High density SNP mapping and QTL analysis for fruit quality characteristics in peach (Prunus persica L.)

Single nucleotide polymorphisms (SNPs) were used to construct an integrated SNP linkage map of peach (Prunus persica (L.) Batsch). A set of 1,536 SNPs were evaluated with the GoldenGate® Genotyping assay in two mapping populations, Pop-DF, and Pop-DG. After genotyping and filtering, a final set of 1,400 high quality SNPs in Pop-DF and 962 in Pop-DG with full map coverage were selected and used to construct two linkage maps with JoinMap®4.0. The Pop-DF map covered 422 cM of the peach genome and included 1,037 SNP markers, and Pop-DG map covered 369 cM and included 738 SNPs. A consensus map was constructed with 588 SNP markers placed in eight linkage groups (n?=?8 for peach), with map coverage of 454 cM and an average distance of 0.81 cM/marker site. Placements of SNPs on the “peach v1.0” physical map were compared to placement on the linkage maps and several differences were observed. Using the SNP linkage map of Pop-DG and phenotypic data collected for three harvest seasons, a QTL analysis for fruit quality traits and chilling injury symptoms was carried out with the mapped SNPs. Significant QTL effects were detected for mealiness (M) and flesh bleeding (FBL) QTLs on linkage group 4 and flesh browning (FBr) on linkage group 5. This study represents one of the first examples of QTL detection for quality traits and chilling injury symptoms using a high-density SNP map in a single peach F1 family.     

Application of Genomic and Quantitative Genetic Tools to Identify Candidate Resistance Genes for Brown Rot Resistance in Peach

The availability of a complete peach genome assembly and three different peach genome sequences created by our group provide new opportunities for application of genomic data and can improve the power of the classical Quantitative Trait Loci (QTL) approaches to identify candidate genes for peach disease resistance. Brown rot caused by Monilinia spp., is the most important fungal disease of stone fruits worldwide. Improved levels of peach fruit rot resistance have been identified in some cultivars and advanced selections developed in the UC Davis and USDA breeding programs. Whole genome sequencing of the Pop-DF parents lead to discovery of high-quality SNP markers for QTL genome scanning in this experimental population. Pop-DF created by crossing a brown rot moderately resistant cultivar ‘Dr. Davis’ and a brown rot resistant introgression line, ‘F8,1–42’, derived from an initial almond × peach interspecific hybrid, was evaluated for brown rot resistance in fruit of harvest maturity over three seasons. Using the SNP linkage map of Pop-DF and phenotypic data collected with inoculated fruit, a genome scan for QTL identified several SNP markers associated with brown rot resistance. Two of these QTLs were placed on linkage group 1, covering a large (physical) region on chromosome 1. The genome scan for QTL and SNP effects predicted several candidate genes associated with disease resistance responses in other host-pathogen systems. Two potential candidate genes, ppa011763m and ppa026453m, may be the genes primarily responsible for M. fructicola recognition in peach, activating both PAMP-triggered immunity (PTI) and effector-triggered immunity (ETI) responses. Our results provide a foundation for further genetic dissection, marker assisted breeding for brown rot resistance, and development of peach cultivars resistant to brown rot.     

Mapping Architectural, Phenological, and Fruit Quality QTLs in Apricot

The F1 population “Harostar”?×?“Rouge de Mauves” was used to perform a quantitative trait loci (QTL) mapping for tree architecture traits (i.e., tree diameter, total branch number, tree shape); time to initial reproductive bud break; and fruit quality traits (i.e., ground color, fruit form, soluble solid content) using data collected from 2010 to 2012. For architectural traits, interval mapping detected QTLs only in “Rouge de Mauves” on linkage group 1 for trunk diameter in 2010, on LG6 for total branch number in 2010, and on LG1 and LG5 for tree shape for both years 2010 and 2011 combined. QTLs were detected only in “Harostar” for time to initial reproductive bud break on LG1 and LG4 in 2011. For fruit quality traits, data were collected in 2011 and 2012. QTLs were identified on LG1 in 2011 and on LG4 in 2012 for soluble solid content, on LG3 for ground color in both years, on LG7 only in 2011, and on LG3 for fruit form in both years. The QTLs that we identified were compared to those previously identified in other Prunus spp.     

