Polyamine metabolism in flax in response to treatment with pathogenic and non–pathogenic Fusarium strains

Abstract

Flax crop yield is limited by various environmental stress factors, but the largest crop losses worldwide are caused by Fusarium infection. Polyamines are one of the many plant metabolites possibly involved in the plant response to infection. However, in flax plants the polyamine composition, genes involved in polyamine synthesis, and in particular their regulation, were previously unknown. The aim of this study was to investigate the polyamine synthesis pathway in flax and its involvement in response to pathogen infection. It is well established that polyamines are essential for the growth and development of both plants and fungi, but their role in pathogen infection still remains unknown. In our study we correlated the expression of genes involved in polyamine metabolism with the polyamine levels in plant tissues and compared the results for flax seedlings treated with two pathogenic and one non-pathogenic strains of Fusarium. We observed an increase in the expression of genes participating in polyamine synthesis after fungal infection, and it was reflected in an increase of polyamine content in the plant tissues. The highest level of mRNA was characteristic for ornithine decarboxylase during infection with all tested, pathogenic and non-pathogenic, Fusarium strains and the arginine decarboxylase gene during infection with the pathogenic strain of Fusarium culmorum. The main polyamine identified in the flax seedlings was putrescine, and its level changed the most during infection. Moreover, the considerable increase in the contents of cell wall-bound polyamines compared to the levels of free and conjugated polyamines may indicate that their main role during pathogen infection lies in strengthening of the cell wall. In vitro experiments showed that the polyamines inhibit Fusarium growth, which suggests that they play an important role in plant defense mechanisms. Furthermore, changes in metabolism and content of polyamines indicate different defense mechanisms activated in flax in response to infection by pathogenic and non-pathogenic Fusarium strains.

Cotton polyamine oxidase is required for spermine and camalexin signalling in the defence response to Verticillium dahliae

“…In addition, Put and Spd accumulated in apoplasts when healthy leaves of rice plants were inoculated with the hemibiotrophic fungus Magnaporthe grisea (race 031) (Yoda et al ., ). A recent article reported that the Put level, but not Spd or Spm, showed considerable increase during infection with two pathogenic strains and one non‐pathogenic strain of Fusarium in flax, whereas the transcript levels of PA degradation genes were not changed (Wojtasik et al ., ).…”

RNA-seq Transcriptome Response of Flax (Linum usitatissimum L.) to the Pathogenic Fungus Fusarium oxysporum f. sp. lini

“…Other studies have addressed responses of specific genes or gene families upon F. oxysporum attack based on the knowledge of the general responses in plant-pathogen interactions; such studies display different stages and mechanisms of defense. For example, a study of changes in polyamine gene expression and polyamine metabolites in response to F. oxysporum and F. culmorum (Wojtasik et al, 2015), was explored due to the regulation of arginine decarboxylase in the aforementioned cDNA subtraction study. Others have used transgenics to modulate secondary metabolites (carotenoid and flavonoid biosynthesis) to increase resistance of flax to the pathogen, using the antioxidant action of these compounds against the reactive oxygen species produced upon infection (Lorenc-Kukuła et al, 2007, 2009; Boba et al, 2011).…”

Role of polyamine metabolism in plant pathogen interactions

“…Lowest induction in the gene expression levels and PA accumulation was detected in the case of the non-pathogenic Fusarium oxysporum strain. Differences observed between the two pathogenic strains also suggested, that the two pathogens have different mechanisms for plant tissues penetration, and they also induced different defence mechanism in lax seedlings [16].…”