Trigonelline antidiabetic metabolite increased in inoculated fenugreek by Trichoderma

Trigonelline is known as an antidiabetic substance extracted from plant sources. The trigonelline content and growth factors of two Trigonella foenum ecotypes (Hamedan and Bandarabbas) treated by two Trichoderma harzianum isolates (chit4215MK and T8-7MK) were investigated in greenhouse conditions. The results showed that the two ecotypes are different in terms of growth factors with the Hamedan ecotype having more stem length and the Bandarabbas ecotype having more lateral branches and pod numbers. It was concluded that the Trichoderma strains had a positive effect on the growth of the Hamadan ecotypes stem, and the T8-7MK strain showed better effects than the chit4215MK. However, no shoot length differences were observed between the control and Trichoderma treated plants in the Bandarabbas ecotype. No significant difference was observed for peroxidase activity and total soluble carbohydrate content between the ecotypes, treatments, and the interaction effects of treatment and ecotypes. The highest Trigonelline content (4 mg g-1 DW) was achieved in the Bandarabbas ecotype treated with Trichoderma strain T8-7MK, which was 1.6- fold higher than the control plants. Also, the Hamedan ecotype treated by Trichoderma strain chit4215MK produced a higher content of Trigonelline  (3.5 mg g-1 DW), which was 1.3- fold higher than the control plants. The content of Trigonelline in the treated Hamedan ecotype was lower than the treated Bandarabbas ecotype (1.3 times more). Our results revealed that Trichoderma strains are able to regulate Trigonelline biosynthesis, and different strains showed various effects on different fenugreek ecotypes.