Genetic analysis of the slow-melting flesh character in peach

The slow-melting flesh (SMF) trait in peach [Prunus persica (L.) Batsch] defines a slower process of postharvest fruit-softening than the prevalent melting flesh (MF) types. This gives a longer shelf life and a delayed harvest-time resulting in better fruit quality. Unlike other known fruit texture traits, SMF is difficult to measure and has a complex inheritance. We examined this character over 2 years in the offspring of two crosses, both with “Big Top,” an SMF nectarine, as the female parent, and with a melting flesh (MF) nectarine as the male parent (“Armking” and “Nectaross”). Following harvest, a texturometer was used to provide a textural profile analysis, and fruit firmness evolution was measured with a penetrometer over a period of 5 days’ storage at 20 °C. Linkage maps were constructed with a high-density SNP chip, and a phenotype-genotype analysis allowed the detection of three independent genomic regions where most QTLs (quantitative trait loci) were located. Two of these, on linkage groups 4 and 5, explained the variability for two characters—maturity date and firmness loss—that is, the QTL on linkage group 4 found in the MF parents and that on linkage group 5 in Big Top. A third region on linkage group 6, which identified a QTL for maturity date only in Armking, has no apparent association to the softening process. The relationship between maturity date and fruit-firmness loss and a hypothesis on the inheritance of the SMF character are discussed.     

QTL mapping for brown rot (Monilinia fructigena) resistance in an intraspecific peach (Prunus persica L. Batsch) F1 progeny

Brown rot (BR) caused by Monilinia spp. leads to significant post-harvest losses in stone fruit production, especially peach. Previous genetic analyses in peach progenies suggested that BR resistance segregates as a quantitative trait. In order to uncover genomic regions associated with this trait and identify molecular markers for assisted selection (MAS) in peach, an F1 progeny from the cross “Contender” (C, resistant)?×?“Elegant Lady” (EL, susceptible) was chosen for quantitative trait loci (QTL) analysis. Over two phenotyping seasons, skin (SK) and flesh (FL) artificial infections were performed on fruits using a Monilinia fructigena isolate. For each treatment, infection frequency (if) and average rot diameter (rd) were scored. Significant seasonal and intertrait correlations were found. Maturity date (MD) was significantly correlated with disease impact. Sixty-three simple sequence repeats (SSRs) plus 26 single-nucleotide polymorphism (SNP) markers were used to genotype the C?×?EL population and to construct a linkage map. C?×?EL map included the eight Prunus linkage groups (LG), spanning 572.92 cM, with an average interval distance of 6.9 cM, covering 78.73 % of the peach genome (V1.0). Multiple QTL mapping analysis including MD trait as covariate uncovered three genomic regions associated with BR resistance in the two phenotyping seasons: one containing QTLs for SK resistance traits near M1a (LG C?×?EL-2, R ²?=?13.1–31.5 %) and EPPISF032 (LG C?×?EL-4, R ²?=?11–14 %) and the others containing QTLs for FL resistance, near markers SNP_IGA_320761 and SNP_IGA_321601 (LG3, R ²?=?3.0–11.0 %). These results suggest that in the C?×?EL F1 progeny, skin resistance to fungal penetration and flesh resistance to rot spread are distinguishable mechanisms constituting BR resistance trait, associated with different genomic regions. Discovered QTLs and their associated markers could assist selection of new cultivars with enhanced resistance to Monilinia spp. in fruit.     

Electrophysiological and behavioral response of the oriental fruit moth <Emphasis Type="Italic">Grapholita</Emphasis><Emphasis Type="Italic">molesta</Emphasis> (Busck, 1916) (Lepidoptera: Tortricidae) to the volatiles of apple fruits at different stages of development

The oriental fruit moth, Grapholita molesta, occurs in Southern Brazil throughout the year, and migrates from peach to apple orchards. Because moths rely on volatile organic compounds (VOCs) during the host-location process, variations in the emission of these compounds during fruit maturation can influence the time of infestation and preference of the moths for a particular genotype. The aim of this work was to identify VOCs emitted by the apples “Eva” and “Gala” at different stages of development and to determine the behavioral and electrophysiological responses of G. molesta to these compounds. For this purpose, VOCs from immature, maturing, and mature fruits of both cultivars were collected and analyzed by gas chromatography and gas chromatography-mass spectroscopy. The response of the antennae of virgin males and females and mated females to volatiles released by the three fruit stages was registered by gas chromatography coupled to an electroantennography. A dual-choice behavioral test for the different combinations of insect groups and fruit stage was also performed. Amongst the volatiles released by mature fruits, twelve compounds elicited a response. The antennae of the oriental fruit moth did respond to isoamyl hexanoate and α-farnesene emitted by “Eva” maturing fruits. In general, virgin females did not respond to volatiles in olfactometer bioassays and mated females were attracted to volatiles released by mature fruits. Our results show that the variation in the emission during the maturation of fruits can influence the orientation of G. molesta.     

