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

Abstract

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 (CsTPS1) and its alternative splicing isoform (CsTPS1- AS) could catalyze the formation of geraniol when GPP was used as a substrate in vitro, whereas the expression of CsTPS1- AS was only significantly induced by Colletotrichum gloeosporioides and Neopestalotiopsis sp. infection. Silencing of CsTPS1 and CsTPS1- AS resulted in a significant decrease of geraniol content in tea plants. The geraniol content and disease resistance of tea plants were compared when CsTPS1 and CsTPS1- AS were silenced. Down-regulation of the expression of CsTPS1- AS 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 CsTPS1-silenced plants and control plants in the tea plants infected with two pathogens. Further analysis showed that silencing of CsTPS1- AS led to a decrease in the expression of the defense-related genes PR1 and PR2 and SA pathway-related genes in tea plants, which increased the susceptibility of tea plants to pathogens infections. Both in vitro and in vivo results indicated that CsTPS1 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.

Acknowledgements

This research was funded by National Key Research and Development Program of China (2021YFD1601103 and 2022YFF1003103), National Natural Science Foundation of China (31902075, 32150017 and 32022076).

Author contributions

H.J., W.S., X.W., and C.S. conceptualized the initial study and experimental layout; H.J., M.Z., and F. Y. carried out the experiment and analysed the experiment results; H.J., X.L., J.J., Y.Z., and T.J. analysed experiment results; Q.W. and M.Z. performed the subcellular localization experiments; H.J. drafted the original manuscript and provided funding; C.S. provided funding and edited the manuscript.

Data availability

All relevant data can be found within the paper and its supporting materials.

Conflict of interest statement

The authors declare that they have no conflict of interest.

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