The role of trehalose 6-phosphate in shoot branching – local and non-local effects on axillary bud outgrowth in arabidopsis rosettes

Abstract

16-Trehalose 6-phosphate (Tre6P) is a sucrose signalling metabolite that has been implicated in 17 regulation of shoot branching, but its precise role is not understood. 18 -We expressed tagged forms of TREHALOSE-6-PHOSPHATE SYNTHASE1 (TPS1) to determine 19where Tre6P is synthesized in arabidopsis (Arabidopsis thaliana), and investigated the impact 20 of localized changes in Tre6P levels, in axillary buds or vascular tissues, on shoot branching in 21 wild-type and branching mutant backgrounds. 22 -TPS1 is expressed in axillary buds and the subtending vasculature, as well as in the leaf and 23 stem vasculature. Expression of a heterologous trehalose-6-phosphate phosphatase (TPP) to 24 lower Tre6P in axillary buds strongly delayed bud outgrowth in long days and inhibited 25 branching in short days. TPP expression in the vasculature also delayed lateral bud outgrowth 26 and decreased branching. Increased Tre6P in the vasculature enhanced branching and was 27 accompanied by higher expression of FLOWERING LOCUS T (FT) and up-regulation of sucrose 28 transporters. Increased vascular Tre6P levels enhanced branching in branched1 but not in ft 29 mutant backgrounds. 30 -These results provide direct genetic evidence of a local role for Tre6P in regulation of axillary 31 bud outgrowth within the buds themselves, and also connect Tre6P with systemic regulation 32 of shoot branching via FT. 33 34

Genetic manipulation of trehalose‐6‐phosphate synthase results in changes in the soluble sugar profile in transgenic sugarcane stems

“…Multiple physiological processes can affect sucrose content, such as leaf photosynthetic rates, phloem loading in the leaf and offloading in the internodes (Lalonde et al, 2003 ; Walsh et al, 2005 ) as well as metabolism within culm tissue (Uys et al, 2007 ). The source‐sink regulation model of sugarcane (McCormick et al, 2009 ) postulates that sucrose could have an indirect relationship with Tre6P, functioning in a potential signaling role, which is further supported by the Tre6P‐sucrose nexus module described by Lunn et al ( 2014 ), and evidence for a major role of Tre6P in signaling and regulation movement of sucrose within the phloem (Fichtner et al, 2021 ; Fichtner & Lunn, 2021 ).…”

“…The main metabolic effect we observed was increased sucrose in culm tissue of some lines that will have an obvious commercial benefit for the sugarcane industry. Use of a constitutive promoter to overexpress TPS or TPP has been observed in other plants to affect partitioning between starch and sugars in photosynthetic tissue as well as affecting phloem loading and unloading (Fichtner et al, 2021 ; Fichtner & Lunn, 2021 ). Although we did not observe any obvious effect on growth in our experiments, it would be interesting to examine the roles of these genes in more detail using cell or tissue specific promoters, similar to experiments in maize that increased drought resistance (Nuccio et al, 2015 ).…”

Assessing dynamic changes in flavor-related compounds during durian fruit ripening using metabolome and transcriptome analyses

“…One interesting metabolite is trehalose-6-phosphate, which is an intermediate for trehalose biosynthesis. It is an important signaling molecule for sucrose consumption and a negative feedback molecule for sucrose biosynthesis in plants 15 . Therefore, the increase in trehalose-6-phosphate in durian pulp possibly helps to control the sucrose content and supports trehalose content at the same time.…”