Quantitative trait loci identification reveals cell-wall invertase 4 as a new candidate gene controlling tiller...

Tillering is an important agronomic trait involved in determining plant architecture and yield. Orchardgrass (Dactylis glomerata L.) is one of the most important economic forage grasses in the world. Tillering not only affects its biomass yield and plant architecture, but also influences its vegetative reproduction and regeneration potential. Due to its perennial nature, the tillering regulatory mechanism of orchardgrass is highly complex, and there have been few genes reported so far. To identify more tillering regulatory genes of orchardgrass, we constructed an F₂ population (275 individuals) and combined it with previous BC₁F₁ population (269 individuals) for Bulked Segregant Analysis sequencing (BSA-seq) and analysis. One hundred and two candidate genes were identified within the overlapping candidate regions of the F₂ population and BC₁F₁ population, and fifty-one of them are differentially expressed genes associated with tillering. Among these, DG2C06349 (DgCIN4), a homologous gene of the cell-wall invertase 4, increased the rosette branch number when overexpressed in Arabidopsis. These results indicate that DgCIN4 potentially regulates tiller number in orchardgrass and holds significant potential for breeding application aimed at improving branching ability in orchardgrass and other forage species.