Cytosolic/Plastid Glyceraldehyde-3-Phosphate Dehydrogenase Is a Negative Regulator of Strawberry Fruit Ripening.

Haoru Tang,Yong Zhang,Qing Chen,Yu Long,Min Yang,Bo Sun,Cong Ge,Mengyao Li,Yan Wang,Xiaorong Wang,Ya Luo

doi:10.3390/genes11050580

Abstract

Cytosolic glyceraldehyde-3-phosphate dehydrogenase (GAPC) and plastid glyceraldehyde-3-phosphate dehydrogenase (GAPCp) are key enzymes in glycolysis. Besides their catalytic function, GAPC/GAPCp participates in the regulation of plant stress response and growth and development. However, the involvement of GAPC/GAPCp in the regulation of fruit ripening is unclear. In this study, FaGAPC2 and FaGAPCp1 in strawberries were isolated and analyzed. FaGAPC2 and FaGAPCp1 transcripts showed high transcript levels in the fruit. Transient overexpression of FaGAPC2 and FaGAPCp1 delayed fruit ripening, whereas RNA interference promoted fruit ripening and affected fruit anthocyanins and sucrose levels. Change in the expression patterns of FaGAPC2 and FaGAPCp1 also influenced the expression of several glycolysis-related and ripening-related genes such as CEL1, CEL2, SS, ANS, MYB5, NCED1, ABI1, ALDO, PK, and G6PDH, and H2O2 level and reduced glutathione (GSH)/glutathione disulfide (GSSG) redox potential. Meanwhile, metabolomics experiments showed that transient overexpression of FaGAPCp1 resulted in a decrease in anthocyanins, flavonoids, organic acid, amino acids, and their derivatives. In addition, abscisic acid (ABA) and sucrose treatment induced the production of large amounts of H2O2 and inhibited the expression of FaGAPC2/FaGAPCp1 in strawberry fruit. These results revealed that FaGAPC2/FaGAPCp1 is a negative regulator of ABA and sucrose mediated fruit ripening which can be regulated by oxidative stress.

Highlights

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is an important enzyme in the two sugar metabolism pathways of glycolysis and gluconeogenesis
In recent years, GAPDH has been found to have multiple localizations. Based on their different cellular localization, GAPDH can be divided into three isoforms: (1) cytosolic glyceraldehyde-3-phosphate dehydrogenase (GAPC)/plastid glyceraldehyde-3-phosphate dehydrogenase (GAPCp) which is located in the cytoplasm/plastid and uses NAD+ as a coenzyme
GAPA and GAPB are usually located in chloroplasts, while GAPC is located in cytoplasm, and GAPCp is located in non-green plastids

Summary

Introduction

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is an important enzyme in the two sugar metabolism pathways of glycolysis and gluconeogenesis. In recent years, GAPDH has been found to have multiple localizations. Based on their different cellular localization, GAPDH can be divided into three isoforms: (1) cytosolic glyceraldehyde-3-phosphate dehydrogenase (GAPC)/plastid glyceraldehyde-3-phosphate dehydrogenase (GAPCp) which is located in the cytoplasm/plastid and uses NAD+ as a coenzyme. (2) NP-GAPDH is located in the cytosol where it catalyzes the “bypass” reaction of glycolysis by directly oxidizing G3P to 3-phosphoglycerate and simultaneously producing NADPH [3]. The four consist of four identical subunits with high structural similarity [2]. (2) NP-GAPDH is located in the cytosol where it catalyzes the “bypass” reaction of glycolysis by directly oxidizing G3P to 3-phosphoglycerate and simultaneously producing NADPH [3]. (3) GAPA/GAPB is present in the chloroplast and requires

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Conclusion