Displaying publications 21 - 40 of 53 in total

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  1. Ho CL
    Genomics, 2020 03;112(2):1536-1544.
    PMID: 31494197 DOI: 10.1016/j.ygeno.2019.09.002
    Red algae are a major source of marine sulfated galactans. In this study, orthologs and inparalogs from seven red algae were analyzed and compared with the aim to discover differences in algal galactan biosynthesis and related pathways of these algae. Red algal orthologs for putative carbohydrate sulfotransferases were found to be prevalent in Porphyridium purpureum, Florideophytes and Bangiophytes, while red algal orthologs for putative chondroitin sulfate synthases, sulfurylases, and porphyranases /carrageenases were found exclusively in Florideophytes and Bangiophytes. The acquirement of these genes could have happened after the divergence from Cyanidiales red algae. Cyanidiales red algae were found to have more number and types of putative sulfate permeases, suggesting that these genes could have been acquired in adaptation to the environmental stresses and biogeochemistry of respective habitats. The findings of this study shed lights on the evolution of different homeostasis mechanisms by the early and late diverging red algal orders.
    Matched MeSH terms: Genome, Plant*
  2. Wong CK, Bernardo R
    Theor Appl Genet, 2008 Apr;116(6):815-24.
    PMID: 18219476 DOI: 10.1007/s00122-008-0715-5
    Oil palm (Elaeis guineensis Jacq.) requires 19 years per cycle of phenotypic selection. The use of molecular markers may reduce the generation interval and the cost of oil-palm breeding. Our objectives were to compare, by simulation, the response to phenotypic selection, marker-assisted recurrent selection (MARS), and genomewide selection with small population sizes in oil palm, and assess the efficiency of each method in terms of years and cost per unit gain. Markers significantly associated with the trait were used to calculate the marker scores in MARS, whereas all markers were used (without significance tests) to calculate the marker scores in genomewide selection. Responses to phenotypic selection and genomewide selection were consistently greater than the response to MARS. With population sizes of N = 50 or 70, responses to genomewide selection were 4-25% larger than the corresponding responses to phenotypic selection, depending on the heritability and number of quantitative trait loci. Cost per unit gain was 26-57% lower with genomewide selection than with phenotypic selection when markers cost US $1.50 per data point, and 35-65% lower when markers cost $0.15 per data point. With population sizes of N = 50 or 70, time per unit gain was 11-23 years with genomewide selection and 14-25 years with phenotypic selection. We conclude that for a realistic yet relatively small population size of N = 50 in oil palm, genomewide selection is superior to MARS and phenotypic selection in terms of gain per unit cost and time. Our results should be generally applicable to other tree species that are characterized by long generation intervals, high costs of maintaining breeding plantations, and small population sizes in selection programs.
    Matched MeSH terms: Genome, Plant*
  3. Meng Z, Han J, Lin Y, Zhao Y, Lin Q, Ma X, et al.
    Theor Appl Genet, 2020 Jan;133(1):187-199.
    PMID: 31587087 DOI: 10.1007/s00122-019-03450-w
    KEY MESSAGE: A novel tetraploid S. spontaneum with basic chromosome x = 10 was discovered, providing us insights in the origin and evolution in Saccharum species. Sugarcane (Saccharum spp., Poaceae) is a leading crop for sugar production providing 80% of the world's sugar. However, the genetic and genomic complexities of this crop such as its high polyploidy level and highly variable chromosome numbers have significantly hindered the studies in deciphering the genomic structure and evolution of sugarcane. Here, we developed the first set of oligonucleotide (oligo)-based probes based on the S. spontaneum genome (x = 8), which can be used to simultaneously distinguish each of the 64 chromosomes of octaploid S. spontaneum SES208 (2n = 8x = 64) through fluorescence in situ hybridization (FISH). By comparative FISH assay, we confirmed the chromosomal rearrangements of S. spontaneum (x = 8) and S. officinarum (2n = 8x = 80), the main contributors of modern sugarcane cultivars. In addition, we examined a S. spontaneum accession, Np-X, with 2n = 40 chromosomes, and we found that it was a tetraploid with the unusual basic chromosome number of x = 10. Assays at the cytological and DNA levels demonstrated its close relationship with S. spontaneum with basic chromosome number x = 8 (the most common accessions in S. spontaneum), confirming its S. spontaneum identity. Population genetic structure and phylogenetic relationship analyses between Np-X and 64 S. spontaneum accessions revealed that Np-X belongs to the ancient Pan-Malaysia group, indicating a close relationship to S. spontaneum with basic chromosome number of x = 8. This finding of a tetraploid S. spontaneum with basic chromosome number of x = 10 suggested a parallel evolution path of genomes and polyploid series in S. spontaneum with different basic chromosome numbers.
