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Septins play a key regulatory role in cell division, cytokinesis, and cell polar growth of the rice blast fungus (Magnaporthe oryzae). We found that the organization of the septin ring, which is essential for appressorium-mediated infection in M. oryzae, requires long-chain fatty acids (LCFAs), which act as mediators of septin organization at membrane interfaces. However, it is unclear how septin ring formation and LCFAs regulate the pathogenicity of the rice blast fungus. In this study, a novel protein was named MoLfa1 because of its role in LCFAs utilization. MoLfa1 affects the utilization of LCFAs, lipid metabolism, and the formation of the septin ring by binding with phosphatidylinositol phosphates (PIPs), thereby participating in the construction of penetration pegs of M. oryzae. In addition, MoLfa1 is localized in the endoplasmic reticulum (ER) and interacts with the ER-related protein MoMip11 to affect the phosphorylation level of Mps1. (Mps1 is the core protein in the MPS1-MAPK pathway.) In conclusion, MoLfa1 affects conidia morphology, appressorium formation, lipid metabolism, LCFAs utilization, septin ring formation, and the Mps1-MAPK pathway of M. oryzae, influencing pathogenicity. [ABSTRACT FROM AUTHOR]

Sphingolipids are critically significant in a range of biological processes in animals, plants, and fungi. In mammalian cells, they serve as vital components of the plasma membrane (PM) in maintaining its structure, tension, and fluidity. They also play a key role in a wide variety of biological processes, such as intracellular signal transduction, cell polarization, differentiation, and migration. In plants, sphingolipids are important for cell development and for cell response to environmental stresses. In pathogenic fungi, sphingolipids are crucial for the initiation and the development of infection processes afflicting humans. However, our knowledge on the metabolism and function of the sphingolipid metabolic pathway of pathogenic fungi affecting plants is still very limited. In this review, we discuss recent developments on sphingolipid pathways of plant pathogenic fungi, highlighting their uniqueness and similarity with plants and animals. In addition, we discuss recent advances in the research and development of fungal-targeted inhibitors of the sphingolipid pathway, to gain insights on how we can better control the infection process occurring in plants to prevent or/and to treat fungal infections in crops. [ABSTRACT FROM AUTHOR]

Macroautophagy/autophagy is an evolutionarily conserved biological process among eukaryotes that degrades unwanted materials such as protein aggregates, damaged mitochondria and even viruses to maintain cell survival. Our previous studies have demonstrated that MoVast1 acts as an autophagy regulator regulating autophagy, membrane tension, and sterol homeostasis in rice blast fungus. However, the detailed regulatory relationships between autophagy and VASt domain proteins remain unsolved. Here, we identified another VASt domain-containing protein, MoVast2, and further uncovered the regulatory mechanism of MoVast2 in M. oryzae. MoVast2 interacted with MoVast1 and MoAtg8, and colocalized at the PAS and deletion of MoVAST2 results in inappropriate autophagy progress. Through TOR activity analysis, sterols and sphingolipid content detection, we found high sterol accumulation in the ΔMovast2 mutant, whereas this mutant showed low sphingolipids and low activity of both TORC1 and TORC2. In addition, MoVast2 colocalized with MoVast1. The localization of MoVast2 in the MoVAST1 deletion mutant was normal; however, deletion of MoVAST2 leads to mislocalization of MoVast1. Notably, the wide-target lipidomic analyses revealed significant changes in sterols and sphingolipids, the major PM components, in the ΔMovast2 mutant, which was involved in lipid metabolism and autophagic pathways. These findings confirmed that the functions of MoVast1 were regulated by MoVast2, revealing that MoVast2 combined with MoVast1 maintained lipid homeostasis and autophagy balance by regulating TOR activity in M. oryzae. [ABSTRACT FROM AUTHOR]

Plant diseases caused by fungi are one of the major threats to global food security and understanding the interactions between fungi and plants is of great significance for plant disease control. The interaction between pathogenic fungi and plants is a complex process. From the perspective of pathogenic fungi, pathogenic fungi are involved in the regulation of pathogenicity by surface signal recognition proteins, MAPK signaling pathways, transcription factors, and pathogenic factors in the process of infecting plants. From the perspective of plant immunity, the signal pathway of immune response, the signal transduction pathway that induces plant immunity, and the function of plant cytoskeleton are the keys to studying plant resistance. In this review, we summarize the current research progress of fungi–plant interactions from multiple aspects and discuss the prospects and challenges of phytopathogenic fungi and their host interactions. [ABSTRACT FROM AUTHOR]

The conidia of Pyricularia oryzae were cultured on barley grain medium for 17 days in this study. Two hundred milliliters of barley grains of each tested strain were cultured in a 500 mL Erlenmeyer flask. The conidia were eluted with 300 mL of sterile water from the cultivated barley grains in each flask. The barley grains were placed in aluminum plates for continued cultivation. The conidia were eluted with 48 h of interval culture, and the elution method used each time was the same as that used for the first elution. All the tested strains could be eluted 6 times; thus, we obtained a large number of conidia. The numbers of conidia produced in the elutions of all the strains were significantly different, with the smallest number produced in the first elution, followed by a gradual increase and then a gradual decrease after reaching the peak; the number of conidia produced in the sixth elution, that is, the final elution, was also low. The total number of conidia and the total number of effective conidia differed among the strains. A large number of effective conidia can be obtained by using the method described in this study, and much time can be saved because the conidia can be eluted six times in one culture cycle. [ABSTRACT FROM AUTHOR]

