Evidence of salicylic acid regulatory mechanisms of disease resistance against banana vascular wilt Fusarium oxysporium f.sp. cubense in Arabidopsis thaliana

Symptomatological studies on Arabidopsis- Fusarium oxysporium f.sp. cubense (Foc) interaction has led to the identification of signaling pathways required for plant resistance to Foc, as well as key regulators of innate immunity against this type of vascular wilt pathogens. From the in planta symptom expressions of Foc on Arabidopsis, there is a clear indication of involvement of salicylic acid (SA) and jasmonic acid (JA) for disease resistance. Mutations occur in synthesis of salicylic acid and Jasmonic acid, which modulate disease resistance with the evident of severe veinal necrosis on leaves and petiole. The typical symptom of leaf rosetting was the clear indication of the active participation of SA biosynthesis for Foc resistance in nahG, npr-1 plants. This analysis revealed that salicylic acid, ethylene (ET) and jasmonic acid (JA) pathways influence the Foc disease outcome in Arabidopsis. All the three signaling pathways interact in a positive way in the activation of Arabidopsis resistance to Foc. Hence, there must be co-ordinate regulation of both SA and JA for Foc resistance in Arabidopsis. Constitutive expressions of some transcriptional regulators of these pathways are sufficient to confer enhanced resistance to Foc and it might be an oligogenic trait.Keywords: Fusarium oxysporium f.sp.cubense, Arabidopsis thaliana, disease resistance.African Journal of Biotechnology, Vol 13(30) 3030-302