Contrasting gene expression patterns during floral induction in two <i>Chenopodium ficifolium</i> genotypes reveal putative flowering regulators

<i>Chenopodium ficifolium</i> is a close diploid relative of the tetraploid crop <i>Chenopodium quinoa</i>. Owing to its reproducible germination and seedling development, it becomes a promising model for studying floral induction, providing a basis for the comparison with <i>C. quinoa</i>. Two <i>C. ficifolium</i> genotypes differ in photoperiodic requirement: <i>C. ficifolium</i> 283 accelerates flowering under long days, whereas <i>C. ficifolium</i> 459 flowers earlier under short days. This study conducted a comprehensive transcriptomic and hormonomic analysis of floral induction in the long-day <i>C. ficifolium</i> 283 and compared the findings to previous experiments with the short-day <i>C. ficifolium</i>. Phytohormone concentrations and gene expression profiles during floral induction were largely similar between the two genotypes. However, a subset of genes exhibited contrasting expression patterns, aligning with the genotypes’ differing photoperiodic requirements. These genes, predominantly homologs of flowering-related genes in <i>Arabidopsis thaliana</i>, were activated under long days in <i>C. ficifolium</i> 283 and under short days in <i>C. ficifolium</i> 459. Notably, the contrasting expression of the <i>FLOWERING LOCUS T-LIKE 2–1</i> gene, which was previously shown to induce precocious flowering in <i>A. thaliana</i>, confirmed its role as a floral activator, despite its low expression levels.