Mapping quantitative trait loci associated with resistance to bacterial spot (Xanthomonas arboricola pv. pruni) in peach

Bacterial spot, caused by Xanthomonas arboricola pv. pruni (Xap), is a serious disease that can affect peach fruit quality and production worldwide. This disease causes severe defoliation and blemishing of fruit, particularly in areas with high rainfall, strong winds, high humidity, and sandy soil. The molecular basis of its tolerance and susceptibility in peach is yet to be understood. An F₂ population of 63 genotypes derived from a cross between peaches “O’Henry” (susceptible) and “Clayton” (resistant) has been used for linkage map construction and quantitative trait loci (QTL) mapping. Phenotypic data for leaf and fruit response to Xap infection were collected over 2 years at two locations. A high-density genetic linkage map that covers a genetic distance of 421.4 cM with an average spacing between markers of 1.6 cM was developed using the International Peach Single Nucleotide Polymorphism Consortium (IPSC) 9K array v1. Fourteen QTLs with an additive effect on Xap resistance were detected, including four major QTLs on linkage groups (LG) 1, 4, 5, and 6. Major QTLs, Xap.Pp.OC-4.1 and Xap.Pp.OC-4.2, on LG4 were associated with Xap resistance in leaf; Xap.Pp.OC-5.1 on LG5 was associated with Xap resistance in both leaf and fruit, while Xap.Pp.OC-1.2 and Xap.Pp.OC-6.1 on LG1 and LG6, respectively, were associated with Xap resistance in fruit. This suggested separate regulation of leaf and fruit resistance for Xap in peach as well as participation of genes involved in general plant response to biotic stress. The potential for marker-assisted selection for Xap resistance in peach is discussed.     

Mapping quantitative trait loci associated with blush in peach [Prunus persica (L.) Batsch]

Blush is an important trait for marketing peaches. The red skin pigmentation develops through the flavonoid and anthocyanin pathways, and both genetic and environmental stimuli, and their interaction, control the regulation of these pathways. The molecular basis of blush development in peach is yet to be understood. An F₂ blush population (ZC²) derived from a cross between two peach cultivars with contrasting phenotypes for blush, “Zin Dai” (～30 % red) and “Crimson Lady” (～100 % red), was used for linkage map construction and quantitative trait loci (QTLs) mapping. The segregating population was phenotyped for blush for 4 years using a visual rating scale and quantified using a colorimeter (L*, a*, and b*) 1 year. The ZC² population was genotyped with the IPSC 9 K peach single-nucleotide polymorphism (SNP) array v1, and a high-density ZC² genetic linkage map was constructed. The map covers genetic a distance of ～452.51 cM with an average marker spacing of 2.38 cM/marker. Four QTLs were detected: one major QTL on LG3 (Blush.Pp.ZC-3.1) and three minor QTLs on LG 4 and 7 (Blush.Pp.ZC-4.1; Blush.Pp.ZC-4.2; Blush.Pp.ZC-7.1), indicating the presence of major and minor genes involved in blush development. Candidate genes involved in skin and flesh coloration of peach (PprMYB10), cherry (PavMYB10), and apple (MdMYB1/MdMYBA/MdMYB10) are located within the interval of the major QTL on LG3, suggesting the same genetic control for color development in the Rosaceae family. Marker-assisted selection (MAS) for blush is discussed.     

Development and mapping of peach candidate genes involved in fruit quality and their transferability and potential use in other Rosaceae species

The goal of the present study was to identify candidate genes (CGs) involved in fruit quality in peach that can be transferred to other Rosaceae species. Two cDNA libraries from fruit of the “Fantasia” peach cultivar, constructed at two stages of development, were used to generate a set of expressed sequence tag sequences. A total of 1,730 peach unigenes were obtained after clustering. Sequences and corresponding annotations were stored in a relational database and are available through a web interface. Fifty-nine CGs involved in fruit growth and development or fruit quality at maturity, focusing on sweetness, acidity, and phenolic compound content, were selected according to their annotation. Fifty-five primer pairs, designed from peach CG sequences and giving PCR products in peach, were tested in strawberry and 36 gave amplified products. Eight CGs were mapped in peach, 14 in strawberry, four in both species and confirmed the pattern of synteny already proposed using comparative mapping. In peach, the CGs are located in three linkage groups (3, 5, 7), and in strawberry they are distributed in all seven Fragaria linkage groups. Colocalization between some of these CGs and quantitative trait loci for fruit quality traits were identified and are awaiting confirmation in further analyses.     