    Matched MeSH terms: Genome, Plant*
  4. Kwong QB, Teh CK, Ong AL, Chew FT, Mayes S, Kulaveerasingam H, et al.
    BMC Genet, 2017 Dec 11;18(1):107.
    PMID: 29228905 DOI: 10.1186/s12863-017-0576-5
    BACKGROUND: Genomic selection (GS) uses genome-wide markers as an attempt to accelerate genetic gain in breeding programs of both animals and plants. This approach is particularly useful for perennial crops such as oil palm, which have long breeding cycles, and for which the optimal method for GS is still under debate. In this study, we evaluated the effect of different marker systems and modeling methods for implementing GS in an introgressed dura family derived from a Deli dura x Nigerian dura (Deli x Nigerian) with 112 individuals. This family is an important breeding source for developing new mother palms for superior oil yield and bunch characters. The traits of interest selected for this study were fruit-to-bunch (F/B), shell-to-fruit (S/F), kernel-to-fruit (K/F), mesocarp-to-fruit (M/F), oil per palm (O/P) and oil-to-dry mesocarp (O/DM). The marker systems evaluated were simple sequence repeats (SSRs) and single nucleotide polymorphisms (SNPs). RR-BLUP, Bayesian A, B, Cπ, LASSO, Ridge Regression and two machine learning methods (SVM and Random Forest) were used to evaluate GS accuracy of the traits.

    RESULTS: The kinship coefficient between individuals in this family ranged from 0.35 to 0.62. S/F and O/DM had the highest genomic heritability, whereas F/B and O/P had the lowest. The accuracies using 135 SSRs were low, with accuracies of the traits around 0.20. The average accuracy of machine learning methods was 0.24, as compared to 0.20 achieved by other methods. The trait with the highest mean accuracy was F/B (0.28), while the lowest were both M/F and O/P (0.18). By using whole genomic SNPs, the accuracies for all traits, especially for O/DM (0.43), S/F (0.39) and M/F (0.30) were improved. The average accuracy of machine learning methods was 0.32, compared to 0.31 achieved by other methods.

    CONCLUSION: Due to high genomic resolution, the use of whole-genome SNPs improved the efficiency of GS dramatically for oil palm and is recommended for dura breeding programs. Machine learning slightly outperformed other methods, but required parameters optimization for GS implementation.

    Matched MeSH terms: Genome, Plant*
  5. Fan X, Chen J, Wu Y, Teo C, Xu G, Fan X
    Int J Mol Sci, 2020 Mar 06;21(5).
