Overexpression of Polypogon fugax Type I–Like MADS-Box Gene PfAGL28 Affects Flowering Time and Pod Formation in Transgenic Arabidopsis

Herbicide-driven selective pressures on weeds promote genetic changes in various physiological traits, including flowering time and fructification, allowing weeds to evade control techniques. Previously, we showed that early flowering was associated with resistance to acetyl coenzyme A carboxylase (ACCase) inhibitor herbicides in a population of Polypogon fugax. Here, we isolated the type I–like MADS-box gene PfAGL28 from ACCase inhibitor-resistant P. fugax, and showed that this gene was strongly upregulated in the resistant compared to susceptible populations at the flowering stage. Overexpression of PfAGL28 in Arabidopsis thaliana resulted in the early-flowering phenotype and early seed formation likely due to the upregulation of FLOWERING LOCUS T (FT), and AGMOUS-LIKE 23 (AGL23), AGMOUS-LIKE 61 (AGL61), and AGMOUS-LIKE 80 (AGL80). These results indicate that PfAGL28 gene is likely involved in the regulation of early flowering and pod formation in P. fugax. Our study thus provides a reference for future explorations of the flowering mechanisms of herbicide-resistant weeds.