Two new glucosides from the pellicle of the walnut (Juglans regia)
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ABSTRACT: Electronic Supplementary Material
Supplementary material is available for this article at 10.1007/s13659-012-0009-0 and is accessible for authorized users.
SUBMITTER: Cai L
PROVIDER: S-EPMC4131628 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Walnut (Juglans regia L.) is an important nut fruit crop mainly grown for its high nutritional and medicinal value. In walnut fruit, the pellicle is the main source of polyphenols (such as proanthocyanidins), which are natural bioactive compounds but also cause astringency and bitterness for walnut fruit consumption. However, the gene regulatory networks of phenolic biosynthetic pathways remain largely unknown in walnut pellicles. Here, we performed RNA sequencing (RNA-seq) to identify differentially expressed genes (DEGs) associated with pellicle development in walnut. In this study, seven developmental stages (8-, 9-, 11-, 13-, 15-, 17-, and 19-week after pollination) of ‘Xinwen179’ pellicle tissues were harvested to conduct further transcriptome-wide profiles. Via RNA-seq, we explored several key DEGs involved in the phenolic biosynthetic pathway, such as dihydroflavonol-4-reductase (DFR), leucoanthocyanidin reductase (LAR), anthocyanidin synthase (ANS) and anthocyanidin reductase (ANR), which are dynamically expressed at developmental stages of the walnut pellicle. Taken together, our preliminary investigation on DEGs associated with pellicle development will not only elucidate the gene regulatory networks of the phenolic biosynthetic pathway for pellicle development, but also contribute to the broad spectrum of RNA-seq data resources for further genetic improvement of walnut.
2022-08-30 | GSE209790 | GEO
Project description:Walnuts (Juglans regia L.) are a valuable dietary source of polyphenols and lipids, with increasing worldwide consumption. California is a major producer, with 'Chandler' and 'Tulare' among the cultivars more widely grown. 'Chandler' produces kernels with extra light color at a higher frequency than other cultivars, gaining preference by growers and consumers. Here we performed a deep comparative proteome analysis of kernel pellicle tissue from these two valued genotypes at three harvest maturities, detecting a total of 4937 J. regia proteins. Late and early maturity stages were compared for each cultivar, revealing many developmental responses common or specific for each cultivar. Top protein biomarkers for each developmental stage were also selected based on larger fold-change differences and lower variance among replicates, including proteins for biosynthesis of lipids and phenols, defense-related proteins and desiccation stress-related proteins. Comparison between the genotypes also revealed the common and specific protein repertoires, totaling 321 pellicle proteins with differential abundance at harvest stage. The proteomics data provides clues on antioxidant, secondary, and hormonal metabolism that could be involved in the loss of quality in the pellicles during processing for commercialization.
| S-EPMC7760677 | biostudies-literature
Project description:Yield, nut quality, and ability to adapt to specific climate conditions, are all important factors to consider in the development and selection of new Persian walnut (Juglans regia L.) varieties. The genetic control of these traits is still unknown in walnut, limiting the accuracy and rapidity of releasing new cultivars for commercial use. We studied the genetic architecture of five traits crucial for either marketing (i.e., yield, lateral fruit-bearing, and pellicle color) or selection of individuals with specific phenology (i.e., leafing and harvest date). By combining over 30 years of phenotypic data with genetic profiles generated using the latest Axiom™ J. regia 700K SNP array, we were able to identify and confirm major loci for all these traits. In particular, we revealed that a genomic region at the beginning of Chr1 controls both leafing and harvest date in walnut, consistent with the observed strong phenotypical correlation between these traits, and including candidate genes involved in plant development, leaf formation, and cell division. In addition, a large genomic region on Chr11 that includes genes with a central role in flowering control and shoot meristem growth underlies both lateral fruit-bearing and yield in walnut. We observed a more complex genetic architecture for pellicle color, strongly influenced by the environment (h 2 = 0.43). We identified two marker-trait associations on Chr6 and 7 for pellicle color, where genes encoding a UDP-glycosyltransferase or involved in the response to oxidation were found. In conclusion, by combining classical quantitative trait loci (QTL) mapping and genome-wide association mapping, we deciphered, for the first time, the molecular pathways controlling walnut phenology, yield, lateral fruitfulness, and pellicle color. Our findings represent a further milestone in the transition from conventional to genome-assisted breeding in Persian walnut.
