3.2 Accumulation of H2O2 and
O2- in melon leaves after GSB infection
Accumulation of H2O2 and
O2- in the leaves of PI511890 and Payzawat was
determined using DAB and NBT staining methods at 12, 24, 36, and 48 hpi,
respectively. The results of DAB staining showed that
H2O2 accumulation in infected leaves was
higher than that in the control for both Payzawat and PI511890,
indicating that GSB promotes H2O2accumulation (Figure 1B). Compared with the control, significantly
higher accumulation of H2O2 was observed
in Payzawat after 24 hpi (Figure 1D). However, significantly higher
accumulation of H2O2 was only observed
at 24 hpi in infected leaves of PI511890 compared with the control.
Moreover, H2O2 accumulation in infected
leaves of Payzawat was consistently higher than that of PI511890.
Similar accumulation patterns of O2- were also
observed in the leaves of Payzawat and PI511890, indicating that GSB
also induces the accumulation of O2- (Figure 1C).
Additionally, O2- accumulation in infected leaves of
Payzawat was significantly higher than that of PI511890 at 24 hpi
(Figure 1E). The lower accumulation of
H2O2 and O2- in
PI511890 suggested that reactive oxygen homeostasis is possibly involved
in the resistance to GSB.