The present study was conducted to evaluate the genetic control of a mutation, induced in sunflower by the in vitro tissue culture, that affects the content of photosynthetic pigments. The homozygous mutant plants are not viable developing yellow-green cotyledons and only seven-eight paleyellow leaves. The mutant, designed as chlorina1 (ch1), can be maintained as heterozygote and the genetic analysis, performed on segregating progenies, indicates that the trait is controlled by one recessive nuclear gene. Pigment analysis of ch1 leaf extracts reveals that the chlorophyll a (Chl a), Chl b, β-carotene, lutein, neoxanthin and violaxanthin contents are significantly reduced in comparison to normal leaves. By contrast, both the zeaxanthin level and the de-epoxidation state (DEPS) displayed by the ch1 leaves are higher with respect to wild-type, indicating that in the mutant the energy adsorbed was higher than the capacity of photochemical dissipation. In addition, Chl a fluorescence analysis suggested that the capacity of photosystem II (PS II) to absorb and drive the light energy into chemical energy was largely impaired. The mutant seedlings exhibit a reduced accumulation of Ch1 (a and b) also in dim light but δ-aminolevulinic acid (δ-ALA) feeding experiments suggest that the steps of chlorophyll biosynthesis downstream from the ALA-deydratase are not impaired.
Characterization of a Pigment-Deficient Chlorina Mutant in Sunflower (Helianthus annuus), Induced by in vitro Tissue Culture
SALVINI, Mariangela;
2003
Abstract
The present study was conducted to evaluate the genetic control of a mutation, induced in sunflower by the in vitro tissue culture, that affects the content of photosynthetic pigments. The homozygous mutant plants are not viable developing yellow-green cotyledons and only seven-eight paleyellow leaves. The mutant, designed as chlorina1 (ch1), can be maintained as heterozygote and the genetic analysis, performed on segregating progenies, indicates that the trait is controlled by one recessive nuclear gene. Pigment analysis of ch1 leaf extracts reveals that the chlorophyll a (Chl a), Chl b, β-carotene, lutein, neoxanthin and violaxanthin contents are significantly reduced in comparison to normal leaves. By contrast, both the zeaxanthin level and the de-epoxidation state (DEPS) displayed by the ch1 leaves are higher with respect to wild-type, indicating that in the mutant the energy adsorbed was higher than the capacity of photochemical dissipation. In addition, Chl a fluorescence analysis suggested that the capacity of photosystem II (PS II) to absorb and drive the light energy into chemical energy was largely impaired. The mutant seedlings exhibit a reduced accumulation of Ch1 (a and b) also in dim light but δ-aminolevulinic acid (δ-ALA) feeding experiments suggest that the steps of chlorophyll biosynthesis downstream from the ALA-deydratase are not impaired.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
