MOJ eISSN: 2374-6912 MOJCSR

Cell Science & Report
Mini Review
Volume 5 Issue 2

Regulation of trehalose/sucrose-non-fermenting-related protein kinase1 and its signaling pathways involved in drought stress responses

Omid Askari-Khorasgani
Department of Horticultural sciences, Islamic Azad University, Iran
Received: April 01, 2018 | Published: May 21, 2018

Corresponding author: Omid Askari-Khorasgani, Young Researchers and Elite Club, Department of Horticultural Sciences, College of Agriculture and Natural Resources, Isfahan (Khorasgan) Branch, Islamic Azad University, Isfahan, Iran, Tel +989132676955, Email

Citation: Askari-Khorasgani O. Regulation of trehalose/sucrose-non-fermenting-related protein kinase1 and its signaling pathways involved in drought stress responses. MOJ Cell Sci Rep. 2018;5(2):39‒41. DOI: 10.15406/mojcsr.2018.05.00111


Trehalose/sucrose-non-fermenting-related protein kinase1 (Tre/SnRK1) interaction regulates a myriad of plant responses to drought stress by regulating cell signaling pathways implicated in gene expression, metabolism, protein and membrane stabilization, sink-source balance, hormone homeostasis, carbohydrate allocation and use, and photosynthesis. It has been shown that protein-protein interactions, post-translational modifications, and phytohormones such as abscisic acid (ABA) regulate the activity and signaling pathways of SnRK1. The aim of this review is to incentivize further studies on the elucidation of molecular mechanisms underlying the interactions between Tre/SnRK1 signaling pathways with mitogen-activated protein kinases (MAPKs), domain of unknown function (DUF) 581, and calcium-dependent protein kinase (CDPK) for improved drought tolerance and performance.


ABA, abscisic acid; CDPK, calcium-dependent protein kinase; DUF, domain of unknown function; JA, jasmonic acid; MAPK, mitogen-activated protein kinases; NO, nitric oxide; PA, phosphatidic acid; PLDα1, phospholipase Dα1; SnRK1, sucrose-non-fermenting-related protein kinase 1; TOR, target of rapamycin; Tre, trehalose; TPP1, trehalose phosphate phosphatase1; Tre6P, Trehalose-6-phosphate; Tre6PP, trehalose-6-phosphate phosphatase; Tre6PS, trehalose-6-phosphate synthase; UDP, uridine diphosphate


Trehalose (Tre; α-D-glucopyranosyl-(1→1)-α-D-glucopyranoside) is a non-reducing disaccharide composed of two molecules of glucose that functions as a compatible solute for the stabilization of biological structures (proteins and membranes) under various abiotic stresses in plants, bacteria, fungi, yeasts, insects, and invertebrates.1–4 Genetic modification of Tre biosynthesis and regulation of its signaling pathways has the potential to improve plant performance and stress responses to meet the rising world’s demand for food, which is in direct correlation with demographic trends.5 Accordingly, this short review discusses the regulatory pathways of Tre biosynthesis and its interactions with other molecular signals that require further studies for designing drought tolerant plants with improved performance.

Trehalose biosynthesis and its regulation

In plants, Tre is synthesized in a two-step process. Trehalose-6-phosphate synthase (Tre6PS) generates trehalose-6-phosphate (Tre6P) from uridine diphosphate (UDP)-glucose and glucose-6-phosphate followed by dephosphorylation to yield Tre by trehalose-6-phosphate phosphatase (Tre6PP).2 Tre is not thought to accumulate to detectable levels in most plants, with the exception of the desiccation-tolerant ‘‘resurrection plants’’. Among vascular plants only a few desiccation-tolerant resurrection plants, such as Selaginella lepidophylla and Myrothamnus flebellifolius, accumulate substantial amounts of Tre.6 In maize, expression of rice (Oryza sativa) TREHALOSE PHOSPHATE PHOSPHATASE1 (TPP1) from the rice MADS6 promoter, which was most active in reproductive tissues, altered the expression and activity of the gene for SnRK1. Consequently, Tre6P/SnRK1 acted as the central regulator to promote the primary and secondary metabolism balance, assimilate distribution and use, sink-source balance and thus optimized photosynthetic capacity and yield improvement under water stress condition.7 Up regulation of Tre6P has been shown to repress the expression of genes encoding SnRK1, the molecular mechanisms of which remains to be investigated. Further studies are yet required to elucidate how Tre6P/SnRK1 signaling pathways regulate gene expression at molecular levels. Interestingly, Griffiths et al.5 study showed that a chemical intervention strategy based on a ‘signaling-precursor’ concept for permeability can be employed to directly modulate Tre6P uptake and sunlight-triggered release in planta, leading to markedly higher grain yield, drought tolerance and recovery in wheat. Their results suggested that stimulation of synthetic exogenous small-molecule signal precursors can be used to directly enhance plant performance5. The finding that Tre6P activates nitrite reductase suggests a possible role for Tre6P in ABA-mediated regulation of stomata conductance, involving covalent modifications of nitrite reductase and SnRK2.6, with nitric oxide (NO) as an intermediary signal.6 The findings suggest that the correct interpretation of Tre6P effects require the evaluation of variations in Tre6P:sucrose:starch ratio in different cell, tissue, and organ types during day/night cycles at different growth stages in response to environmental changes.5,6