    PMID: 32155767 DOI: 10.3390/ijms21051819
    Transgenic technologies have been applied to a wide range of biological research. However, information on the potential epigenetic effects of transgenic technology is still lacking. Here, we show that the transgenic process can simultaneously induce both genetic and epigenetic changes in rice. We analyzed genetic, epigenetic, and phenotypic changes in plants subjected to tissue culture regeneration, using transgenic lines expressing the same coding sequence from two different promoters in transgenic lines of two rice cultivars: Wuyunjing7 (WYJ7) and Nipponbare (NP). We determined the expression of OsNAR2.1 in two overexpression lines generated from the two cultivars, and in the RNA interference (RNAi) OsNAR2.1 line in NP. DNA methylation analyses were performed on wild-type cultivars (WYJ7 and NP), regenerated lines (CK, T0 plants), segregation-derived wild-type from pOsNAR2.1-OsNAR2.1 (SDWT), pOsNAR2.1-OsNAR2.1, pUbi-OsNAR2.1, and RNAi lines. Interestingly, we observed global methylation decreased in the T0 regenerated line of WYJ7 (CK-WJY7) and pOsNAR2.1-OsNAR2.1 lines but increased in pUbi-OsNAR2.1 and RNAi lines of NP. Furthermore, the methylation pattern in SDWT returned to the WYJ7 level after four generations. Phenotypic changes were detected in all the generated lines except for SDWT. Global methylation was found to decrease by 13% in pOsNAR2.1-OsNAR2.1 with an increase in plant height of 4.69% compared with WYJ7, and increased by 18% in pUbi-OsNAR2.1 with an increase of 17.36% in plant height compared with NP. This suggests an absence of a necessary link between global methylation and the phenotype of transgenic plants with OsNAR2.1 gene over-expression. However, epigenetic changes can influence phenotype during tissue culture, as seen in the massive methylation in CK-WYJ7, T0 regenerated lines, resulting in decreased plant height compared with the wild-type, in the absence of a transformed gene. We conclude that in the transgenic lines the phenotype is mainly determined by the nature and function of the transgene after four generations of transformation, while the global epigenetic modification is dependent on the genetic background. Our research suggests an innovative insight in explaining the reason behind the occurrence of transgenic plants with random and undesirable phenotypes.
    Matched MeSH terms: Genome, Plant*
  6. Chan KL, Rosli R, Tatarinova TV, Hogan M, Firdaus-Raih M, Low EL
    BMC Bioinformatics, 2017 Jan 27;18(Suppl 1):1426.
    PMID: 28466793 DOI: 10.1186/s12859-016-1426-6
    BACKGROUND: Gene prediction is one of the most important steps in the genome annotation process. A large number of software tools and pipelines developed by various computing techniques are available for gene prediction. However, these systems have yet to accurately predict all or even most of the protein-coding regions. Furthermore, none of the currently available gene-finders has a universal Hidden Markov Model (HMM) that can perform gene prediction for all organisms equally well in an automatic fashion.

    RESULTS: We present an automated gene prediction pipeline, Seqping that uses self-training HMM models and transcriptomic data. The pipeline processes the genome and transcriptome sequences of the target species using GlimmerHMM, SNAP, and AUGUSTUS pipelines, followed by MAKER2 program to combine predictions from the three tools in association with the transcriptomic evidence. Seqping generates species-specific HMMs that are able to offer unbiased gene predictions. The pipeline was evaluated using the Oryza sativa and Arabidopsis thaliana genomes. Benchmarking Universal Single-Copy Orthologs (BUSCO) analysis showed that the pipeline was able to identify at least 95% of BUSCO's plantae dataset. Our evaluation shows that Seqping was able to generate better gene predictions compared to three HMM-based programs (MAKER2, GlimmerHMM and AUGUSTUS) using their respective available HMMs. Seqping had the highest accuracy in rice (0.5648 for CDS, 0.4468 for exon, and 0.6695 nucleotide structure) and A. thaliana (0.5808 for CDS, 0.5955 for exon, and 0.8839 nucleotide structure).

    CONCLUSIONS: Seqping provides researchers a seamless pipeline to train species-specific HMMs and predict genes in newly sequenced or less-studied genomes. We conclude that the Seqping pipeline predictions are more accurate than gene predictions using the other three approaches with the default or available HMMs.

    Matched MeSH terms: Genome, Plant/genetics*
  7. Kwong QB, Ong AL, Teh CK, Chew FT, Tammi M, Mayes S, et al.
    Sci Rep, 2017 06 06;7(1):2872.