| S-EPMC6764078 | biostudies-literature
Project description:Walnut pellicle color is a key quality attribute that drives consumer preference and walnut sales. For the first time a high-throughput, computer vision-based phenotyping platform using a custom algorithm to quantitatively score each walnut pellicle in L* a* b* color space was deployed at large-scale. This was compared to traditional qualitative scoring by eye and was used to dissect the genetics of pellicle pigmentation. Progeny from both a bi-parental population of 168 trees ('Chandler' × 'Idaho') and a genome-wide association (GWAS) with 528 trees of the UC Davis Walnut Improvement Program were analyzed. Color phenotypes were found to have overlapping regions in the 'Chandler' genetic map on Chr01 suggesting complex genetic control. In the GWAS population, multiple, small effect QTL across Chr01, Chr07, Chr08, Chr09, Chr10, Chr12 and Chr13 were discovered. Marker trait associations were co-localized with QTL mapping on Chr01, Chr10, Chr14, and Chr16. Putative candidate genes controlling walnut pellicle pigmentation were postulated.
| S-EPMC7718756 | biostudies-literature
Project description:The purpose of investigation was to assess the phytochemical and nutraceutical of walnut in leaf extracts through diverse quantitative and qualitative phytochemical tests followed by array of assays. The screening of 50 elite walnut genotypes which exhibited wide range of discrepancy in terms of phytochemicals as well as their anti-oxidant potential was done. Walnut genotypes displayed maximum divergence in quercetin content (2.86-5.78 mg/100 g) as represented by cluster analysis. The phenolic rich genotypes exhibiting total phenols (37.61-46.47 mg/g GAE) having higher DPPH potential (IP of 32.82-73.50) where as genotypes that accumulate flavonoids/flavanols (5.52-28.48 mg/g QE and 4.11-21.76 mg/g QE showed immense FRAP activity (418.92-1067.94 µM Fe2+/g FW). There was positive correlation between the phenolics content and anti-oxidant potential. The results showed oil content of 50.1-85.08% and kernel percentage 25.21-81.92% of all walnut genotypes. To evaluate the anti-proliferative potential of walnut genotypes, Trypan blue exclusion test, MTT assay and Griess assay was used. Each assay was repeated with different positive controls against a panel of human cancer cell lines viz THP-1, U2OS, IMR-32 and HBL-100 and then compared with the walnut extracts for their efficiency in anti-proliferative activity. The SPS 1 walnut extract at concentration of 500 µg/ml exhibited 10% cell viability and with 1000 µg/ml walnut extract there was consequent decline towards (6.25%) viability. The results indicated that walnut leaf constitutes an excellent source of effective natural antioxidants and chemo-preventive agents that can act as anti cancer agents.
| S-EPMC5785386 | biostudies-literature
Project description:Kernel oxidation susceptibility and pellicle darkening are among the biggest concerns regarding walnut quality. Monitoring oxidation is crucial to preserve quality from production to consumption. Chemical oxidation parameters (peroxide value and UV absorbances), fatty acid profile, tocopherols, phenols, and volatiles in 'Chandler' and 'Howard' kernels were studied at different time points during 28 weeks of storage to evaluate potential oxidation markers. During storage, peroxide value, UV absorbances, and volatiles concentration increased; oxidative stability, phenols, and tocopherols decreased, while fatty acid profile was unaffected. 'Chandler' had a lower peroxide value, K232, and K268; and higher kernel and oil oxidative stability compared to 'Howard'. Phenols and tocopherols decreased 1.2-fold in 'Chandler' and 1.3-fold in 'Howard'. Using multivariate analysis, samples were discriminated in three groups according with their oxidative levels. Increases of volatiles in oil and kernel were associated with higher oxidative levels. Pentanal, 2-methylpropanal, hexanal, (E)-2-pentenal, 3-octanone, octanal, (Z)-2-penten-1-ol, hexanol, (E)-2-octenal, 1-octen-3-ol, benzaldehyde, (E,E)-2,4-nonadienal, and hexanoic acid in kernels were adequate at distinguishing oxidation levels and as oxidative markers in walnuts. Kernel volatiles is a useful measurement for walnut oxidation during storage without any prior fat extraction.
| S-EPMC7913853 | biostudies-literature
Project description:Common walnut (Juglans regia L.) is cultivated in temperate regions worldwide for its wood and nuts. The complete chloroplast genome of J. regia was sequenced using the Illumina MiSeq platform. This is the first complete chloroplast sequence for the Juglandaceae, a family that includes numerous species of economic importance. The chloroplast genome of J. regia was 160 367 bp in length, with 36.11% GC content. It contains a pair of inverted repeats (26 035 bp) which were separated by a large single copy (89 872 bp) and a small single copy region (18 425 bp). A total of 137 genes were annotated, which included 86 protein-coding genes, three pseudogenes (two ycf15 and one infA), 40 tRNA genes and eight rRNA genes. The neighbour-joining phylogenetic analysis with the reported chloroplast genomes showed that common walnut chloroplasts are most closely related to those of the Fagaceae family.
