Enhanced protection of tomato against Fusarium wilt through biopriming with Trichoderma harzianum

Microbial priming represents an adaptive strategy to enhance the plant defense against subsequent challenges incited by pathogenic microbes. The aim of the study was to investigate the effect of priming with Trichoderma harzianum (Th) on the induced resistance potential of tomato after challenged with Fusarium oxysporum f. sp. lycopersici (Fol) pathogen. This work demonstrated antioxidative and defense related enzyme activities and qRT-PCR to study the resistance mechanisms of tomato plants bioprimed with T. harzianum against Fol pathogen. Microbial biopriming with T. harzianum resulted into enhanced expression of tomato defense-related genes and was accompanied by increased antioxidative enzymic activities. The study reported that the T. harzianum primed plants showed 2.71-fold higher SOD than control and 1.34-fold (Fol + Th) higher SOD activity compared to Fol challenged plants. In contrast, Fol + Th treated showed 5.87-fold and 1.34-fold higher CAT enzyme activity as compared to control and pathogen exposed plants. T. harzianum bioprimed plants noted 1.47- and 11.47-fold enhanced PPO activity as compared to Fol challenged and controls, respectively. PAL and PO activities were also found higher in T. harzianum primed plants. The qRT-PCR revealed that expression of defense related gene showed higher up-regulation in T. harzianum primed plants as compared to pathogen challenged plants. As compared to control, Fol + Th treated plants also showed higher up-regulation of all the studied genes. The study concluded T. harzianum priming aggravates the plant defense system against the Fol challenged condition and accompanied by higher expression of defense related genes and increased antioxidative activities against subsequent Fol attack.