    PMID: 28588233 DOI: 10.1038/s41598-017-02602-6
    Genomic selection (GS) uses genome-wide markers to select individuals with the desired overall combination of breeding traits. A total of 1,218 individuals from a commercial population of Ulu Remis x AVROS (UR x AVROS) were genotyped using the OP200K array. The traits of interest included: shell-to-fruit ratio (S/F, %), mesocarp-to-fruit ratio (M/F, %), kernel-to-fruit ratio (K/F, %), fruit per bunch (F/B, %), oil per bunch (O/B, %) and oil per palm (O/P, kg/palm/year). Genomic heritabilities of these traits were estimated to be in the range of 0.40 to 0.80. GS methods assessed were RR-BLUP, Bayes A (BA), Cπ (BC), Lasso (BL) and Ridge Regression (BRR). All methods resulted in almost equal prediction accuracy. The accuracy achieved ranged from 0.40 to 0.70, correlating with the heritability of traits. By selecting the most important markers, RR-BLUP B has the potential to outperform other methods. The marker density for certain traits can be further reduced based on the linkage disequilibrium (LD). Together with in silico breeding, GS is now being used in oil palm breeding programs to hasten parental palm selection.
    Matched MeSH terms: Genome, Plant
  8. Khalidah-Syahirah Ashari, Zeti-Azura Mohamed-Hussein, Muhammad-Redha Abdullah-Zawawi, Sarahani Harun
    Sains Malaysiana, 2018;47:2993-3002.
    Aliphatic glucosinolate is an important secondary metabolite responsible in plant defense mechanism and carcinogenic
    activity. It plays a crucial role in plant adaptation towards changes in the environment such as salinity and drought.
    However, in many plant genomes, there are thousands of genes encoding proteins still with putative functions and
    incomplete annotations. Therefore, the genome of Arabidopsis thaliana was selected to be investigated further to identify
    any putative genes that are potentially involved in the aliphatic glucosinolate biosynthesis pathway, most of its gene are
    with incomplete annotation. Known genes for aliphatic glucosinolates were retrieved from KEGG and AraCyc databases.
    Three co-expression databases i.e., ATTED-II, GeneMANIA and STRING were used to perform the co-expression network
    analysis. The integrated co-expression network was then being clustered, annotated and visualized using Cytoscape plugin,
    MCODE and ClueGO. Then, the regulatory network of A. thaliana from AtRegNet was mapped onto the co-expression
    network to build the transcriptional regulatory network. This study showed that a total of 506 genes were co-expressed
    with the 61 aliphatic glucosinolate biosynthesis genes. Five transcription factors have been predicted to be involved
    in the biosynthetic pathway of aliphatic glucosinolate, namely SEPALLATA 3 (SEP3), PHYTOCHROME INTERACTING FACTOR
    3-like 5 (AtbHLH15/PIL5), ELONGATED HYPOCOTYL 5 (HY5), AGAMOUS-like 15 (AGL15) and GLABRA 3 (GL3). Meanwhile,
    three other genes with high potential to be involved in the aliphatic glucosinolates biosynthetic pathway were identified,
    i.e., methylthioalkylmalate-like synthase 4 (MAML-4) and aspartate aminotransferase (ASP1 and ASP4). These findings
    can be used to complete the aliphatic glucosinolate biosynthetic pathway in A. thaliana and to update the information
    on the glucosinolate-related pathways in public metabolic databases.
    Matched MeSH terms: Genome, Plant
  9. Hu L, Xu Z, Wang M, Fan R, Yuan D, Wu B, et al.
    Nat Commun, 2019 10 16;10(1):4702.