The objective of this study was to preliminarily analyze the differences in pathogenicity and physiologic races between Pyricularia oryzae isolates from indica and japonica rice varieties. Five to 7 isolates of P. oryzae from indica and japonica, having good sporulation capacity, were screened out in each experimental year. To determine the pathogenicity of P. oryzae, different kinds of rice varieties were inoculated with mixtures of indica and japonica isolates. A total of 46 isolates, including 23 indica isolates and 23 japonica isolates, were screened out in four years. In total, 1252 rice varieties, including 490 indica, 296 japonica and 466 indica-japonica hybrid rice varieties, were inoculated. Our results suggested that the degree of disease was more severe in most indica varieties infected with indica isolates than in those infected with japonica isolates. That is, indica isolates were more inclined to infect indica varieties. A majority of japonica and indica-japonica hybrid rice varieties infected with japonica isolates showed more severe infection than those infected with indica isolates. In other words, japonica isolates more easily infected japonica and indica-japonica hybrid rice varieties. The differences in quantity among the varieties indicated high resistance to rice blast in the corresponding kinds of rice inoculated with indica and japonica isolates, fully explaining the above viewpoint. Most of the 23 indica isolates belonged to indica races. Among the 23 japonica isolates, half were indica races and half were japonica races. In addition, there were significant differences between the isolates selected in the first two years and those selected in the second two years. The isolates in the first two years were all of indica races, and those of japonica races all appeared in the second two years. The results showed that the race of isolates shared little association with the kind of rice variety collected but was associated with the year of neck blast sample collection. [ABSTRACT FROM AUTHOR]

Contamination control and removal are very important technical aspects of microbiological research. Bacterial contamination is very common in fungal cultures. Currently, the commonly used approach for inhibiting bacteria is antibiotic treatment; however, there are drawbacks to using antibiotics, including incomplete removal, limited antibacterial spectra, tendency toward recontamination, effects to fungal strains, and potential risks to the environment. Therefore, in the present work, we developed a new method for bacterial removal from fungi cultured on solid medium, the Cabin-Sequestering (CS) method, based on the different culture characteristics between fungi and bacteria. First, 3–5 mm round or square holes (the "cabin") are excavated on a solid medium plate. The fungal strain containing possible bacterial contamination is inoculated into the cabin. The cabin is then covered with a sterilized coverslip, followed by incubation at the appropriate temperature. After 7–10 days of culturing, fungal hyphae grow out along the edge of the coverslip; however, the contaminating bacteria cannot pass through the space formed between the medium and the coverslip and, thus, remain in the cabin. The newly grown fungal hyphae around the coverslip are re-inoculated into fresh culture plates, where they form bacteria-free fungal colonies. The CS method is easy handling, with a short experimental cycle and rare recontamination. When necessary, it can also be used in combination with antibiotics in bacterial removal operations. [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]

Extracting global texture feature through sparse representation faced some problems, which mainly caused by high dimension. In order to solve those problems, this paper proposed a feature extraction and classification method based on random feature dictionary. The proposed method utilized the distribution of non-zero coefficients, which were computed by sparse decomposition, to generate a statistics histogram feature. The acquired histogram could reflect the dictionary atoms' using frequency in sparse decomposition, and was able to reflect the class information. Thus, the classification could be realized. For the sake of improving classification accuracy, it fused multi-scale and multi-direction wavelet features through random projection, and then trained a more descriptive dictionary by those fused features. In the classification experiments, it achieved 94.79% classification accuracy. Further experiments and analysis prove that the proposed method is robust under noisy and bad illumination conditions, and has characteristics of effective and stable in global texture feature extraction. [ABSTRACT FROM AUTHOR]

Abstract: Inoculation methods for rice blast fungus Magnaporthe oryzae to Brachypodium distachyon were developed to investigate the infection process and symptom development in comparison with those on rice (Oryza sativa) and barley (Hordeum vulgare). M. oryzae could infect leaves, sheathes, stems and panicles of B. distachyon and cause blast disease. Spraying conidial suspension on either intact seedlings or leaf segments induced typical symptoms on B. distachyon. During the intact seedling inoculation, the symptom developed on B. distachyon leaves closely resembled that on rice; but the lesions on B. distachyon had better uniformity in shapes and sizes than those on rice or barley. In the leaf segments inoculation, only initial and low-developed lesions could be found on rice, while normal symptoms on B. distachyon and barley. Inoculated with low-virulent mutants of M. oryzae, B. distachyon produced low-level symptoms. The symptom level of each mutant on B. distachyon corresponded well to that on rice. In addition, typical infection processes presented on B. distachyon leaves: forming melanized appressoria, penetrating into host epidermis and then forming hyphae in epidermal cells. According to these results, B. distachyon can be used as a candidate for studying fungus-plant interactions and as a probable source of disease resistance. [Copyright &y& Elsevier]

Abstract: To find new genes involved in fungal pathogenicity, a mutant (B11) exhibiting enhanced pathogenicity was isolated from an Agrobacterium-mediated transformed Magnaporthe oryzae mutant library. Southern blotting analysis showed that T-DNA insertion in the B11 genome was a single copy. TAIL-PCR and sequence alignment analyses revealed that a putative gene locus MG01679 was interrupted by the T-DNA fragment. By using the PCR-based method, the DNA and cDNA of the mutant gene MG01679 was cloned and sequenced. The open reading frame of MG01679 includes one intron and two exons, and the coding sequence is 696 bp in length and encodes a 231 amino acid peptide. Protein similarity analysis indicated that the gene belongs to the ThiJ/Pfp I protein family, and the gene was thus designated MgThiJ1. MgThiJ1 showed 57% similarity to FOXG_09029 from Fusarium oxysporum and 54% similarity to FGSG_08979 from F. graminearum in protein sequence. MgThiJ1 gene might act as a negative regulator in vegetative growth and pathogenesis in filamentous fungi, and its specific mechanism needs to be studied further. [Copyright &y& Elsevier]