Identification and characterization of the peroxin 1 gene MoPEX1 required for infection-related morphogenesis and pathogenicity in Magnaporthe oryzae

Abstract

Peroxisomes are required for pathogenicity in many phytopathogenic fungi, but the relationships between fungal pathogenicity and peroxisomal function are not fully understood. Here, we report the identification of a T-DNA insertional mutant C445 of Magnaporthe oryzae, which is defective in pathogenicity. Analysis of the mutation confirmed an insertion into the gene MoPEX1, which encodes a putative homologue to peroxin 1. Targeted gene deletion mutants of MoPEX1 were nonpathogenic and were impaired in vegetative growth, conidiation, and appressorium formation. ΔMopex1 mutants formed abnormal, less pigmented, and nonfunctional appressoria, but they were unable to penetrate plant cuticle. The ΔMopex1 mutants were defective in the utilization of fatty acids (e.g., olive oil and Tween-20). Moreover, deletion of MoPEX1 significantly impaired the mobilization and degradation of lipid droplets during appressorium development. Interestingly, deletion of MoPEX1 blocked the import of peroxisomal matrix proteins. Analysis of an M. oryzae strain expressing GFP-MoPEX1 and RFP-PTS1 fusions revealed that MoPex1 localizes to peroxisomes. Yeast two hybrid experiments showed that MoPex1 physically interacts with MoPex6, a peroxisomal matrix protein important for fungal morphogenesis and pathogenicity. Taken together, we conclude that MoPEX1 plays important roles in peroxisomal function and is required for infection-related morphogenesis and pathogenicity in M. oryzae.

Pex13 and Pex14, the key components of the peroxisomal docking complex, are required for peroxisome formation, host infection and pathogenicity-related morphogenesis inMagnaporthe oryzae

“…In higher organisms such as Arabidopsis thaliana and humans, Pex13 is also crucial for the import of matrix proteins [39,49]. Moreover, Δmopex13 exhibited typical disorders, which have been observed in other M. oryzae pex mutants with severely impaired peroxisome biogenesis, such as reduced vegetative growth and sporulation, defective melanization and appressorial glycerol accumulation, as well as the inability to initiate host infection [9,[11][12][13]25]. Taken together, these data suggest that Pex13 is conserved in yeasts, plants, mammals and fungi and is crucial in peroxisomal import for both PTS1-and PTS2containing matrix proteins, fully reflecting that the peroxisomal docking complex plays key important roles in fungal development and pathogenicity.…”

“…Notably, in plant pathogenic fungi such as M. oryzae, Colletotrichum orbiculare (syn. C. lagenarium) and Fusarium graminearum, pex1, pex5, pex6, pex11, pex13 and pex19 mutants exhibit disorders in host infection and pathogenicity-related processes [9,[11][12][13][14][15][16]25].…”

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

“…Mutations of peroxisomal fatty acids β-oxidation encoding genes MFP1 and PEX6 delayed the mobilisation and degradation of the lipid droplets in the appressorium and abolished plant infection and penetration (Wang et al 2007). Non-functional and less pigmented appressoria were formed by pex1 mutants in M. oryzae (Deng et al 2016). Cytological studies unveiled lipid bodies are mobilised from the germinating conidium and degraded during the appressorium maturation and turgor generation (Weber et al 2001).…”

The COMPASS-like complex modulates fungal development and pathogenesis by regulating H3K4me3-mediated targeted gene expression in Magnaporthe oryzae

“…MoABC7 has been previously revealed to be involved in virulence, conidiation and abiotic stress tolerance, and MoPEX1 has been shown to be involved in infection-related morphogenesis and pathogenicity. And were previously demonstrated to be involved in mycelium development (Kim et al ., 2013a; 2013b; Deng et al, 2016; Kou et al, 2016). We also selected three overlapped target genes, MGG_04682, MGG_14719 and MGG_02775, and confirmed that the H3K4me3 coverages are significantly decreased in Δ mobre2 , Δ mospp1 and Δ moswd2 deletion mutants (Fig.…”

“…6B-D; Supporting Information Table S7). Some selected candidate genes such as PTH11 (MGG_05871), MoVelC (MGG_14719) and MGG_03593 are all involved in spore germination and pathogenesis (Supporting Information Table S11; Kim et al ., 2013a; 2013b; Deng et al ., 2016; Kou et al ., 2016). These genes affected in Δ mobre2 , Δ mospp1 and Δ moswd2 were more likely to be involved in developmental processes such as spore germination, transcriptional regulation (transcription factor activities) and pathogenesis (Fig.…”