Study on the in situ desulfurization and viscosity reduction of heavy oil over MoO_(3)–ZrO_(2)/HZSM-5 catalyst

Heavy oil is characterized by high viscosity.High viscosity makes it challenging to recover and transport.HZSM-5,MoO_(3)/HZSM-5,ZrO_(2)/HZSM-5 and MoO_(3)–ZrO_(2)/HZSM-5 catalysts were developed to promote in situ desulfurization and viscosity reduction of heavy oil.The physical and chemical properties of catalysts were characterized by XPS,XRD,TEM,NH3-TPD,etc.The effects of temperature,catalyst type and addition amount on viscosity and composition of heavy oil were evaluated.The results showed that the presence of MoO_(3)–ZrO_(2)/HZSM-5 nanoparticles during aquathermolysis could improve the oil quality by reducing the heavy fractions.It reduced viscosity by 82.56%after the reaction at 280℃ and catalyst addition of 1 wt%.The contents of resins and asphaltic in the oil samples were 5.69%lower than that in the crude oil.Sulfur content decreased from 1.45%to 1.03%.The concentration of H2S produced by the reaction was 2225 ppm.The contents of sulfur-containing functional groups sulfoxide and sulfone sulfur in the oil samples decreased by 19.92%after the catalytic reaction.The content of stable thiophene sulfur increased by 5.71%.This study provided a basis for understanding the mechanism of heavy oil desulfurization and viscosity reduction.

CRISPR/Cas9-mediated VvPR4b editing decreases downy mildew resistance in grapevine(Vitis vinifera L.)

Downy mildew of grapevine(Vitis vinifera L.),caused by the oomycete pathogen Plasmopara viticola,is one of the most serious concerns for grape production worldwide.It has been widely reported that the pathogenesis-related 4(PR4)protein plays important roles in plant resistance to diseases.However,little is known about the role of PR4 in the defense of grapevine against P.viticola.In this study,we engineered loss-of-function mutations in the VvPR4b gene from the cultivar“Thompson Seedless”using the CRISPR/Cas9 system and evaluated the consequences for downy mildew resistance.Sequencing results showed that deletions were the main type of mutation introduced and that no off-target events occurred.Infection assays using leaf discs showed that,compared to wild-type plants,the VvPR4b knockout lines had increased susceptibility to P.viticola.This was accompanied by reduced accumulation of reactive oxygen species around stomata.Measurement of the relative genomic abundance of P.viticola in VvPR4b knockout lines also demonstrated that the mutants had increased susceptibility to the pathogen.Our results confirm that VvPR4b plays an active role in the defense of grapevine against downy mildew.

Pathogen development and host responses to Plasmopara viticola in resistant and susceptible grapevines:an ultrastructural study

The downy mildew disease in grapevines is caused by Plasmopara viticola.This disease poses a serious threat wherever viticulture is practiced.Wild Vitis species showing resistance to P.viticola offer a promising pathway to develop new grapevine cultivars resistant to P.viticola which will allow reduced use of environmentally unfriendly fungicides.Here,transmission and scanning microscopy was used to compare the resistance responses to downy mildew of three resistant genotypes of V.davidii var.cyanocarpa,V.piasesezkii and V.pseudoreticulata and the suceptible V.vinifera cultivar‘Pinot Noir’.Following inoculation with sporangia of P.viticola isolate‘YL’on V.vinifera cv.‘Pinot Noir’,the infection was characterized by a rapid spread of intercellular hyphae,a high frequency of haustorium formation within the host’s mesophyll cells,the production of sporangia and by the absence of host-cell necrosis.In contrast zoospores were collapsed in the resistant V.pseudoreticulata‘Baihe-35-1’,or secretions appeared arround stomata at the beginning of the infection period in V.davidii var.cyanocarpa‘Langao-5’and V.piasezkii‘Liuba-8’.The main characteristics of the resistance responses were the rapid depositions of callose and the appearance of empty hyphae and the plasmolysis of penetrated tissue.Moreover,collapsed haustoria were observed in V.davidii var.cyanocarpa‘Langao-5’at 5 days post inoculation(dpi)and in V.piasezkii‘Liuba-8’at 7 dpi.Lastly,necrosis extended beyond the zone of restricted colonization in all three resistant genotypes.Sporangia were absent in V.piasezkii‘Liuba-8’and greatly decreased in V.davidii var.cyanocarpa‘Langao-5’and in V.pseudoreticulata‘Baihe-35-1’compared with in V.vinifera cv.‘Pinot Noir’.Overall,these results provide insights into the cellular biological basis of the incompatible interactions between the pathogen and the host.They indicate a number of several resistant Chinese wild species that could be used in developing new cultivars having good levels of downy mildew resistance.

