Jasmonic acid and abscisic acid play important roles in host–pathogen interaction between Fusarium graminearum and wheat during the early stages of fusarium head blight

• Infection of wheat heads with Fusarium graminearum affects phytohormone levels.
• Exogenous treatments shows crosstalk between phytohormones.
• Abscisic acid treatment accelerates fusarium head blight symptoms.
• Jasmonic acid treatment reduces fusarium head blight symptoms on wheat heads.
• Jasmonic acid directly inhibits F. graminearum growth.

The effect of phytohormones on the defense response of wheat against Fusarium graminearum infection was investigated. Infection of heads with F. graminearum induced accumulation of salicylic acid (SA), jasmonic acid (JA), abscisic acid (ABA), and indole acetic acid (IAA). Exogenous phytohormone treatments showed crosstalk between them and a complex effect on expression of the genes ATB2, ExpB6, LEA Td16, PR1, Pdf1.2, PR4. JA treatment reduced F. graminearum growth and fusarium head blight (FHB) symptoms while an increase in FHB was observed with ABA. Transient down-regulation of allene oxide synthase (AOS) supports a complex role for JA in wheat head.