Publications by authors named "Xiao-Xiao Feng"

16 Publications

  • Page 1 of 1

Effects of rice straw/wood sawdust addition on the transport/conversion behaviors of heavy metals during the liquefaction of sewage sludge.

J Environ Manage 2020 Sep 10;270:110824. Epub 2020 Jun 10.

School of Land Resources and Environment, Key Laboratory of Agricultural Resource and Ecology in the Poyang Lake Basin of Jiangxi Province, Jiangxi Agricultural University, Nanchang, 330045, PR China. Electronic address:

Lignocellulosic biomass has been widely introduced into the liquefaction process of sewage sludge (SS) to improve the yield/quality of liquefaction products (bio-oil/biochar). This study explores the effect of adding rice straw (RS) and wood sawdust (WS) on the transport/conversion behaviors of heavy metals (HMs) during the liquefaction of SS. The introduction of lignocellulosic biomass, especially for RS, substantially lowers the total content of HMs in biochar. Most HMs (except Cd) still remain in biochar, although the introduction of RS/WS enhances the transport of HMs into bio-oils. The addition of RS/WS raises the percentage of HMs in active form, but the contents of bioavailable/leachable HMs are not considerably increased and even decreased in some cases, especially when RS is introduced. The overall pollution degree and environmental risk of HMs in biochars are lowered to a certain extent with the addition of RS/WS. Considering that the pollution degree and environmental risk of HMs present in biochars are still at a considerable level, appropriate pollution management measures should be undertaken when using such biochars for agricultural use.
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http://dx.doi.org/10.1016/j.jenvman.2020.110824DOI Listing
September 2020

Xuefu Zhuyu Oral Liquid () Prevents Apoptosis of Ischemic Myocardium Cells in Rats by Regulating SIRT1 and Its Pathway-Related Genes.

Chin J Integr Med 2020 Jun 23;26(6):442-447. Epub 2019 Dec 23.

Department of Cardiology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, 100053, China.

Objective: To observe the changes of ischemic myocardial cells apoptosis in rats following intervention with Xuefu Zhuyu Oral Liquid (, XFZY), as well as changes of protein expression of silent information regulator 1 (SIRT1) and SIRT1 pathway-related genes.

Methods: H9c2 rat myocardial cells were divided into 6 groups: control group, oxygen glucose deprivation (OGD) group, SIRT1 siRNA group, OGD+SIRT1 siRNA group, OGD+XFZY group, and OGD+SIRT1 siRNA+XFZY group. Quantitative fluorescent polymerase chain reaction (PCR) and Western blot were used to detect the concentration variations of SIRT1 and its pathway-related genes and corresponding protein expression after XFZY intervention and SIRT1 transfection.

Results: Compared with the control group, the mRNA and protein expressions of SIRT1 were decreased obviously, while the mRNA and protein levels of P53, FoxO1, FoxO3, FoxO4 and nuclear factor kappa B (NF-ΚB) were increased in the OGD group, SIRT1 siRNA group, and OGD+SIRT1 siRNA group (P<0.01). Compared with the OGD group and OGD+SIRT1 siRNA group, the treatment of XFZY inhibited the decline in SIRT1 mRNA and protein expressions (P<0.01), and down-regulated the mRNA and protein levels of P53, FoxO1, FoxO3, FoxO4 and NF-ΚB, respectively (P<0.05 or P<0.01).

Conclusion: XFZY could prevent myocardial cells apoptosis probably by increasing the mRNA and protein expressions of SIRT1 and inhibiting the mRNA and protein expressions of P53, NF- K B, FoxO1, FoxO3 and FoxO4.
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http://dx.doi.org/10.1007/s11655-019-3076-9DOI Listing
June 2020

MoFap7, a ribosome assembly factor, is required for fungal development and plant colonization of .

Virulence 2019 12;10(1):1047-1063

State Key Laboratory for Rice Biology, Biotechnology Institute, Zhejiang University, Hangzhou, China.