Regulation of Tre/SnRK1 activity and its signaling pathways

As a signaling molecule Tre functions at least partially as inhibitor of sucrose-non-fermenting-related protein kinase 1 (SnRK1), which results in up-regulation of biosynthetic reactions supporting photosynthesis and starch synthesis among others.1,6 Tre6P, a central sugar signal in plants, regulates gene expressions and metabolic pathways involved in plant growth and development via SnRK1, and early flowering associated with sucrose, nutrients, and starch supply and allocation, underpinning improvement of crop performance and tolerance to abiotic stresses.5,6,8‒11 Under proper symbiotic relationship, Tre has the higher capacity to confer drought tolerance by regulating hormone homeostasis, essentially abscisic acid (ABA) and jasmonic acid (JA), transcription factors targeting gene expression, and biosynthesis of osmoprotectants such as proline.12 Under salinity and drought stresses, intracellular calcium elevation stimulates phospholipase Dα1 (PLDα1)-mediated phosphatidic acid (PA) production which subsequently interacts with SnRKs. PA/SnRKs regulates drought stress responses such as stomata movement by regulating the activity of vacuolar H+-ATPases. These proton pumps help to maintain the proton gradient that drives Na+/H+ antiporter activity.13,14 Thus, the interaction between PLDα1-induced PA with SnRKs may affect Tre/SnRK1 and thus remains to be investigated. Regulation of SnRK1 and its signaling pathways are highly dependent on post-translational modifications, such as, myristoylation,15 SUMOylation,16 phosphorylation and ubiquitination.17 SnRK1 signaling is under the influence of its interactions with other proteins, such as TARGET OF RAPAMYCIN (TOR),18,19 MAPKs, domain of unknown function (DUF) 581,18 CDPK,20 and phytohormones such as ABA.21 Therefore, understanding the molecular pathways underlying the relationships between Tre/SnRK1 with these regulatory components provide more information in order to improve drought stress responses in planta.

Conclusions and future remarks

Optimization of Tre/SnRK1 regulation and its signaling pathways to obtain drought tolerance with improved yield depend on Tre precursors, carbohydrate metabolism, post-translational modifications of SnRK1, symbiotic relationships, and Tre/SnRK1 interaction with molecular signals such ABA, TOR, MAPKs, DUF581, and CDPK. Carbohydrate metabolism, which can be improved by Tre/SnRK1 signals, is one of the most important parameters to establish efficient symbiotic performance and thereby stress responses. In this context, breeding programs not only for improved plant Tre/SnRK1 signaling pathways, but also for their symbionts have the potential to improve responses to multiple stresses and symbiotic performance with optimized yield, which require further studies.


My Institute’s (Young Researchers and Elite Club, Department of Horticultural sciences, College of Agriculture and Natural Resources, Isfahan (Khorasgan) Branch, Islamic Azad University, Isfahan, Iran) representative is fully aware of this submission.

Conflict of interest

The author declares there is no conflict of interest.