    PMID: 31619678 DOI: 10.1038/s41467-019-12607-6
    Black pepper (Piper nigrum), dubbed the 'King of Spices' and 'Black Gold', is one of the most widely used spices. Here, we present its reference genome assembly by integrating PacBio, 10x Chromium, BioNano DLS optical mapping, and Hi-C mapping technologies. The 761.2 Mb sequences (45 scaffolds with an N50 of 29.8 Mb) are assembled into 26 pseudochromosomes. A phylogenomic analysis of representative plant genomes places magnoliids as sister to the monocots-eudicots clade and indicates that black pepper has diverged from the shared Laurales-Magnoliales lineage approximately 180 million years ago. Comparative genomic analyses reveal specific gene expansions in the glycosyltransferase, cytochrome P450, shikimate hydroxycinnamoyl transferase, lysine decarboxylase, and acyltransferase gene families. Comparative transcriptomic analyses disclose berry-specific upregulated expression in representative genes in each of these gene families. These data provide an evolutionary perspective and shed light on the metabolic processes relevant to the molecular basis of species-specific piperine biosynthesis.
    Matched MeSH terms: Genome, Plant*
  10. Chang Y, Liu H, Liu M, Liao X, Sahu SK, Fu Y, et al.
    Gigascience, 2019 03 01;8(3).
    PMID: 30535374 DOI: 10.1093/gigascience/giy152
    BACKGROUND: The expanding world population is expected to double the worldwide demand for food by 2050. Eighty-eight percent of countries currently face a serious burden of malnutrition, especially in Africa and south and southeast Asia. About 95% of the food energy needs of humans are fulfilled by just 30 species, of which wheat, maize, and rice provide the majority of calories. Therefore, to diversify and stabilize the global food supply, enhance agricultural productivity, and tackle malnutrition, greater use of neglected or underutilized local plants (so-called orphan crops, but also including a few plants of special significance to agriculture, agroforestry, and nutrition) could be a partial solution.

    RESULTS: Here, we present draft genome information for five agriculturally, biologically, medicinally, and economically important underutilized plants native to Africa: Vigna subterranea, Lablab purpureus, Faidherbia albida, Sclerocarya birrea, and Moringa oleifera. Assembled genomes range in size from 217 to 654 Mb. In V. subterranea, L. purpureus, F. albida, S. birrea, and M. oleifera, we have predicted 31,707, 20,946, 28,979, 18,937, and 18,451 protein-coding genes, respectively. By further analyzing the expansion and contraction of selected gene families, we have characterized root nodule symbiosis genes, transcription factors, and starch biosynthesis-related genes in these genomes.

    CONCLUSIONS: These genome data will be useful to identify and characterize agronomically important genes and understand their modes of action, enabling genomics-based, evolutionary studies, and breeding strategies to design faster, more focused, and predictable crop improvement programs.

    Matched MeSH terms: Genome, Plant*
  11. Bhalla R, Narasimhan K, Swarup S
    Plant Cell Rep, 2005 Dec;24(10):562-71.
    PMID: 16220342
    A natural shift is taking place in the approaches being adopted by plant scientists in response to the accessibility of systems-based technology platforms. Metabolomics is one such field, which involves a comprehensive non-biased analysis of metabolites in a given cell at a specific time. This review briefly introduces the emerging field and a range of analytical techniques that are most useful in metabolomics when combined with computational approaches in data analyses. Using cases from Arabidopsis and other selected plant systems, this review highlights how information can be integrated from metabolomics and other functional genomics platforms to obtain a global picture of plant cellular responses. We discuss how metabolomics is enabling large-scale and parallel interrogation of cell states under different stages of development and defined environmental conditions to uncover novel interactions among various pathways. Finally, we discuss selected applications of metabolomics.
    Matched MeSH terms: Genome, Plant/genetics
  12. Liaw Y, Liu Y, Teo C, Cápal P, Wada N, Fukui K, et al.
    Int J Mol Sci, 2021 May 21;22(11).
