Fig. 2

NbCERK1 and NbLYK4 are essential for plant resistance to Sclerotinia sclerotiorum and chitin perception. a Representative leaves showing lesions of Nicotiana benthamiana (pre-treated with TRV:GFP, TRV:NbCERK1, TRV:NbLYK2, TRV:NbLYK3, TRV:NbLYK4, or TRV:NbLYK5) caused by S. sclerotiorum. Photos were captured at 24 h post-inoculation (hpi). Bars, 1 cm. b Lesion areas caused by S. sclerotiorum on TRV-treated plants. Six leaves were counted in each replicate. The experiment was repeated three times. Error bars indicate ± SD (Student’s t-test, **P < 0.01; ***P < 0.001). c ROS production of N. benthamiana (pre-treated with TRV:GFP, TRV:NbCERK1, TRV:NbLYK2, TRV:NbLYK3, TRV:NbLYK4, or TRV:NbLYK5) treated with 200 μg/mL chitin. d The total RLU was the sum of the RLUs for the first 30 min. Error bars indicate ± SD (Student’s t-test, ***P < 0.001). e MAPK activation of N. benthamiana (pre-treated with TRV:GFP, TRV:NbCERK1, or TRV:NbLYK4) treated with 200 μg/mL chitin. α-pTEpY antibody was used to detect the MAPK activation. Protein loading was determined by Ponceau S staining. f Relative expression of PTI marker genes (PTI5 and Acre31) in N. benthamiana (pre-treated with TRV:GFP, TRV:NbCERK1, or TRV:NbLYK4) induced by 200 μg/mL chitin at 3 hpi. Error bars represent fold changes ± SD (Student's t-test, **P < 0.01). g NbLYK4 associates with NbCERK1 upon chitin treatment in N. benthamiana. GFP-tagged NbLYK4 and HA-tagged NbCERK1 were co-expressed in N. benthamiana for 36–48 h. Samples were treated with 200 μg/mL chitin for 15 min before harvesting. Protein associations were detected by Co-IP assays