Fap7, an important ribosome assembly factor, plays a vital role in pre-40S small ribosomal subunit synthesis in via its ATPase activity. Currently, the biological functions of its homologs in filamentous fungi remain elusive. Here, MoFap7, a homologous protein of ScFap7, was identified in the rice blast fungus , which is a devastating fungal pathogen in rice and threatens food security worldwide. Δ mutants exhibited defects in growth and development, conidial morphology, appressorium formation and infection, and were sensitive to oxidative stress. In addition, site-directed mutagenesis analysis confirmed that the conserved Walker A motif and Walker B motif in MoFap7 are essential for the biological functions of . We further analyzed the regulation mechanism of MoFap7 in pathogenicity. MoFap7 was found to interact with MoMst50, a regulator functioning in the MAPK Pmk1 signaling pathway, that participates in modulating plant penetration and cell-to-cell invasion by regulating the phosphorylation of MoPmk1. Moreover, MoFap7 interacted with the GTPases MoCdc42 and MoRac1 to control growth and conidiogenesis. Taken together, the results of this study provide novel insights into MoFap7-mediated orchestration of the development and pathogenesis of filamentous fungi.
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http://dx.doi.org/10.1080/21505594.2019.1697123DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6930019PMC
December 2019

Identification and characterization of new Muscodor endophytes from gramineous plants in Xishuangbanna, China.

Microbiologyopen 2019 04 21;8(4):e00666. Epub 2018 Jun 21.

State Key Laboratory for Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, China.

The endophytic fungi Muscodor spp. produce volatile organic compounds (VOCs) which can inhibit and even kill pathogenic fungi, bacteria, and nematodes. Nine endophytic fungal strains, isolated from the shoots of gramineous plants including Arthraxon hispidus, Eleusine indica, Oplismenus undulatifolius, and Oryza granulata, were identified as Muscodor through phylogenetic analysis of the internal transcribed spacer. Through an SPSS K-means cluster analysis, the nine Muscodor strains were divided into four groups based on the antifungal activities of the VOCs produced by these fungi determined by a two-section confrontation test. The first group contains the strains Y-L-54, W-S-41, Y-S-35, W-T-27, and Y-L-56, which showed the strongest activity. The second and third groups contain W-S-35 and Y-L-43, which showed stronger and moderate activity, respectively. The fourth group contains W-S-38 and N-L-7, which were the weakest in inhibiting the tested pathogens. Thirty-five compounds and the relative amounts of VOCs were determined by SPME-GC-MS and comparison with the NIST14 mass spectrometry database and Agilent MassHunter qualitative and quantitative analyses. These 35 compounds were classified into two different categories: (a) the product of fatty acid degradation, and (b) the intermediate and final metabolite of the metabolic pathway with the precursor of mevalonic acid. SPSS clustering analysis showed that the chemical components of VOCs might be correlated with their bioactivity rather than their phylogenetic assignment and some of the identified compounds might be responsible for antifungal activity. In conclusion, new Muscodor endophytes were recorded in tropical gramineous plants and a number of strains showed remarkable bioactive properties. Therefore, they have important potential applications in the fields of plant disease control.
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http://dx.doi.org/10.1002/mbo3.666DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6460276PMC
April 2019

Intravitreal anti-VEGF agents, oral glucocorticoids, and laser photocoagulation combination therapy for macular edema secondary to retinal vein occlusion: preliminary report.

Int J Ophthalmol 2018 18;11(3):429-437. Epub 2018 Mar 18.

State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, Guangdong Province, China.

Aim: To evaluate the efficacy and safety of combined anti-vascular endothelial growth factor (VEGF) agents, oral glucocorticoid, and laser photocoagulation therapy for macular edema (ME) secondary to retinal vein occlusion (RVO).

Methods: This study included 16 eyes of 16 patients with RVO-associated ME. Patients were initially treated with oral prednisone and an intravitreal anti-VEGF agent. Two weeks later, patients underwent standard laser photocoagulation. Best-corrected visual acuity (BCVA), central retinal thickness (CRT), and retinal vessel oxygenation were examined over 12mo.

Results: Patients received 1.43±0.81 anti-VEGF injections. Mean baseline and 12-month logMAR BCVA were 0.96±0.51 (20/178) and 0.31±0.88 (20/40), respectively, in eyes with central retinal vein occlusion (CRVO) (<0.00), and 1.02±0.45 (20/209) and 0.60±0.49 (20/80), respectively, in eyes with branch retinal vein occlusion (BRVO) (<0.00). At 12mo, CRT had significantly decreased in eyes with CRVO (<0.00) and BRVO (<0.00). Venous oxygen saturation had significantly increased in eyes with CRVO (<0.00) and BRVO (<0.00). No examined parameters were significantly different between the 2 RVO groups. No serious adverse effects occurred.

