Effect of a novel chemical mixture on senescence processes and plant-fungus interaction in solanaceae plants

The effects of exogenous application of a chemical mixture consisting of ad ipic acid monoethyl ester, furfurylamine, and 1,2,3,4-tetra-O-acetyl-beta - D-glucopyranose (FGA) on various metabolic pathways and the plant-fungus in teraction have been studied in Solanaceae plants. Tomato and pepper plants were sprayed with the FGA mixture, and different biochemical parameters suc h as gas exchange, chlorophyll concentration, protein, cell wall sugar and phenolics contents, and peroxidase and phenylalanine ammonia lyase (PAL) ac tivities were measured. FGA-treated plants showed, in general, an increase in cell wall sugar content and decreases in the chlorophyll degrading rate and the peroxidase activity. These results suggest that FGA (a possible syn thetic regulator) could act as a retardant-antisenescence agent in Solanace ae plants. The FGA mixture increased the PAL activity and promoted an overa ll rise in the concentration of flavonoids and phenolic compounds. Therefor e, FGA induced the synthesis of compounds that could give protection to pla nts against pathogens or insects. To further verify this putative protectio n, several fungi were inoculated in intact plants. Exogenous FGA applicatio ns on intact plants delayed fungus-provoked lesion development. In addition , data also showed that applications of 1,2,3,4-tetra-O-acetyl-beta -D-gluc opyranose inhibited fungal growth in vitro. These results confirm that FGA can activate protective mechanisms in plants upon contact with invaders suc h as fungi.