An Electrochromic Ag-Decorated WO3-x Film with Adjustable Defect States for Electrochemical Surface-Enhanced Raman Spectroscopy.

Electrochemical surface-enhanced Raman scattering (EC-SERS) spectroscopy is an ultrasensitive spectro-electrochemistry technique that provides mechanistic and dynamic information on electrochemical interfaces at the molecular level. However, the plasmon-mediated photocatalysis hinders the intrinsic electrochemical behavior of molecules at electrochemical interfaces. This work aimed to develop a facile method for constructing a reliable EC-SERS substrate that can be used to study the molecular dynamics at electrochemical interfaces. Herein, a novel Ag-WO3-x electrochromic heterostructure was synthesized for EC-SERS. Especially, the use of electrochromic WO3-x film suppresses the influence of hot-electrons-induced catalysis while offering a reliable SERS effect. Based on this finding, the real electrochemical behavior of p-aminothiophenol (PATP) on Ag nanoparticles (NPs) surface was revealed for the first time. We are confident that metal-semiconductor electrochromic heterostructures could be developed into reliable substrates for EC-SERS analysis. Furthermore, the results obtained in this work provide new insights not only into the chemical mechanism of SERS, but also into the hot-electron transfer mechanism in metal-semiconductor heterostructures.

Distinct replication and gene expression strategies of the Rice Stripe virus in vector insects and host plants.

Persistent propagative plant viruses are usually transmitted between a vector insect and a host plant. To adapt to the two different organisms, viruses may show distinct genomic replication or gene expression patterns. To verify this hypothesis, we applied an aboslute real-time quantitative PCR method to measure and compare the replication levels of four genomic RNA segments and the expression levels of seven genes of rice stripe virus (RSV) according to the infection time in the small brown planthopper and rice plant, respectively. In the vector insect, RNA3 began replicating later than the other segments, and RNA2 remained nearly constant during the infection process. RNA1 was the dominant segment, and a difference of over 300-fold appeared among the four segments. In rice plants, the size of the four segments increased with infection time, but decreased to a low level in the late infection period. The ratios of the four segments varied by no more than 15-fold. In planthoppers, three expression patterns were observed for the seven viral genes during viral infection, while in rice plants, the expression patterns of the seven viral genes were similar. These results reflect distinct genomic replication and gene expression patterns in a persistent propagative plant virus in adapting to vector insects and host plants.

Immune responses induced by different genotypes of the disease-specific protein of Rice stripe virus in the vector insect.

Persistent plant viruses circulate between host plants and vector insects, possibly leading to the genetic divergence in viral populations. We analyzed the single nucleotide polymorphisms (SNPs) of Rice stripe virus (RSV) when it incubated in the small brown planthopper and rice. Two SNPs, which lead to nonsynonymous substitutions in the disease-specific protein (SP) of RSV, produced three genotypes, i.e., GG, AA and GA. The GG type mainly existed in the early infection period of RSV in the planthoppers and was gradually substituted by the other two genotypes during viral transmission. The two SNPs did not affect the interactions of SP with rice PsbP or with RSV coat protein. The GG genotype of SP induced stronger immune responses than those of the other two genotypes in the pattern recognition molecule and immune-responsive effector pathways. These findings demonstrated the population variations of RSV during the circulation between the vector insect and host plant.

Genome sequence of the small brown planthopper, Laodelphax striatellus.

Background: Laodelphax striatellus Fallén (Hemiptera: Delphacidae) is one of the most destructive rice pests. L. striatellus is different from 2 other rice planthoppers with a released genome sequence, Sogatella furcifera and Nilaparvata lugens, in many biological characteristics, such as host range, dispersal capacity, and vectoring plant viruses. Deciphering the genome of L. striatellus will further the understanding of the genetic basis of the biological differences among the 3 rice planthoppers. Findings: A total of 190 Gb of Illumina data and 32.4 Gb of Pacbio data were generated and used to assemble a high-quality L. striatellus genome sequence, which is 541 Mb in length and has a contig N50 of 118 Kb and a scaffold N50 of 1.08 Mb. Annotated repetitive elements account for 25.7% of the genome. A total of 17 736 protein-coding genes were annotated, capturing 97.6% and 98% of the BUSCO eukaryote and arthropoda genes, respectively. Compared with N. lugens and S. furcifera, L. striatellus has the smallest genome and the lowest gene number. Gene family expansion and transcriptomic analyses provided hints to the genomic basis of the differences in important traits such as host range, migratory habit, and plant virus transmission between L. striatellus and the other 2 planthoppers. Conclusions: We report a high-quality genome assembly of L. striatellus, which is an important genomic resource not only for the study of the biology of L. striatellus and its interactions with plant hosts and plant viruses, but also for comparison with other planthoppers.