GENE EXPRESSION IN PECAN SOMATIC EMBRYOS

Repetitive somatic embryogenic lines of pecan (Carya illinoensis) were obtained and subcultured on basal WPM, following a one week induction of zygotic embryo tissue on modified WPM with 6 mg/L NAA. Gene expression of somatic embryos has been studied and compared with that occurring in zygotic embryos. Somatic embryos simultaneously expressed mRNA classes that are specific to each of the zygotic embryo cotyledon (Cot), maturation (Mat), and post abscission stages (Late embryogenesis, Lea). Somatic embryos exhibiting such multiple, nonregulated gene expression patterns have a low germination rate. Treatments found to enhance embryo germination (cold and desiccation) may be effective in part, by modifying gene expression patterns. Some of the Cot and Mat mRNA classes decreased following such treatments, while Lea mRNAs were not effected. Cold and desiccation treatments appear to coordinate gene expression in pecan somatic embryos, which might be associated with embryo germination.

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GENE EXPRESSION PATTERNS OF PECAN ZYGOTIC AND SOMATIC EMBRYOS DURING MATURATION AND GERMINATION

HortScience ◽

10.21273/hortsci.25.9.1131b ◽

1990 ◽

Vol 25 (9) ◽

pp. 1131b-1131

Author(s):

Amnon Levi ◽

Hazel Y. Wetzstein ◽

Glen A. Galau

Keyword(s):

Gene Expression ◽

Somatic Embryo ◽

Somatic Embryos ◽

Expression Patterns ◽

Gene Expression Patterns ◽

Zygotic Embryos ◽

Carya Illinoensis ◽

Maturation Stages ◽

Somatic Embryo Conversion ◽

Late Maturation

The coordinate expression of mRNA classes in pecan (Carya illinoensis) zygotic and somatic embryos has been studied. MRNA was isolated from zygotic embryos at early and late maturation stages (12 to 22 weeks post-pollination) and during germination. Additionally, mRNA was isolated from somatic embryos derived from a repetitive embryogenic system prior and after cold (6 weeks at 4°C) and desiccation treatments (5 days). These treatments have been determined to enhance somatic embryo conversion. The abundance of embryogenic mRNA classes was determined using various cloned cotton mRNA probes (Hughes and Galau, 1989). This study is a part of our efforts to elucidate the developmental and physiological differences between zygotic and somatic embryo systems in pecan.

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Manifestation of embryogenic potential in culture of zygotic embryos of Quercus robur L.

Acta Societatis Botanicorum Poloniae ◽

10.5586/asbp.1996.006 ◽

2014 ◽

Vol 65 (1-2) ◽

pp. 37-41 ◽

Cited By ~ 3

Author(s):

Maria G. Ostrolucká ◽

Diana Krajmerová

Keyword(s):

Somatic Embryogenesis ◽

Somatic Embryos ◽

Zygotic Embryo ◽

Casein Hydrolysate ◽

Zygotic Embryos ◽

Embryo Germination ◽

Repetitive Somatic Embryogenesis ◽

Secondary Embryos ◽

Somatic Embryo Conversion

For the initiation of somatic embryogenesis early cotyledonary stage of zygotic embryo explants (from 15th July until late August) was suitable. The highest frequency of differentiation of somatic embryos was obtained on cotyledons of zygotic embryos cultured on basal modified medium MS (with 1/2 concentration macronutrients) or WPM medium containing 500 mg•l-1 glutamine, proline and casein hydrolysate and supplemented with 2,4-D (1,0-2,0 mg•l-1) and BAP (0,5-1,0 mg•l-1). The development of somatic embryos was direct and indirect and the process was continuous over a long period. Primary somatic embryos were able to produce secondary embryos. Repetitive somatic embryogenesis led to the proliferation of a large number of new somatic embryos on their cotyledons, hypocotyl or radicula. The process of embryo differentation is asynchronous - various stages of somatic embryos could be observed in embryogenic culture. A somatic embryo conversion was rare on tested media. Embryo germination occured on medium containing BAP (0,1 mg•l-1) or on medium with ABA and GA3 (each 0,2 mg•l-1) after a previous culture on WPM medium without plant growth regulators supplemented with sorbitol (6%). The embryo germination occurred also on WPM medium with 0.2 mg•l-1 BAP when cultures were mantained at 2oC for 4 weeks. Only 8 somatic embryos developed into plantlets. Their transplantation to in vivo conditions was unsuccessful.

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