Peroxisomal fission is induced during appressorium formation and is required for full virulence of the rice blast fungus

Abstract

Peroxisomes are involved in various metabolic processes and are important for virulence in different pathogenic fungi. How peroxisomes rapidly emerge in the appressorium during fungal infection is poorly understood. Here, we describe a gene, PEF1, which can regulate peroxisome formation in the appressorium by controlling peroxisomal fission, and is required for plant infection in the rice blast fungus Magnaporthe oryzae. Targeted deletion of PEF1 resulted in a reduction in virulence and a delay in penetration and invasive growth in host cells. PEF1 was particularly expressed during appressorial development, and its encoding protein was co-localized with peroxisomes during appressorial development. Compared with the massive vesicle-shaped peroxisomes formed in the wild-type appressorium, the Δpef1 mutant could only form stringy linked immature peroxisomes, suggesting that PEF1 was involved in peroxisomal fission during appressorium formation. We also found that the Δpef1 mutant could not utilize fatty acids efficiently, which can improve significantly the expression level of PEF1 and induce peroxisomal fission. As expected, the Δpef1 mutant showed reduced intracellular production of reactive oxygen species (ROS) during appressorium formation and induced ROS accumulation in host cells during infection. Taken together, PEF1-mediated peroxisomal fission is important for fungal infection by controlling the number of peroxisomes in the appressorium.

MoDnm1 Dynamin Mediating Peroxisomal and Mitochondrial Fission in Complex with MoFis1 and MoMdv1 Is Important for Development of Functional Appressorium in Magnaporthe oryzae

“…To explore whether the attenuated virulence in Δ Modnm1 , Δ Momdv1 , and Δ Mofis1 mutants is due to defects in peroxisomal and mitochondrial fission, appressoria from the mutants and wild type strain were treated with oleate and glycerol to induce peroxisomal and mitochondrial fission, respectively [ 32 , 61 – 63 ]. Globular peroxisomes and mitochondria were markedly increased in deletion mutants as well as in the wild type after treated with 0.1% V/V oleate or 1% V/V glycerol for 10 h, respectively ( S5A–S5D Fig ).…”

“…This is consistent with recent studies that showed Pex11A, Pex19 and MoPef1 (Mdv1) are required for peroxisomal proliferation and virulence of M . oryzae [ 14 , 28 , 32 ].…”

“…oryzae [ 14 , 28 ]. A recent study showed that a peroxisome-related protein, Pef1, mediated peroxisomal fission during appressorium formation is important for infection of the rice blast fungus [ 32 ]. Mitochondria regulate virulence in Heterobasidion annosum [ 33 ] and the loss of mitochondrial function in Candida glabrata and C .…”

A glycine-rich protein MoGrp1 functions as a novel splicing factor to regulate fungal virulence and growth in Magnaporthe oryzae

“…The expression levels of MoGRP1 were examined by quantitative RT-PCR (qRT-PCR). Wildtype samples were prepared from vegetative hyphae, conidia, appressoria, and infected barley leaves (Chen et al 2017). MoGRP1 was widely expressed among these samples, among which the conidia exhibited the highest expression level (Fig.…”

Roles of Peroxisomes in the Rice Blast Fungus

“…There is only one counterpart of Mdv1/Caf4 protein in M. oryzae , named PEF1 [peroxisome fission protein 1] [ 33 ]. This gene may play dual roles of Mdv1 and Caf4, because deletion of PEF1 will lead to evident peroxisomal fission defect during the fission inducing conditions.…”