Biochemical reaction of resistant and susceptible genotypes of flax (Linum usitatissimum L.) to Fusarium wilt disease

Fusarium wilt caused by Fusarium oxysporum L. is one of the most important destructive flax diseases that markedly decrease the production and yield of this crop. The cultivation of flax cultivars resistant to F. oxysporum is the most effective method for managing this disease. In this study, the changes in content of phenylalanine ammonia lyase, peroxidase and polyphenol oxidase enzymes, total protein, proline and soluble sugars were measured in 12 different genotypes of flax infected to wilt Fusarium and non-infected conditions under greenhouse conditions. The experiment was conducted in a randomized complete block design with three replications. 21 days after inoculation of the plant with the pathogen, biochemical components changes were measured by spectrophotometry. Based on the results of ANOVA, the soluble sugars content in infected genotypes was higher compared to control and healthy genotypes. Also, this parameter increased in resistant and highly resistant genotypes of flax, meanwhile this trait decreased in susceptible genotypes in contaminated conditions. The activity of phenylalanine ammonia lyase, peroxidase and polyphenol oxidase enzymes as well as proline content in leaves of resistant and highly resistant genotypes were significantly increased in wilt Fusarium infected treatment. Total protein content in non-infected genotypes of flax was higher than infected genotypes. Therefore, increasing the activity of antioxidant enzymes, proline content and soluble sugars can play a possible role in inducing resistance to Fusarium wilt disease in flax genotypes.