A glimpse of light on the mystery of regulating temperate fruit tree blooming time

Spring frost damage poses a major threat to fruit production in temperate climates, which has become more severe in some regions due to climate change. Management techniques to prevent or mitigate such damage are expensive and their effectiveness often variable, increasing the demand for breeding solutions, such as the exploitation of late flowering traits to avoid frost injury in spring. Due to the relative scarcity of late flowering traits in germplasm, gene editing technology represents a feasible option to engineer temperate fruit crops, which requires an in-depth understanding of how target genes regulate flower development and blooming time. Such information is currently unavailable for temperate fruit trees due to lack of proper tools (e.g. effective regeneration-transformation and mutagenesis manipulation methods) to probe the intricate mechanisms complicated by a slow developmental pace, seasonal change, a dormancy cycle, cold and warm requirements. Thus, for both gene editing- and conventional breeding of late flowering cultivars, a comprehensive understanding of flower regulatory mechanisms is essential.