Conclusion: Anti-VEGF, glucocorticoid, and photocoagulation combination therapy improves visual outcome, prolongs therapeutic effect, and reduces the number of intravitreal injections in eyes with RVO-associated ME.
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http://dx.doi.org/10.18240/ijo.2018.03.13DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5861233PMC
March 2018

[Pharmacological mechanism analysis of oligopeptide from Pinctada fucata based on in silico proteolysis and protein interaction network].

Zhongguo Zhong Yao Za Zhi 2017 Sep;42(17):3424-3429

Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China.

Thoracic obstruction is mainly attributed to the scope of coronary heart disease in modern medicine, and traditional Chinese medicine(TCM) shows a significant effect in the treatment of thoracic obstruction. In this research, a network pharmacology method was carried out to systemically study the underlying mechanism of the core herbal compatibility in TCM on the thoracic obstruction. First, we collected the literature about TCM prescriptions for treating thoracic obstruction from CNKI. Then, a prescription database was establish by TCM inheritance support platform system(V2.5) to determine the medication rules and core herbal compatibility in TCM. Finally, to obtain the potential signaling pathways, KEGG pathway analysis was performed by BATMAN-TCM online analysis tool. Results showed that the potential signal pathway of core herbal compatibility in TCM for the clinical treatment of thoracic obstruction was calcium ion and cGMP-PKG signaling pathway. This study provided a new research strategy for the study of the medication rules and mechanism of traditional Chinese medicine in the treatment of thoracic obstruction.
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http://dx.doi.org/10.19540/j.cnki.cjcmm.20170731.009DOI Listing
September 2017

A Novel Derivative of (-)mycousnine Produced by the Endophytic Fungus , Exhibits High and Selective Immunosuppressive Activity on T Cells.

Front Microbiol 2017 5;8:1251. Epub 2017 Jul 5.

Institute of Materia Medica, Zhejiang Academy of Medical SciencesHangzhou, China.

An endophytic fungus, ZJLQ129, was isolated from the leaves of the traditional Chinese medicine Smilax china. From the fermentation broth and mycelium, a dibenzofurane compound (-)mycousnine (1) was isolated. Chemical modification of it to the amide derivative (-)mycousnine enamine (2), which is new to science, was found to have high and selective immunosuppressive activity: similar to cyclosporin A, (-)mycousnine enamine (2) selectively inhibited T cell proliferation, suppressed the expression of the surface activation antigens CD25 and CD69 and the formation and expression of the cytokines interleukin-2 as well as interferon γ in activated T cells, but did not show any effect on the proliferation of B cells and cancer cells (PANC-1 and A549) and the activation of macrophages. Furthermore, the cytotoxicity of (-)mycousnine enamine was lower than that of cyclosporin A, and its therapeutic index (TC50/EC50) was 4,463.5, which is five-fold higher than that of cyclosporin A. We conclude that (-)mycousnine enamine (2), the semi-synthestic product prepared from the native product (-)mycousnine (1) of the endophyte M. nawae is a novel effective immunosuppressant showing low toxicity and high selectivity.
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http://dx.doi.org/10.3389/fmicb.2017.01251DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5496962PMC
July 2017

An autophagy gene, HoATG5, is involved in sporulation, cell wall integrity and infection of wounded barley leaves.

Microbiol Res 2016 Nov 12;192:326-335. Epub 2016 Aug 12.

State Key Laboratory for Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, 310058, China. Electronic address:

The endophytic fungus Harpophora oryzae is a beneficial endosymbiont isolated from wild rice. H. oryzae can not only promote rice growth and biomass accumulation but also protect rice roots from invasion by its close relative Magnaporthe oryzae. Autophagy is a highly evolutionary conserved process from lower to higher eukaryotic organisms, and is involved in the maintenance of normal cell differentiation and development. In this study, we isolated a gene (HoATG5) which encodes an essential protein required for autophagy from the beneficial endophyte fungus H. oryzae. Using targeted gene replacement, a ΔHoATG5 mutant was generated and used to investigate the biological functions of autophagy in H. oryzae. We found that the autophagic process was blocked in the HoATG5 deletion mutant. The mutant showed increased vegetative growth and sporulation, and was sensitive to nutrient starvation. The ΔHoATG5 mutant lost its ability to penetrate and infect the wounded barley leaves. These results provide new knowledge to elaborate the molecular machinery of autophagy in endophytic fungi.
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http://dx.doi.org/10.1016/j.micres.2016.08.008DOI Listing
November 2016

Trichoderma Biodiversity of Agricultural Fields in East China Reveals a Gradient Distribution of Species.

