Transgenic Sunflower - Genetics, Genomics and Breeding of Crop Plants - page 291

Table 9-1 Explants used for sunflower plant regeneration through organogenesis and
somatic embryogenesis.

Tissue References

Organogenesis
Cotyledon Knittel et al. 1991; Chraibi et al. 1991, 1992a, b; Ceriani et al.

1992; Deglene et al. 1997; Baker et al. 1999; Flores Berrios et
al. 1999; Dhaka and Kothari 2002; Mayor et al. 2003

Shoot tip or Bohorova et al. 1986; Lupi et al. 1987;Bidney et al. 1992;

embryonic axis Knittel et al. 1994; Molinier et al. 2002

Hypocotyl Paterson and Everett 1985; Lupi et al. 1987

Immature embryo Power 1987; Espinasse and Lay 1989; Bronner et al. 1994;

Jeannin et al. 1995

Leaves Greco et al. 1984; Lupi et al. 1987

Protoplasts Burrus et al. 1991; Krasnyanski and Menczel 1993;

Wingender et al. 1996

Somatic embryogenesis
Hypocotyl Paterson and Everett 1985; Freyssinet and Freyssinet 1988;

Pelissier et al. 1990; Prado and Berville 1990

Immature embryo Finner 1987; Freyssinet and Freyssinet 1988; Witrzens et al.

1988; Jeannin and Hahne 1991; Bronner et al. 1994; Jeannin et
al. 1995; Sujatha and Prabhakaran 2001

Anther Thengane et al. 1994

Unpollinated ovary Gelebart and San 1987

can be screened for green fluorescence protein, GFP (Müller et al. 2001; Hess
2006). Rooting proved to be an effective selection method when using
kanamycin as a selective agent, with no detected escapes (Radonic et al.
2006). Regeneration largely depends on genotype, showing cytoplasmic
and nuclear effects (Nestares et al. 1998, 2002; Vasic et al. 2001; Azadi et al.
2002). Genetic control of organogenesis is polygenic, mainly additive (Sarrafi
et al. 1996; Flores-Berrios et al. 2000), and might be improved based on the
combining ability of related traits (Bolandi et al. 2000; Mayor et al. 2003,
2006). More efficient protocols have been developed through phenylacetic
acid (Dhaka and Kothari 2002), cotransformation with the ipt gene of
Agrobacterium vitis , which is involved in cytokinin synthesis (Molinier et al.
2002), macerating enzymes (Weber et al. 2003), rooting promotion (Koopmann
and Kutschera 2005), and biolistics (Mohamed et al. 2006a, b). Post-
transcriptional gene silencing, a mechanism that organisms have developed
to destroy invasive nucleic acids, can be achieved by RNA hybridized to
transgene target sequences (Hewezi et al. 2005). Severe developmental
abnormalities following silencing suggested that some genes could have a
second role in developmental regulation (Hewezi et al. 2006).