Author
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SUN, QINGRONG - TAIAN PR CHINA |
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WEI, WEI - TAIAN PR CHINA |
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Hammond, Rosemarie |
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Davis, Robert |
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Zhao, Yan |
Submitted to: In Vitro Biology Meeting
Publication Type: Abstract Only Publication Acceptance Date: 1/26/2006 Publication Date: 1/26/2006 Citation: Sun, Q., Wei, W., Hammond, R., Davis, R.E., Zhao, Y. 2006. High-efficiency agrobacterium-mediated transformation of pear (pyrus communis l.) leaf segments and regeneration of transgenic plants. In Vitro Biology Meeting. 42:47A. Interpretive Summary: Technical Abstract: Pear (Pyrus communis L.) is a nutrient-dense fruit with strong consumer demand and high commercial value. However, most cultivated pear varieties are often susceptible to diseases caused by fungi, bacteria, and viruses. Since pear is highly heterozygotic and has a long juvenile period, conventional breeding for disease resistance is difficult to achieve. With the recent advances in molecular biology, artificially engineered resistance has become a new approach to plant disease control. Such genetic engineering requires transformation of parent tissues to introduce foreign genes and subsequent regeneration of transgenic plants with desired characters. Major factors that influence transformation and regeneration of pear cultivars were examined and optimal conditions were established for efficient transformation and regeneration from leaves of a popular pear cultivar, ‘Old Home’. High transformation efficiency was achieved due to an improved induction stage following initial Agrobacterium infection. In the induction stage, Agrobacterium cells and parent leaf segments were co-cultivated on a liquid induction medium, which yielded a five-fold increase of transformation frequency over conventional co-cultivation on a solid medium. Transgenic shoots were regenerated from transformed cells via an indirect regeneration pathway, which involves a callus proliferation / shoot primordium induction phase using a combination of thidiazuron (TDZ) and naphthalene acetic acid (NAA) as growth regulators, and a shoot elongation phase using a combination of 6-benzylaminopurine (BA) and indole 3-butyric acid (IBA). With the new protocol, independent transgenic pear lines carrying three foreign genes, i.e. a beta-glucuronidase reporter gene, an antimicrobial peptide gene, and an anti-apoptotic gene, were regenerated. The transgenic pear plants are being analyzed for foreign gene expression and for their potential disease resistance. |