Regulatory network of genes associated with stimuli sensing, signal transduction and physiological transformation of appressorium inMagnaporthe oryzae

Abstract

Rice blast caused by Magnaporthe oryzae is the most destructive disease affecting the rice production (Oryza sativa), with an average global loss of 10–30% per annum. Recent reports have indicated that the fungus also inflicts blast disease on wheat (Triticum aestivum) posing a serious threat to the wheat production. Due to its easily detected infectious process and manoeuvrable genetic manipulation, M. oryzae is considered a model organism for exploring the molecular mechanism underlying fungal pathogenicity during the pathogen–host interaction. M. oryzae utilises an infectious structure called appressorium to breach the host surface by generating high turgor pressure. The appressorium development is induced by physical and chemical cues which are coordinated by the highly conserved cAMP/PKA, MAPK and calcium signalling cascades. Genes involved in the appressorium development have been identified and well studied in M. oryzae, a summary of the working gene network linking stimuli sensing and physiological transformation of appressorium is needed. This review provides a comprehensive discussion regarding the regulatory networks underlying appressorium development with particular emphasis on sensing of appressorium inducing stimuli, signal transduction, transcriptional regulation and the corresponding developmental and physiological responses. We also discussed the crosstalk and interaction of various pathways during the appressorium development.

The rice blast fungus MoRgs1 functioning in cAMP signaling and pathogenicity is regulated by casein kinase MoCk2 phosphorylation and modulated by membrane protein MoEmc2

“…G-protein/cAMP signaling is required for appressorium formation and pathogenicity in the rice blast fungus M . oryzae [ 28 , 62 , 63 ]. The regulators of G-protein signaling, in particular MoRgs1, also plays an important role in these function [ 21 ].…”

The molecular mechanism underlying pathogenicity inhibition by sanguinarine in Magnaporthe oryzae

“…3(A)). Since hydrophobins mediate the proper and timely sensing of the host surface cues, 37 we speculated that sanguinarine may target the fungal hydrophobins and impair germ tube development. To test this, we quantified the expression profiles of four hydrophobin encoding genes by qRT‐PCR and found that a crucial fungal hydrophobin MoMPG1 is dramatically reduced by ≥95% change while MoMHP1 , MGG_09134 and MGG_10105 are up‐regulated by several fold in sanguinarine‐treated strains (Fig.…”

Diversity and Function of Appressoria

“…Genomics and their interconnected disciplines have provided a fertile platform to address most of these issues and controversies related to the formation and functioning of appressoria. Genomic data and novel techniques have contributed towards a better understanding of these fungal-host interactions from appressorium formation to host invasion [28][29][30][31][32]. Advances in reverse genetic techniques have enabled cloning of diverse genes predicted to be involved in these interactions, and many are characterized via various functional genomic approaches [17,21,28,[33][34][35][36][37][38][39][40][41][42].…”