Isolation and Identification of Squash Leaf Curl China Virus in Zucchini

[Objectives]In 2019,virus diseases occurred widely on zucchini planted in Shandong Province.The disease symptom was different from previous reports.This study aimed to identify the pathogen causing the zucchini virus disease.[Methods]Ten diseased zucchini leaves were collected in the field and used as materials for PCR and sequencing.[Results]PCR detection and sequencing showed that the nucleotide sequence of the amplified fragment had the highest identity with the squash isolate of squash leaf curl China virus(SLCCNV)(MW389919.1)in Guangdong Province.Primers were further designed for amplifying the full-length SLCCNV.The full-length DNA-A was 2730 bp(OM692270.1),and the full-length DNA-B was 2711 bp(OM692269.1).Through sequence alignment,it was found that the DNA-A sequence shared identity of 89.65%-99.42%with registered SLCCNV,and the identity with the SLCCNV-GDHY pumpkin isolate(MW389919.1)in Guangdong was the highest,at 99.42%.The DNA-B sequence was identical with registered SLCCNV in the range of 81.82%-97.29%,and the identity with the SLCCNV-GDHY pumpkin isolate(MW389918.1)in Guangdong,was the highest,at 97.29%.Therefore,it was speculated that SLCCNV is the pathogen of zucchini virus disease.Since the virus was first found on zucchini in Shandong,it was named SLCCNV-SD.[Conclusions]This study provides materials for the research on the spread of SLCCNV in China and the analysis of population genetic characteristics,as well as a reference for the prevention and control of the virus in zucchini.

Carbon Dots Promote the Performance of Anodized Nickel Passivation Film on Ethanol Oxidation by Enhancing Oxidation of the Intermediate

Ethanol is considered a better fuel than methanol in direct alcohol fuel cells because of the high energy density and low toxicity.Compared with noble metal catalysts,nickel-based catalysts are much cheaper in price.However,present nickel-based catalysts still surfer from some disadvantages such as low activity and high overpotential.In this paper;we show a new and high efficient nickel-based catalyst for ethanol oxidation.A layer of anodized nickel passivation film(Ni-APF)was formed on the surface of nickel sheet by anodic oxidation method with carbon dots(CDs)as co-catalyst.At the current density of 110 mA·cm^(-2),the potential for Ni-APF/CDs was only 0.541 V(vs.Ag/AgCI),which was 18.8% lower than that of Ni-APF.Low overpotential could reduce electrode thermal loss and increase output energy.Ni-APF/CDs showed 144.4 mA·cm^(-2) peak current density at peak potential 0.662 V(vs.Ag/AgCI),which was 31% higher than that of Ni-APF(110.3 mA·cm^(-2)).In this system,CDs mainly function in the increase of charge-transfer capacity and the promotion oxidation of carbonaceous intermediates.

Boosting electrocatalytic selectivity in carbon dioxide reduction:The fundamental role of dispersing gold nanoparticles on silicon nanowires

Carbon dioxide electrochemical reduction(CO_(2)RR)has been recognized as an efficient way to mitigate CO_(2)emissions and alleviate the pressure on global warming and associated environmental consequences.Gold(Au)is reported as stable and active electrocatalysts to convert CO_(2)to CO at low overpotential due to its moderate adsorption strength of^(*)COOH and^(*)CO.The request for improved catalytic performance,however,is motivated by current unsatisfied catalytic selectivity because of the side hydrogen evolution reaction.In this context,the design of Au based binary catalysts that can boost CO selectivity is of great interest.In the present work,we report that Au nanoparticles can be feasibly dispersed and anchored on silicon nanowires to form Au-Si binary nanomaterials.The Au-Si may stably drive CO_(2)RR with a CO Faraday efficiency of 95.6%at−0.6 V vs.RHE in 0.5 mol/L KHCO_(3)solution.Such selectivity outperforms Au particles by up to 61%.Controlled experiments illustrate that such catalytic enhancement can chiefly be ascribed to electronic effects of binary catalysts.Theoretical calculations reveal that spontaneously produced silicon oxide may not only inhibit hydrogen evolution reaction,but also stabilize the key intermediate^(*)COOH in CO formation.