Response of antioxidant enzymes and some metabolic activities in wheat to Fusarium spp. Infections

Abstract

Inoculating wheat (cv. Giza 164) with variousFusariumspecies had different effects on the catalase (CAT), peroxidase (POX) and ascorbate peroxidase (APX) activity in different plant tissues. The CAT activity induced in the shoots of wheat plants by some pathogens (F. merismoides, F. moniliforme, F. poaeandF. sambucinum) was relatively higher than that induced by other pathogens. The results showed an increase in POX activity in infected shoots except those inoculated withF. sambucinum, where the POX activity decreased. Inoculating wheat plants with individualFusariumspecies or with a mixture of pathogens caused an increase in APX in the shoots, except for those treated withF. poae, where the APX activity decreased. The activity of these antioxidant enzymes thus increased in most cases in the shoot system of wheat plants underFusariuminfection. Investigations on the metabolic activity of wheat plants inouculated with individualFusariumspecies or with a mixture of pathogens showed higher contents of all the protein fractions, soluble sugars, total free amino acids and proline. The K+and Ca2+concentrations decreased to various extents in different cases. The Na+content increased in wheat shoots, especially after inoculation withF. merismoides. The results signify that the most serious infection was caused byF. culmorum, F. graminearumandF. oxysporumand by a mixture of all theFusariumspecies.