Simultaneous silencing of CaNAC2c and CaNAC2dsignificantly inhibited resistance of pepper plant to RSI
The silencing of CaNAC2c did not produced obvious symptoms upon RSI, while its overexpression in pepper and N. benthamiana plants did promoted immunity against RSI, implying that CaNAC2c may function redundantly with other genes in response to RSI. As CaNAC2dshares the highest sequence identity to CaNAC2c and exhibited similar upregulation in response to RSI (Figure S2), we speculate that it might act redundantly with CaNAC2c in pepper response to RSI. To test this hypothesis, we assay the effect of simultaneous silencing of CaNAC2c and CaNAC2d on response of pepper plants to RSI and HTS. The result showed that the silencing of CaNAC2d alone did not significantly affect either pepper thermotolerance or immunity against RSI (Figure 7A), while CaNAC2c and CaNAC2dsimultaneously silenced pepper plants exhibited obvious wilt soymptoms at 192 hpi when inoculated with R. solanacearum , and the highest disease index from 2 to 12 dpi, while their individually silenced plants did not exhibit obvious wilt soymptoms (Figure 7B-E).The simultaneous silencing of CaNAC2c and CaNAC2d and their silencing alone pepper plants exhibited enlarged size compared to the control plants(Figure S10). Consistently, the thermotolerance relatedCaHSP24 , CaHSP70 and CaHSFB2a were not downregulated by silencing of CaNAC2d , their transcript levels inCaNAC2c silencing were similar to that in CaNAC2c andCaNAC2d simultaneously silenced pepper plants (Figure 7F). By contrast, transcript levels of CaDEF1 were not downregulated by silencing of either CaNAC2c or CaNAC2d , but was significantly decreased by simultaneous silencing of CaNAC2c andCaNAC2d, indicating that CaNAC2c and CaNAC2dfunction redundancy in pepper immunity against RSI mediated by JA signaling.