Phenotypic variation within organisms is driven primarily by genetic diversity. However, there is a growing appreciation that epigenetic variation, resulting from a multitude of diverse chemical modifications to the DNA and chromatin, can have profound effects on phenotype. Heritable epigenetic marks persist through meiosis and can be stably transmitted to the next generation, resulting in transgenerational epigenetic inheritance. Importantly, when epigenetic changes occur near coding genes, affecting their transcriptional state, heritable epigenetic variation can result in heritable phenotypic variation. Large-scale interrogation of epigenome inheritance in Arabidopsis has revealed that spontaneous variation in DNA methylation occurs at a rate that is orders of magnitude greater than genetic mutation, indicating the key importance of epigenetic variation during evolution. Thus, there is a potential for epigenetics to play a role in crop improvement, including regulation of transgene expression and creation of novel epialleles. Here, we review cases of naturally occurring and genetically induced epialleles, and discuss how the studies from two epigenetic populations are rapidly increasing our understanding of epigenetic diversity.
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DNA barcoding is a technique that provides rapid identification of species without using morphological cues. The method employs relatively small-standardized DNA fragments as tags to define or discover species. In plants, the mitochondrial genome evolves much more slowly than in animals. There is currently no consensus on which candidate markers comprise the best plant DNA barcoding region; however, DNA barcodes such as
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Eating and cooking qualities are the most important trait in
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To utilize the favorable gene(s) from winter wheat for genetic improvement of spring wheat, this study was carried out to identify the quantitative trait loci (QTL) associated with grain protein content (GPC) and grain hardness (GH) by analysis of recombinant inbred lines (RILS) derived from a cross between spring wheat and spring version of winter wheat. A genetic map of 334 loci was constructed which covered 1575.30cM on all 21 chromosomes. Two QTLs on 3B and 5B chromosome were detected for GPC. A QTL identified barc77 on chromosome 3B had additive effect of 0.17 and the other QTL identified by gwm499 on chromosome 5B had additive effect of 0.19. There were two major QTLs for GH identified on Chromosome 1B and chromosome 5A. The QTL on 1B was localized within a 18.7cM region flanked by wmc719 and wmc367-1 with 1.75 additive effect. The QTL on chromosome 5A flanked by SNP markers, IWA6573 and IWA2363, had additive effect of 1.44.
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We analyzed the transcriptional profile of the
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Tomato was considered as one of the most widely cultivated vegetable crops in the world. Tomato plant has high antioxidant capacity which can be attributed to the high levels of carotenoids, phenols, vitamins C and E. However, most of tomato plants have been discarded as waste after fruit harvesting. In order to identify genetic resources with high antioxidant level for use in food or as feed additives, we investigated the ABTS, DPPH antioxidant activity and polyphenol content in tomato leaves and stems. A total of 112 tomato accessions were classified into three groups by latitude of their collected countries: 30°~60° North (50 accessions), 0°~30° North (40 accessions), and 0°~30° South (22 accessions). Stem and leaf extracts showed wide variation in ABTS antioxidant activity ranging from 1.6 ± 1.0 to 48.4 ± 6.1 μg Trolox mg−1 dw. The antioxidant activity of DPPH was in the range of 6.3 ± 0.2 to 40.0 ± 0.3 μg ASC mg−1 dw. Total polyphenol content ranged from 6.1 ± 0.2 to 38.9 ± 0.7 μg GAE mg−1 dw. ABTS, DPPH antioxidant activities and polyphenol content in accessions from 30°~60°N latitude were significantly higher (P<0.05) than those from 0°~30°N latitude. ABTS values showed a significant positive correlation (r = 0.700**) with DPPH activity. IT100506 (KOR) and 702959 (UKR) were recommended as potential sources of natural antioxidants due to their highest antioxidant activity among accessions. This study will provide valuable information for tomato breeders in developing and producing functional food or feed additives resources.
