STUDY ON EXPRESSION OF PHENYLALANINE AMMONIA-LYASE AND PATHOGENESIS-RELATED GENES IN WHEAT SYMBIONT WITH ENDOMYCORRHIZAL FUNGUS PIRIFORMOSPORA INDICA AFTER INFECTION WITH POWDERY MILDEW

Endomycorrhizal fungus Piriformospora indica protects host plants against biotic and abiotic stresses via induced systemic resistance. In the present study, the ability of this fungus to induce resistance in wheat against powdery mildew fungus (Blumeria graminis f. sp. Tritici, Bgt)was evaluated. Forty Iranian wheat genotypes were screened for sensitivity to wheat powdery mildew and Falat cultivar was selected as the most susceptible genotype. To investigate the expression patterns of PR1, PR2, PR5 and PAL defense genes, Falat genotype was colonized by P. indica and then exposed to Bgt together with non-colonized plants. Results showed peak expression of the resistance genes have at 24 hours after inoculation in both treated and control plants. The expression rate of the evaluated genes increased slowly in control plants but elevated earlier and higher in P. indica colonized plantsafter inoculation with Bgt. These results indicate that P. indica causes early and faster induction of plant defense genes and their elevation causes induced systemic resistance in plants. At 48 hours after inoculatin, transcript levels of early induced genes started to dampen in both groups of experimental plants, indicating effective suppression of defense-associated genes upon haustorium development.