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ARS Home » Northeast Area » Kearneysville, West Virginia » Appalachian Fruit Research Laboratory » Innovative Fruit Production, Improvement, and Protection » Research » Publications at this Location » Publication #279828
Title: Tress transformed with Poplar FT1 result in architecture, dormancy requirement, and continuous flowering

Author
item Srinivasan, Chinnathambi
item Dardick, Christopher - Chris
item Callahan, Ann
item Scorza, Ralph

Submitted to: PLOS ONE
Publication Type: Abstract Only
Publication Acceptance Date: 6/12/2012
Publication Date: 7/30/2012
Citation: Srinivasan, C., Dardick, C.D., Callahan, A.M., Scorza, R. 2012. Tress transformed with Poplar FT1 result in architecture, dormancy requirement, and continuous flowering. PLoS One. 7(7):e40715.

Interpretive Summary:

Technical Abstract: Long juvenile period is a major obstacle in traditional breeding and genetic engineering of temperate fruit trees. European plum (Prunus domestica L.) has a juvenility of up to seven years. We engineered plum trees with the Flowering Locus T1 from Populus tremula (PtFT1) under the control of the 35S promoter to induce early flowering and fruiting. A total of 196 transgenic plum lines expressing the PtFT1 gene were regenerated. Although 32 transgenic lines flowered early, four lines flowered consistently and profusely. Growing in 6-9 inch pots in a temperature-controlled greenhouse, these lines have continued to flower and produce fruits with viable seeds for 3 years. Over-expression of the PtFT1 gene altered plum tree architecture from upright growth habit to a highly-branched shrub-like growth habit. These early flowering greenhouse-cultured FT plum plants bear fruits continuously without requiring dormancy or winter-chilling. When grown in the field, they have survived -23 degrees C winter, flowered from early spring into the summer, and produced fruits. Flowering habit was also modified in these FT plums. On one-year-old shoots of non-transgenic plum trees, one vegetative bud at each node is flanked by 2-4 flower buds, each producing 1-2 individual flowers. In FT plums, along with individual flowers, flowering panicles are often produced. FT flowers may have multiple carpels which when pollinated produced 2-5 fruits with viable seeds Early flowering transgenic plum lines reduce the generation time for plum from 4-7 years to 1 year. Early flowering plum lines have been incorporated into a ‘FasTrack’ breeding program which is being used to develop improved plum varieties with resistance to plum pox virus and improved fruit quality traits (http://ucanr.org/sites/fastrack/). ‘FasTrack’ integrates genetic engineering and traditional breeding to produce non-transgenic plum cultivars which are exempted from genetically-engineered plant regulations by USDA-APHIS.