  1. Peleg Z, Apse MP, Blumwald E. Engineering salinity and water-stress tolerance in crop plants: getting closer to the field. Advances in Botanical Research.2011;57:405–443.
  2. Krasensky J, Jonak C. Drought, salt, and temperature stress-induced metabolic rearrangements and regulatory networks. J Exp Bot. 2012;63(4);1593–1608.
  3. Zhou B, Fang Y, Fan Y, et al. Expressional characterization of two class I trehalose– 6– phosphate synthase genes in Hevea brasiliensis (para rubber tree) suggests a role in rubber production. New Forests. 2017;48(4):513–526.
  4. Farooq M, Ullah A, Lee DJ, et al. Desi chickpea genotypes tolerate drought stress better than kabuli types by modulating germination metabolism, trehalose accumulation, and carbon assimilation. Plant Physiol Biochem. 2018;126:47–54.
  5. Griffiths CA, Sagar R, Geng Y, et al. Chemical intervention in plant sugar signaling increases yield and resilience. Nature.2016;540(7634):574–578.
  6. Figueroa CM, Lunn JE. A Tale of Two Sugars: Trehalose 6-Phosphate and Sucrose. Plant Physiol. 2016;172(1):7–27.
  7. Oszvald M, Primavesi LF, Griffiths CA, et al. Trehalose 6-phosphate regulates photosynthesis and assimilate partitioning in reproductive tissue. Plant Physiol. 2018;176(4):2623–2638.
  8. Almeida AM, Cardoso LA, Santos DM, et al. Trehalose and its applications in plant biotechnology. In Vitro Cellular & Developmental Biology – Plant. 2007;43(3):167–177.
  9. Duan Y, Xing Z, Diao Z, Xu, et al. Characterization of Osmads6-5, a null allele, reveals that OsMADS6 is a critical regulator for early flower development in rice (Oryza sativa L.). Plant Mol Biol. 2012;80(4):429–442.
  10. Zhang J, Nallamilli BR, Mujahid H, et al. OsMADS6 plays an essential role in endosperm nutrient accumulation and is subject to epigenetic regulation in rice (Oryza sativa). Plant J. 2010;64(4):604–617.
  11. Nuccio ML, Wu J, Mowers R, et al. Expression of trehalose-6-phosphate phosphatase in maize ears improves yield in well- watered and drought conditions. Nat Biotechnol. 2015;33(8):862–869.
  12. Asaf S, Khan AL, Khan MA, et al. Osmoprotective functions conferred to soybean plants via inoculation with Sphingomonas sp. LK11 and exogenous trehalose. Microbiol Res. 2017;205:135–145.
  13. Bargmann BO, Laxalt AM, ter Riet B, et al. Multiple PLDs required for high salinity and water deficit tolerance in plants. Plant Cell Physiol. 2009;50(1):78–89.
  14. Hong Y, Zhang W, Wang X. Phospholipase D and phosphatidic acid signalling in plant response to drought and salinity. Plant Cell Environ. 2010;33(4):627–635.
  15. Eckardt NA. Shoot meristem development depends on n-myristoylation of snrk1. The Plant Cell. 2007;19(9):2703–2703.
  16. Crozet P, Margalha L, Butowt R, et al. SUMOylation represses SnRK1 signaling in Arabidopsis. Plant J. 2016;85(1):120–133.
  17. Broeckx T, Hulsmans S, Rolland F. The plant energy sensor: evolutionary conservation and divergence of SnRK1 structure, regulation, and function. J Exp Bot. 2016;67(22):6215–6252.
  18. Nietzsche M, Landgraf R, Tohge T, et al. A protein–protein interaction network linking the energy-sensor kinase SnRK1 to multiple signaling pathways in Arabidopsis thaliana. Current Plant Biology. 2016;5:36–44.
  19. Baena-González E, Hanson J. Shaping plant development through the SnRK1–TOR metabolic regulators. Curr Opin Plant Biol. 2017;35:152–157.
  20. Wu P, Wang W, Duan W, et al. Comprehensive analysis of the cdpk-snrk superfamily genes in chinese cabbage and its evolutionary implications in plants. Front Plant Sci. 2017;8:162.
  21. Coello P, Hirano E, Hey SJ, et al. Evidence that abscisic acid promotes degradation of SNF1-related protein kinase (SnRK) 1 in wheat and activation of a putative calcium-dependent SnRK2. J Exp Bot. 2012;63(2):913–924.
©2018 Askari. This is an open access article distributed under the terms of the Creative Commons Attribution License , which permits unrestricted use, distribution, and build upon your work non-commercially.
© 2014-2018 MedCrave Group, All rights reserved. No part of this content may be reproduced or transmitted in any form or by any means as per the standard guidelines of fair use.
Creative Commons License Open Access by MedCrave Group is licensed under a Creative Commons Attribution 4.0 International License.
Based on a work at
Best viewed in Mozilla Firefox | Google Chrome | Above IE 7.0 version | Opera |Privacy Policy