3.7 The distribution and subcellular localization of CsTPS1 and
CsTPS1-AS differ
Monoterpenes are synthesized exclusively by plastids in higher plants;
thus, plant monoterpene synthases are localized to the chloroplast. To
verify this prediction, the two CsTPS1 and CsTPS1-AS proteins were fused
to the N-terminal of eYFP, and the fusion proteins were transiently
expressed in tobacco leaves. The eYFP signals of CsTPS1 and CsTPS1-AS
fusion proteins were consistent with chlorophyll autofluorescence and
showed no overlap with the cytosolic mCherry signals from the negative
controls (Figure 6C). These findings confirmed that the two CsTPS1 and
CsTPS1-AS proteins are localized to the chloroplast. However, the
distribution and localization of the CsTPS1 and CsTPS1-AS proteins in
the chloroplast varied (Figure 6C). The CsTPS1 protein is likely
localized in the stroma of the chloroplast and exhibits a highly
homogeneous distribution. Conversely, the CsTPS-AS protein might be
localized to the outer membrane of the chloroplast and exhibit a
sporadic distribution (Figure 6C). The distribution and localization ofCsTPS1 and its AS forms in the chloroplast differ, and this might
explain the distinct levels of disease resistance that they confer to
tea plants.