A geraniol synthase regulates plant defense via alternative splicing in tea plants.

Geraniol is an important contributor to the pleasant floral scent of tea products and one of the most abundant aroma compounds in tea plants; however, its biosynthesis and physiological function in response to stress in tea plants remain unclear. The proteins encoded by the full-length terpene synthase () and its alternative splicing isoform (-) could catalyze the formation of geraniol when GPP was used as a substrate , whereas the expression of - was only significantly induced by and sp. infection. Silencing of and - resulted in a significant decrease of geraniol content in tea plants. The geraniol content and disease resistance of tea plants were compared when and - were silenced. Down-regulation of the expression of - reduced the accumulation of geraniol, and the silenced tea plants exhibited greater susceptibility to pathogen infection than control plants. However, there was no significant difference observed in the geraniol content and pathogen resistance between -silenced plants and control plants in the tea plants infected with two pathogens. Further analysis showed that silencing of - led to a decrease in the expression of the defense-related genes and and SA pathway-related genes in tea plants, which increased the susceptibility of tea plants to pathogens infections Both and results indicated that is involved in the regulation of geraniol formation and plant defense via alternative splicing in tea plants. The results of this study provide new insights into geraniol biosynthesis and highlight the role of monoterpene synthases in modulating plant disease resistance via alternative splicing.