Structure of sensilla, olfactory perception, and behaviour of the bedbug, Cimex lectularius, in response to its alarm pheromone

When deprived of the terminal antennal segments, male and female bedbugs failed to respond to their alarm pheromone and to their assembling scent. Trans-oct-2-en-1-al or trans-hex-2-en-1-al, being the major constituents of the former, induce in adults and larvae of Cimex lectularius a typical alarm behaviour resulting in dispersal of assembled bedbugs; the rapidity of escape depends on the aldehyde concentration in the air. The behavioural threshold for adults is about 9×10¹⁴ molecules of trans-oct-2-en-1-al or 6×10¹⁵ molecules of trans-hex-2-en-1-al per ml air.The distal part of the terminal antennal segment of C. lectularius reveals the following sensilla: bristles (type A1), immersed cones (type B1), plates (type B2), grooved pegs (type C), smooth pegs (type D), hairs with even (type E1), and uneven wall thickness (type E2). The number and distribution of these sensilla is relatively constant and similar in both sexes, but differs slightly in neonate larvae. The pegs and hairs of types C, D, E1 and E2 were shown to have porous walls, a prerequisite for olfactory function.Receptor potentials were recorded from olfactory sensilla of types E1 and E2 after stimulation with trans-hex-2-en-1-al and trans-oct-2-en-1-al. The minimal concentration of trans-hex-2-en-1-al evoking a receptor potential is about 2×10¹⁰ molecules per ml air. The above olfactory sensilla were found to respond also to hexan-1-al, but almost no responses to pentan-1-al, butan-1-al, trans-hex-2-ene, and trans-oct-2-ene were observed. A minimum chain length of six carbons atoms and a terminal carbonyl group are molecular prerequisites for optimal odorant activity, while the presence of a Δ²-double bond is not essential for stimulation of the alarm pheromone receptors of the bedbug.     

QTL mapping of pre-harvest sprouting resistance in a white wheat cultivar Danby

Key message

One major and three minor QTLs for resistance to pre-harvest sprouting (PHS) were identified from a white wheat variety “Danby.” The major QTL on chromosome 3A is TaPHS1, and the sequence variation in its promoter region was responsible for the PHS resistance. Additive?×?additive effects were detected between two minor QTLs on chromosomes 3B and 5A, which can greatly enhance the PHS resistance.

Abstract

Pre-harvest sprouting (PHS) causes significant losses in yield and quality in wheat. White wheat is usually more susceptible to PHS than red wheat. Therefore, the use of none grain color-related PHS resistance quantitative trait loci (QTLs) is essential for the improvement in PHS resistance in white wheat. To identify PHS resistance QTLs in the white wheat cultivar “Danby” and determine their effects, a doubled haploid population derived from a cross of Danby?×?“Tiger” was genotyped using genotyping-by-sequencing markers and phenotyped for PHS resistance in two greenhouse and one field experiments. One major QTL corresponding to a previously cloned gene, TaPHS1, was consistently detected on the chromosome arm 3AS in all three experiments and explained 21.6–41.0% of the phenotypic variations. A SNP (SNP?222) in the promoter of TaPHS1 co-segregated with PHS in this mapping population and was also significantly associated with PHS in an association panel. Gene sequence comparison and gene expression analysis further confirmed that SNP?222 is most likely the causal mutation in TaPHS1 for PHS resistance in Danby in this study. In addition, two stable minor QTLs on chromosome arms 3BS and 5AL were detected in two experiments with allele effects consistently contributed by Danby, while one minor QTL on 2AS was detected in two environments with contradicted allelic effects. The two stable minor QTLs showed significant additive?×?additive effects. The results demonstrated that pyramiding those three QTLs using breeder-friendly KASP markers developed in this study could greatly improve PHS resistance in white wheat.