    PMID: 34063996 DOI: 10.3390/ijms22115426
    Methylation systems have been conserved during the divergence of plants and animals, although they are regulated by different pathways and enzymes. However, studies on the interactions of the epigenomes among evolutionarily distant organisms are lacking. To address this, we studied the epigenetic modification and gene expression of plant chromosome fragments (~30 Mb) in a human-Arabidopsis hybrid cell line. The whole-genome bisulfite sequencing results demonstrated that recombinant Arabidopsis DNA could retain its plant CG methylation levels even without functional plant methyltransferases, indicating that plant DNA methylation states can be maintained even in a different genomic background. The differential methylation analysis showed that the Arabidopsis DNA was undermethylated in the centromeric region and repetitive elements. Several Arabidopsis genes were still expressed, whereas the expression patterns were not related to the gene function. We concluded that the plant DNA did not maintain the original plant epigenomic landscapes and was under the control of the human genome. This study showed how two diverging genomes can coexist and provided insights into epigenetic modifications and their impact on the regulation of gene expressions between plant and animal genomes.
    Matched MeSH terms: Genome, Plant/genetics
  13. Biswas MK, Bagchi M, Biswas D, Harikrishna JA, Liu Y, Li C, et al.
    Genes (Basel), 2020 12 09;11(12).
    PMID: 33317074 DOI: 10.3390/genes11121479
    Trait tagging through molecular markers is an important molecular breeding tool for crop improvement. SSR markers encoded by functionally relevant parts of a genome are well suited for this task because they may be directly related to traits. However, a limited number of these markers are known for Musa spp. Here, we report 35136 novel functionally relevant SSR markers (FRSMs). Among these, 17,561, 15,373 and 16,286 FRSMs were mapped in-silico to the genomes of Musa acuminata, M. balbisiana and M. schizocarpa, respectively. A set of 273 markers was validated using eight accessions of Musa spp., from which 259 markers (95%) produced a PCR product of the expected size and 203 (74%) were polymorphic. In-silico comparative mapping of FRSMs onto Musa and related species indicated sequence-based orthology and synteny relationships among the chromosomes of Musa and other plant species. Fifteen FRSMs were used to estimate the phylogenetic relationships among 50 banana accessions, and the results revealed that all banana accessions group into two major clusters according to their genomic background. Here, we report the first large-scale development and characterization of functionally relevant Musa SSR markers. We demonstrate their utility for germplasm characterization, genetic diversity studies, and comparative mapping in Musa spp. and other monocot species. The sequences for these novel markers are freely available via a searchable web interface called Musa Marker Database.
    Matched MeSH terms: Genome, Plant/genetics
  14. Song BK, Hein I, Druka A, Waugh R, Marshall D, Nadarajah K, et al.
    Funct Integr Genomics, 2009 Feb;9(1):97-108.
    PMID: 18633654 DOI: 10.1007/s10142-008-0091-x
    Common wild rice (Oryza rufipogon) plays an important role by contributing to modern rice breeding. In this paper, we report the sequence and analysis of a 172-kb genomic DNA region of wild rice around the RM5 locus, which is associated with the yield QTL yld1.1. Comparative sequence analysis between orthologous RM5 regions from Oryza sativa ssp. japonica, O. sativa ssp. indica and O. rufipogon revealed a high level of conserved synteny in the content, homology, structure, orientation, and physical distance of all 14 predicted genes. Twelve of the putative genes were supported by matches to proteins with known function, whereas two were predicted by homology to rice and other plant expressed sequence tags or complementary DNAs. The remarkably high level of conservation found in coding, intronic and intergenic regions may indicate high evolutionary selection on the RM5 region. Although our analysis has not defined which gene(s) determine the yld1.1 phenotype, allelic variation and the insertion of transposable elements, among other nucleotide changes, represent potential variation responsible for the yield QTL. However, as suggested previously, two putative receptor-like protein kinase genes remain the key suspects for yld1.1.
    Matched MeSH terms: Genome, Plant/genetics*
  15. Wu D, Shen E, Jiang B, Feng Y, Tang W, Lao S, et al.
    Nat Commun, 2022 02 03;13(1):689.
