3.5 Silencing of CsTPS1 and CsTPS1-AS reduces the
geraniol content and pathogen resistance of tea plants
The expression of CsTPS1 and CsTPS1-AS was simultaneous
suppressed in tea leaves using a shared AsODN according to a previously
described procedure (Zhao et al., 2020b). The expression ofCsTPS1/1-AS transcripts in tea leaves treated with
AsODN-CsTPS1/1-AS for 24 h was significantly reduced compared
with that in the control leaves (Figure 4A).Consistent with the gene
expression patterns, the abundance of geraniol was significantly reduced
in CsTPS- silenced leaves compared with control leaves (Figure 4B
and 4C), indicating that CsTPS1/1-AS plays a key role in the
formation of geraniol in tea plants.
Because the content of geraniol was increased in response to pathogen
infection, we asked whether the formation of geraniol mediated byCsTPS1/1-AS plays a role in pathogen infection. To address this
question, we silenced the expression of CsTPS1/1-AS in tea
leaves, and silenced and control leaves were infected with C.
gloeosporioides and Neopestalotiopsis sp. The leaves ofCsTPS1/1-AS- silenced and control tea plants showed typical
disease symptoms 72 h post-infection (hpi) (Figure 4D and 4F). However,
the average surface area of disease spots in CsTPS1/1-AS- silenced
leaves was significantly larger than that in control leaves (Figure 4E
and 4G). These results suggested that tea leaves became more susceptible
to infection to both fungi when CsTPS1/1-AS was silenced.
Overall, our results indicate that CsTPS1/1-AS plays a key role
in the biosynthesis of geraniol and pathogen resistance of tea plants.