PLoS One 2016 2;11(8):e0160613. Epub 2016 Aug 2.

State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang, China.

We surveyed the Trichoderma (Hypocreales, Ascomycota) biodiversity in agricultural fields in four major agricultural provinces of East China. Trichoderma strains were identified based on molecular approaches and morphological characteristics. In three sampled seasons (spring, summer and autumn), 2078 strains were isolated and identified to 17 known species: T. harzianum (429 isolates), T. asperellum (425), T. hamatum (397), T. virens (340), T. koningiopsis (248), T. brevicompactum (73), T. atroviride (73), T. fertile (26), T. longibrachiatum (22), T. pleuroticola (16), T. erinaceum (16), T. oblongisporum (2), T. polysporum (2), T. spirale (2), T. capillare (2), T. velutinum (2), and T. saturnisporum (1). T. harzianum, T. asperellum, T. hamatum, and T. virens were identified as the dominant species with dominance (Y) values of 0.057, 0.052, 0.048, and 0.039, respectively. The species amount, isolate numbers and the dominant species of Trichoderma varied between provinces. Zhejiang Province has shown the highest diversity, which was reflected in the highest species amount (14) and the highest Shannon-Wiener diversity index of Trichoderma haplotypes (1.46). We observed that relative frequencies of T. hamatum and T. koningiopsis under rice soil were higher than those under wheat and maize soil, indicating the preference of Trichoderma to different crops. Remarkable seasonal variation was shown, with summer exhibiting the highest biodiversity of the studied seasons. These results show that Trichoderma biodiversity in agricultural fields varies by region, crop, and season. Zhejiang Province (the southernmost province in the investigated area) had more T. hamatum than Shandong Province (the northernmost province), not only in isolate amounts but also in haplotype amounts. Furthermore, at haplotype level, only T. hamatum showed a gradient distribution from south to north in correspondence analysis among the four dominant species. The above results would contribute to the application of Trichoderma biocontrol strains.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0160613PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4970770PMC
July 2017

Agrobacterium tumefaciens-mediated transformation: An efficient tool for insertional mutagenesis and targeted gene disruption in Harpophora oryzae.

Microbiol Res 2016 Jan 9;182:40-8. Epub 2015 Oct 9.

State Key Laboratory for Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, China; China Tobacco Gene Research Center, Zhengzhou Tobacco Institute of CNTC, Zhengzhou, China. Electronic address:

The endophytic filamentous fungus Harpophora oryzae is a beneficial endosymbiont isolated from the wild rice. H. oryzae could not only effectively improve growth rate and biomass yield of rice crops, but also induce systemic resistance against the rice blast fungus, Magnaporthe oryzae. In this study, Agrobacterium tumefaciens-mediated transformation (ATMT) was employed and optimized to modify the H. oryzae genes by either random DNA fragment integration or targeted gene replacement. Our results showed that co-cultivation of H. oryzae conidia with A. tumefaciens in the presence of acetosyringone for 48 h at 22 °C could lead to a relatively highest frequency of transformation, and 200 μM acetosyringone (AS) pre-cultivation of A. tumefaciens is also suggested. ATMT-mediated knockout mutagenesis was accomplished with the gene-deletion cassettes using a yeast homologous recombination method with a yeast-Escherichia-Agrobacterium shuttle vector pKOHo. Using the ATMT-mediated knockout mutagenesis, we successfully deleted three genes of H. oryzae (HoATG5, HoATG7, and HoATG8), and then got the null mutants ΔHoatg5, ΔHoatg7, and ΔHoatg8. These results suggest that ATMT is an efficient tool for gene modification including randomly insertional mutagenesis and gene deletion mutagenesis in H. oryzae.
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http://dx.doi.org/10.1016/j.micres.2015.09.008DOI Listing
January 2016

Friend or foe: differential responses of rice to invasion by mutualistic or pathogenic fungi revealed by RNAseq and metabolite profiling.

Sci Rep 2015 Sep 8;5:13624. Epub 2015 Sep 8.

State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, 310058, China.

