Influence of Sugar and Photoperiod on Flavonoid Biosynthetic Pathway in Arachis hypogaea

Abstract

Peanut (Arachis hypogaea) is an oilseed crop that harbor plethora of flavonoids produced via biosynthetic enzymes of phenylpropanoid pathway. Flavonoids, biologically active phytochemicals with diverse structures, are tightly regulated at transcriptional level by various external and internal stimuli. Expression analysis of flavonoid biosynthetic genes in Arachis hypogaea has revealed their genotype dependent regulation in leaves under the influence of sugar and photoperiod treatment. Photoperiod alterations with 8 hr, 12, hr, 16 hr and 24 hr light durations have depicted significant variation in expression of genes at Day 7 and Day 15. In Bari 2011, most of the genes have been found up-regulated with greater extent on Day 15 than on Day 7 while opposite trend has been observed in PG 1247 variety. Sugar treatment has revealed the differential expression of genes using various concentrations (200mM, 400mM, 600mM) of sucrose and glucose, respectively. Moreover, the expression of flavonoid biosynthetic genes has shown specificity for sugar as sucrose has up-regulated while glucose has down-regulated most of the genes in both varieties. The study concluded that flavonoid production in peanut plant depends on genotype, sugar concentrations, specificity of sugar and alternation of photoperiod. Given study will provide better understanding related to transcriptional regulation flavonoid biosynthetic genes under the influence of light and sugar.