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Assessment of the genetic variation and biochemical traits among various germplasm collections are necessary for utilization of valuable genetic resource and effective strategies of germplasm conservation. The aims of this study were to analyze the genetic diversity using SSR markers and compare protein, oil content and fatty acid composition of about 185 soybean germplasm which is comprised of Korean landraces and collections from six different global regions. Seventy two SSR markers were selected based on their distribution on the 17 genetic linkage groups of soybean. A total of 784 alleles were detected from all accessions, with an average of 10.9 alleles per microsatellite locus. The genetic diversity observed was high wherein three distinct groups were formed containing several subgroups according to their geographic origins. Biochemical contents assay revealed significant differences in their protein and oil contents. Generally, the crude protein content was highest among India and Myanmar collections, while oil content was highest among accessions from USA and China. A negative correlation was observed between protein and oil contents, and between oleic and linolenic acids. The highest value observed for biochemical content among all germplam tested was 45.8% for crude protein, 26.7% for crude oil and 35.7% for oleic acid composition. Our study provided a better understanding of genetic relationships and geographical origin among various germplasm collections, and it could contribute to more efficient utilization of valuable genetic resources.
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There is a rising interest of moving towards hybrid breeding in outcrossing species. Self-compatibility (SC), which occurs at low rates in self-incompatible species, could be used to develop inbred lines, a key requirement for hybrid breeding programs. In perennial ryegrass, the existence of SC independent from the self-incompatibility (SI) loci S and Z has been reported.
In this study, we used 98 F2 individuals from a cross between a self-compatible ecotype and an individual of the VrnA mapping population that were tested with markers for two candidate linkage groups 3 and 5 as well as markers for candidate regions at the S and Z locus. We were able to determine a tentative location of a SC locus and tested the possible interaction to other loci involved in SI and SC. This information will help to fine map the SC locus, and for marker-assisted selection.
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The
objective
s of the study were to investigate the genetic behavior of some biological and economical traits of 14 okra populations collected from Dakahlia Governorate, which underwent two cycles of inbreeding with selection. Selection of individual plants based on earliness, high number of pods, and minimum neck/pod ratio was carried out in all generations. The results showed that the means and ranges of all studied traits for all families became smaller in the S2 generation than those in the S0 generation. Highly significant variations were observed among populations for all the studied traits. The mean performance clearly indicated the agronomic superiority of some families over the others. Family 9 followed by family 12 showed the earliest flowering plants and the highest yield per plant. Phenotypic variances were higher than the corresponding genotypic variances indicating predominance of environmental effects on the expression of these characters. The magnitude of phenotypic and genotypic coefficients of variation varied from one trait to another. High broad-sense heritability coupled with high genetic advance as percent of mean were shown by the different traits, especially, plant height, number of branches per plant, number of pods per plant, pod length, neck/pod ratio and plant yield. This implicates that these traits were under the control of additive genetic effects, and could be effectively improved through selection. Plant yield had positive and highly significant correlation at genotypic and phenotypic level with number of pods per plant, plant height and neck/pod ratio.
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Resveratrol, a plant phenolic compound, has potential therapeutic benefits due to its antioxidant properties. This is substantiated by previous studies that show that resveratrol derived from rice grains is an effective treatment agent for metabolic syndrome. Here, we characterized the T-DNA sequence, inserted T-DNA structure, copy number, integrity of the transgene locus, resveratrol synthase gene expression and resveratrol contents in the grains of two resveratrol transgenic rice lines, Iksan515 and Iksan526. The T-DNA transformation vector contained two expression cassettes of the resveratrol synthase gene under the control of the ubiquitin promoter and the bar selection marker gene under the control of the CaMV35S promoter. Flanking sequence analysis indicated that the T-DNAs were inserted into intergenic regions of chromosome 4 for Iksan515 and chromosome 12 for Iksan526. Two T-DNAs connected in an inverted repeat structure at a single locus of the rice genome were identified by whole genome sequencing and Southern blot hybridization in both Iksan515 and Iksan526. No novel open reading frames (ORFs) around insertion sites, sequences encoding allergenic or toxic protein, or other unintended effects by T-DNA insertion were found in either case. In addition, resveratrol synthase gene expression in leaves and resveratrol detection in brown rice grains suggested the successful expression of the inserted foreign resveratrol synthase gene in two transgenic rice lines.
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