Sugar-induced plant growth is dependent on brassinosteroids

Gupta

et al. 2017

Sci Rep

Plants possess exuberant plasticity that facilitates its ability to adapt and survive under challenging environmental conditions. The developmental plasticity largely depends upon cellular elongation which is governed by a complex network of environmental and phytohormonal signals. Here, we report role of glucose (Glc) and Glc-regulated factors in controlling elongation growth and shade response in Arabidopsis. Glc controls shade induced hypocotyl elongation in a dose dependent manner. We have identified a Glc repressed factor REGULATED BY SUGAR AND SHADE1 (RSS1) encoding for an atypical basic helix-loop-helix (bHLH) protein of unknown biological function that is required for normal Glc actions. Phenotype analysis of mutant and overexpression lines suggested RSS1 to be a negative regulator of elongation growth. RSS1 affects overall auxin homeostasis. RSS1 interacts with the elongation growth-promoting proteins HOMOLOG OF BEE2 INTERACTING WITH IBH 1 (HBI1) and BR ENHANCED EXPRESSION2 (BEE2) and negatively affects the transcription of their downstream targets such as YUCs, INDOLE-3-ACETIC ACID INDUCIBLE (IAAs), LONG HYPOCOTYL IN FAR-RED1 (HFR1), HOMEOBOX PROTEIN 2 (ATHB2), XYLOGLUCAN ENDOTRANSGLUCOSYLASE/HYDROLASES (XTHs) and EXPANSINS. We propose, Glc signals might maintain optimal hypocotyl elongation under multiple signals such as light, shade and phytohormones through the central growth regulatory bHLH/HLH module.

Section: Resultsmentioning

confidence: 99%

Arabidopsis RSS1 Mediates Cross-Talk Between Glucose and Light Signaling During Hypocotyl Elongation Growth

Gupta

et al. 2017

Sci Rep

“…The participation of ABI3 as well as ABF2 and ABF4 transcription factors has been demonstrated in sugar signal transduction, either dependent or independent of hexokinase [6,28,36,63]. In addition, more recent results indicated the interaction of cytokinins, gibberellins, jasmonic acid, salicylic acid, and brassinosteroids with sugar pathways during plant development [57,103,104]. It was suggested that the function of HXK1 is dependent on the presence of brassinosteroids, which might act downstream of HXK1 to regulate hypocotyl elongation in A. thaliana in darkness (in a glucose-dependent reaction) [104].…”

Section: Receiving and Transmitting The Signals Triggered By Sugarsmentioning

confidence: 99%

“…In addition, more recent results indicated the interaction of cytokinins, gibberellins, jasmonic acid, salicylic acid, and brassinosteroids with sugar pathways during plant development [57,103,104]. It was suggested that the function of HXK1 is dependent on the presence of brassinosteroids, which might act downstream of HXK1 to regulate hypocotyl elongation in A. thaliana in darkness (in a glucose-dependent reaction) [104]. Recent studies have indicated the involvement of several miRNAs in phytohormone signaling pathways [105] and in sugar responses in plants [106], but more research is needed to fill in some gaps in knowledge.…”

Section: Receiving and Transmitting The Signals Triggered By Sugarsmentioning

confidence: 99%

Regulatory roles of sugars in plant growth and development

Ciereszko

2018

Acta Soc Bot Pol

In recent years, several studies have focused on the factors and mechanisms that regulate plant growth and development, as well as the functioning of signaling pathways in plant cells, unraveling the involvement of sugars in the processes regulating such growth and development. Saccharides play an important role in the life of plants: they are structural and storage substances, respiratory substrates, and intermediate metabolites of many biochemical processes. Sucrose is the major transport form of assimilates in plants. Sugars can also play an important role in the defense reactions of plants. However, it has been shown that glucose, sucrose, or trehalose-6-phosphate (Tre6P) can regulate a number of growth and metabolic processes, acting independently of the basal functions; they can also act as signaling molecules. Changes in the concentration, qualitative composition, and transport of sugars occur continuously in plant tissues, during the day and night, as well as during subsequent developmental stages. Plants have developed an efficient system of perception and transmission of signals induced by lower or higher sugar availability. Changes in their concentration affect cell division, germination, vegetative growth, flowering, and aging processes, often independently of the metabolic functions. Currently, the mechanisms of growth regulation in plants, dependent on the access to sugars, are being increasingly recognized. The plant growth stimulating system includes hexokinase (as a glucose sensor), trehalose-6-phosphate, and TOR protein kinase; the lack of Tre6P or TOR kinase inhibits the growth of plants and their transition to the generative phase. It is believed that the plant growth inhibition system consists of SnRK1 protein kinases and C/S1 bZIP transcription factors. The signal transduction routes induced by sugars interact with other pathways in plant tissues (for example, hormonal pathways) creating a complex communication and signaling network in plants that precisely controls plant growth and development.

“…Furthermore, T6P-related gene expression was specifically upregulated in the root phloem cells (Fàbregas et al, 2018, Figure 1E). In turn, by mediating BR signaling, sugars act as signaling molecules in Arabidopsis to control different aspects of root system architecture, such as primary root elongation, lateral root development, and root directional response (Gupta et al, 2015;Zhang and He, 2015). Notably, manipulation of BR signaling results in an increase in osmoprotectant metabolites including proline, an amino acid long known for conferring drought and salinity tolerance (Kishor et al, 1995).…”

Section: Carbon Allocationmentioning

confidence: 99%

Drought Resistance by Engineering Plant Tissue-Specific Responses

et al. 2020

Drought is the primary cause of agricultural loss globally, and represents a major threat to food security. Currently, plant biotechnology stands as one of the most promising fields when it comes to developing crops that are able to produce high yields in water-limited conditions. From studies of Arabidopsis thaliana whole plants, the main response mechanisms to drought stress have been uncovered, and multiple drought resistance genes have already been engineered into crops. So far, most plants with enhanced drought resistance have displayed reduced crop yield, meaning that there is still a need to search for novel approaches that can uncouple drought resistance from plant growth. Our laboratory has recently shown that the receptors of brassinosteroid (BR) hormones use tissue-specific pathways to mediate different developmental responses during root growth. In Arabidopsis, we found that increasing BR receptors in the vascular plant tissues confers resistance to drought without penalizing growth, opening up an exceptional opportunity to investigate the mechanisms that confer drought resistance with cellular specificity in plants. In this review, we provide an overview of the most promising phenotypical drought traits that could be improved biotechnologically to obtain drought-tolerant cereals. In addition, we discuss how current genome editing technologies could help to identify and manipulate novel genes that might grant resistance to drought stress. In the upcoming years, we expect that sustainable solutions for enhancing crop production in water-limited environments will be identified through joint efforts.