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Magnaporthe oryzae is a pathogenic fungus that seriously harms rice production. Phosphatases and carbon metabolism play crucial roles in the growth and development of eukaryotes. However, it remains unclear how serine/threonine phosphatases regulate the catabolism of triglycerides, a major form of stored lipids. In this study, we identified a serine/threonine protein phosphatase regulatory subunit, Smek1, which is required for the growth, conidiation, and virulence of M. oryzae. Deletion of SMEK1 led to defects in the utilization of lipids, arabinose, glycerol, and ethanol. In glucose medium, the expression of genes involved in lipolysis, long‐chain fatty acid degradation, β‐oxidation, and the glyoxylate cycle increased in the Δsmek1 mutant, which is consistent with ΔcreA in which a carbon catabolite repressor CREA was deleted. In lipid medium, the expression of genes involved in long‐chain fatty acid degradation, β‐oxidation, the glyoxylate cycle, and utilization of arabinose, ethanol, or glycerol decreased in the Δsmek1 mutant, which is consistent with Δcrf1 in which a transcription activator CRF1 required for carbon metabolism was deleted. Lipase activity, however, increased in the Δsmek1 mutant in both glucose and lipid media. Moreover, Smek1 directly interacted with CreA and Crf1, and dephosphorylated CreA and Crf1 in vivo. The phosphatase Smek1 is therefore a dual‐function regulator of the lipid and carbohydrate metabolism, and controls fungal development and virulence by coordinating the functions of CreA and Crf1 in carbon catabolite repression (CCR) and derepression (CCDR). [ABSTRACT FROM AUTHOR]

Summary: The development and pathogenicity of the fungus Magnaporthe oryzae, the causal agent of destructive rice blast disease, require it to perceive external environmental signals. Opy2, an overproduction‐induced pheromone‐resistant protein 2, is a crucial protein for sensing external signals in Saccharomyces cerevisiae. However, the biological functions of the homologue of Opy2 in M. oryzae are unclear. In this study, we identified that MoOPY2 is involved in fungal development, pathogenicity, and autophagy in M. oryzae. Deletion of MoOPY2 resulted in pleiotropic defects in hyphal growth, conidiation, germ tube extension, appressorium formation, appressorium turgor generation, and invasive growth, therefore leading to attenuated pathogenicity. Furthermore, MoOpy2 participates in the Osm1 MAPK pathway and the Mps1 MAPK pathway by interacting with the adaptor protein Mst50. The interaction sites of Mst50 and MoOpy2 colocalized with the autophagic marker protein MoAtg8 in the preautophagosomal structure sites (PAS). Notably, the ΔMoopy2 mutant caused cumulative MoAtg8 lipidation and rapid GFP‐MoAtg8 degradation in response to nitrogen starvation, showing that MoOpy2 is involved in the negative regulation of autophagy activity. Taken together, our study revealed that MoOpy2 of M. oryzae plays an essential role in the orchestration of fungal development, appressorium penetration, autophagy and pathogenesis. [ABSTRACT FROM AUTHOR]

Summary: Magnaporthe oryzae is an important plant pathogen that causes rice blast. Hse1 and Vps27 are components of ESCRT‐0 involved in the multivesicular body (MVB) sorting pathway and biogenesis. To date, the biological functions of ESCRT‐0 in M. oryzae have not been determined. In this study, we identified and characterized Hse1 and Vps27 in M. oryzae. Disruption of MoHse1 and MoVps27 caused pleiotropic defects in growth, conidiation, sexual development and pathogenicity, thereby resulting in loss of virulence in rice and barley leaves. Disruption of MoHse1 and MoVps27 triggered increased lipidation of MoAtg8 and degradation of GFP‐MoAtg8, indicating that ESCRT‐0 is involved in the regulation of autophagy. ESCRT‐0 was determined to interact with coat protein complex II (COPII), a regulator functioning in homeostasis of the endoplasmic reticulum (ER homeostasis), and disruption of MoHse1 and MoVps27 also blocked activation of the unfolded protein response (UPR) and autophagy of the endoplasmic reticulum (ER‐phagy). Overall, our results indicate that ESCRT‐0 plays critical roles in regulating fungal development, virulence, autophagy and ER‐phagy in M. oryzae. [ABSTRACT FROM AUTHOR]