The rice endophyte Harpophora oryzae shares a common pathogenic ancestor with the rice blast fungus Magnaporthe oryzae. Direct comparison of the interactions between a single plant species and two closely-related (1) pathogenic and (2) mutualistic fungi species can improve our understanding of the evolution of the interactions between plants and fungi that lead to either mutualistic or pathogenic interactions. Differences in the metabolome and transcriptome of rice in response to challenge by H. or M. oryzae were investigated with GC-MS, RNA-seq, and qRT-PCR. Levels of metabolites of the shikimate and lignin biosynthesis pathways increased continuously in the M. oryzae-challenged rice roots (Mo-roots); these pathways were initially induced, but then suppressed, in the H. oryzae-challenged rice roots (Ho-roots). Compared to control samples, concentrations of sucrose and maltose were reduced in the Ho-roots and Mo-roots. The expression of most genes encoding enzymes involved in glycolysis and the TCA cycle were suppressed in the Ho-roots, but enhanced in the Mo-roots. The suppressed glycolysis in Ho-roots would result in the accumulation of glucose and fructose which was not detected in the Mo-roots. A novel co-evolution pattern of fungi-host interaction is proposed which highlights the importance of plant host in the evolution of fungal symbioses.
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http://dx.doi.org/10.1038/srep13624DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4642567PMC
September 2015

The rice endophyte Harpophora oryzae genome reveals evolution from a pathogen to a mutualistic endophyte.

Sci Rep 2014 Jul 22;4:5783. Epub 2014 Jul 22.

State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, 310058, China.

The fungus Harpophora oryzae is a close relative of the pathogen Magnaporthe oryzae and a beneficial endosymbiont of wild rice. Here, we show that H. oryzae evolved from a pathogenic ancestor. The overall genomic structures of H. and M. oryzae were found to be similar. However, during interactions with rice, the expression of 11.7% of all genes showed opposing trends in the two fungi, suggesting differences in gene regulation. Moreover, infection patterns, triggering of host defense responses, signal transduction and nutritional preferences exhibited remarkable differentiation between the two fungi. In addition, the H. oryzae genome was found to contain thousands of loci of transposon-like elements, which led to the disruption of 929 genes. Our results indicate that the gain or loss of orphan genes, DNA duplications, gene family expansions and the frequent translocation of transposon-like elements have been important factors in the evolution of this endosymbiont from a pathogenic ancestor.
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http://dx.doi.org/10.1038/srep05783DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4105740PMC
July 2014

Evidence for biotrophic lifestyle and biocontrol potential of dark septate endophyte Harpophora oryzae to rice blast disease.

PLoS One 2013 18;8(4):e61332. Epub 2013 Apr 18.

State Key Laboratory for Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, China.

The mutualism pattern of the dark septate endophyte (DSE) Harpophora oryzae in rice roots and its biocontrol potential in rice blast disease caused by Magnaporthe oryzae were investigated. Fluorescent protein-expressing H. oryzae was used to monitor the colonization pattern. Hyphae invaded from the epidermis to the inner cortex, but not into the root stele. Fungal colonization increased with root tissue maturation, showing no colonization in the meristematic zone, slight colonization in the elongation zone, and heavy colonization in the differentiation zone. H. oryzae adopted a biotrophic lifestyle in roots accompanied by programmed cell death. Real-time PCR facilitated the accurate quantification of fungal growth and the respective plant response. The biocontrol potential of H. oryzae was visualized by inoculation with eGFP-tagged M. oryzae in rice. H. oryzae protected rice from M. oryzae root invasion by the accumulation of H2O2 and elevated antioxidative capacity. H. oryzae also induced systemic resistance against rice blast. This systemic resistance was mediated by the OsWRKY45-dependent salicylic acid (SA) signaling pathway, as indicated by the strongly upregulated expression of OsWRKY45. The colonization pattern of H. oryzae was consistent with the typical characteristics of DSEs. H. oryzae enhanced local resistance by reactive oxygen species (ROS) and high antioxidative level and induced OsWRKY45-dependent SA-mediated systemic resistance against rice blast.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0061332PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3630206PMC
December 2013

Biotin tagging coupled with amino acid-coded mass tagging for efficient and precise screening of interaction proteome in mammalian cells.

Proteomics 2009 Dec;9(24):5414-24

Department of Proteomics and System Biology, Institute of Biomedical Science, Fudan University, Shanghai, PR China.

