Exogenous trehalose improves growth under limiting nitrogen through upregulation of nitrogen metabolism

Abstract

BackgroundThe trehalose (Tre) pathway has strong effects on growth and development in plants through regulation of carbon metabolism. Altering either Tre or trehalose 6-phosphate (T6P) can improve growth and productivity of plants as observed under different water availability. As yet, there are no reports of the effects of modification of Tre orT6P on plant performance under limiting nutrition.ResultsHere we report that nitrogen (N) metabolism is positively affected by exogenous application of Tre in nitrogen-deficient growing conditions. Spraying foliage of tobacco (Nicotiana tabacum) with trehalose partially alleviated symptoms of nitrogen deficiency through upregulation of nitrate and ammonia assimilation and increasing activities of nitrate reductase (NR), glycolate oxidase (GO), glutamine synthetase (GS) and glutamine oxoglutarate aminotransferase (GOGAT) with concomitant changes in ammonium (NH4 +) and nitrate (NO3 −) concentrations, glutamine and amino acids. Chlorophyll and total nitrogen content of leaves and rates of photosynthesis were increased compared to nitrogen-deficient plants without applied Tre. Total plant biomass accumulation was also higher in Tre -fed nitrogen-deficient plants, with a smaller proportion of dry weight partitioned to roots, compared to nitrogen-deficient plants without applied Tre. Consistent with higher nitrogen assimilation and growth, Tre application reduced foliar starch. Minimal effects of Tre feeding were observed on nitrogen-sufficient plants.ConclusionsThe data show, for the first time, significant stimulatory effects of exogenous Tre on nitrogen metabolism and growth in plants growing under deficient nitrogen. Under such adverse conditions metabolism is regulated for survival rather than productivity. Application of Tre can alter this regulation towards maintenance of productive functions under low nitrogen. This has implications for considering approaches to modifying the Tre pathway for to improve crop nitrogen-use efficiency and production.

Exogenous Carbon Compounds Modulate Tomato Root Development

“…It is known that NH 4 + accumulation in roots needs to be assimilated by the GS/GOGAT cycle [ 57 , 58 ]. Lin et al [ 12 ] showed that by spraying tobacco leaves with trehalose, N assimilation was induced together with GS and GOGAT activities under N-deficient growing conditions. In our experimental system, GS1 was strongly induced by Suc, and to a lesser extent by Gluc, while GOGAT seems to be induced by Gluc addition and repressed by Suc.…”

“…Moreover, incremented lateral root (LR) development has been observed in Arabidopsis mutants with defects in the leaf cuticle, which took up more sucrose (Suc) from the medium under high NO 3 − conditions [ 11 ]. Furthermore, exogenous spraying application of trehalose promotes Nicotiana tabacum plant growth under N-limiting conditions by up-regulating N assimilation enzyme activities [ 12 ].…”

Physiological and transcriptomic analyses reveal the molecular networks of responses induced by exogenous trehalose in plant

“…Furthermore, in tobacco, at low concentration (e.g. 8 mM), exogenous Tre can recover the nitrate reductase activity partially, and chlorophyll and total nitrogen content of leaves and rates of photosynthesis were increased through a long-term effect, which can be observed 1–2 weeks after the treatments [23]. In stark contrast, we did not find the expression level of any nitrate reductase genes were changed in our RNA-seq data (S7 and S8 Data).…”

“…A couple of studies have been done to investigate gene expression patterns in response to Tre treatment in Arabidopsis seedling cultured in liquid medium by DNA microarray[21, 22]. In tobacco, interestingly, exogenous Tre can effectively increase nitrogen metabolism, and promote tobacco growth under deficient nitrogen that restrict plant growth severely[23].…”

Development and Application of a PCR-Based Molecular Marker for the Identification of High Temperature Tolerant Cabbage (Brassica oleracea var. capitata) Genotypes

“…TRE also acts as a potential signaling metabolite for mediating interactions of plants with pathogenic or symbiotic microorganisms and herbivorous insects. In plants, TRE is involved in tolerance to abiotic stresses, such as high salinity [36], HT [37], nitrogen deficiency [38], and drought [39,40], and biotic stresses such as microorganisms [41] (reviewed in Fernandez et al, 2010 [33]).…”