Summary: Amino acids are vital components in cell metabolism. Leucine is a regulatory factor that generates significant impact on protein synthesis/turnover, modulates diverse cellular signalling pathways and participates in oxidative processes and immune responses. Here, we identified and characterized the functions of a leucine‐associated Zn2Cys6‐type transcription factor, MoLeu3. Disruption of MoLEU3 resulted in significantly reduced pathogenicity in barley and rice. Quantitative RT‐PCR showed that the expression levels of the putative leucine biosynthesis‐related genes, MoLEU1, MoLEU2 and MoLEU4 were downregulated in the ΔMoleu3 mutant. We used high‐throughput gene knockout method to generate the null mutants of MoLEU1, MoLEU2 and MoLEU4 respectively. The ΔMoleu1, ΔMoleu2 and ΔMoleu4 mutants are leucine auxotroph and showed similar phenotypic characterizations, including reduced conidiation, delayed mobilization and degradation of glycogen and lipid droplets, limited appressorium‐mediated penetration, and restricted invasive hyphae growth within host cells. Collectively, MoLEU1, MoLEU2, and MoLEU4 regulated by MoLEU3 play crucial roles in fungal development and infectious processes through modulation of leucine biosynthesis in Magnaporthe oryzae. [ABSTRACT FROM AUTHOR]

Summary: The Skp1‐Cul1‐F‐box‐protein (SCF) ubiquitin ligases are important parts of the ubiquitin system controlling many cellular biological processes in eukaryotes. However, the roles of SCF ubiquitin ligases remain unclear in phytopathogenic Magnaporthe oryzae. Here, we cloned 24 F‐box proteins and confirmed that 17 proteins could interact with MoSkp1, showing their potential to participate in SCF complexes. To determine their functions, null mutants of 21 F‐box‐containing genes were created. Among them, the F‐box proteins MoFwd1, MoCdc4 and MoFbx15 were found to be required for growth, development and full virulence. Fluorescent‐microscopy observations demonstrated that both MoFbx15 and MoCdc4 were localized to the nucleus, compared with MoFwd1, which was distributed in the cytosol. MoCdc4 and MoFwd1 bound to MoSkp1 via the F‐box domain, the deletion of which abrogated their function. Race tube and qRT‐PCR assays confirmed that MoFwd1 was involved in circadian rhythm by regulating transcription and protein stability of the core circadian clock regulator MoFRQ. Moreover, MoFWD1 also orchestrates conidial germination by influencing conidial amino acids pools and oxidative stress release. Overall, our results indicate that SCF ubiquitin ligases play indispensable roles in development and pathogenicity in M. oryzae. [ABSTRACT FROM AUTHOR]

Summary: Pyricularia oryzae is the causal pathogen of rice blast disease. Autophagy has been shown to play important roles in P. oryzae development and plant infection. The P. oryzae endosomal system is highly dynamic and has been shown to be associated with conidiogenesis and pathogenicity as well. To date, the crosstalk between autophagy and endocytosis has not been explored in P. oryzae. Here, we identified three P. oryzae VPS9 domain‐containing proteins, PoVps9, PoMuk1 and PoVrl1. We found that PoVps9 and PoMuk1 are localized to vesicles and are each co‐localized with PoVps21, a recognized marker of early endosomes. Deletion of PoVPS9 resulted in severe defects in endocytosis and autophagosome degradation and impaired the localization of PoVps21 to endosomes. Additionally, deletion of the PoMUK1 gene in the ΔPovps9 mutant background exhibited more severe defects in development, autophagy and endocytosis compared with the ΔPovps9 mutant. Pull‐down assay showed that PoVps9 interacts with PoVps21, PoRab11 and PoRab1, which have been verified to participate in endocytosis. Furthermore, yeast two‐hybrid and co‐immunoprecipitation assays confirmed that PoVps9 directly interacts with the GDP form of PoVps21. Thus, PoVps9 is a key protein involved in autophagy and in endocytosis. [ABSTRACT FROM AUTHOR]

