Systematic Analysis of Gene Family in Unveils Candidate Regulators for Enhancing Cold Tolerance.

Late-spring frost events severely damage low-chill peach blossoms, causing significant yield losses. Although 5-aminolevulinic acid (ALA) enhances cold tolerance through the PpC3H37-PpWRKY18 module, the regulatory mechanism of ALA on remains to be elucidated. Using yeast one-hybrid screening with the promoter as bait, we identified PpDof9 as a key interacting transcription factor. A genome-wide analysis revealed 25 genes in peaches (). These genes exhibited variable physicochemical properties, with most proteins predicted as nuclear-localized. Subcellular localization experiments in tobacco revealed that was localized to the nucleus, consistent with predictions. A synteny analysis indicated nine segmental duplication pairs and tandem duplications on chromosomes 5 and 6, suggesting duplication events drove family expansion. A conserved motif analysis confirmed universal presence of the domain (Motif 1). Promoter cis-element screening identified low-temperature responsive (LTR) elements in 12 , including , , , and . The quantitative real-time PCR (qRT-PCR) results showed that , , , , , and were significantly upregulated under low-temperature stress, and this upregulation was further enhanced by ALA pretreatment. Our findings demonstrate ALA-mediated modulation of specific TFs in cold response and provide candidates (, , , ) for enhancing floral frost tolerance in peaches.