An Evolutionary Analysis of B-Box Transcription Factors in Strawberry Reveals the Role of FaBBx28c1 in the Regulation of Flowering Time

Abstract

Flowering connects vegetative and generative developmental phases and plays a significant role in strawberry production. The mechanisms that regulate strawberry flowering time are unclear. B-box transcription factors (BBXs) play important roles in the flowering time regulation of plants. Nevertheless, BBXs in octoploid cultivated strawberry (Fragaria ananassa) and their functions in flowering time regulation have not been identified. Here, we identified 51 FaBBXs from cultivated strawberry and 16 FvBBXs from diploid wild strawberry (Fragaria vesca), which were classified into five groups according to phylogenetic analysis. Further evolutionary analysis showed that whole-genome duplication or segmental duplication is a crucial factor that leads to the expansion of the BBX gene family in two strawberry species. Moreover, some loss and acquisition events of FaBBX genes were identified in the genome of cultivated strawberry that could have affected traits of agronomic interest, such as fruit quality. The promoters of FaBBX genes showed an enrichment in light-responsive, cis-regulatory elements, with 16 of these genes showing changes in their transcriptional activity in response to blue light treatment. On the other hand, FaBBX28c1, whose transcriptional activity is reduced in response to blue light, showed a delay in flowering time in Arabidopsis transgenic lines, suggesting its role in the regulation of flowering time in cultivated strawberry. Our results provide new evolutionary insight into the BBX gene family in cultivated strawberry and clues regarding their function in flowering time regulation in plants.

B-Box Transcription Factor FaBBX22 Promotes Light-Induced Anthocyanin Accumulation in Strawberry (Fragaria × ananassa)

“…In our previous study, a total of 51 members of the BBX family were identified in octoploid strawberry [ 52 ], but most of their functions are unknown. In this work, specific primers were designed to amplify the FaBBX22 gene, according to the transcriptome data described in the previous study [ 53 ].…”

“…In our previous work, a total of 51 members of the BBX family were identified in octoploid strawberry, and a BBX gene ( FaBBX22 ) was found to be differentially expressed during light quality treatment on strawberry [ 52 ]. In the present study, the FaBBX22 gene was isolated from the cultivated strawberry variety ‘Benihoppe’.…”

The sweet potato B-box transcription factor gene IbBBX28 negatively regulates drought tolerance in transgenic Arabidopsis

“…AtBBX28 , a repressor of light signaling, delayed the flowering time in Arabidopsis under long day conditions ( Lin et al, 2018 ; Liu et al, 2020 ). Furthermore, heterologous expression of strawberry FaBBX28C1 have been found to negatively regulate the flowering time in Arabidopsis ( Ye et al, 2021 ). In this study, there existed drought response and hormone response cis -elements in IbBBX28 -Pro, including MBS, P-box, ABRE, CGTCA-motif.…”

Genome-Wide Identification of Strawberry C2H2-ZFP C1-2i Subclass and the Potential Function of FaZAT10 in Abiotic Stress

“…The amplified CDS of FaZAT10 and green fluorescent protein (GFP) was inserted into the plasmid vector (PYTSL-16) by homologous recombination, which was modified with pMDC83-35S and Psite-2NB [ 53 ]. The fusion expression of FaZAT10 and GFP (FaZAT10:GFP) was driven by the 35S promoter, and the nuclear localization maker for HY5-mCherry had the same 35S promoter drive [ 54 ].…”