Germination and appressorium formation of Pyricularia oryzae Cavara can be inhibited by reduced concentration of Blasin~? Flowable with carbon dioxide microbubbles

We investigated the possibility to reduce the usage of Blasin^Flowable （BF）, a disinfectant inhibiting the germination and appressorium formation of Pyricularia oryzae Cavara conidia, by using carbon dioxide microbubbles （CO2MB）. Germination was significantly inhibited by 10 000-fold diluted BF solution containing CO2MB generated by the decompression-type generator compared to CO2 millibubbles （CO2MMB） and CO2MB generated by the gas-water circulating-type generator. Appressodum formation in the 10 000-fold diluted BF solution containing both CO2MBs was less than that in CO2MMB. Scanning electron microscopy showed wrinkles and dents on the surface of conidia treated with 5 000-fold diluted BF solution containing both CO2MBs. Via transmission electron microscopy, we observed the expansion of the vacuole and the intracellular space and bloated or absent lipid granules in the conidia treated with BF solution containing both CO2MBs. Our results show that inhibition of the conidium germination and appressorium formation of P. oryzae Cavara by 10 000-fold diluted BF solution could be achieved by using the decompression-type CO2MB.

Studies on the bioactivity of marine microorganisms using Pyricularia oryzae model

A total of 2 088 marine microorganisms including 1 392 strains of bacteria and 696 strains of fungi were isolated from diverse marine environment such as the South Pole, the North Pole, and Qingdao tideland, etc. Through a systematic screening process involving the use of Pyricularia oryzae mode, 90 bacteria and 31 fungi strains demonstrating positive bioactivities were identified. The rates of active strains of marine bacteria and marine fungi were 6.5% and 4.5%, respectively. The relationships between the active strains and the sampling locations and hosts were studied. For marine bacteria, the three locations showing the highest rotes of active strains were 8.4% in the Zhujiang Estuary, 7.2% at the North Pole and 6.3% in the Bohai Sea. For marine fungi, the highest rates observed were 7.8% at the South Pole, 7.4% in the South China Sea and 6.8% at the Qingdao tideland. An analysis of the host showed that the three highest rates of active strain for marine bacteria were 8.2% for seawater from the Zhujiang Estuary, 8% for alga from the Qingdao tideland and 7.6% for sea mud from the North Pole. For marine fungi, the highest rates observed were 8.3% for Qingdao actiniae, 7.4% for South China Sea poriferan and 4.5% for soil of Qingdao Suaeda salsa. Four fungi and two bacteria samples were selected for further study because of their high bioactivity. They were found to be active towards several pathogenic microorganisms, and demonstrated stable genetic and thermal characteristics and conservation activities.

Separation of Pyricularia oryzae chromosomal DNA by PFGE

Pyricularia oryzae is a fungal pathogen of rice.Few researches had been reported on the analysisof its genome, partly because the genomes can’t beseparated by general agarose gel electrophoresis.We herein report a technique to separatePyricularia oryzae genomic DNA by pulse-fieldgel electrophoresis(PFGE).The tested blast strain was 2539w.Chromosomal DNAs were directly prepared from

Triterpenoid Saponins from Eclipta prostrata L.

Five triterpenoid saponins were isolated from the Chinese traditional medicine Eclipta prostrata L.. On the basis of their chemical properties and spectral data, they were identified as eclalbasaponins II(1), I(2), III(3), 3-O-[b-D-glucopyranosyl(12)-b-D-glucopyranosyl]-16a-ethoxy-olean-12-ene-28-oic acid-28-O-b-D-glu-copyranoside(4) and 3-O-[(2-O-sulfuryl-b-D-glucopyranosyl)(12)-b-D-glucopyranosyl]-echinocystic acid-28-O-b-D-glucopyranoside(5). Compounds 4 and 5 are new compounds and named eclalbasaponins XI and XII, respectively. Compounds 1 and 5 induced morphological deformation of Pyricularia oryzae mycelia.

A New Steroidal Saponin from Dioscorea deltoidea Wall var. orbiculata

Bioactivity-guided fractionation led to the isolation of a new steroidal saponin, orbiculatoside B, together with a pair of furostanol saponins, protobioside and methyl protobioside, from the fresh rhizomes of Dioscorea deltoidea Wall var. orbiculata. The new compound was identified to be isonarthogenin 3 O - a - L - rhamnopyranosyl (12) - [ a - L - rhamnopyranosyl - ( 1 4 ) ] - b - D - glucopyranoside by various NMR techniques in combination with chemical methods. The three saponins showed strong activity against Pyricularia oryzae, and were cytotoxic to cancer cell line K562, HCT-15, A549, and A2780a in vitro.

A New Spirostanol Saponin from Dioscorea futshauensis

A new spirostanol saponin presenting strong activity of inducing morphological deformation of Pyricularia oryzae mycelia was isolated from Dioscorea futshauensis R. Kunth by bioactivity-guided fractionation. The structure was established as (25S)-spirost-5-en-3 beta, 27-diol-3-O- [alpha -L-rhamnopyranosyl (1 -->2)-beta -D glucopyranosyl (1 -->3)]-beta -D-glucopyranoside on the basis of chemical evidences and spectral analysis, especially by 2D-NMR techniques.

