AUTHOR=Lv Lin , Huo Ximei , Wen Luhua , Gao Zhihong , Khalil-ur-Rehman Muhammad 

TITLE=Isolation and Role of PmRGL2 in GA-mediated Floral Bud Dormancy Release in Japanese Apricot (Prunus mume Siebold et Zucc.)

JOURNAL=Frontiers in Plant Science

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2018.00027

DOI=10.3389/fpls.2018.00027

ISSN=1664-462X

ABSTRACT=<p>Bud dormancy release is regulated by gibberellins (GAs). DELLA proteins are highly conserved and act as negative regulators in GA signaling pathway. The present study established a relationship between <italic>PmRGL2</italic> in Japanese apricot and GA<sub>4</sub> levels during dormancy release of floral buds. Overexpression of <italic>PmRGL2</italic> in poplar delayed the onset of bud dormancy and resulted in dwarf plants, relative to wild-type trees. <italic>PmRGL2</italic> exhibited higher expression during ecodormancy and relatively lower expression during endodormancy. The relative level of GA<sub>4</sub> exhibited an increasing trend at the transition from endodormancy to ecodormancy and displayed a similar expression pattern of genes related to GA metabolism, <italic>PmGA20ox2</italic>, <italic>PmGA3ox1, PmGID1b</italic>, in both Japanese apricot and transgenic poplar. These results suggests that <italic>PmRGL2</italic> acts as an integrator and negative regulator of dormancy via a GA-signaling pathway. Moreover, an interaction between <italic>RGL2</italic> and SLY1 in a yeast two hybrid (Y2H) system further suggests that SCF E3 ubiquitin ligases, such as <italic>SLY1</italic>, may be a critical factor in the regulation of <italic>RGL2</italic> through an SCF<sup><italic>SLY1</italic></sup>-proteasome pathway. Our study demonstrated that <italic>PmRGL2</italic> plays a negative role in bud dormancy release by regulating the GA biosynthetic enzymes, <italic>GA20ox</italic> and <italic>GA3ox1</italic> and the GA receptor, <italic>GID1b</italic>.</p>