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United States Department of Agriculture

Agricultural Research Service

Research Project: GENETIC IMPROVEMENT OF FRUIT CROPS THROUGH FUNCTIONAL GENOMICS AND BREEDING

Location: Appalachian Fruit Research Laboratory: Innovative Fruit Production, Improvement and Protection

Title: Ectopic expression of Malus domestica class 1 knox genes altered growth and development of Nicotiana tabacum and Prunus domestica, and induced adventitious shoot regeneration from leaf explants without exogenous cytokinin

Authors
item Srinivasan, Chinnathambi
item Liu, Zongrang
item Scorza, Ralph

Submitted to: Mid Atlantic Plant Molecular Biology Society Conference
Publication Type: Abstract Only
Publication Acceptance Date: August 20, 2009
Publication Date: N/A

Technical Abstract: Transgenic tobacco (Nicotiana tabacum L) and plum (Prunus domestica L) plants were regenerated by transforming with apple class 1 KNOX genes (MdKNP1 and MdKNP2) or a corn KN1 (ZmKN1) gene. Transgenic tobacco plants were produced in vitro from transformed leaf discs in the absence of cytokinin in the culture medium. Ectopic expression of KNOX genes retarded shoot growth by suppressing elongation of internodes in both tobacco and plum plants. When over-expressed, all three KNOX genes reduced leaf lamina expansion and induced extensive lobing and malformation of leaves. In vitro culture of leaf explants and stem sections excised from in vitro grown MdKN1 expressing tobacco shoots regenerated adventitious shoots on Murashiege and Skoog basal medium without exogenous cytokinin. However, leaf explants excised from in vitro grown shoots of MdKN1 over-expressing plum required 7.5 µM thidiazuron in the culture medium for adventitious shoot regeneration. In situ regeneration of adventitious shoots was observed from leaves and roots of transgenic tobacco plants expressing apple KNOX genes.

Last Modified: 9/10/2014