     

Triterpenoids with antimicrobial activity from Drypetes inaequalis

The air-dried stems and ripe fruit of Drypetes inaequalis Hutch. (Euphorbiaceae) were studied. Four triterpene derivatives, characterized as lup-20(29)-en-3β,6α-diol, 3β-acetoxylup-20(29)-en-6α-ol, 3β-caffeoyloxylup-20(29)-en-6α-ol and 28-β d-glucopyranosyl-30-methyl 3β-hydroxyolean-12-en-28,30-dioate along with 10 known compounds were isolated from the whole stems. One triterpene, characterized as 3α-hydroxyfriedelan-25-al along with six known compounds were isolated from the ripe fruit. Their structures were established on the basis of spectroscopic analysis and chemical evidence. The triterpenes were tested for antimicrobial activity against some Gram-positive and Gram-negative bacteria, and two of them appeared to be modestly active.     

Terpenoid metabolites from the aerial part of Artemisia lagocephala

Six naturally occurring terpenoids were isolated from the hexane extract of rabbit-head wormwood Artemisia lagocephala (Fisch. ex Besser) DC. The terpenoids’ structures were elucidated by spectroscopic and chemical methods as 3β-acetoxycycloartan-24-ozonide (1), 3β-acetoxycycloartan-24-al (2), 25,26,27-trisnor-3β-acetoxycycloartan-24-ol (3), 24,25,26,27-tetranor-3β-acetoxycycloartan-23-ol (4), and the previously known caryophyllene oxide (5) and (1R,4S)-p-menth-2-en-1-ol (6).     

Development and evaluation of a 9K SNP array for peach by internationally coordinated SNP detection and validation in breeding germplasm

Although a large number of single nucleotide polymorphism (SNP) markers covering the entire genome are needed to enable molecular breeding efforts such as genome wide association studies, fine mapping, genomic selection and marker-assisted selection in peach [Prunus persica (L.) Batsch] and related Prunus species, only a limited number of genetic markers, including simple sequence repeats (SSRs), have been available to date. To address this need, an international consortium (The International Peach SNP Consortium; IPSC) has pursued a coordinated effort to perform genome-scale SNP discovery in peach using next generation sequencing platforms to develop and characterize a high-throughput Illumina Infinium® SNP genotyping array platform. We performed whole genome re-sequencing of 56 peach breeding accessions using the Illumina and Roche/454 sequencing technologies. Polymorphism detection algorithms identified a total of 1,022,354 SNPs. Validation with the Illumina GoldenGate® assay was performed on a subset of the predicted SNPs, verifying ∼75% of genic (exonic and intronic) SNPs, whereas only about a third of intergenic SNPs were verified. Conservative filtering was applied to arrive at a set of 8,144 SNPs that were included on the IPSC peach SNP array v1, distributed over all eight peach chromosomes with an average spacing of 26.7 kb between SNPs. Use of this platform to screen a total of 709 accessions of peach in two separate evaluation panels identified a total of 6,869 (84.3%) polymorphic SNPs.The almost 7,000 SNPs verified as polymorphic through extensive empirical evaluation represent an excellent source of markers for future studies in genetic relatedness, genetic mapping, and dissecting the genetic architecture of complex agricultural traits. The IPSC peach SNP array v1 is commercially available and we expect that it will be used worldwide for genetic studies in peach and related stone fruit and nut species.     

Seasonal and diel variations in scent composition of ephemeral Murraya paniculata (Linn.) Jack flowers are contributed by separate volatile components

Scent profile of the ephemeral nocturnal floral species Murraya paniculata was characterized to assess diel and seasonal variability. The floral fragrance was found to constitute a characteristic set of 15 major volatile organic compounds (VOCs) dominated by benzenoids, terpenoids and phenylethanoids. Strong diel variability was detected due to dominantly endogenous regulation of 2-phenylethanol and (E)-β-ocimene emission levels, along with temperature-correlated emission rates of 2-phenylethanal, methyl benzoate, methyl anthranilate and germacrene D, resulting in high diurnal contents of the former two VOCs and high nocturnal contents of the latter four VOCs in the fragrance. Significant seasonal variation was contributed by a separate suite of VOCs including linalool, nonanal, decanal, methyl salicylate and methyl palmitate. Higher abundances of these components in certain seasons were found to add subtle variations in the strong diurnal/nocturnal division in the scent profile. Emission rate of linalool is endogenously regulated on a seasonal scale, but that of (E,E)-α-farnesene was maintained at consistent proportions even if correlated to temperature variations. It was concluded that the two sub-sets of major scent compounds, each comprising six VOCs, are adaptive responses such that the strong day/night component of variation in maintained along with necessary physiological adjustments to changing seasons. The varying effects of climatic factors on the 15 major VOCs indicated different regulating mechanisms comprising environmental and endogenous mechanisms in different degrees.     

