Gene-edited Mtsoc1 triple mutant Medicago plants do not flower

• DOI: 10.3389/fpls.2024.1357924
• Publication Date: 2024-02-26T14:37:31Z
• Authors: Axel Poulet; Min Zhao; Yongyan Peng; FangFei Tham; Mauren Jaudal; Lulu Zhang; Josien C. van Wol...; Joanna Putterill
• Keywords: 0301 basic medicine; 0303 health sciences; MtSOC1b; MtSOC1c; Medicago; Plant culture; legume; flowering time; Plant Science; MtSOC1a; SB1-1110

Optimized flowering time is an important trait that ensures successful plant adaptation and crop productivity. SOC1-like genes encode MADS transcription factors, which are known to play roles in control many plants. This includes the best-characterized eudicot model Arabidopsis thaliana (Arabidopsis), where SOC1 promotes functions as a floral integrator gene integrating signals from different flowering-time regulatory pathways. Medicago truncatula (Medicago) temperate reference legume with strong genomic genetic resources used study pathways legumes. Interestingly, despite responding similar floral-inductive cues of extended cold (vernalization) followed by warm long days (VLD), such winter annual Arabidopsis, lacks FLC CO key regulators Arabidopsis. Unlike one gene, multiple duplication events have given rise three MtSOC1 paralogs within genus legumes: Fabaceae group A MtSOC1a, two tandemly repeated B genes, MtSOC1b MtSOC1c. Previously, we showed MtSOC1a has unique promotion Medicago. The Mtsoc1a Tnt1 retroelement insertion single mutant moderately delayed long- short-day photoperiods, without prior vernalization, compared wild-type. In contrast, Mtsoc1b mutants did not altered or flower development, indicating it was redundant otherwise wild-type background. Here, describe generation Mtsoc1c triple lines using CRISPR-Cas9 editing. We studied independent segregated plants were bushy under inductive VLD. Genotyping indicated these non-flowering homozygous for predicted alleles genes. Gene expression analyses RNA-seq RT-qPCR remained vegetative. Overall, dramatically soc1 mutant; implicating critical overlapping transition