A genome-wide association study reveals that DgFH18 and DgCMO-like are associated with flowering time in orchardgrass (Dactylis glomerata).

Abstract

Background: Flowering is a tightly regulated process influencing yield and promoting plant genetic diversity and conservation. Orchardgrass (Dactylis glomerata) exhibits excellent yield traits and stress resistance, making it ideal for animal husbandry and ecological restoration. However, the molecular regulatory factors of the flowering time of orchardgrass are still unknown, limiting its molecular breeding.

Results: To speed up molecular breeding to enhance flowering traits in orchardgrass, we conducted a genome-wide association study (GWAS). A diverse panel of 249 orchardgrass accessions was phenotyped for heading stage and flowering time. GWAS analysis identified 359 candidate genes that overlapped or were adjacent to effective single-nucleotide polymorphisms (SNPs), which were considered potential flowering time-related genes. Furthermore, we validated that formin-like protein 18 (DgFH18) and choline monooxygenase (DgCMO-like) was two important flowering candidate genes by overexpressing them in Arabidopsis to unravel their potential functions. Overexpression of DgFH18 and DgCMO-like positively regulated flowering time by inducing the expression of flowering-related genes. Moreover, sucrose treatment could significantly promote the expression of flavonoid pathway genes and enhance the content of total flavonoids and anthocyanins in the DgCMO-like-overexpressing lines compared to the wild type.

Conclusion: These results provide valuable resources for future orchardgrass breeding programs and broaden the current comprehension of flowering time regulation in perennial grasses.