The Russian dandelion Taraxacum kok-saghyz Rodin (TKS),a member of the Composite family and apotential alteative source of natural rubber (NR) and inulin,is an ideal model system for studying rubberbiosynthesis.Here we present the draft genome of TKS,the first assembled NR-producing weed plant.Thedraft TKS genome assembly has a length of 1.29 Gb,containing 46 731 predicted protein-coding genes and68.56％ repeats,in which the LTR-RT elements predominantly contribute to the genome enlargement.Weanalyzed the heterozygous regions/genes,suggesting its possible involvement in inbreeding depression.Through comparative studies between rubber-producing and non-rubber-producing plants,we found thatenzymes of the mevalonate (MVA) pathway and rubber elongation might be critical for rubberbiosynthesis,and several key isoforms have been isolated and shown to be predominantly expressed in thelatex,indicating their crucial functions in rubber biosynthesis.Moreover,for two important families inrubber elongation,the CPT/CPTL and REF/SRPP families,diverse evolutionary tracks have beenrevealed.These results provide valuable resources and new insights into the mechanism of NR biosynthesis,and facilitate the development of alteative NR-producing crops.