Genome evolution and diversity of wild and cultivated potatoes.

Potato (Solanum tuberosum L.) is the world's most important non-cereal food crop, and the vast majority of commercially grown cultivars are highly heterozygous tetraploids. Advances in diploid hybrid breeding based on true seeds have the potential to revolutionize future potato breeding and production1-4. So far, relatively few studies have examined the genome evolution and diversity of wild and cultivated landrace potatoes, which limits the application of their diversity in potato breeding. Here we assemble 44 high-quality diploid potato genomes from 24 wild and 20 cultivated accessions that are representative of Solanum section Petota, the tuber-bearing clade, as well as 2 genomes from the neighbouring section, Etuberosum. Extensive discordance of phylogenomic relationships suggests the complexity of potato evolution. We find that the potato genome substantially expanded its repertoire of disease-resistance genes when compared with closely related seed-propagated solanaceous crops, indicative of the effect of tuber-based propagation strategies on the evolution of the potato genome. We discover a transcription factor that determines tuber identity and interacts with the mobile tuberization inductive signal SP6A. We also identify 561,433 high-confidence structural variants and construct a map of large inversions, which provides insights for improving inbred lines and precluding potential linkage drag, as exemplified by a 5.8-Mb inversion that is associated with carotenoid content in tubers. This study will accelerate hybrid potato breeding and enrich our understanding of the evolution and biology of potato as a global staple food crop.

A nonS-locus F-box gene breaks self-incompatibility in diploid potatoes.

Potato is the third most important staple food crop. To address challenges associated with global food security, a hybrid potato breeding system, aimed at converting potato from a tuber-propagated tetraploid crop into a seed-propagated diploid crop through crossing inbred lines, is under development. However, given that most diploid potatoes are self-incompatible, this represents a major obstacle which needs to be addressed in order to develop inbred lines. Here, we report on a self-compatible diploid potato, RH89-039-16 (RH), which can efficiently induce a mating transition from self-incompatibility to self-compatibility, when crossed to self-incompatible lines. We identify the S-locusinhibitor (Sli) gene in RH, capable of interacting with multiple allelic variants of the pistil-specific S-ribonucleases (S-RNases). Further, Sli gene functions like a general S-RNase inhibitor, to impart SC to RH and other self-incompatible potatoes. Discovery of Sli now offers a path forward for the diploid hybrid breeding program.

Evolution of surgical paediatrics in China.

Pediatric surgery of China was established in 1950. Being isolated from the world, China's first-generation pediatric surgeons were mainly self-taught. The technology of pediatric surgery of China practically followed Gross, and the aim of pediatric surgery was similar to that of BAPS, "not to seek a monopoly." Since 1980, after the scientific exchange with Western countries, the clinical results of common pediatric surgical diseases have reached the acceptable level of the world. China is a huge country with poor transportation, one-child family planning, and Chinese traditional medicine, which made certain peculiarities in the practice of paediatric surgery.