SlSPS, a Sucrose Phosphate Synthase Gene, Mediates Plant Growth and Thermotolerance in Tomato

Abstract

Heat stress (HS) has been considered as a severe threat to crop yields in recent years. Sucrose, as a major product of photosynthesis, plays an important role in plant growth and stress response. Sucrose phosphate synthase (SPS) is a key rate-limiting enzyme in the sucrose synthesis pathway in plants. However, its molecular mechanism and signaling pathway remain unclear. In this study, we identified a novel SPS gene (SlSPS) in tomato and generated over-expression and knock-out of SlSPS gene transgenic tomato plants to investigate its biological functions related to the growth and thermotolerance of tomato. Over-expression of SlSPS gene increased the growth and biomass of transgenic tomato plants, such as fresh weight, dry weight, plant height, fruit weight and root length. In contrast, knock-out of SlSPS gene decreased the growth and biomass of transgenic tomato plants. Under heat stress, the survival rates were positively correlated with the expression level of SlSPS gene in different tomato varieties. Furthermore, SlSPS-overexpressing tomato plants showed higher SPS activity and sucrose content and heat stress resistant phenotypes. By comparison, knock-out tomato plants showed lower SPS activity and sucrose content and susceptible to heat stress. The determination of several reference values of oxidative stress parameters were also consistent with their heat resistance of these transgenic plants. In summary, SlSPS gene could positively mediate the growth and thermotolerance in tomato plants.

New Insights into MdSPS4-Mediated Sucrose Accumulation under Different Nitrogen Levels Revealed by Physiological and Transcriptomic Analysis

“…The results indicated that different nitrogen levels increased the fructose, glucose, sucrose, and sorbitol content of apple compared to the control at different development periods. The results obtained in this paper are similar to those in citrus [25], tomatoes [17], melon [33], and date palm [34].…”

“…Genes-encoding SPS was first discovered in wheat [13]. Subsequently, SPS has been cloned from various plants, including rice, maize, sorghum [14], Arabidopsis [15], tobacco [16], tomato [17], sugarcane [18], and poplar [19]. These previous studies indicated that the activity of SPS played a positive regulatory role in sucrose accumulation, and that the total sugar is mainly in the form of sucrose in sorghum stalks [13,20].…”

“…SPS overexpression in tobacco affected carbon allocation and the carbohydrate metabolism, accelerated plant growth, and increased sucrose synthesis in the old leaves of transgenic plants [21]. Moreover, SPS overexpression has increased the sucrose/starch ratio and photosynthetic rate in the leaves of transgenic Arabidopsis [15] and tomato [17]. Meanwhile, SPS overexpression also increased sucrose unloading in tomato fruit [17].…”

“…Moreover, SPS overexpression has increased the sucrose/starch ratio and photosynthetic rate in the leaves of transgenic Arabidopsis [15] and tomato [17]. Meanwhile, SPS overexpression also increased sucrose unloading in tomato fruit [17]. The effects of SPS overexpression on plant growth and biomass were also examined in transgenic Arabidopsis [22] and poplar [19], tobacco [16], and brachypodium [18].…”

Physiological and transcriptomic analysis of tomato in response to sub-optimal temperature stress

“…Differentially, one sucrose-phosphate synthase was up-regulated only in S708 and the gene involve in the sucrose synthesis pathway in plants. 61 Interestingly, we found that the genes involved in the processes of trehalose synthesis were up-regulated only in T722, which encoding the trehalose-6-phosphate phosphatase (TPP) and trehalose-6-phosphate synthase (TPS), respectively. 62 Mollavali and Börnke 62 found that most of tomato of TPS/TPP genes were induced by temperature stress, suggesting that trehalose synthesis pathway may play important role in plants temperature stress adaptation.…”