| S-EPMC7871657 | biostudies-literature
Project description:We showed previously that gallic acid is produced in walnut from 3-dehydroshikimate by a shikimate dehydrogenase (JrSkDH). This study focuses on the next step in the hydrolysable tannin pathway, the formation of 1-O-galloyl-β-D-glucose from the phenolic gallic acid and UDP glucose by a glycosyltransferase. JrGGT1 (UGT84A73) and JrGGT2 (UGT84A74) are predicted to be two such glycosyltransferases, which we expressed in tobacco plants. GC-MS analysis of the transgenic tobacco revealed moderate, yet significant alterations in plant secondary metabolism, such as depleted phenolic acids, including gallic acid. We postulate that these effects are due to JrGGT1 and JrGGT2 activity, as JrGGT orthologs glycosylate these phenolic compounds in vitro. Moreover, JrGGT expression in tobacco caused upregulation of shikimic acid pathway metabolites and differing responses in phenylpropanoids, such as phenolic acids and flavonoids. In transcriptome analysis of walnut pellicle tissues, both JrGGTs showed substantial and significant expression correlations with the gallic acid-producing JrSkDHs and were highly coexpressed with the genetic circuits constituting the shikimic acid and phenylpropanoid biosynthetic pathways. Verification of JrGGT gene expression by transcriptome analysis of 20 walnut tissues revealed striking similarities with that of the pellicle data, with the greatest expression in roots, wood, buds, and leaves of Juglans regia cv. Chandler: tissues that typically accumulate hydrolysable tannins. Like the transgenic tobacco, pellicle metabolomic analyses revealed that many phenylpropanoids correlated negatively with JrGGT expression, while shikimic acid pathway metabolites correlated positively with JrGGT expression. This research supports the hypothesis that JrGGT1 and JrGGT2 play non-trivial roles in metabolism of phenolic acids, flavonoids, and ostensibly, tannins.
| S-EPMC7943615 | biostudies-literature
Project description:The distribution and survival of trees during the last glacial maximum (LGM) has been of interest to paleoecologists, biogeographers, and geneticists. Ecological niche models that associate species occurrence and abundance with climatic variables are widely used to gain ecological and evolutionary insights and to predict species distributions over space and time. The present study deals with the glacial history of walnut to address questions related to past distributions through genetic analysis and ecological modeling of the present, LGM and Last Interglacial (LIG) periods. A maximum entropy method was used to project the current walnut distribution model on to the LGM (21-18 kyr BP) and LIG (130-116 kyr BP) climatic conditions. Model tuning identified the walnut data set filtered at 10 km spatial resolution as the best for modeling the current distribution and to hindcast past (LGM and LIG) distributions of walnut. The current distribution model predicted southern Caucasus, parts of West and Central Asia extending into South Asia encompassing northern Afghanistan, Pakistan, northwestern Himalayan region, and southwestern Tibet, as the favorable climatic niche matching the modern distribution of walnut. The hindcast of distributions suggested the occurrence of walnut during LGM was somewhat limited to southern latitudes from southern Caucasus, Central and South Asian regions extending into southwestern Tibet, northeastern India, Himalayan region of Sikkim and Bhutan, and southeastern China. Both CCSM and MIROC projections overlapped, except that MIROC projected a significant presence of walnut in the Balkan Peninsula during the LGM. In contrast, genetic analysis of the current walnut distribution suggested a much narrower area in northern Pakistan and the surrounding areas of Afghanistan, northwestern India, and southern Tajikistan as a plausible hotspot of diversity where walnut may have survived glaciations. Overall, the findings suggest that walnut perhaps survived the last glaciations in several refugia across a wide geographic area between 30° and 45° North latitude. However, humans probably played a significant role in the recent history and modern distribution of walnut.
| S-EPMC5638312 | biostudies-literature
Project description:Low molecular weight (LMW) proteins were purified from English walnuts (J. regia cv. Chandler). The LMW proteins were separated by anion exchange chromatography. The anion exchange fractions were analyzed by SDS-PAGE, and protein bands were excised. In gel trypsin digestion was conducted (following reduction with DTT and alkylation with iodoacetamide). Peptides were separated by RP-HPLC and analyzed with an LTQ Orbitrap XL. Peptide and protein identifications were obtained with Mascot.
2019-11-28 | PXD000634 | Pride