Dataset Information

Novel flax orbitide derived from genetic deletion.

ABSTRACT: BACKGROUND:Flaxseed orbitides are homodetic plant cyclic peptides arising from ribosomal synthesis and post-translation modification (N to C cyclization), and lacking cysteine double bonds (Nat Prod Rep 30:108-160, 2013). Screening for orbitide composition was conducted on the flax core collection (FCC) grown at both Saskatoon, Saskatchewan and Morden, Manitoba over three growing seasons (2009-2011). Two flax (Linum usitatissimum L.) accessions 'Hollandia' (CN 98056) and 'Z 11637' (CN 98150) produce neither [1-9-N?C]-linusorb B2 (3) nor [1-9-N?C]-linusorb B3 (1). Mass spectrometry was used to identify novel compounds and elucidate their structure. NMR spectroscopy was used to corroborate structural information. RESULTS:Experimental findings indicated that these accessions produce a novel orbitide, identified in three oxidation states having quasimolecular ion peaks at m/z 1072.6 (18), 1088.6 (19), and 1104.6 (20) [M?+?H]+ corresponding to molecular formulae C57H86N9O9S, C57H86N9O10S, and C57H86N9O11S, respectively. The structure of 19 was confirmed unequivocally as [1-9-N?C]-OLIPPFFLI. PCR amplification and sequencing of the gene coding for 18, using primers developed for 3 and 1, identified the putative linear precursor protein of 18 as being comprised of the first three amino acid residues of 3 (MLI), four conserved amino acid residues of 3 and/or 1 (PPFF), and the last two residues of 1 (LI). CONCLUSION:Comparison of gene sequencing data revealed that a 117 base pair deletion had occurred that resulted in truncation of both 3 and 1 to produce a sequence encoding for the novel orbitide precursor of 18. This observation suggests that repeat units of flax orbitide genes are conserved and suggests a novel mechanism for evolution of orbitide gene diversity. Orbitides 19 and 20 contain MetO and MetO2, respectively, and are not directly encoded, but are products of post-translation modification of Met present in 18 ([1-9-N?C]-MLIPPFFLI).

SUBMITTER: Burnett PG

PROVIDER: S-EPMC5963108 | biostudies-literature | 2018 May

REPOSITORIES: biostudies-literature

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Novel flax orbitide derived from genetic deletion.

Burnett Peta-Gaye Gillian PG Young Lester Warren LW Olivia Clara Marisa CM Jadhav Pramodkumar Dinkar PD Okinyo-Owiti Denis Paskal DP Reaney Martin John Tarsisius MJT

BMC plant biology 20180521 1

<h4>Background</h4>Flaxseed orbitides are homodetic plant cyclic peptides arising from ribosomal synthesis and post-translation modification (N to C cyclization), and lacking cysteine double bonds (Nat Prod Rep 30:108-160, 2013). Screening for orbitide composition was conducted on the flax core collection (FCC) grown at both Saskatoon, Saskatchewan and Morden, Manitoba over three growing seasons (2009-2011). Two flax (Linum usitatissimum L.) accessions 'Hollandia' (CN 98056) and 'Z 11637' (CN 98 ...[more]

PMID: 29783946

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Project description:BACKGROUND:A sustainable breeding program requires a minimum level of germplasm diversity to provide varied options for the selection of new breeding lines. To maximize genetic gain of the North Dakota State University (NDSU) flax breeding program, we aimed to increase the genetic diversity of its parental stocks by incorporating diverse genotypes. For this purpose, we analyzed the genetic diversity, linkage disequilibrium, and population sub-structure of 350 globally-distributed flax genotypes with 6200 SNP markers. RESULTS:All the genotypes tested clustered into seven sub-populations (P1 to P7) based on the admixture model and the output of neighbor-joining (NJ) tree analysis and principal coordinate analysis were in line with that of structure analysis. The largest sub-population separation arose from a cluster of NDSU/American genotypes with Turkish and Asian genotypes. All sub-populations showed moderate genetic diversity (average H?=?0.22 and I?=?0.34). The pairwise Fst comparison revealed a great degree of divergence (Fst?>?0.25) between most of the combinations. A whole collection mantel test showed significant positive correlation (r?=?0.30 and p?<?0.01) between genetic and geographic distances, whereas it was non-significant for all sub-populations except P4 and P5 (r?=?0.251, 0.349 respectively and p?<?0.05). In the entire collection, the mean linkage disequilibrium was 0.03 and it decayed to its half maximum within <?21?kb distance. CONCLUSIONS:To maximize genetic gain, hybridization between NDSU stock (P5) and Asian individuals (P6) are potentially the best option as genetic differentiation between them is highest (Fst?>?0.50). In contrast, low genetic differentiation between P5 and P2 may enhance the accumulation of favorable alleles for oil and fiber upon crossing to develop dual purpose varieties. As each sub-population consists of many genotypes, a Neighbor-Joining tree and kinship matrix assist to identify distantly related genotypes. These results also inform genotyping decisions for future association mapping studies to ensure the identification of a sufficient number of molecular markers to tag all linkage blocks.

Dataset Information

Novel flax orbitide derived from genetic deletion.

Publications

Novel flax orbitide derived from genetic deletion.

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