## 2 Results
### Measurement of Ascorbic Acid Content  
The AsA content was measured in WT and _OsVTC1-1_ RI1-2 line at 0, 6, 12, 24, and 48 h post inoculation (hpi) with the rice blast 10100 isolate. AsA content was significantly different between the WT and _OsVTC1-1_ RI1-2 line at all time points (Figure 4). A high AsA content was observed at 6 and 12 hpi, followed by a dramatic decline at 24 hpi. AsA contents were lower in the _OsVTC1-1_ RNAi line than in the WT at 0, 6, and 12 hpi, but they were higher at 24 and 48 hpi in the _OsVTC1-1_ RNAi line when compared to the WT (Figure 4). These results suggest that AsA is significant during rice blast fungus infection.  
Figure 3: Leaf photosynthetic efficiency in wild-type (WT) and _OsVTC1-1_ RNAi lines (RI1-2 and RI1-3) at 5 days post inoculation with Guy11 isolate. (**a**) Maximal efficiency of PSII (F\({}_{\rm v}\)/F\({}_{\rm m}\)); (**b**) chlorophyll fluorescence image showing photosynthetic activity across the leaf surface (scale bar = 1 cm). Data are presented as the mean \(\pm\) standard error of three replicates. Asterisk indicates statistically significant differences from WT analyzed using Student’s \(t\)-test (**\(p<0.01\)).  
Figure 2: Cell wall monosaccharide composition (mmol g\({}^{-1}\) fresh weight) of 3-week-old rice leaves from wild-type (WT) and _OsVTC1-1_ RNAi lines at 4 days after inoculation with Guy11 isolate. (**a**) Xylose; (**b**) arabinose; (**c**) galactose; (**d**) galacturonic acid; (**e**) fucose; (**f**) mannose; (**g**) glucuronic acid. Data are presented as the mean \(\pm\) standard error of three replicates. Asterisk indicates statistically significant differences between mock and infected plants for each rice line analyzed using Student’s \(t\)-test (* \(p<0.05\) and **\(p<0.01\)).  
Detection of Superoxide Anion by Nitroblue Tetrazolium (NBT) Staining and Measurement of Malondialdehydedehyde (MDA) Content  
To investigate the mechanism of OsVTC1-1 in response to rice blast fungal infection, O\({}_{2}\)\({}^{-}\) accumulation was measured in WT and RI1-2 leaves at 24 hpi with the 10100 isolate. The _OsVTC1-1_ RNAi line accumulated more O\({}_{2}\)\({}^{-}\) than the WT (Figure 5a,b, Table S1). A reduction in OsVTC1-1 activity leads to a higher ROS accumulation after rice blast inoculation.  
The production of malondialdehydedehyde (MDA), a byproduct of lipid peroxidation, was measured in WT and _OsVTC1-1_ RI1-2 line at 24 hpi. After rice blast inoculation, there was no change in MDA content in WT leaves. Meanwhile, a significat  
Figure 4: Ascorbic acid content in wild-type (WT) and _OsVTC1-1_ RI1-2 line after rice fungus inoculation with 10100 isolate at 0, 6, 12, 24, and 48 h. Data are presented as the mean \(\pm\) standard error of three replicates. Asterisk indicates statistically significant differences from WT at each time point analyzed using Student’s \(t\)-test (* \(p<0.05\), ** \(p<0.01\)).  
Figure 5: _OsVTC1-1_ RNAi (RI1-2) line induces accumulation of superoxide anion and lipid peroxidation at 24 hpi with 10100 isolate. (**a**) Visualization of O\({}_{2}\)\({}^{-}\) detected by nitroblue tetrazolium (NBT) staining; (**b**) the percentage of the leaf area covered by O\({}_{2}\)\({}^{-}\) accumulation; (**c**) determination of lipid peroxidation by MDA measurement. Data are presented as the mean \(\pm\) standard error of three replicates. Asterisk indicates statistically significant differences between mock and infected plants for each rice lines analyzed using Student’s \(t\)-test (* \(p<0.05\)).  
in MDA content between the uninfected and infected leaves of the RI1-2 line (Figure 5c). A higher level of MDA was produced in infected leaves compared to uninfected leaves. These results indicate that reducing the AsA level caused the _OsVTC1-1_ RNAi line to suffer more from cell damage than WT after rice blast inoculation.