Trichoderma harzianum INAT11 elicits systemic resistance in maize against Fusarium verticillioides and Fusarium graminearum

Pink Ear Rot (PER) and Red Ear Rot (RER) are common fungal diseases of maize mainly caused by Fusarium verticillioides and Fusarium graminearum, respectively. Ear rots result in yield losses and reduced kernel quality due to contamination by mycotoxins. Since no chemical treatments are available to control Fusarium disease in maize, biological control could represent a promising sustainable strategy. A commercial strain of Trichoderma harzianum (INAT11) was evaluated as seed treatment to manage PER and RER through induction of a systemic resistance response in maize. Infection trials on maize plants under controlled greenhouse conditions showed the capacity of INAT11 when applied to seed to reduce both F. verticillioides and F. graminearum disease incidence (37% and 18.5%, respectively) and severity (33% and 28%, respectively). The expression of some genes belonging to both ISR (LOX10, AOS, HPL and OPR8) and SAR pathways (PAL and PR1), and also a stress-related gene (POX), were analysed in the hours following infection by quantitative real-time PCR. In treated plants during Fusarium infection some ISR and SAR markers were upregulated. The up-regulation occurred at different levels likely related to their pathogenic lifestyles.