No abstract

No abstract

Background Ophiopogon japonicus, mainly planted in Sichuan (CMD) and Zhejiang (ZMD) province in China, has a lengthy cultivation history. During the long period of domestication, the genetic diversity of cultivated O. japonicus has substantially declined, which will affect the population continuity and evolutionary potential of this species. Therefore, it is necessary to clarify the phylogeography of cultivated O. japonicus to establish a theoretical basis for the utilization and conservation of the genetic resources of O. japonicus. Result The genetic diversity and population structure of 266 O. japonicus individual plants from 23 sampling sites were analyzed based on 4 chloroplast DNA sequences (atpB-rbcL, rpl16, psbA-trnH and rpl20-5’rps12) to identify the effects of domestication on genetic diversity of cultivars and determine their geographic origins. The results showed that cultivated O. japonicus and wild O. japonicus had 4 and 15 haplotypes respectively. The genetic diversity of two cultivars (Hd = 0.35700, π = 0.06667) was much lower than that of the wild populations (Hd = 0.76200, π = 0.20378), and the level of genetic diversity in CMD (Hd = 0.01900, π = 0.00125) was lower than that in ZMD (Hd = 0.06900, π = 0.01096). There was significant difference in genetic differentiation between the cultivated and the wild (FST = 0.82044), especially between the two cultivars (FST = 0.98254). This species showed a pronounced phylogeographical structure (NST > GST, P < 0.05). The phylogenetic tree showed that the genetic difference between CMD and ZMD was not enough to distinguish the cultivars between the two producing areas by using O. amblyphyllus Wang et Dai as an outgroup. In addition, both CMD and ZMD have a closer relationship with wild populations in Sichuan than that in Zhejiang. The results of the TCS network and species distribution model suggested that the wild population TQ located in Sichuan province could serve as the ancestor of cultivated O. japonicus, which was supported by RASP analysis. Conclusion These results suggest that cultivated O. japonicus has experienced dramatic loss of genetic diversity under anthropogenic influence. The genetic differentiation between CMD and ZMD is likely to be influenced by founder effect and strong artificial selection for plant traits. It appears that wild populations in Sichuan area are involved in the origin of not only CMD but also ZMD. In addition, we also raise some suggestions for planning scientific strategies for resource conservation of O. japonicus based on its genetic diversity and population structure.

Because of issues such as viewpoint changes, posture variations, and background cluttering, the task of person reidentification (Re-ID) remains challenging. The model of combining global features and part features has been widely used in person Re-ID technology in recent years, but these efforts ignored feature interaction between the convolutional layers and thus lost detailed information conducive to identifying pedestrians under different cameras. To achieve interaction between hierarchical features, a multibranch network with hierarchical bilinear pooling (MBN-HBP) is proposed. The network consists of a global branch, a part-level branch, and a hierarchical bilinear pooling (HBP) branch. The person features extracted by the network include not only global and part-level features but also detailed HBP features. The final feature representation will be more robust to deal with the complex surveillance environment. By conducting comprehensive experiments, competitive performance on the Market-1501, DukeMTMC-Re-ID, and CUHK03 datasets is obtained.This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.

Background Ophipogon japonicus, planted in Sichuan (CMD) and Zhejiang (ZMD) Province in China, has a long cultivation history that can trace back to Ming dynasty (500 years ago) and Song dynasty (600 years ago) respectively. During the long period of domestication, the genetic diversity of cultivated O. japonicus has decreased a lot so that this species is facing with plant degradation. Therefore, it is urgent to clarify the genetic diversity and origin of cultivated O. japonicus to establish a theoretical basis for the utilization and conservation of the genetic resources of O. japonicus. Result We analyzed the genetic diversity and population structure of 266 O. japonicus individuals from 23 sampling sites based on 4 chloroplast DNA sequences (atpB-rbcL、rpl16、psbA-trnH and rpl20-5’rps12), identified the effects of domestication on genetic diversity of cultivars and determined the geographic origins of cultivars. The results showed that cultivated O. japonicus and wild O. japonicus had 4 haplotypes and 15 haplotypes respectively. The genetic diversity of two cultivars (Hd = 0.35700, π = 0.06667) was much lower than the wild populations (Hd = 0.76200, π = 0.20378), and the level of genetic diversity in CMD (Hd = 0.01900, π = 0.00125) was lower than that in ZMD (Hd = 0.06900, π = 0.01096). Genetic differentiation between the cultivated and the wild (FST= 0.82044) was significant, especially between the two cultivars (FST= 0.98254). This species showed a more pronounced phylogeographical structure (NST > GST, P < 0.05). The result of phylogenetic tree showed that demonstrated with the outgroup O. amblyphyllus Wang et Dai, the genetic difference between CMD and ZMD is not enough to distinguish the cultivars from two producing area. Besides, both CMD and ZMD have a closer relationship with wild populations in Sichuan than that in Zhejiang. In addition, according to the TCS network and MaxEnt suggested that the wild population TQ located in Sichuan Province should be served as the ancestor of cultivated O. japonicus, which is supported by RASP analysis. Conclusion These results suggest that cultivated O. japonicus has experienced dramatic loss of genetic diversity under anthropogenic influence. The genetic differentiation between CMD and ZMD was likely to be influenced by founder effect and strong artificial selection for plant traits. It appears that wild populations in Sichuan area were involved in the origin of not only CMD but also ZMD. Furthermore, some scientific strategies are suggested for resource conservation of O. japonicus based on its genetic diversity and population structure in this study.