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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 #409236
Research Project: Superior Fruit Tree Cultivars for Orchard Resilience, Sustainability, and Consumer Appeal

Location: Innovative Fruit Production, Improvement, and Protection

Title: euAP2a, a key gene that regulates flowering time in peach (Prunus persica) by modulating thermo-responsive transcription programming

Author
item LIU, JIANYANG - Oak Ridge Institute For Science And Education (ORISE)
item Bennett, Dennis
item Demuth, Mark
item Burchard, Erik
item Artlip, Timothy - Tim
item Dardick, Christopher - Chris
item Liu, Zongrang

Submitted to: Horticulture Research
Publication Type: Review Article
Publication Acceptance Date: 3/5/2024
Publication Date: 4/8/2024
Citation: Liu, J., Bennett Jr, D.R., Demuth, M.A., Burchard, E.A., Artlip, T.S., Dardick, C.D., Liu, Z. 2024. euAP2a, a key gene that regulates flowering time in peach (Prunus persica) by modulating thermo-responsive transcription programming. Horticulture Research. 11(5). https://doi.org/10.1093/hr/uhae076.
DOI: https://doi.org/10.1093/hr/uhae076

Interpretive Summary: Spring frost damage can severely affect fruit production, and current solutions are limited to breeding late-flowering cultivars to reduce the risk of frost damage. However, this trait is often scarce in the germplasm pool, or is linked with undesired traits, making the breeding process lengthy and laborious. To address this, we analyzed a late-flowering trait in peach (LFP) and identified a gene mutation responsible for the late-flowering trait. We characterized the nature of this mutation and underlying regulatory mechanism, and uncovered a novel regulatory mechanism to control flowering time in peach. Our findings have important implications for improving late flower traits in fruit crops through genetic breeding and gene-editing approaches.

Technical Abstract: Spring frost poses a considerable risk to fruit production, and the only current solution is to breed late-flowering cultivars to avoid frost damage. In this study, we analyzed Late-Flowering Peach (LFP) germplasm and showed its floral buds require longer chilling and warming periods during dormancy than the control cultivar, ‘John Boy’ (JB). We identified a 983-bp deletion in one of the AP2 gene, dubbed euAP2a, only in LFP but not in other 14 peach genomes. This mutation also eliminates miR172's binding sites, allowing the euAP2a transcript to accumulate preferentially during chilling. These findings together with an early report that a deletion in the same euAP2a causes increasing floral petals, a morphological mark that also occurs in the LFP, implies that the 983-bp deletion is responsible for late-flowering phenotype. Furthermore, we found that two chilling- and three warm-responsive co-expression modules, which were composed of 2,931 genes, are differentially activated at four of 13 stages. This activation is concurrent with a transient, stage-specific down-regulation of euAP2a. However, the mutation in euAP2a erases its wave-like downregulation trajectory and the concurrent activations of the five modules at the same stages, leading to virtual loss of activation of two chilling-responsive modules and a delay of three warm-responsive modules for 8-12 days, which corresponds to the longer chilling requirement and delayed flowering time in the LFP buds. These findings support euAP2a as a master gene regulator to control bloom time in peach. Our findings provide important insight into the gene that controls flowering time in peach, as well as a novel regulatory mechanism for peaches and other plants. This is crucial for breeding new cultivars with late-flowering traits.