Drought has a strong effect on the biocompetitive (phytoalexins, antifungal protein) or protective compounds (phenols), which influence the growth of A. flavus and aflatoxin synthesis. It also prevents proper maturation of groundnut seeds. Aflatoxin contamination decreases in seeds which are mature when harvested. As the moisture content in groundnut seed decreased during drought the capacity of the seed to produce phytoalexin decreased, resulting in fungal activity and aflatoxin contamination.
Due to their free-radical nature, fatty acid hydroperoxides and primary products of LOXs are capable of producing membrane damage and promoting cell death. PnLOX1 gene being constitutively expressed in immature cotyledon, its activity is probably required for proper maturation of groundnut. Interestingly, some of the enzymes involved in the responses to fungal attacks such as chitinases, osmotins, peroxidases, and proteases are also involved in drought stress response through cell membrane-mediated mechanisms. Then, it is assumed that examining enzyme role and function, through cloning enzymes involved in cell membrane stability under infestation associated to drought controlled conditions, could lead to the detection of useful variations between genotypes, and provide molecular tools for selection of resistant lines. |