Effects of Trichoderma and endophytic fungus Piriformospora indica on cucumber physiology and Fusarium wilt disease of Cucumber

Abstract

Trichoderma species and endophytic fungus Piriformospora indica can enhance plant growth and increase disease resistance. Several investigations showed that the combined use of Trichoderma strains causes better results than a single Trichoderma strain. This study aimed to investigate the effect of combined applications of 5 Trichoderma strains (total wild-types) including T. harzianum (NAS-101), T. auroviridae (NAS-105), T. ghanens ،(NAS-108)  T. Virens (NAS-115), T. atroviride (NAS-112) and their mutants (total mutants) and P. indica on preventing cucumber (Cucumis sativus) Fusarium wilt caused by Fusarium oxysporum f. sp. radices-cucumerinum and some physiological features of cucumber. Soluble protein, chlorophyll a, b, carotenoids, malondialdehyde (MDA) content, and measurement of polyphenol oxidase(PPO) and peroxidase(POD) activity were determined spectrophotometrically. All the treatments were successful in significantly reducing disease incidence and MDA content. Our results showed that Trichoderma, P. indica, and pathogenic fungus increased PPO and POD activities. The highest chlorophyll a, b, and carotenoid contents were observed in plants treated with total mutants. Cucumber seedlings treated with the combination of total mutants and P. indica exhibited significantly higher levels of soluble protein contents. To the best of our knowledge, this is the first report of an enhancement in defense-related enzyme activity and chlorophyll a, chlorophyll b, carotenoids, and total soluble protein content of cucumber by combination use of Trichoderma strains and P. indica.