In mammalian cells, when tandem affinity purification approach is employed, the existence of untagged endogenous target protein and repetitive washing steps together result in overall low yield of purified/stable complexes and the loss of weakly and transiently interacting partners of biological significance. To avoid the trade-offs involving in methodological sensitivity, precision, and throughput, here we introduce an integrated method, biotin tagging coupled with amino acid-coded mass tagging, for highly sensitive and accurate screening of mammalian protein-protein interactions. Without the need of establishing a stable cell line, using a short peptide tag which could be specifically biotinylated in vivo, the biotin-tagged target/bait protein was then isolated along with its associates efficiently by streptavidin magnetic microbeads in a single step. In a pulled-down complex amino acid-coded mass tagging serves as "in-spectra" quantitative markers to distinguish those bait-specific interactors from non-specific background proteins under stringent criteria. Applying this biotin tagging coupled with amino acid-coded mass tagging approach, we first biotin-tagged in vivo a multi-functional protein family member, 14-3-3epsilon, which was expressed at close to endogenous level. Starting with approximately 20 millions of 293T cells which were significantly less than what needed for a tandem affinity purification run, 266 specific interactors of 14-3-3epsilon were identified in high confidence.
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http://dx.doi.org/10.1002/pmic.200800864DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4302342PMC
December 2009

An autophagy gene, MgATG5, is required for cell differentiation and pathogenesis in Magnaporthe oryzae.

Curr Genet 2009 Aug 24;55(4):461-73. Epub 2009 Jul 24.

College of Life Sciences, Zhejiang University, Yuhangtang Road 388, 310058, Hangzhou, China.

Autophagy is a conserved degradation pathway that is involved in the maintenance of normal cell differentiation and development. The Saccharomyces cerevisiae ATG5 gene is an important component of the autophagy process. In this study, we identified MgATG5 as an autophagy-related gene in Magnaporthe oryzae that is homologous to ATG5. Using targeted gene replacement, an Mgatg5Delta mutant was generated and fungal autophagy was blocked. Cytological analysis revealed that the mutant had poor fungal morphogenic development, including a shortened aerial hyphae lifespan, decreased conidiation and perithecia formation, delayed conidial germination and appressorial formation, postponement of conidial cytoplasm transfer during appressorium formation, and reduction in formation of the penetration peg. Turnover of endogenous matter in the Mgatg5 mutant was also affected, as demonstrated by defects in the formation of conidial lipid droplets, and in the degradation of conidial glycogen deposits during appressorium formation. Lipid droplets and glycogen are necessary to generate adequate turgor in appressoria for invading the host surface. As a result of the decreased appressorium turgor and differentiation in the penetration peg, Mgatg5Delta pathogenicity was deficient in two host plants tested. The developmental and pathogenic phenotypes were restored by the introduction of an intact copy of MgATG5 into Mgatg5Delta, demonstrating that the MgATG5 deletion was responsible for the cellular defects. Taken together, these findings suggest that autophagy promotes cell differentiation through turnover of endogenous matter during fungal development, and is thus essential for the pathogenicity of the rice blast fungus.
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http://dx.doi.org/10.1007/s00294-009-0259-5DOI Listing
August 2009

Mnh6, a nonhistone protein, is required for fungal development and pathogenicity of Magnaporthe grisea.

Fungal Genet Biol 2007 Sep 20;44(9):819-29. Epub 2007 Jun 20.

Biotechnology Institute, Zhejiang University, Kaixuan Road 268, Hangzhou 310029, China.

Mnh6, a nonhistone protein containing an HMG1 box, was isolated from the rice blast fungus, Magnaporthe grisea. In the current study, we utilized an MNH6-deletion mutant to investigate the role of Mnh6 in the disease cycle of M. grisea. The Deltamnh6 mutant exhibited pleiotropic effects on fungal morphogenesis, including reduction in mycelial growth, conidiation, appressorium development, plant penetration, and infectious growth in host cells. Furthermore, Deltamnh6 mutant had greatly reduced pathogenicity on barley and rice compared to the wild-type. The reintroduction of an intact copy of MNH6 into the Deltamnh6 mutant restored morphological features and pathogenicity, suggesting that Mnh6 is required for fungal development, effective pathogenicity, and completion of the disease cycle of M. grisea.
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http://dx.doi.org/10.1016/j.fgb.2007.06.003DOI Listing
September 2007