Regulatory roles of sugars in plant growth and development

Abstract

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.

Phosphoproteomic analysis of lettuce (Lactuca sativa L.) reveals starch and sucrose metabolism functions during bolting induced by high temperature

“…High levels of sugar lead to the activation of trehalose-6-phosphate and TOR protein kinase, and the upregulation of trehalose-6-phosphate and TOR protein kinase expression is important for cell growth in plants. It has been reported that trehalose-6-phosphate plays an essential role in the growth of A. thaliana [33,34], and a lack of trehalose-6-phosphate or TOR kinases inhibits growth and transition to the reproductive phase [35,36]. Additionally, sugar has been shown to reduce water movement, which affects leaf growth [37].…”

Effects of Two Protein Hydrolysates Obtained From Chickpea (Cicer arietinum L.) and Spirulina platensis on Zea mays (L.) Plants

“…Based on these considerations, higher phenol content measured in CA could have been responsible for greater stimulation of maize plant growth. In addition, CA contained elevate levels of the amino acid Arg, which is a precursor of polyamines, i.e., pivotal compounds required to start the cell division process in plants (Popko et al, 2018), and of the reducing sugars glucose and fructose, whose availability to plants has been reported to affect cell division as well (Ciereszko, 2018). In this respect, total phenols, amino acids and sugars in CA likely acted synergically and in combination with high hormone (IAA and IPA) content and IAA-like activity to stimulate plant growth.…”

Molecular insight into somaclonal variation phenomena from transcriptome profiling of cucumber (Cucumis sativus L.) lines

“…Saccharides play an important role in the plant's life: they are structural and storage substances, respiratory substrates, and intermediate metabolites of many biochemical processes. 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 (Ciereszko 2018).…”