Expression analysis of PpDAM5 and PpDAM6 during flower bud development in peach (Prunus persica)

We previously reported transcript amounts of peach PpDAM5 and PpDAM6 (Prunus persica Dormancy-Associated MADS 5 and 6) were negatively correlated with endodormancy release of peach vegetative buds ( Yamane et al., 2011). We here investigated PpDAM5 and PpDAM6 expressions in lateral flower buds of peach in relation to seasonal flower bud development by using peach cultivars differing in their chilling requirements, and thus, in their flowering time. Up-regulation of PpDAM5 and PpDAM6 during the flower organ differentiation stage was followed by down-regulation during the flower organ enlargement stage. Furthermore, artificial cold temperature treatments in winter simultaneously induced down-regulation of PpDAM5 and PpDAM6 and flower organ enlargement. Based on these results, we discuss a possible involvement of PpDAM5 and PpDAM6 in the phenological control of peach flower bud development.

► Peach flower bud dormancy can be defined by the arrest of flower organ enlargement.
► PpDAM5 and PpDAM6 were up-regulated during the flower organ differentiation stage.
► PpDAM5 and PpDAM6 expressions were negatively correlated with flower bud enlargement.
► Cold temperature treatments induced down-regulation of PpDAM5 and PpDAM6.
► Cold temperature treatments induced flower organ enlargement.