Evaluation of characteristic aroma compounds of Citrus natsudaidai Hayata (Natsudaidai) cold-pressed peel oil

The characteristic aroma compounds of Citrus natsudaidai Hayata essential oil were evaluated by a combination of instrumental and sensory methods. Sixty compounds were identified and quantified, accounting for 94.08% of the total peel oil constituents. Limonene was the most abundant compound (80.68%), followed by gamma-terpinene (5.30%), myrcene (2.25%) and alpha-pinene (1.30%). Nineteen compounds which could not be identified in the original oil were identified in the oxygenated fraction. Myrcene, linalool, alpha-pinene, beta-pinene, limonene, nonanal, gamma-terpinene, germacrene D, and perillyl alcohol were the active aroma components (FD-factor > 3(6)), whereas beta-copaene, cis-sabinene hydrate and 1-octanol were suggested as characteristic aroma compounds, having a Natsudaidai-like aroma in the GC effluent. Three other compounds, heptyl acetate, (E)-limonene oxide and 2,3-butanediol, which each showed a high RFA value (>35) were considered to be important in the reconstruction of the original Natsudaidai oil from pure odor chemicals. The results indicate that 1-octanol was the aroma impact compound of C. natsudaidai Hayata peel oil.     

Exploring almond genetic variability useful for peach improvement: mapping major genes and QTLs in two interspecific almond × peach populations

Genetic analysis of a diverse set of 42 traits for flower (5), phenology (9), fruit quality (19), leaf (8) and disease resistance (1) was carried out in two interspecific almond × peach populations, an F₂ (T × E) and a BC₁ (T1E), from the cross between ‘Texas’ almond and ‘Earlygold’ peach. Traits related to flower, phenology, fruit quality, leaf morphology and resistance to powdery mildew were phenotyped over 3 years in two locations and studied for co-segregation with a large set of SNP and SSR markers. Three maps were used, one for the T × E and two for the T1E (T1E and E) population. Nine major genes were identified and mapped: anther color (Ag/ag and Ag2/ag2), flower color (Fc2/fc2), maturity date (MD/md), almond fruit type (almond vs. peach; Alf/alf), juiciness (Jui/jui), blood flesh (DBF2/dbf2), powdery mildew resistance (Vr3) and flower type (showy/non-showy; Sh/sh). These genes were often located in genome positions different from those for major genes for similar traits mapped before. Two of them explain fundamental aspects that define the fruit of peach with respect to that of almond: Alf and Jui, for its thick and juicy mesocarp, respectively. The genetics of quantitative traits was studied, and 32 QTLs were detected, with consistent behavior over the years. New alleles identified from almond for important traits such as red skin color, blood flesh, fruit weight and powdery mildew resistance may prove useful for the introduction of new variability into the peach gene pool used in commercial breeding programs.     

Biologically active abietane and ent-kaurane diterpenoids and other constituents from Erythroxylum suberosum

Bioassay-guided fractionation of the ethanol extract from the branches of Erythroxylum suberosum, which was toxic to brine shrimp larvae, afforded five diterpenes bearing abietane and ent-kaurane-type skeletons from an active fraction. From these, four were new, 7-oxo-16-hydroxy-abiet-15(17)-en-19-al, 16-hydroxyabiet-15(17)-en-7-one, 7α,16-dihydroxy-abiet-15(17)-en-19-al and ent-12α-hydroxy-kaur-16-en-19-al, while methyl ent-7α,15β-dihydroxy-kaur-16-en-19-oate is reported for the first time as a natural product. This is also the first reported occurrence of abietane-type diterpenes in the genus Erythroxylum. The flavonoid ombuin-3-rutinoside was isolated from an inactive fraction, while rutin (quercetin-3-rutinoside) was obtained from the non-toxic ethanol extract of the leaves. The structures of the new and known compounds were established by analyses of 1D- and 2D-NMR and mass spectrometry data.     

利用电子鼻评价桃果实香气

为了明确不同桃品种资源果实香气差异,对桃果实香气评价和品质改良提供参考,本研究利用电子鼻系统对桃品种资源果实整果香气进行测定和区分.通过PEN 3.5电子鼻系统采集74份不同品种资源桃果实芳香成分并得到了不同传感器的响应值,采用主成分(PCA)、线性判别法(LDA)和负荷加载(LO)方法分析数据.LO分析结果显示,硫化...