Transcriptome of Erysiphe necator-infected Vitispseudoreticulata leaves provides insight into grapevineresistance to powdery mildew

Powdery mildew(PM),which is caused by the pathogen Erysiphe necator(Schw.)Burr.,is the single most damaging disease of cultivated grapes(Vitis vinifera)worldwide.However,little is known about the transcriptional response of grapes to infection with PM.RNA-seq analysis was used for deep sequencing of the leaf transcriptome to study PM resistance in Chinese wild grapes(V.pseudoreticulata Baihe 35-1)to better understand the interaction between host and pathogen.Greater than 100 million(M)90-nt cDNA reads were sequenced from a cDNA library derived from PM-infected leaves.Among the sequences obtained,6541 genes were differentially expressed(DEG)and were annotated with Gene Ontology terms and by pathway enrichment.The significant categories that were identified included the following:defense,salicylic acid(SA)and jasmonic acid(JA)responses;systemic acquired resistance(SAR);hypersensitive response;plant–pathogen interaction;flavonoid biosynthesis;and plant hormone signal transduction.Various putative secretory proteins were identified,indicating potential defense responses to PMinfection.In all,318 putative R-genes and 183 putative secreted proteins were identified,including the defense-related R-genes BAK1,MRH1 and MLO3 and the defense-related secreted proteins GLP and PR5.The expression patterns of 16 genes were further illuminated by RT-qPCR.The present study identified several candidate genes and pathways that may contribute to PM resistance in grapes and illustrated that RNA-seq is a powerful tool for studying gene expression.The RT-qPCR results reveal that effective resistance responses of grapes to PM include enhancement of JA and SAR responses and accumulation of phytoalexins.

Proteomic analysis of early-stage incompatible and compatible interactions between grapevine and P.viticola

Wild grapevines can show strong resistance to the downy mildew pathogen P.viticola,but the associated mechanisms are poorly described,especially at early stages of infection.Here,we performed comparative proteomic analyses of grapevine leaves from the resistant genotype V.davidii“LiuBa-8”(LB)and susceptible V.vinifera“Pinot Noir”(PN)12h after inoculation with P.viticola.By employing the iTRAQ technique,a total of 444 and 349 differentially expressed proteins(DEPs)were identified in LB and PN,respectively.The majority of these DEPs were related to photosynthesis,respiration,cell wall modification,protein metabolism,stress,and redox homeostasis.Compared with PN,LB showed fewer downregulated proteins associated with photosynthesis and more upregulated proteins associated with metabolism.At least a subset of PR proteins(PR10.2 and PR10.3)was upregulated upon inoculation in both genotypes,whereas HSP(HSP70.2 and HSP90.6)and cell wall-related XTH and BXL1 proteins were specifically upregulated in LB and PN,respectively.In the incompatible interaction,ROS signaling was evident by the accumulation of H_(2)O_(2),and multiple APX and GST proteins were upregulated.These DEPs may play crucial roles in the grapevine response to downy mildew.Our results provide new insights into molecular events associated with downy mildew resistance in grapevine,which may be exploited to develop novel protection strategies against this disease.