The molecular mechanism underlying pathogenicity inhibition by sanguinarine in Magnaporthe oryzae.

Abstract

BACKGROUND\nSanguinarine (SAN) is a benzophenanthridine alkaloid that broadly targets a range of pathways in mammalian and fungal cells. In this study we set to explore the molecular mechanism how sanguinarine inhibits fungal development and pathogenicity of Magnaporthe oryzae with the hope that sanguinarine will bolster the development of anti-blast agents.\n\n\nRESULTS\nWe found that the fungus exhibited a significant reduction in the vegetative growth and hyphal melanization while the spores produced long germ tubes on the artificial hydrophobic surface characteristic of a defect in thigmotropic sensing when exposed to 4\u2009μM, 8\u2009μM and 0.5\u2009μM of sanguinarine respectively. Consistent with these findings, we observed that the genes involved in melanin biosynthesis and the fungal hydrophobin MoMPG1 were remarkably suppressed in mycelia treated with 8\u2009μM of sanguinarine. Additionally, sanguinarine inhibited appressorium formation at a dose of 1.0\u2009μM and this defect was restored by supplementing 5\u2009mM of exogenous cAMP. By qRT-PCR assay we found cAMP pathway signalling genes such as MoCAP1, MoCpkA were significantly repressed whereas MoCDTF1 and MoSOM1 were upregulated in sanguinarine treated strains. Furthermore, we showed that sanguinarine does not selectively inhibit vegetative growth and appressorium formation of Guy11 but also other strains of M. oryzae. Finally treatment of sanguinarine impaired the appressorium mediated penetration, and pathogenicity of M.oryzae in a dose dependent manner.\n\n\nCONCLUSION\nBased on our results we concluded that sanguinarine is an attractive antimicrobial candidate for fungicide development in the control of rice blast disease. This article is protected by copyright. All rights reserved.