Phylogenetic Analysis of Citrus tristeza virus Isolates of Wild Type Citrus in China

The genetic variation and phylogenetic relationships of Citrus tristeza virus （CTV） isolates collected from Chinese wild type citrus were analyzed by comparing the sequences of nine genomic regions （p23, p20, p13, p18, p25, p27, POL, HEL and k17） with the CTV isolates of cultivated citrus from different countries. The results showed that the divergence pattern of genomic RNA of the CTV isolates from wild type citrus was similar to that of other isolates from cultivated citrus, the 3′ proximal region was relatively conserved, and the 5′ proximal region had greater variability. The nine genomic regions of CTV isolates analyzed were found to have been under purifying selection in the evolution process. Phylogenetic analysis showed that the eleven Chinese wild CTV isolates were located at different clades and did not relfect their geographical origins, suggesting genetic diversity among the Chinese wild CTV populations. These results will aid in the understanding of molecular evolution of the Chinese CTV populations.

Species Composition, Richness and Aboveground Biomass of Natural Grassland in Hilly-Gully Regions of the Loess Plateau, China

In order to study the characteristics of species composition, richness and aboveground biomass of natural grasslands, and then ifnd out the relations between species richness and aboveground productivity of the communities and possible mechanisms to form the relations, four typical grassland communities （Artemisia capillaries （AC）, Thymus quinquecostatus （TQ）, Stipa bungeana （SB） and Stipa grandis （SG）） along with a succession sequence in hilly-gully regions of the Loess Plateau, China, were investigated by ifeld survey and laboratory analysis. The results were summarized as follows：Different succession stages had different species compositions as well as different proportions of plant life forms and photosynthetic types, and Asteraceae, Poaceae and Leguminosae were their dominant species as well as their dominant perennial herb species;and different succession stages had signiifcantly different species richness and aboveground biomasses. There were many relation patterns （linear positive correlation, unrelated relations and unimodal relations） between the species richness and aboveground biomass in different succession stages and a signiifcant unimodal relation between the species richness and aboveground biomass in all the grassland communities and the highest species diversity appeared at a moderate level of productivity. The results suggest the unimodal relations in all the grassland communities are accumulative results of the relations in each succession stage.

Single-cell transcriptomics reveals cell type diversity of human prostate

Extensive studies have been performed to describe the phenotypic changes occurring during malignant transformation of the prostate.However,the cell types and associated changes that contribute to the development of prostate diseases and cancer remain elusive,largely due to the heterogeneous composition of prostatic tissues.Here,we conduct a comprehensive evaluation of four human prostate tissues by singlecell RNA sequencing(sc RNA-seq)to analyze their cellular compositions.We identify 18 clusters of cell types,each with distinct gene expression profiles and unique features;of these,one cluster of epithelial cells(Ep)is found to be associated with immune function.In addition,we characterize a special cluster of fibroblasts and aberrant signaling changes associated with prostate cancer(PCa).Moreover,we provide insights into the epithelial changes that occur during the cellular senescence and aging.These results expand our understanding of the unique functional associations between the diverse prostatic cell types and the contributions of specific cell clusters to the malignant transformation of prostate tissues and PCa development.

Effects of landscape heterogeneity and breeding habitat diversity on rice frog abundance and body condition in agricultural landscapes of Yangtze River Delta,China

Amphibia ns play a key role in structuring biological assemblages of agricultural landscapes,but they are threatened by global agricultural intensification.Landscape structure is an important variable in flue ncing biodiversity in agricultural la ndscapes.However,in the Yangtze River Delta,where a"farmland-orchard-fishpond"agricultural pattern is common,the effects of landscape construction on anuran populations are unclear.In this study,we examined the effects of agricultural landscape parameters on the abundance and body condition of the rice frog(Fejervarya multistriata),which is a dominant anuran species in farmland in China.Employing a visual encounter method,we surveyed rice frog abundance for 3years across 20 agricultural landscapes.We also calculated the body condition index(BCD of 188 male frog individuals from these agricultural landscapes.Landscape variables,comprising landscape compositional heterogeneity(using the Shannon diversity in dex of all land cover types except buildings and roads),Ian dscape con figurational heterogeneity(using landscape edge density),breeding habitat diversity(using the number of 5 waterbody types available as breeding habitats),and areas of forest were also measured for each 1-km radius landscape.We found that the amount of forest in each agricultural Iandscape had a sign讦icant positive relationship with rice frog abundance,and breeding habitat diversity was positively related to the BCI of male rice frogs.However,body condition was negatively impacted by landscape configurational heterogeneity.Our results suggested the importance of nonagricultural habitats in agricultural landscapes,such as waterbodies and forest,to benefit rice frog population persistenee.