The poplar ARGOS-LIKE gene promotes leaf initiation and cell expansion, and controls organ size

Abstract

We identified Populus nigra auxin-regulated gene involved in organ size (PnARGOS)-LIKE encoding one of organ size related (OSR)-proteins in black poplar which is homologous to AtARGOS and AtARGOS-LIKE genes of Arabidopsis thaliana. ABRE-like, G-box, GATA and Ibox motifs were discovered in the promoter region of poplar ARGOS-LIKE gene. In wild type aspen (Populus tremula) plants, ortholog of PnARGOS-LIKE gene (PtrARGOS-LIKE) was noticeably expressed in the actively dividing and expanding young leaves and calli, whereas its mRNA content increased in response to exogenous 6-benzylaminopurine, 1-naphthaleneacetic acid, and 24-epibrassinolide. The expression of PtrARGOS-LIKE gene was reduced under salinity treatment. In addition, we generated transgenic tobacco and aspen plants with up-regulated expression of PnARGOS-LIKE gene. Constitutive expression of the gene contributed to an increase in size of stems and leaves of transgenic tobacco plants. In transgenic aspen constitutive expression of PnARGOS-LIKE gene promoted an increase in the frequency of leaf initiation and in the leaf length and area. The size of transgenic tobacco and aspen leaves increased due to the enlargement of individual cells. The results show the significance of PnARGOS-LIKE gene for the control of leaf initiation and organ growth by cell expansion in poplar.

The module mir156/spl affects bixin biosynthesis pathway in annatto (Bixa orellana L.)

“…initiation in Arabidopsis and Poplar (Hu et al 2003;Kuluev et al 2016). Besides, we observed a higher phytomer number in both transgenic lines 30 days onwards under greenhouse (Figure 2B).…”