ARS | Publication request: Constitutive expression of a peach AP2/ERF transcription factor in apple confers short day cessation of growth

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: March 22, 2010
Publication Date: April 10, 2011
Citation: Artlip, T.S., Wisniewski, M.E., Norelli, J.L., Bassett, C.L. 2011. Constitutive expression of a peach AP2/ERF transcription factor in apple confers short day cessation of growth. Meeting Abstract. Book of Abstracts. p. 97.

Technical Abstract: Cold acclimation and dormancy in Prunus persica (peach) are regulated by both photoperiod and temperature, whereas in Malus x domestica (apple), they are regulated solely by temperature. To understand the process of cold acclimation and dormancy regulation in fruit crops, we have begun a functional analysis of several environmentally-regulated AP2/ERF – family transcription factors. We report here on the molecular and phenotypic analysis of several lines of transgenic apple ('M.26') that constitutively overexpress a specific AP2/ERF transcription factor gene (PpSD1) obtained from a cDNA library constructed from 'Loring' peach bark tissues harvested in December. Phenotypic analysis indicated that, compared to untransformed plants, the transgenic lines varied in levels of cold hardiness and their response to short day (SD) photoperiod (8 h day:16 h night). Molecular analysis indicated that the level of phenotypic change was associated with the level of expression of PpSD1. The highest expressing line exhibited several degrees (C) of improved cold hardiness in both the non-acclimated and acclimated state. Unexpectedly, the transgenic apple lines also exhibited photoperiod-induced cessation of growth. Transgenic lines of apple placed under SD conditions for one to four weeks and then returned to optimum growth conditions in the greenhouse did not resume growth but rather set terminal buds and the leaves began to senesce. The rapidity of dormancy induction increased with the length of SD exposure. In contrast, while growth slowed in untransformed 'M.26' apple plants under the same SD conditions, normal growth resumed once plants were returned to optimum growth conditions. This gene could provide a means to mitigate bloom damage from temperature swings during spring.