Abstract: [Objective] This study aimed at detecting the protein expression differences and the protein base of defense reaction in Chinese pine (Pinus tabulaeformis) induced by leaf-cutting and different number pine caterpillar(Dendrolimus tabulaeformis) feeding stimulation in the natural environment.[Method] 15-year-old Chinese pines with the similar growth potential were selected as the research object. The sample trees were treated with feeding stimulation by 10 or 30 pine caterpillars laid on the branch or with leaf-cutting, and the untreated trees served as the control in a Pinus tabulaeformis-Ameniaca sibirica mixed forest in Pingquan County, Hebei Province. The protein expression differences of the Chinese pine were studied by dimensional electrophoresis method.[Result] Through the calculation of protein point expression, compared with control, after feeding with 10 pine caterpillars the up-regulated protein spots were 9, down-regulated protein spots were 4, new increased protein spots were 20, and disappeared protein spots were 18. After feeding with 30 pine caterpillars the up-regulated protein spots were 5, down-regulated protein spots were 31, new increased protein spots were 23, and disappeared protein spots were 13. After leaf-cutting stimulation the up-regulated protein spots were 8, down-regulated protein spots were 9, new increased protein spots were 25, and disappeared protein spots were 17. Differential expression proteins were further identified by mass spectrometry. The database retrieval results showed that new increased proteins in the insect feeding trees were chloroplast ATP synthase CF0 β subunit, ascorbate peroxidase (APX), thiazole biosynthetic enzyme, Lhcb5 protein, ATP synthase β subunit and glutathione S-transferase, and down-regulated proteins were proteasome subunit and hypothesis protein CL304Contig1_01. In the trees simulated by leaf-cutting, new increased proteins were glutathione S-transferase and rubisco activase, down-regulated proteins were phosphoglycerate kinase Ⅰ and ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) large subunit. Further analysis showed that the proteins involved in photosynthesis were the most, but the stress and defense related proteins were not expressed in the control tree. The stress and defense related proteins were highly expressed in the trees by insect feeding, and after feeding with 30 pine caterpillars, the proteins associated with synthesis were also expressed. After leaf-cutting stimulation, the stress and defense related proteins were also expressed, and the down-regulated proteins were related to energy-metabolism.[Conclusion] The results indicated tha t feeding and leaf-cutting stimulation could induce the stress and defense related proteins expressed, enhance photosynthesis, synthetic protein, reduce energy-metabolism protein in the Chinese pine. These changes are the protein base of defense reaction induced by pine caterpillar.

Key words: Pinus tabulaeformis, Dendrolimus tabulaeformis, induced defense responses, feeding stimulation, leaf-cutting stimulation, difference of protein expression