Dissection of AT-Hook Motif Nuclear-Localized Genes and Their Potential Functions in Peach Growth and Development

Abstract

The AT-hook motif nuclear-localized (AHL) family members play key roles in plant biological processes via protein–protein and protein-DNA interactions. Here, 22 non-redundant PpAHL genes were identified and analyzed in peach (Prunus persica), one of economically important non-timber forestry crops. The maximum-likelihood (ML) tree classified the PpAHLs into two clades (Clade-A and Clade-B) with three subfamilies: Type_I, Type_II, and Type_III. Exon–intron analysis exhibited that the PpAHLs from Type_I except one (Prupe.1G530300.1) lacked introns, and the PpAHLs from Type_II and Type_III gradually emerged with intron additions, indicating spatial expression patterns, evolutionarily distinct temporal patterns and, likely, neofunctionalization. Duplication event analysis suggested that PpAHLs in peach were mainly expanded through the large-scale duplication events. RNA-seq data showed that PpAHLs were induced by drought stress, and two genes (Prupe.1G530300.1 and Prupe.1G034400.1) from Type_I AHLs were induced at all time points, indicating that they might play key roles in the response to drought stress in peach. The tissue-specific expression pattern of PpAHLs exhibited their biological functions in the development of these specific tissues. In addition, the transient overexpression of Prupe.1G530300.1 and Prupe.1G034400.1 resulted in significant changes in sugar content, suggesting that they may be positive regulators of sugar accumulation in peach fruits. Our study provided novel insights into the roles of PpAHLs in plant development, which was helpful for the functional analysis of peach and related woody fruit trees, and for formulating new strategies for further breeding.