Potential role for Trichoderma harzianum, Clonostachys rosea and salicylic acid to induce resistance of date palm roots to Bayoud disease (Fusarium oxysporum f. sp. albedinis)

Bayoud disease caused by Fusarium oxysporum f. sp. albedinis (FOA) poses a major problem to date palm (Phoenix dactylifera L.) in Northern Africa. To solve this issue, biocontrol agents and chemicals inducers were used to trigger defense reactions. The present study indicates the direct effect of two antagonistic fungi, Trichoderma harzianum (TH) and Clonostachys rosea (CR), and salicylic acid (SA) application (1 mM, 1.5 mM) in date palm against FOA. Date palm plants were infected by FOA, inoculated with TH or CR, 3 days earlier, or immersed at two SA concentrations (1 mM, 1,5 mM), daily for 3 days. Plants were harvested and examined 3 days after FOA inoculation with pathogen. FOA alone treated plants were led to strong induction of phenylalanine ammonia-lyase (PAL) and peroxidase (POX), all biocontrol treatments showed an increase in chitinase (CHI) and glucanase (GLU) activi-ties. SA 1mM treated plants also showed high levels of lipoxygenase (LOX), SA 1,5 mM treated plants were increased in POX. Histochemical localization of POX activity and lignin content showed that high POX activity was already observed in plants treated with TH and CR. These findings support are useful in understanding the role of two antagonists and inducer abiotic to trigger defense related enzymes in imparting resistance to date palm against FOA.