Identification of peanut seed prolamins with an antifungal role by 2D-GE and drought treatment

Abstract

This work revealed peanut seed prolamins likely displaying a defensive role besides the known nitrogen storage. Drought stress and proteomic approaches were used in varieties of peanuts to explore the prolamin member in association with a test against Aspergillus flavus spore germination. The stress effect was showed by aerial biomass, leaf content of malondialdehyde, and seed contamination by A. flavus. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis profiles were not informative for the antifungal polypeptides. From two-dimensional gel electrophoresis, the suspected polypeptides were those with pI 5.45–5.75 and sizes of 22.0–30.5 kDa specifically in Spanish-type peanuts. Regarding to the drought effect in most of these peanuts, the spot peak volume analysis deduced three novel prolamin-related antifungal polypeptides at pI 5.75–5.8 with 30.5, 27.5–28.5, and 22.0–22.5 kDa, which was confirmed after isoelectric purification at pH 5.60. The data could not yet conclude their correlation with resistance to drought and to seed infection by A. flavus.

Graphical Abstract

Antifungal peanut prolamins were related with polypeptides 1, 2, and 3 in pellet (Fig. A) not with spots 4, 5, and 6 in the supernatant (Fig. B) portion on precipitation at pH 5.60.

Key words:

• 2D-GE maps
• antifungus
• Aspergillus flavus
• peanut seed prolamins

Acknowledgment

Miss Senakoon is grateful to a scholarship from the Graduate School Khon Kaen University for her short term work at the National Chiayi University, Taiwan.