Fig. 1: OsChtBL1 impairs the performance of SBPH by hindering its feeding behavior.

a RT-qPCR assay showing the relative expression level of OsChtBL1 within 48 h of SBPH feeding on NIP plants. b The quantity of honeydew collected from NIP, OsChtBL1-OE and oschtbl1 plants after SBPH feeding for 48 h. n = 12 individual SBPH. c The mortality rate of SBPH fed with NIP, OsChtBL1-OE and oschtbl1 plants after 15 d. d The predicted structural domain of OsChtBL1. e, f IP assay showing OsChtBL1 exhibits a strong binding affinity with chitin in N. benthamiana and rice. g The protein degradation assay showing chitin enhanced the protein stability of OsChtBL1. The concentration of chitin used was 10 μg/ml. h The survival rate of SBPH feeding on purified GST or GST-OsChtBL1 in vitro for 48 h. i Detailed Schematic diagram of the stylet of SBPH. Mg midgut, Sg salivary gland, Fc food canal, Sc salivary canal, Lmx left maxillary stylet, Rmx right maxillary stylet, Lmd left mandibular stylet, Rmd right mandibular stylet, * dendritic canal. j IF assay showing OsChtBL1 binds and aggregates on the stylets of SBPH. Scale bar, 50 μm. k. The food canal of SBPH feeding on purified GST and GST-OsChtBL1 in vitro observed by TEM. Scale bar, 200 nm. l. IEM assay showing OsChtBL1 accumulation in the food canal of SBPH. Scale bar, 200 nm. SBPH fed on purified GST and GST-OsChtBL1 (50 μg/ml) for 36 h were subjected to IF, TEM, and IEM assays (j–l). OsUBQ5 serves as an internal reference gene (a). n = 3 (a, c, h) independent biological replicates. Error bars represent SD, and values are means ± SD. All the statistical analysis data were performed using a two-tailed Student’s t test. *At the top of columns indicates significant differences with the control group at P < 0.05. Rubisco serves as an internal reference protein for Western blot analysis and detected by anti-RUB antibody (g). Experiments in (e–g) were repeated three times with similar results.