The trehalose 6-phosphate pathway impacts vegetative phase change in Arabidopsis thaliana.

Jathish Ponnu,Christin Abel,Armin Schlereth,Markus Schmid,Regina Feil,Vanessa Wahl,Vasiliki Zacharaki,Magdalena A Działo

doi:10.1111/tpj.14965

Abstract

The vegetative phase change marks the beginning of the adult phase in the life cycle of plants and is associated with a gradual decline in the microRNA miR156, in response to sucrose status. Trehalose 6-phosphate (T6P) is a sugar molecule with signaling function reporting the current sucrose state. To elucidate the role of T6P signaling in vegetative phase change, molecular, genetic, and metabolic analyses were performed using Arabidopsis thaliana loss-of-function lines in TREHALOSE PHOSPHATE SYNTHASE1 (TPS1), a gene coding for an enzyme that catalyzes the production of T6P. These lines show a significant delay in vegetative phase change, under both short and long day conditions. Induced expression of TPS1 complements this delay in theTPS1 knockout mutant (tps1-2 GVG::TPS1). Further analyses indicate that the T6P pathway promotes vegetative phase transition by suppressing miR156 expression and thereby modulating the levels of its target transcripts, the SQUAMOSA PROMOTER BINDING PROTEIN-LIKE genes. TPS1 knockdown plants, with a delayed vegetative phase change phenotype, accumulate significantly more sucrose than wild-type plants as a result of a feedback mechanism. In summary, we conclude that the T6P pathway forms an integral part of an endogenous mechanism that influences phase transitions dependent on the metabolic state.

Highlights

A plant’s life cycle progresses through characteristic phases
The vegetative phase change marks the beginning of the adult phase in the life cycle of plants and is associated with a gradual decline in the microRNA miR156, in response to sucrose status
To elucidate the role of Trehalose 6-phosphate (T6P) signaling in vegetative phase change, molecular, genetic, and metabolic analyses were performed using Arabidopsis thaliana loss-of-function lines in TREHALOSE PHOSPHATE SYNTHASE1 (TPS1), a gene coding for an enzyme that catalyzes the production of T6P

Summary

Introduction

A plant’s life cycle progresses through characteristic phases. Following germination, plants pass through a vegetative phase of growth before flowering. The duration of the vegetative phase differs among plant species, but is divided into a juvenile and an adult phase, the transition between which is tightly controlled. Competency to induce flowering in Arabidopsis thaliana (Arabidopsis) is achieved after the shoot transition from the juvenile to the adult phase (Poethig, 1990; Kerstetter and Poethig, 1998; Poethig, 2003). Adult leaves have short petioles, curled laminae, and serrated leaf margins and are more lanceolate with trichomes formed on the abaxial side of the leaf (Chien and Sussex, 1996; Telfer et al, 1997; Tsukaya et al, 2000; Usami et al, 2009). Abaxial trichomes are formed initially at the base of the midrib, subsequently progressing towards the tip. While it has been shown that flowering time genes, i.e., FLOWERING

Results

Discussion

Conclusion