Fusarielin E,a new antifungal antibiotic from Fusarium sp.

A new antifungal antibiotic, fusarielin E, was isolated from the marine-derived fungus Fusarium sp. Its structure was established on the basis of various NMR spectroscopic analyses and HR-FAB-MS. Fusarielin E displayed significant biological activity against Pyricularia oryzae.

The putative elongator complex protein Elp3 is involved in asexual development and pathogenicity by regulating autophagy in the rice blast fungus

Autophagy is responsible for maintaining fundamental cellular homeostasis and is,therefore,essential for diverse development processes.This study reported that PoElp3,the putative catalytic subunit of Elongator complex,is involved in the maintenance of autophagy homeostasis to facilitate asexual development and pathogenicity in the rice blast fungus Pyricularia oryzae.It was found that the ΔPoelp3 strains were defective in vegetative growth,conidiation,stress response,and pathogenicity.The mutants exhibited hyper-activated autophagy in the vegetative hyphae under both nutrient-rich and nutrient-deficient conditions.The hyper-activation of autophagy possibly suppressed the production of vegetative hyphae in the ΔPoelp3 strains.Moreover,the ΔPoelp3 strains were found to be more sensitive to rapamycin during vegetative-and invasive-hyphal growth but have no effect on Target-of-Rapamycin(TOR)signaling inhibition.Taken together,these results demonstrated that PoElp3 is involved in asexual development and pathogenicity by regulating autophagy in the rice blast fungus.

5′-Hydroxyzearalenol,a new β-resorcylic macrolide from Fusarium sp. 05ABR26

A new β-resorcylic macrolide, 5＇-hydroxyzearalenol （1）, was isolated from the culture broth of a marine-derived fungus Fusarium sp. 05ABR26. Three known compounds, zearalenone （2）, 8＇-hydroxyzearalenone （3） and zearalenol （4） were also isolated. The structure and relative stereochemistry of 1 were elucidated on the basis of spectroscopic data and single-crystal X-ray diffraction data. Compound 2 displayed potent inhibitory activity against Pyricularia oryzae with a MIC value of 6.25 μg/mL, while compound 3 was much less active; however, 1 and 4 showed no obvious activity.

A New Triterpenoid Spaonin Isolated from the Seeds of Aesculus assamica Griff

A new triterpenoid saponin, 21 β-angeloylprotoaescigenin-3β-O- [α-L-rhamnopyranosyl- （1-3）]β-D-glucopyranosiduronic acid 1, was isolated from the seeds of Aesculus assamica Griff. Its structure was elucidated on the basis of spectroscopic data analysis.

A New Furostanol Saponin from Dioscorea futshauensis

A new furostanol saponin presenting moderate bioactivity of inducing morphological deformation of Pyricularia oryzae mycelia was isolated from Dioscorea futshauensis R.Kunth by bioactivity-guided fractionation. The structure was established as 26-O-b-D-glucopyranosyl-3b, 26-diol-23(S)-methoxyl-(25R)-furost-5,20 (22)-diene-3-O-[a-L-rhamnopyranosyl (12)-b-D- glucopyranosyl (13)]-b-D-glucopyranoside on the basis of chemical evidencesand spectral analysis, especially by 2D-NMR techniques.

A New Pregnane Glycoside from Dioscorea collettii var. hypoglauca

A new pregnane glycoside hypoglaucin G was isolated from Dioscorea collettii var. hypoglauca by bioactivity-guided fractionation, which showed a moderate activity of inducing morphological deformation of the Pyricularia oryzae mycelia. The structure of hypoglaucin G was established as 16 beta-(4'-methyl-5'-O-beta-D-glucopyranosyl-pentanoyloxy)-pregn-5-en-3 beta-ol-20-one 3-O-alpha-L-rhamnopyranosyl-(1-->2)-[alpha-L-rhamnopyranosyl-(1-->4)-]-beta-D-glucopyranoside by chemical evidence and spectral analysis, especially by 2D-NMR techniques.

Identification of propranolol and derivatives that are chemical inhibitors of phosphatidate phosphatase as potential broad-spectrum fungicides

Plant diseases cause enormous economic losses in agriculture and threaten global food security,and application of agrochemicals is an important method of crop disease control.Exploration of disease-resis-tance mechanisms and synthesis of highly bioactive agrochemicals are thus important research objectives.Here,we show that propranolol,a phosphatidate phosphatase(Pah)inhibitor,effectively suppresses fungal growth,sporulation,sexual reproduction,and infection of diverse plants.The MoPah1 enzyme activity of the rice blast fungus Magnaporthe oryzae is inhibited by propranolol.Alterations in lipid metabolism are associated with inhibited hyphal growth and appressorium formation caused by propranolol in M.oryzae.Propranolol inhibits a broad spectrum of 12 plant pathogens,effectively inhibiting infection of barley,wheat,maize,tomato,and pear.To improve antifungal capacity,we synthesized a series of propranolol derivatives,one of which shows a 16-fold increase in antifungal ability and binds directly to MoPah1.Propranolol and its derivatives can also reduce the severity of rice blast and Fusarium head blight of wheat in thefield.Taken together,our results demonstrate that propranolol suppresses fungal development and infection through mechanisms involved in lipid metabolism.Propranolol and its derivatives may therefore be promising candidates for fungicide development.