To assess genetic diversity in populations of the brown planthopper (Nilaparvata lugens Stål) (Homoptera: Delphacidae), we have developed and applied microsatellite, or simple sequence repeat (SSR), markers from expressed sequence tags (ESTs). We found that the brown planthopper clusters of ESTs were rich in SSRs with unique frequencies and distributions of SSR motifs. Three hundred and fifty-one EST-SSR markers were developed and yielded clear bands from samples of four brown planthopper populations. High cross-species transferability of these markers was detected in the closely related planthopper N. muiri. The newly developed EST-SSR markers provided sufficient resolution to distinguish within and among biotypes. Analyses based on SSR data revealed host resistance-based genetic differentiation among different brown planthopper populations; the genetic diversity of populations feeding on susceptible rice varieties was lower than that of populations feeding on resistant rice varieties. This is the first large-scale development of brown planthopper SSR markers, which will be useful for future molecular genetics and genomics studies of this serious agricultural pest.
In this study, the PEST-SWOT model was adopted to analyze how to construct a well-developed smart city. Based on data from the National Bureau of Statistics and industry reports, we found that smart city construction is faced with threats such as a lack of overall planning and experience, narrow financing channels, data security issues, information islands, and the scarcity of talent. It follows that efforts should be made to resource guarantee, technology improvement and talent construction. Last but not least, it is high-quality and sustainable development that we should pursue in building smart cities.
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