Pre-soaking in Weed Extracts is a Reasonable Approach to Mitigate Fusarium graminearum Infection in Wheat

Root rot and head blight caused by soil-borne fungi are prevalent diseases endanger the global food security. The purpose of this study is to provide insight into the interaction of Fusarium graminearum with two weed extracts, concentrating on growth rate, physiological responses, molecular changes in wheat seedlings and yield parameters. In a pot experiment, wheat grains pre-soaked for 12 h either in distilled water or 25% aqueous weed extracts (purslane or chard) were germinated either in free or F. graminearum pre-inoculated sandy soil. The results revealed that F. graminearum inoculation resulted in reduced growth rate and chlorophyll content in wheat seedlings. However, following the fungal invasion, carotenoids, stress markers (EL, MDA, C = O, OH˙ and H 2 O 2 ), non-enzymatic antioxidants (ascorbate and flavonoids), osmoregulators (GB, proline and free amino acids), antioxidant enzymes activity (CAT, POX, SOD and PPO) and the expression of some stress-induced genes (CAT, GR and PR4) were substantially increased. Nevertheless, priming of wheat grains with purslane or chard extracts resulted in enhanced growth rate, balanced chlorophyll content, decreased stress symptoms, restoration of the normal level of osmoregulators and antioxidant enzymes activity, as well as down-regulation of stress-induced genes in F. graminearum -infected wheat seedlings, besides improving yield characteristics. However, PR2 gene expression was not affected by either fungal infection or weed priming. In conclusion, natural weed extracts as supplement to chemical antifungals, can be safely employed to increase the growth rate and reconfigure the pathophysiological status of wheat seedlings by reducing the detrimental effects of F. graminearum infection.