Effects of the Chloroplast Fructose-1,6-Bisphosphate Aldolase Gene on Growth and Low-Temperature Tolerance of Tomato.

Bingbing Cai,Yu Ning,Xizhen Ai,Qingyun Li,Qiang Li

doi:10.3390/ijms23020728

Abstract

Tomato (Solanum lycopersicum) is one of the most important greenhouse vegetables, with a large cultivated area across the world. However, in northern China, tomato plants often suffer from low-temperature stress in solar greenhouse cultivation, which affects plant growth and development and results in economic losses. We previously found that a chloroplast aldolase gene in tomato, SlFBA4, plays an important role in the Calvin-Benson cycle (CBC), and its expression level and activity can be significantly altered when subjected to low-temperature stress. To further study the function of SlFBA4 in the photosynthesis and chilling tolerance of tomato, we obtained transgenic tomato plants by the over-expression and RNA interference (RNAi) of SlFBA4. The over-expression of SlFBA4 led to higher fructose-1,6-bisphosphate aldolase activity, net photosynthetic rate (Pn) and activity of other enzymes in the CBC than wild type. Opposite results were observed in the RNAi lines. Moreover, an increase in thousand-seed weight, plant height, stem diameter and germination rate in optimal and sub-optimal temperatures was observed in the over-expression lines, while opposite effects were observed in the RNAi lines. Furthermore, over-expression of SlFBA4 increased Pn and enzyme activity and decreased malonaldehyde (MDA) content under chilling conditions. On the other hand, Pn and MDA content were more severely influenced by chilling stress in the RNAi lines. These results indicate that SlFBA4 plays an important role in tomato growth and tolerance to chilling stress.

Highlights

Fructose-1,6-bisphosphate aldolase (FBA, EC 4.1.2.13) has been extensively found in various organisms, such as bacteria, higher plants and animals [1,2]
We focus on SlFBA4, one of the chloroplast/plastid FBA (CpFBA), to investigate the function of this gene and demonstrate that it plays an important role in regulating tomato growth and chilling tolerance
To test whether SlFBA4 regulates plant growth, especially under low temperature, an over-expression cassette that contained the SlFBA4 coding sequence (CDS) controlled by the CaMV-35S promoter (35S-SlFBA4) and an RNA interference (RNAi) vector that contained a reverse-complementary hairpin structure (RNAi-SlFBA4) were created and introduced into tomato via Agrobacterium tumefaciens-mediated genetic transformation (Figure S1)

Summary

Introduction

Fructose-1,6-bisphosphate aldolase (FBA, EC 4.1.2.13) has been extensively found in various organisms, such as bacteria, higher plants and animals [1,2]. In the CBC, FBA catalyzes the reversible conversion of fructose-1,6-bisphosphate (FBP) to dihydroxyacetone phosphate (DHAP) and glyceraldehyde-3-phosphate (G3P) [5–7]. Both DHAP and G3P are substrates or metabolic products in the tricarboxylic acid cycle, phenylpropanoid pathway and oxidative/nonoxidative pentose phosphate pathway [8]. Class I FBAs have been extensively identified and characterized in various plants, such as Arabidopsis [10], rice [14,15], maize [16], spinach [9], soybean [17], potato [18], oat [19], tobacco [20], Sesuvium portulacastrum L. In tomato, decreased FBA activity resulted in the slower growth of plants [23,24]. In oat (Avena sativa L.), FBA activity can be induced by heat [19], whereas in chickpea (Cicer arietinum L.), FBA activity was repressed by water-deficit stress [28]

Methods

Results

Conclusion