The effect of auxins, time exposure to auxin and genotypes on somatic embryogenesis from mature embryos of wheat

Abstract

The effects of different factors on the embryogenesis and plant regeneration from mature embryos of Russian spring and winter genotypes were studied. Embryogenic callus induction was achieved on MS medium supplemented with different concentrations of 2,4-D (2,4-dichlorophenoxyacetic acid), 2,4,5-T (2,4,5-trichlorophenoxyacetic acid) or Dicamba (3,6-dichloro-o-anisic acid). Although all auxins were able to induce callus from explants with high frequency (98-100%), Dicamba was more effective for the induction of embryogenic callus (21.8-38.3%). Maximum embryogenic callus formation and high number of regenerated plants were observed at 12 mg l )1 of Dicamba. The time exposure to Dicamba (7, 14, 21 and 28 days) had a significant effect on efficiency of somatic embryogenesis. When contact of explants with callus induction medium was increased from 7 to 21 days the rate of somatic embryogenesis and number of regenerated plants per embryogenic callus gradually increased from 13.0 to 38.4% and 3.6 to 8.0%, respectively. Supplement of additional auxins (indoleacetic acid (IAA), indolebutyric acid (IBA), and naphthaleneacetic acid (NAA)) to callus induction medium with Dicamba had a positive effect on the rate of embryogenic callus formation, while the average number of regenerated shoots was not affected. The best rate of somatic embryogenesis was observed at the addition of 0.5 mg l )1 IAA with Dicamba (61.0%). The optimum combination of Dicamba and IAA increased the efficiency of somatic embryogenesis and plant regeneration from seven spring and winter wheat genotypes, thought overall morphogenic capacity was still genotype dependent.

Tissue culture efficiency of wheat species with different genomic formulas

“…After 30 days of culturing at 25 °C in the dark, the number of explants that produced embryogenic/nonembryogenic callus was scored. Endosperm-supported mature embryo culture was performed according to a protocol based on the combined application of 3,6-dichloro-o-anisic acid (Dicamba) and indoleacetic acid (IAA), for embryogenic callus induction (Filippov et al 2006, Miroshnichenko et al 2011. Prepared seeds were placed furrow down in Petri dishes and incubated at 25 °C in the dark for 25 days.…”

“…Mature wheat embryos are thought to be more recalcitrant to tissue culture than immature embryos, due to differences in the physiological and biochemical tissue status (Özgen et al 1998, Filippov et al 2006, Delporte et al 2014, Yang et al 2015. The acquisition of embryogenic competence in tissues of zygotic wheat embryos was shown to depend significantly on the endogenous level of growth regulators and total contents of phenols and soluble sugars (Jiménez andBangerth 2001, Yang et al 2015).…”

“…The acquisition of embryogenic competence in tissues of zygotic wheat embryos was shown to depend significantly on the endogenous level of growth regulators and total contents of phenols and soluble sugars (Jiménez andBangerth 2001, Yang et al 2015). With regard to the dormancy of the mature embryos at the stage of culture initiation, the particular interaction of the medium and other environmental parameters with genotype-specific endogenous factors was frequently required to achieve efficient morphogenesis, especially in endosperm-supported culture (Filippov et al 2006, Bi et al 2007, Chauhan et al 2007, Yu et al 2008, Miroshnichenko et al 2011, Yin et al 2011, Chang et al 2012, Delporte et al 2014). With the media tested here however, immature embryos are the preferable explant material.…”

Plant regeneration from mature embryo of commercial Indian bread wheat (Triticum aestivum L.) cultivars

“…Zhou and Lee (1984) were the first to achieve successful plant regeneration from wheat mature embryos. Subsequently, several workers have used various techniques for explant preparation, such as endosperm-supported embryo (Ozgen et al 1998;Filippov et al 2006), thin mature embryo fragments (Delporte et al 2001;Mendoza and Kaeppler 2002) and longitudinally bisected mature embryos (Yu et al 2008) and pretreatment of embryo with high levels of 2,4-D prior to culture or during culture for callus induction and plant regeneration. Since high levels of 2,4-D cause somaclonal variation in cereal crops, it has been argued to develop protocols with low levels of auxin (Mendoza and Kaeppler 2002).…”

“…Further, the effect of various factors, e. g., genotype (Ozgen et al 1996(Ozgen et al , 1998Zale et al 2004), type and concentration of auxin (Mendoza and Kaeppler 2002;Filippov et al 2006) and media components (Redway et al 1990;Mendoza and Kaeppler 2002;Greer et al 2009) either alone or in combinations has been evaluated for callus induction and subsequent regeneration. In spite of these studies, the regeneration has been found to be low (Ozgen et al 1998;Delporte et al 2001;Mendoza and Kaeppler 2002) and genotype dependent (Zale et al 2004;Filippov et al 2006;Yu et al 2008). One of the important factors which has not been paid proper attention is the role of non-embryogenic (NE) callus in regeneration from mature embryos (Redway et al 1990;Delporte et al 2001;Mendoza and Kaeppler 2002).…”