Expression of modified tocopherol content and profile in sunflower tissues

Moral, Lidia del; Fernández‐Martínez, José M.; Pérez‐Vich, Begoña; Velasco, Leonardo

doi:10.1002/jsfa.4585

Cited by 4 publications

(4 citation statements)

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“…Putative modifying genes located at LG 1, 9, 14 and 16 were identified in the present research, being the effect of those on LG 1, 14 and 16 highly significant in the epistatic interaction with the Tph2 locus on LG 8. Studies on expression of Tph2 mutations in plant tissues other than seeds also pointed to differences between T2100 and IAST-1 lines, as the latter showed lower gamma-tocopherol content in leaves, roots, and pollen [22]. …”

Section: Discussionmentioning

confidence: 99%

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

et al. 2012

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BackgroundTocopherols 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.ResultsMale 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. F2 seeds showed continuous segregation for gamma-tocopherol content from 1.0 to 99.7%. Gamma-tocopherol content in F2 plants (average of 24 individual F3 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.ConclusionsUnstable expression of high gamma-tocopherol content is produced by the effect of modifying genes on tph2a 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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Section: Discussionmentioning

confidence: 99%

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

et al. 2012

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“…Exceptions in naturally occurring plants are very scarce, for example in lettuce and spinach, which contain higher proportions of γ-tocopherol in leaves (Szymańska and Kruk, 2008). There are also several examples in which modified tocopherol profiles have been obtained in mutant and transgenic lines of plants, with the modified tocopherol profiles being expressed both in seeds and leaves, for example in Arabidopsis (Cheng et al , 2003; Bergmüller et al , 2003; Kanwischer et al , 2005; Mène-Saffrané et al , 2010), tobacco ( Nicotiana tabacum L.; Abbasi et al , 2007) and sunflower ( Helianthus annuus L.; Del Moral et al , 2012). Line BCT-4 was selected for its low α-/γ-tocopherol ratio in seeds in the course of a conventional breeding programme in which two other lines with similarly low α-/γ-tocopherol ratio in seeds, BCT-2 and BCT-5, were developed (Velasco et al , 2013).…”

Section: Discussionmentioning

confidence: 99%

“…The mutation resulting in high γ-tocopherol accumulation in BCT-4 is expressed in plant tissues other than seeds, whereas those in BCT-2 and BCT-5 are seed-specific, which suggests genetic differences between BCT-4 and both BCT-2 and BCT-5. In sunflower, two lines with increased levels of γ-tocopherol in seeds also showed expression of increased γ-tocopherol levels in other plant tissues, such as roots, leaves and pollen (Del Moral et al , 2012). Similarly, Arabidopsis mutants carrying a functional null mutation of the gene encoding for the γ-TMT showed a drastic reduction of α-tocopherol and a concomitant increase of γ-tocopherol in leaves (Bergmüller et al , 2003).…”

Section: Discussionmentioning

confidence: 99%

Changes in plastochromanol-8 and tocopherols during germination in Ethiopian mustard lines with contrasting tocopherol levels

2014

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Plastochromanol-8 and tocopherols are natural antioxidants with vitamin E activity that protect seeds and plants from oxidative damage. Whereas a-tocopherol is predominant in photosynthetic tissues, g-tocopherol is more abundant in seeds. Ethiopian mustard (Brassica carinata A. Braun) seeds contain varying levels of both tocopherol forms. The objective of this research was to study changes in plastochromanol-8 and tocopherol contents during seed germination in Ethiopian mustard lines with contrasting seed tocopherol levels, and to evaluate their influence on seed germination and seedling growth. Cotyledons and radicles of seven lines with contrasting seed tocopherol levels and a control line were sampled periodically until 120 h after sowing (HAS) under light and dark conditions, and were analysed for plastochromanol-8 and tocopherol contents. The main factors genotype, tissue, light and HAS were significant for all the traits, excepting the light effect for total tocopherol content. Most of the lines showed a gradual decrease in g-tocopherol that was nearly completely replaced by a-tocopherol at 120 HAS. However, line BCT-4, with high g-tocopherol content in seeds, exhibited unusually high g-tocopherol content in cotyledons and radicles during the whole sampling period. Light treatment and initial seed tocopherol levels had no influence on germination percentage. Despite significant differences for seedling development among genotypes, no clear association between seedling development and seed tocopherols was observed. The results revealed that the unusual presence of high g-tocopherol levels in cotyledons and radicles of line BCT-4 did not have an effect on seedling growth.

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“…Modifications of seed tocopherols were also reflected at other plant levels. In particular, increased levels of β -, γ -, and δ -tocopherol in the seeds were paralleled by increased levels of these tocopherol forms in roots, leaves, and pollen grains [ 10 ]. A line with reduced total content of α -tocopherol in seeds also showed a reduced content in roots and pollen grains [ 10 ].…”

Section: Introductionmentioning

confidence: 99%

Tocopherols in Sunflower Seedlings under Light and Dark Conditions

Moral

Pérez‐Vich

Velasco

2015

The Scientific World Journal

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The objective of this study was to evaluate the dynamics of tocopherols in cotyledons and radicles from sunflower seeds with high and low total tocopherol content, mainly in the α-tocopherol form, and from seeds with increased proportions of β-, γ-, and δ-tocopherol, both under dark and light conditions. Tocopherol content was measured every 24 h from 1 to 12 days after sowing. In all cases, the content of individual tocopherol forms in the cotyledons and radicles was reduced along the sampling period, which was more pronounced under light conditions. The presence of light had a slightly greater effect on α- and γ-tocopherol than on β- and δ-tocopherol. A marked light effect was also observed on total tocopherol content, with light promoting the reduction of tocopherol content in cotyledons and radicles. The study revealed only slight differences in the patterns of tocopherol losses in lines with different tocopherol profiles, both under dark and light conditions, which suggested that the partial replacement of α-tocopherol by other tocopherol forms had no great impact on the protection against oxidative damage in seedlings.

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Expression of modified tocopherol content and profile in sunflower tissues

Cited by 4 publications

References 33 publications

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

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

Changes in plastochromanol-8 and tocopherols during germination in Ethiopian mustard lines with contrasting tocopherol levels

Tocopherols in Sunflower Seedlings under Light and Dark Conditions

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