Identification and molecular characterization of important flowering genes in Bambusa tulda Roxb with major emphasis on photoperiodic pathway and integrator genes

Abstract

Bamboos belong to the subfamily Bambusoideae, family Poaceae and are phylogenetically close to the reference monocot rice (O. sativa). They display extensive variations with respect to flowering time, which may extend upto 120 years. Besides, another ecological feature is mass death of all the flowering culms, known as semelparity. Therefore, it has direct impact on forest dynamics and indirect impact on the sustainability of crops. Flower induction is a very important developmental events in plants' life. It takes place in a favorable environment as a result of regulatory crosstalk at the molecular level. Signals from multiple external and internal sources ger synchronized to decide the timing of flowering. The two major environmental stimuli that influence flowering are light and temperature. In particular, duration and nature of light plays very important role, based on which plants can be characterized as long day, short day and day neutral plants.

The main focus of this study is to understand the role of light mediated flowering pathway on bamboo flowering. Therefore, in this study, four circadian clock genes (LHY, TOCI, ZTL, GI) and two clock integrators (CO A. B) of photoperiodic pathway were identified from Bambusa tulda and sequence characterized in comparison to homologous genes. Detailed studies on expression patterns in different tissues, seasons and diurnal conditions provide important clues regarding their possible involvement in flowering. Finally, in planta overexpression analyses of BFD1 and BFD2 genes in Arabidopsis combined with bioinformatics analyses demonstrated that the two genes perform diverse developmental roles in bamboo.