Multifaceted Role of PheDof12-1 in the Regulation of Flowering Time and Abiotic Stress Responses in Moso Bamboo (Phyllostachys edulis)

Abstract

DNA binding with one finger (Dof) proteins, forming an important transcriptional factor family, are involved in gene transcriptional regulation, development, stress responses, and flowering responses in annual plants. However, knowledge of Dofs in perennial and erratically flowering moso bamboo is limited. In view of this, a Dof gene, PheDof12-1, was isolated from moso bamboo. PheDof12-1 is located in the nucleus and has the highest expression in palea and the lowest in bract. Moreover, <i>PheDof12-1</i> expression is high in flowering leaves, then declines during flower development. The transcription level of <i>PheDof12-1</i> is highly induced by cold, drought, salt, and gibberellin A3 (GA₃) stresses. The functional characteristics of <i>PheDof</i> are researched for the first time in Arabidopsis, and the results show that transgenic Arabidopsis overexpressing <i>PheDof12-1</i> shows early flowering under long-day (LD) conditions but there is no effect on flowering time under short-day (SD) conditions; the transcription levels of <i>FT</i>, <i>SOC1</i>, and <i>AGL24</i> are upregulated; and <i>FLC</i> and <i>SVP</i> are downregulated. <i>PheDof12-1</i> exhibits a strong diurnal rhythm, inhibited by light treatment and induced in dark. Yeast one-hybrid (Y1H) assay shows that <i>PheDof12-1</i> can bind to the promoter sequence of <i>PheCOL4</i>. Taken together, these results indicate that <i>PheDof12-1</i> might be involved in abiotic stress and flowering time, which makes it an important candidate gene for studying the molecular regulation mechanisms of moso bamboo flowering.