Structural changes and adaptative evolutionary constraints in FLOWERING LOCUS T and TERMINAL FLOWER1-like genes of flowering plants

Abstract

Regulation of flowering is a crucial event in the evolutionary history of angiosperms. The production of flowers is regulated through the integration of different environmental and endogenous stimuli, many of which involve the activation of different genes in a hierarchical and complex signaling network. The FLOWERING LOCUS T/TERMINAL FLOWER 1 (FT/TFL1) gene family is known to regulate important aspects of flowering in plants. To better understand the pivotal events that changed FT and TFL1 functions during the evolution of angiosperms, we reconstructed the ancestral sequences of FT/TFL1-like genes and predicted protein structures through in silico modeling to identify determinant sites that evolved in both proteins and allowed the adaptative diversification in the flowering phenology and developmental processes. In addition, we demonstrate that the occurrence of destabilizing mutations in residues located at the phosphatidylcholine binding sites of FT structure are under positive selection, and some residues of 4th exon are under negative selection, which is compensated by the occurrence of stabilizing mutations in key regions and the P-loop to maintain the overall protein stability. Our results shed light on the evolutionary history of key genes involved in the diversification of angiosperms.

Insight from expression profiles of FT orthologs in plants: conserved photoperiodic transcriptional regulatory mechanisms

“…Besides its involvement in flowering time regulation, diverse roles of FT-like PEBP have been characterized, which has been summarized and reviewed ( Jin et al., 2021 ). Although FT and its orthologs have distinct as well as shared roles, their gene structures are well-conserved ( Almeida de Jesus et al., 2022 ; Liu et al., 2023 ) ( Figure 2 ). Most FT orthologs consist of four exons, with few exceptions reported in banana and macadamia ( Chaurasia et al., 2017 ; Yang et al., 2023 ).…”