Biochemical and In silico Approaches to Study Glucose-6-Phosphate Dehydrogenase (G6PDH) in Potato (Solanum tuberosum L.)

Abstract

The potato, a Solanaceae member, is a popular non-grain food crop. India ranks third worldwide in terms of potato consumption. It is a short-day crop. Tuberization is a crucial survival strategy for potato plants. It is a sensitive phase that could be easily affected by extreme environmental conditions. G6PDH is an important enzyme interconnecting glycolysis and pentose phosphate pathway (PPP). This enzyme also plays an important role in stress mitigation. In this study, we adopted both biochemical and in silico approaches to characterize G6PDH enzyme. A total of 4 genes encoding 14 isoforms were identified. This family contains both stable and unstable hydrophilic proteins. Protein-protein interactions revealed association with various other carbohydrate metabolism enzymes. In silico expression pattern analysis in the form of Heatmap revealed differential expression in various potato organs. Multiple sequence alignment revealed significant divergence among G6PDH of various plant species of Solanaceae members. Phylogenetic analysis revealed evolutionary relationship between the G6PDH belonging to both Solanaceae and non-Solanaceae members. 3-D structures were also predicted. At biochemical level, enzyme assays of five Indian potato cultivars were performed. Potato organs at various stages of development showed variation in G6PDH enzyme activities. Mature leaves and stems showed maximum enzyme activity. Among tuberization stages, maximum G6PDH was found in young tubers indicating the crucial role of this enzyme in tuber development. The results of this research will be very helpful in understanding the biochemical properties, catalytic effectiveness and evolutionary dynamics of the G6PDH enzyme in the Solanaceae family.