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Genetic basis of unstable expression of high gamma-tocopherol content in sunflower seeds

BACKGROUND: Tocopherols are natural antioxidants with both in vivo (vitamin E) and in vitro activity. Sunflower seeds contain predominantly alpha-tocopherol (>90% of total tocopherols), with maximum vitamin E effect but lower in vitro antioxidant action than other tocopherol forms such as gamma-t...

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Autores principales: García-Moreno, María J, Fernández-Martínez, José M, Velasco, Leonardo, Pérez-Vich, Begoña
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2012
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3463442/
https://www.ncbi.nlm.nih.gov/pubmed/22607470
http://dx.doi.org/10.1186/1471-2229-12-71
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author García-Moreno, María J
Fernández-Martínez, José M
Velasco, Leonardo
Pérez-Vich, Begoña
author_facet García-Moreno, María J
Fernández-Martínez, José M
Velasco, Leonardo
Pérez-Vich, Begoña
author_sort García-Moreno, María J
collection PubMed
description BACKGROUND: Tocopherols are natural antioxidants with both in vivo (vitamin E) and in vitro activity. Sunflower seeds contain predominantly alpha-tocopherol (>90% of total tocopherols), with maximum vitamin E effect but lower in vitro antioxidant action than other tocopherol forms such as gamma-tocopherol. Sunflower germplasm with stable high levels of gamma-tocopherol (>85%) has been developed. The trait is controlled by recessive alleles at a single locus Tph2 underlying a gamma-tocopherol methyltransferase (gamma-TMT). Additionally, unstable expression of increased gamma-tocopherol content in the range from 5 to 85% has been reported. The objective of this research was to determine the genetic basis of unstable expression of high gamma-tocopherol content in sunflower seeds. RESULTS: Male sterile plants of nuclear male sterile line nmsT2100, with stable high gamma-tocopherol content, were crossed with plants of line IAST-1, with stable high gamma-tocopherol content but derived from a population that exhibited unstable expression of the trait. F(2) seeds showed continuous segregation for gamma-tocopherol content from 1.0 to 99.7%. Gamma-tocopherol content in F(2) plants (average of 24 individual F(3) seeds) segregated from 59.4 to 99.4%. A genetic linkage map comprising 17 linkage groups (LGs) was constructed from this population using 109 SSR and 20 INDEL marker loci, including INDEL markers for tocopherol biosynthesis genes. QTL analysis revealed a major QTL on LG 8 that corresponded to the gamma-TMT Tph2 locus, which suggested that high gamma-tocopherol lines nmsT2100 and IAST-1 possess different alleles at this locus. Modifying genes were identified at LGs 1, 9, 14 and 16, corresponding in most cases with gamma-TMT duplicated loci. CONCLUSIONS: Unstable expression of high gamma-tocopherol content is produced by the effect of modifying genes on tph2(a) allele at the gamma-TMT Tph2 gene. This allele is present in line IAST-1 and is different to allele tph2 present in line nmsT2100, which is not affected by modifying genes. No sequence differences at the gamma-TMT gene were found associated to allelic unstability. Our results suggested that modifying genes are mostly epistatically interacting gamma-TMT duplicated loci.
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spelling pubmed-34634422012-10-04 Genetic basis of unstable expression of high gamma-tocopherol content in sunflower seeds García-Moreno, María J Fernández-Martínez, José M Velasco, Leonardo Pérez-Vich, Begoña BMC Plant Biol Research Article BACKGROUND: Tocopherols are natural antioxidants with both in vivo (vitamin E) and in vitro activity. Sunflower seeds contain predominantly alpha-tocopherol (>90% of total tocopherols), with maximum vitamin E effect but lower in vitro antioxidant action than other tocopherol forms such as gamma-tocopherol. Sunflower germplasm with stable high levels of gamma-tocopherol (>85%) has been developed. The trait is controlled by recessive alleles at a single locus Tph2 underlying a gamma-tocopherol methyltransferase (gamma-TMT). Additionally, unstable expression of increased gamma-tocopherol content in the range from 5 to 85% has been reported. The objective of this research was to determine the genetic basis of unstable expression of high gamma-tocopherol content in sunflower seeds. RESULTS: Male sterile plants of nuclear male sterile line nmsT2100, with stable high gamma-tocopherol content, were crossed with plants of line IAST-1, with stable high gamma-tocopherol content but derived from a population that exhibited unstable expression of the trait. F(2) seeds showed continuous segregation for gamma-tocopherol content from 1.0 to 99.7%. Gamma-tocopherol content in F(2) plants (average of 24 individual F(3) seeds) segregated from 59.4 to 99.4%. A genetic linkage map comprising 17 linkage groups (LGs) was constructed from this population using 109 SSR and 20 INDEL marker loci, including INDEL markers for tocopherol biosynthesis genes. QTL analysis revealed a major QTL on LG 8 that corresponded to the gamma-TMT Tph2 locus, which suggested that high gamma-tocopherol lines nmsT2100 and IAST-1 possess different alleles at this locus. Modifying genes were identified at LGs 1, 9, 14 and 16, corresponding in most cases with gamma-TMT duplicated loci. CONCLUSIONS: Unstable expression of high gamma-tocopherol content is produced by the effect of modifying genes on tph2(a) allele at the gamma-TMT Tph2 gene. This allele is present in line IAST-1 and is different to allele tph2 present in line nmsT2100, which is not affected by modifying genes. No sequence differences at the gamma-TMT gene were found associated to allelic unstability. Our results suggested that modifying genes are mostly epistatically interacting gamma-TMT duplicated loci. BioMed Central 2012-05-18 /pmc/articles/PMC3463442/ /pubmed/22607470 http://dx.doi.org/10.1186/1471-2229-12-71 Text en Copyright ©2012 Garcia-Moreno et al.; licensee BioMed Central Ltd. http://creativecommons.org/licenses/by/2.0 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Research Article
García-Moreno, María J
Fernández-Martínez, José M
Velasco, Leonardo
Pérez-Vich, Begoña
Genetic basis of unstable expression of high gamma-tocopherol content in sunflower seeds
title Genetic basis of unstable expression of high gamma-tocopherol content in sunflower seeds
title_full Genetic basis of unstable expression of high gamma-tocopherol content in sunflower seeds
title_fullStr Genetic basis of unstable expression of high gamma-tocopherol content in sunflower seeds
title_full_unstemmed Genetic basis of unstable expression of high gamma-tocopherol content in sunflower seeds
title_short Genetic basis of unstable expression of high gamma-tocopherol content in sunflower seeds
title_sort genetic basis of unstable expression of high gamma-tocopherol content in sunflower seeds
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3463442/
https://www.ncbi.nlm.nih.gov/pubmed/22607470
http://dx.doi.org/10.1186/1471-2229-12-71
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