Somaclonal variants of sunflower with modified coumarin expression under stress

Autor: Roseland, Craig R., Espinasse, Anne, Grosz, Teryl J.
Zdroj: Euphytica; April 1991, Vol. 54 Issue: 2 p183-190, 8p
Abstrakt: Two coumarins, scopoletin and ayapin, have been shown to accumulate in sunflower following insect damage or fungal infection (Tal & Robeson, 1986a, 1986b & Olson, 1989). The technique of shoot regeneration from embryo-derived callus was used to produce somaclonal variants of sunflower with enhanced levels of coumarin expression after an applied stress. Five regenerates (R1–R5) of inbred lines RHA 297 produced viable seeds following self-pollination. One of the S1 families from these plants had significantly higher concentration of scopoletin (12.75 µg/g fresh weight) compared to the parental inbred line (5.66 µg/g). The increased levels of scopoletin in S1 plants were partially inherited after a second self-fertilization (S2 plants). The ploidy of the regenerates and their S1 and S2 progeny was not examined. No consistent correlation between higher levels of scopoletin in stimulated S1 and S2 plants, and deterrence to feeding of Heliothis virescens (Fab) larvae on unstimulated plants was shown after in vivo assays. From inbred line HA 300, three regenerates (H1–H3) were derived which produced S1 progeny with higher or lower concentrations of ayapin or scopoletin than the parental inbred. The inheritance of increased ayapin in the HA 300-derived lines was not assessed in the S2 generation because of poor seed germination. Feeding deterrence of H. virescens larvae was not consistently correlated with ayapin concentrations in S1 progeny of HA 300 regenerates. However, a correlation (-0.61) between ayapin concentration and daily feeding score was observed in one planting of these unstimulated S1 progeny. Sunflower germplasm was developed with enhanced levels of stress-induced coumarin expression through somaclonal variation and this germplasm may also show increased resistance to some leaf-feeding insects.
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