物量和饲用品质,并延长了开花时间;ZxABCG11的超表达对紫花苜蓿叶面积、茎粗和光合能力产生了影响,花期相比野生型有所延长.

采前套袋对苹果梨表皮蜡质结构和化学组分的影响

【目的】探讨采前套袋处理对苹果梨(Pyrus bretschneideri Rehd.cv.Pingguoli)果皮蜡质结构和化学组分的影响。【方法】在花后60 d对苹果梨果实进行双层套袋处理,通过扫描电镜观察和气相色谱-质谱联用(GC/MS)分析,了解套袋微域环境对果皮蜡质含量、结构和化学组分的影响。【结果】套袋处理苹果梨表皮蜡质含量与未套袋相比差异不显著;与未套袋相比,套袋果实表皮蜡质粗糙、蜡膜不均一、裂纹较多,且表面无蜡质结晶形成。对其蜡质组分分析表明,套袋与未套袋果实检出的蜡质组分数量与种类均存在差异;在含量上套袋果实烷烃较未套袋有所提高,链烷酸有所下降。同时采前套袋处理的果实蜡质组分中饱和链烷酸的碳数分布优势也发生了变化,未套袋果实以C28、C30和C26的相对丰度较大,而套袋果实仅以C26和C28的相对丰度较大,并未检测到C30饱和链烷酸。【结论】采前套袋处理对苹果梨表皮蜡质超微结构、化学组分种类和链长均具有明显的影响,但其影响机制尚需进一步研究。