The ubiquitin system modulates protein functions through targeting substrates for ubiquitination. Here, E2 conjugating enzyme MoRad6-related ubiquitination pathways are identified and analyzed in Magnaporthe oryzae, the causal agent of rice blast disease. Disruption of MoRad6 leads to severe defects in growth, sporulation, conidial germination, appressorium formation, and plant infection. To depict the functions of MoRad6, three putative ubiquitin ligases, MoRad18, MoBre1 and MoUbr1, are also characterized. Deletion of MoRad18 causes minor phenotypic changes, while MoBre1 is required for growth, conidiation and pathogenicity in M. oryzae. Defects in ΔMobre1 likely resulted from the reduction in di- and tri-methylation level of Histone 3 lysine 4 (H3K4). Notably, MoUbr1 is crucial for conidial adhesion and germination, possibly by degrading components of cAMP/PKA and mitogen-activated protein kinase (MAPK) Pmk1 signaling pathways via the N-end rule pathway. Germination failure of ΔMoubr1 conidia could be rescued by elevation of cAMP level or enhanced Pmk1 phosphorylation resulting from further deletion of MoIra1, the M. oryzae homolog of yeast Ira1/2. These reveal vital effects of cAMP/PKA and MAPK Pmk1 signaling on conidial germination in M. oryzae. Altogether, our results suggest that MoRad6-mediated ubiquitination pathways are essential for the infection-related development and pathogenicity of M. oryzae. [ABSTRACT FROM AUTHOR]

Rab GTPases are required for vesicle-vacuolar fusion during vacuolar biogenesis in fungi. To date, little is known about the biological functions of the Rab small GTPase components in Magnaporthe oryzae. In this study, we investigated MoYpt7 of M. oryzae, a homologue of the small Ras-like GTPase Ypt7 in Saccharomyces cerevisiae. Cellular localization assays showed that MoYpt7 was predominantly localized to vacuolar membranes. Using a targeted gene disruption strategy, a MoYPT7 mutant was generated that exhibited defects in mycelial growth and production of conidia. The conidia of the MoYPT7 mutant were malformed and defective in the formation of appressoria. Consequently, the MoYPT7 mutant failed to cause disease in rice and barley. Furthermore, the MoYPT7 mutant showed impairment in autophagy, breached cell wall integrity, and higher sensitivity to both calcium and heavy metal stress. Transformants constitutively expressing an active MoYPT7 allele (MoYPT7-CA, Gln67Leu) exhibited distinct phenotypes from the MoYPT7 mutant. Expression of MoYPT7-CA in MoYpt7 reduced pathogenicity and produced more appressoriaforming single-septum conidia. These results indicate that MoYPT7 is required for fungal morphogenesis, vacuole fusion, autophagy, stress resistance and pathogenicity in M. oryzae. [ABSTRACT FROM AUTHOR]

In the title dihalogenated trichodermin mol-ecule, C(17)H(24)Br(2)O(4) (systematic name: 9,10-dibromo-12,13-epoxy-trichothec-9-en-4β-yl acetate), the five-membered ring displays an envelope conformation, whereas the two six-membered rings show the same conformation, viz. chair. As for the seven-membered ring, the dihedral angle between the mean planes formed by the four C atoms of the envelope unit and the three C and one O atoms of the six-membered chair is 69.08 (4)°; these two mean planes are nearly perpendicular to the ep-oxy ring with angles of 87.53 (4) and 88.67 (4)°, respectively.

In the title compound, C(15)H(22)O(3), the five-membered ring displays an envelope conformation, whereas the two six-membered rings show different conformations, viz. chair and half-chair. In the crystal, mol-ecules are linked through inter-molecular O-H⋯O hydrogen bonds, forming chains running along the b axis.

In the title compound, C(15)H(17)ClN(2)OS, the thia-zole ring, which is essentially planar with a maximum deviation of 0.044 (3) Å, makes a dihedral angle of 54.76 (8)° with the benzene ring. In the crystal, adjacent molecules related by twofold rotation symmetry are linked by pairs of N-H⋯N hydrogen bonds.

The title compound, C(16)H(16)O(8), is a potent nonspecific phyto-toxin. The crystal structure is the average of two tauto-mers, 5,6,7,9,10-penta-hydr-oxy-2-meth-oxy-7-methyl-1,4,5,6,7,8-hexa-hydro-anthracene-1,4-dione and 1,4,5,6,7-pentahydr-oxy-2-meth--oxy-7-methyl-5,6,7,8,9,10-hexa-hydro-anthracene-9,10-di-one. The cyclo-hexene rings in both tautomers display a half-chair conformation. An extensive O-H⋯O hydrogen-bonding network is present in the crystal structure.

In the title natural product, C(17)H(24)O(4), which is a very potent inhibitor of protein synthesis in mammalian cells, the five-membered ring displays an envelope conformation, whereas the two six-membered rings show different conformations, viz. chair and half-chair.