Interplay of redox modulators and carbohydrate metabolism enzymes in Dioscorea alata tuber degradation and formation.

Dioscorea tuber undergoes multiple morphological and bio-chemical changes during its 9 month growth period. A stage specific gel free analysis was done to understand the proteomic changes associated with tuber development and assign markers. On the basis of morphological traits the tuber life cycle was divided into four developmental stages namely; root initiation (S1), vegetative growth (S2), new tuber initiation (S3) and tuber maturation (S4) which was validated by principal component analysis (PCA). The first most comprehensive data set was generated by using the pooled genome information from Dioscorea + Solanum + Viridateplantae as reference set identifying 78.2% of the total 3,681 proteins. The over-representation analysis of proteins using PANTHER and KEGG MAPPER revealed both expected and novel biological processes relevant to each developmental stage. A high abundance of the enzymes of ascorbate-glutathione cycle, carbohydrate metabolism, Glycolysis, TCA cycle was detected during tuber degradation and formation. The Glycolytic and starch biosynthesis pathway were re-constructed using the information derived from the proteome data. Novel transcription factors (14) associated with oxidative stress tolerance were identified in D.alata proteome. In conclusion, the data set comprehensively describes the proteome of Dioscorea tuber and provided growth specific markers (APx, MDHAR, invertase for degradation and sucrose synthase for formation) that would pave the way to a systematic study of the tuber. The study provides information that may influence the direction of research for improving the productivity of this under-utilized crop.