    PMID: 35115514 DOI: 10.1038/s41467-022-28359-9
    As one of the great survivors of the plant kingdom, barnyard grasses (Echinochloa spp.) are the most noxious and common weeds in paddy ecosystems. Meanwhile, at least two Echinochloa species have been domesticated and cultivated as millets. In order to better understand the genomic forces driving the evolution of Echinochloa species toward weed and crop characteristics, we assemble genomes of three Echinochloa species (allohexaploid E. crus-galli and E. colona, and allotetraploid E. oryzicola) and re-sequence 737 accessions of barnyard grasses and millets from 16 rice-producing countries. Phylogenomic and comparative genomic analyses reveal the complex and reticulate evolution in the speciation of Echinochloa polyploids and provide evidence of constrained disease-related gene copy numbers in Echinochloa. A population-level investigation uncovers deep population differentiation for local adaptation, multiple target-site herbicide resistance mutations of barnyard grasses, and limited domestication of barnyard millets. Our results provide genomic insights into the dual roles of Echinochloa species as weeds and crops as well as essential resources for studying plant polyploidization, adaptation, precision weed control and millet improvements.
    Matched MeSH terms: Genome, Plant/genetics*
  16. Graham NS, Hammond JP, Lysenko A, Mayes S, O Lochlainn S, Blasco B, et al.
    Plant Cell, 2014 Jul;26(7):2818-30.
    PMID: 25082855 DOI: 10.1105/tpc.114.128603
    Although Ca transport in plants is highly complex, the overexpression of vacuolar Ca(2+) transporters in crops is a promising new technology to improve dietary Ca supplies through biofortification. Here, we sought to identify novel targets for increasing plant Ca accumulation using genetical and comparative genomics. Expression quantitative trait locus (eQTL) mapping to 1895 cis- and 8015 trans-loci were identified in shoots of an inbred mapping population of Brassica rapa (IMB211 × R500); 23 cis- and 948 trans-eQTLs responded specifically to altered Ca supply. eQTLs were screened for functional significance using a large database of shoot Ca concentration phenotypes of Arabidopsis thaliana. From 31 Arabidopsis gene identifiers tagged to robust shoot Ca concentration phenotypes, 21 mapped to 27 B. rapa eQTLs, including orthologs of the Ca(2+) transporters At-CAX1 and At-ACA8. Two of three independent missense mutants of BraA.cax1a, isolated previously by targeting induced local lesions in genomes, have allele-specific shoot Ca concentration phenotypes compared with their segregating wild types. BraA.CAX1a is a promising target for altering the Ca composition of Brassica, consistent with prior knowledge from Arabidopsis. We conclude that multiple-environment eQTL analysis of complex crop genomes combined with comparative genomics is a powerful technique for novel gene identification/prioritization.
    Matched MeSH terms: Genome, Plant/genetics*
  17. Rahman AY, Usharraj AO, Misra BB, Thottathil GP, Jayasekaran K, Feng Y, et al.
    BMC Genomics, 2013;14:75.
    PMID: 23375136 DOI: 10.1186/1471-2164-14-75
    Hevea brasiliensis, a member of the Euphorbiaceae family, is the major commercial source of natural rubber (NR). NR is a latex polymer with high elasticity, flexibility, and resilience that has played a critical role in the world economy since 1876.
    Matched MeSH terms: Genome, Plant/genetics
  18. Ong-Abdullah M, Ordway JM, Jiang N, Ooi SE, Kok SY, Sarpan N, et al.
    Nature, 2015 Sep 24;525(7570):533-7.
