• 한국자원식물학회지
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• 제27권3호
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• pp.242-248
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• 2014

This study was conducted to establish an efficient transformation system by using somatic embryogenesis in an important Korean native conifer, Korean fir (Abies koreana). Embryogenic masses were induced from mature zygotic embryos of the Korean fir on Schenk and Hildebrandt medium, which was supplemented with thidiazuron. For genetic transformation, the embryogenic masses were co-cultivated with a disarmed Agrobacterium tumefaciens strain C58/pMP90 containing the plasmid vector pBIV10 or LBA4404 containing the plasmid vector MP90. Both vectors contain the kanamycin resistance and beta-glucuronidase (GUS) reporter genes. A total of 48 lines of embryogenic masses were selected on mLV medium containing $50{\mu}g/mL$ of kanamycin after 4 weeks of culture, following 3 days of co-cultivation with A. tumefaciens strain C58/pMP90 carrying pBIV10 (none of the lines was cultivated with strain LBA4404 carrying MP90). Quantitative real-time PCR was performed, and high levels of GUS transcripts were observed in the 48 putative transgenic lines; however, the control (non-transgenic line) showed negative results. Results of histochemical staining showed that the expression of the GUS reporter gene was observed in somatic embryos that developed from the embryogenic masses of all 48 lines. Stably transformed cultures were successfully produced by co-cultivation with A. tumefaciens strain C58/pMP90 carrying pBIV10 in Korean fir. Here, we have reported an Agrobacterium-mediated gene transfer protocol via somatic embryogenesis that may be helpful in developing breeding and conservation strategies for the Korean fir.

• Journal of Plant Biotechnology
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• 제6권3호
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• pp.171-179
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• 2004

Hormonal requirements inducing different regeneration pathways with particular emphasis on somatic embryo-genesis in Alhagi graecorum were studied. While combination of 0.5 $\mu{M}$ 2,4-dichlorophenoxyacetic acid (2,4-D), 2.5 $\mu{M}$ 6-benzylaminopurine (BAP) and 5 $\mu{M}$ 1-naphthaleneacetic acid (NAA) in MS medium induced callus formation and callus maintenance from internodal explants, each alone or in combination with other induced distinct regeneration pathway. Adventitious bud formation was induced on MS medium supplemented with 2.5 $\mu{M}$ BAP. It was improved when 2.5 $\mu{M}$ BAP was used in combination with 5 $\mu{M}$ NAA. MS medium containing 0.5 $\mu{M}$ 2,4-D or 5 $\mu{M}$ NAA induced the formation of abnormal direct somatic embryos. While increase of 2,4-D concentration (1.125-9) resulted in the formation of viable embryogenic mass, increase of NAA did not change its effect. NAA should be used in combination with 2,4-D even at low concentration (0.5 $\mu{M}$) to form embryogenic mass. In A. gaecorum, the role of 2,4-D as trigger of somatic embryogenesis and BAP as trigger of adventitious bud formation was deduced, but for maximum yield certain auxin-cytokinin ratio should be applied. Embryogenic masses characterized by high water content, low peroxidase activity, and low number of peroxidase and glutamate oxaloacetate transaminase bands in comparison with calli obtained under conditions stimulating adventitious bud formation. The resulted differential gene expression, which could be detected by native-PAGE patterns, could be used as marker for organogenic pathway in A. graecorum.

• Plant Biotechnology Reports
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• 제3권4호
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• pp.333-340
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• 2009

Developmental anomalies in the plumule meristem of peanut (Arachis hypogaea L.) somatic embryos resulted in poor shoot differentiation and reduced plant recovery. Existing meristems with caulogenic potential have never been tested for embryogenesis in peanut. The present experiment was designed to test the mature zygotic embryo axis derived plumule with three meristems for somatic embryogenesis. Embryogenic masses and embryos developed from the caulogenic meristems in the axils. Exposure of 2 weeks in primary medium with $90.5{\mu}M$ 2,4-D suppressed the shoot tip differentiation temporarily which then regained the ability to form the shoot on withdrawal of 2,4-D. Exposure of 4 weeks in primary medium with $90.5{\mu}M$ 2,4-D suppressed the shoot tip differentiation irreversibly. No shoot formation was noted from the tips in any of the cultures which were in secondary medium with $13.6{\mu}M$ 2,4-D. Development of somatic embryos directly from axillary meristems was confirmed histologically. Conversion frequency of these embryos was 11%. Thus, in this report, we describe a method to obtain somatic embryos from the determined organogenic buds of the axillary meristem, by culturing the nodal explant vertically on embryo induction medium. It also displays the possibility of obtaining both embryogenic and organogenic potential in two parts of the same explant simultaneously. The possibility of extending this approach for genetic transformation in in vivo system through direct DNA delivery or Agrobacterium injection in meristems can also be explored. Using Agrobacterium rhizogenes, we have demonstrated the possibility of gene transfer in the axillary meristems of seed-derived plumule explant.