Recent progress in the study of rubber grass (Taraxacum kok-saghyz Rodin) and main achievements over the past ninety years

Natural rubber is a critical resource for the national defense industry. The tropical para rubber tree (Hevea brasiliensis (Willd. ex A. Juss.) Muell. Arg) is the only commercial source of natural rubber, and the commercialization forms are relatively single. Thus, the potential supply shortages need to be solved urgently, with particular attention on alternative rubber producing crops. The roots of Taraxacum kok-saghyz Rodin (TKS) contain a high natural rubber content, with a similar molecular structure to that produced in the rubber tree. TKS is mainly distributed in temperate and cold zones and can easily be harvested by machine. Its life cycle is short, and genetic transformation is also relatively easy. Thus, TKS is considered a promising candidate for natural rubber production. This review summarized the development history and major achievements of previous studies on rubber grass over the past 90 (1931-2018) years. An in-depth analysis was performed to highlight new achievements from the past decade. We also predicted the future roles of TKS in the natural rubber industry. This review is expected to provide a useful reference and theoretical basis for further TKS research.