Abstract: 【Objective】The plant host resistance protein CC-NBS-LRR harboring CC domain could be activated to mediate plant resistance reaction after non-race-specific disease resistance 1(NDR1)and introduces pathogenic invasion signals into the cell membrane. To explore the function of NDR1, PdtNDR1 from Populus deltoids × P. trichocarpa was cloned and its expression on rust resistance was studied. 【Method】Compatible interactions of P. deltoides × P. trichocarpa and against Melampsora larici-populina E4 were observed by inoculation study. NDR1 genes, PdtNDR1 and PndNDR1 from P.deltoides × P.trichocarpa and P.×earamericama, respectively, were cloned by PCR. Structures and functions of PdtNDR1 and PndNDR1 encoded proteins were studied through bioinformatics analysis. The expressions of PdtNDR1 and PndNDR1 for 7 time points after being inoculated with E4 were analyzed by qPCR. 【Result】The inoculation study showed that P.×earame ricama was susceptible to E4, which was compatible to E4. P. deltoides × P. trichocarpa was a low susceptible species, which was incompatible to E4. The bioinformatics analysis indicated that PdtNDR1 and PndNDR1 belonged to NHL(NDR1/HIN1-like)family. Amino acid sequence analysis illustrated that 13-34 amino acids of the N-terminal and the C-terminal of PdtNDR1 located at the plasma membrane, the middle amino acids of PdtNDR1 located outside of the plasma membrane which could contact pathogenic invasion signals and the N-terminal of Pdt-NDR1 located inside of the cell enabling entrances of pathogenic invasion signals. qPCR results showed that PdtNDR1 and PndNDR1 responded to rust infection significantly differently. PdtNDR1 was enhanced continually after the rust infection, while the expression of PndNDR1 was not enhanced obviously. 【Conclusion】The expression of PdtNDR1 correlated with the susceptibility of P. deltoids × P.trichocarpa positively and determined its in compatible interaction against rust.