    PMID: 26352475 DOI: 10.1038/nature15365
    Somaclonal variation arises in plants and animals when differentiated somatic cells are induced into a pluripotent state, but the resulting clones differ from each other and from their parents. In agriculture, somaclonal variation has hindered the micropropagation of elite hybrids and genetically modified crops, but the mechanism responsible remains unknown. The oil palm fruit 'mantled' abnormality is a somaclonal variant arising from tissue culture that drastically reduces yield, and has largely halted efforts to clone elite hybrids for oil production. Widely regarded as an epigenetic phenomenon, 'mantling' has defied explanation, but here we identify the MANTLED locus using epigenome-wide association studies of the African oil palm Elaeis guineensis. DNA hypomethylation of a LINE retrotransposon related to rice Karma, in the intron of the homeotic gene DEFICIENS, is common to all mantled clones and is associated with alternative splicing and premature termination. Dense methylation near the Karma splice site (termed the Good Karma epiallele) predicts normal fruit set, whereas hypomethylation (the Bad Karma epiallele) predicts homeotic transformation, parthenocarpy and marked loss of yield. Loss of Karma methylation and of small RNA in tissue culture contributes to the origin of mantled, while restoration in spontaneous revertants accounts for non-Mendelian inheritance. The ability to predict and cull mantling at the plantlet stage will facilitate the introduction of higher performing clones and optimize environmentally sensitive land resources.
    Matched MeSH terms: Genome, Plant/genetics*
  19. Teh BT, Lim K, Yong CH, Ng CCY, Rao SR, Rajasegaran V, et al.
    Nat Genet, 2017 Nov;49(11):1633-1641.
    PMID: 28991254 DOI: 10.1038/ng.3972
    Durian (Durio zibethinus) is a Southeast Asian tropical plant known for its hefty, spine-covered fruit and sulfury and onion-like odor. Here we present a draft genome assembly of D. zibethinus, representing the third plant genus in the Malvales order and first in the Helicteroideae subfamily to be sequenced. Single-molecule sequencing and chromosome contact maps enabled assembly of the highly heterozygous durian genome at chromosome-scale resolution. Transcriptomic analysis showed upregulation of sulfur-, ethylene-, and lipid-related pathways in durian fruits. We observed paleopolyploidization events shared by durian and cotton and durian-specific gene expansions in MGL (methionine γ-lyase), associated with production of volatile sulfur compounds (VSCs). MGL and the ethylene-related gene ACS (aminocyclopropane-1-carboxylic acid synthase) were upregulated in fruits concomitantly with their downstream metabolites (VSCs and ethylene), suggesting a potential association between ethylene biosynthesis and methionine regeneration via the Yang cycle. The durian genome provides a resource for tropical fruit biology and agronomy.
    Matched MeSH terms: Genome, Plant*
  20. Miah G, Rafii MY, Ismail MR, Puteh AB, Rahim HA, Latif MA
    C. R. Biol., 2015 Feb;338(2):83-94.
    PMID: 25553855 DOI: 10.1016/j.crvi.2014.11.003
    Backcross breeding is the most commonly used method for incorporating a blast resistance gene into a rice cultivar. Linkage between the resistance gene and undesirable units can persist for many generations of backcrossing. Marker-assisted backcrossing (MABC) along with marker-assisted selection (MAS) contributes immensely to overcome the main limitation of the conventional breeding and accelerates recurrent parent genome (RPG) recovery. The MABC approach was employed to incorporate (a) blast resistance gene(s) from the donor parent Pongsu Seribu 1, the blast-resistant local variety in Malaysia, into the genetic background of MR219, a popular high-yielding rice variety that is blast susceptible, to develop a blast-resistant MR219 improved variety. In this perspective, the recurrent parent genome recovery was analyzed in early generations of backcrossing using simple sequence repeat (SSR) markers. Out of 375 SSR markers, 70 markers were found polymorphic between the parents, and these markers were used to evaluate the plants in subsequent generations. Background analysis revealed that the extent of RPG recovery ranged from 75.40% to 91.3% and from 80.40% to 96.70% in BC1F1 and BC2F1 generations, respectively. In this study, the recurrent parent genome content in the selected BC2F2 lines ranged from 92.7% to 97.7%. The average proportion of the recurrent parent in the selected improved line was 95.98%. MAS allowed identification of the plants that are more similar to the recurrent parent for the loci evaluated in backcross generations. The application of MAS with the MABC breeding program accelerated the recovery of the RP genome, reducing the number of generations and the time for incorporating resistance against rice blast.
    Matched MeSH terms: Genome, Plant
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