CsHSFA1b and CsHSFA2 are involved in the heat
stress inhibition of catechin biosynthesis
To investigate the function of CsHSFA1b and CsHSFA2 in
catechin biosynthesis, we transiently decreased the expression of both
these genes in tea leaves using the antisense oligodeoxynucleotide
(AsODN) suppression strategy. Firstly, to determine the efficiency of
gene suppression at each sampling, we measured the respective transcript
levels of CsHSFA1b and CsHSFA2 (Figure 2a). The qRT-PCR
results revealed an average inhibition of 49% for CsHSFA1b and
53% for CsHSFA2 (Figure 2a). Relative to the sODN group, the
expression levels of catechin biosynthetic genes, includingCsCHS , CsDFR , and CsANS , increased inCsHSFA1b- silenced and CsHSFA2- silenced plants (Figure 2b).
Accordingly, the quantification of catechin contents by HPLC showed that
leaves from CsHSFA1b -silenced plants accumulated 21% more and
those from CsHSFA2- silenced plants accumulated 17% more
catechins than control leaves (Figure 2c). Collectively, our results
suggest that CsHSFA1b and CsHSFA2 negatively regulate
catechin biosynthesis.