Laticifer tissue-specific activation of the Hevea SRPP promoter in Taraxacum brevicorniculatum and its regulation by light, tapping and cold stress

Hevea brasiliensis is an important plant species currently cultivated for the commercial production of natural rubber. As the demand for rubber continues to increase, it is important to identify alternative sources of natural rubber and to increase plant rubber content using molecular approaches. Taraxacum kok-saghyz, a Russian dandelion, produces natural rubber that is of high quality. In this study, the SMALL RUBBER PARTICLE PROTEIN (SRPP) promoter from H. brasiliensis was characterized to determine its suitability for the expression of latex-specific genes in Taraxacum brevicorniculatum which is another Russian dandelion species of T. kok-saghyz from the similar geographical areas. Studies using transgenic Taraxacum plants carrying the SRPP promoter::β-glucuronidase (GUS) sequence indicate that the SRPP promoter does induce gene expression primarily in laticiferous tissues. Additionally, the promoter was regulated by various external conditions including light, tapping, and cold. These findings suggest that the SRPP promoter will be a useful molecular tool for the manipulation of gene expression in the laticiferous tissues of Taraxacum plant species.