Application of RNAi technology in forest trees

A diverse set of small RNAs is involved in the regulation of genome organization and gene expression in plants. These regulatory sRNAs play a central role for RNA in evolution and ontogeny in complex organisms, including forest tree species, providers of indispensable ecosystem services. RNA interference is a process that inhibits gene expression by double-stranded RNA and thus causes the degradation of target messenger RNA molecules. Targeted gene silencing by RNAi has been utilized in various crop plants in order to enhance their characteristics. For forest tree species, most of the successful RNAi modification has been conducted in poplar. Over the past 20 years, successful RNAi-mediated suppression of gene expression has been achieved with a variety of economically important traits. Moreover, the stability of RNAi-mediated transgene suppression has been confirmed in field-grown poplars. In this chapter, we describe examples of successful RNAi applications mainly in poplar but also provide some information about application of RNAi in pest control in forest tree species. Advantages and disadvantages of this technology with respect to the particular features of forest tree species will be discussed.